Fieldlines.com: The Otherpower discussion board
Homebrewed Electricity => Wind => Topic started by: midwoud1 on October 04, 2011, 04:11:34 PM
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Hi All.
I am living in Northwest Holland . Average wind 5-5.5 m/sec . Building windgenerators several years .
Have some experience with making blades ( fixed- and passive pitch and active pitchcontrol )
I see that some of you ( Menelaos ) and other friends on Fieldlines are thinking about pitchcontrolled blades .
For the time of 3 months I have running a DIY active pitch controlled windgenerator.
Must say I am very content about it .
It is controlled by an actuator wich can be switched automatic and manual.
Blade angle from zero to 90 degrees in 8 seconds.
Propeller diam. 290 cm .
Controllable max speed 330 rpm . (adjustable)
Feathering and electrical brake in case of storm.
Generator disc type ( Hugh Piggott design ) 9 coils and 2x 12 neo magnets. 24 volt.
I see some advantages : Never overspeed , No overheat stator, No dumpload , No overload of batteries , controllable voltage and amps for inverters for batteries and grid tied ones. No material stress. With extra sensors No voltage controller.
http://www.youtube.com/user/midwoud1?gl=NL&hl=nl#p/a/u/1/csr2BLBQ6rc (http://www.youtube.com/user/midwoud1?gl=NL&hl=nl#p/a/u/1/csr2BLBQ6rc)
and other uploads Midwoud1 on YouTube
Regards Frans.
[attachment=1]
[attachment=2]
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Well Frans, that is awesome. I expect a feeding frenzy for information real soon. I looks like you are measuring rpm
and that provides your control point?
The hollow shaft is adaptable to almost anything.
Well done :)
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That is absolutely beautiful, it would be nice to see some video if the back side with the pitch control working. ;)
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http://www.youtube.com/user/midwoud1?gl=NL&hl=nl#p/u/7/xOqan-okQ40
[attachment=1]
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so simple..the pitch controller.
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That looks great!
I was very impressed seeing the blades feather in the wind, come to a stop, un-feather, and start up again, all under manual control.
The actuator is a servo, correct?
Do you have the computer control in the nacelle of the turbine, or is it on the ground?
Since there is no passive system to cause the pitch of the blades to adjust (springs, weights, etc.) then I suppose some would ask for a back-up to pitch control alone. The tail appears to be foldable so maybe this serves that purpose?
Thank you very much for posting the video, and I look forward to sharing info with you!
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The controller is a RPM counter with a trigger command at 330 Rpm ( can be set to any Rpm)
The basic circuit I found at Hugh's homepage navigation.Very simple circuit . There is a chip that counts pulses on 1 phase of the generator,the output is a variable Dc voltage.
In my case between 0 and 2.5 volt . As soon as there is 2.5 volt I have 330 Rpm . Than a trigger commands a relay and there is 10 volt on the actuator for half a second and the blade angle is changing about 2 degrees. If there is another windgust this will repeat .
These 2 degrees give an immediate response on the prop revs
The actuator is an old cordless handdrill ( Makita ) ,I can run it fore- and backwards with a switch in my shack manually .
Position 2 is automatic control by rpm counter
All the electronics and switch relays are in the shack . On the film you see also a digtal readout but that is not necessary.
I used it for callibration.
The feather movement is commanded with the trigger relay. The Makita has a Threaded rod M6 with a travelling nut, distance 90 mm, and it also has limit switches to stop at end positions. The actuator has a freerunnig bearing connected with a push pull rod 6 mm inside the hollow mainshaft ,at the end it is connected with a lever system that commands the blade-angle ,possible 90 degrees. Mainshaft is 25 mm dia. The propeller root-shafts are 20 mm . Their bearings are sort of nylon ( POM ) anti wearout .
There is no electronics in the nacelle , just 2 microswitches end stop actuator
Scale-up to more power and larger blades must be possible.
It is quite a bit of work but it is a challenge. New videos will be soon here.
Regards Frans
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It's nice to see other ideas being looked at.
Pitch control certainly has its advantages. With active pitch control you have the additional advantage that you can use it to shut the machine down as well as use it for power( speed) control.
The thing against it is the inevitability that it will fail, if you accept that and have means of keeping the thing under control when it happens then fine. If you don't have a back up then I don't want to be near it in a storm.
It is very much easier making active controls as you have as much control force available as you need, the mechanisms can be relatively crude and simple and you still have enough force to make it work.
When you use cf force to control the blades directly you have a limited force to twist the blades and things need to be engineered well , that is where most home built mechanisms come unstuck.
Some of us have puzzled over these issues for many years and there are many ways to do the job, some are elegant, some are crude, some work beautifully and others just about work well enough to do the job. The environment in which you use it and the time you can spend on maintenance are also factors that you need to consider.
There is little doubt that pitch control is the best way to go, it works beautifully , for very large machines then it will be necessary to use servo control but with very large machines there is more initial money available for first class engineering, years of testing and also for back up and ongoing maintenance.
For the smaller machines I see it being more reliable with direct pitch control, If I had to use a servo on a small machine I would go for passive pitch control and servo yaw and get rid of that lousy tail that causes all those stresses due to gyroscopic, useless wagging about and all its other nuisances.
Thanks for sharing your ideas, it is always good to have new input. As materials and technology change old ideas that couldn't work can become possible, we need to keep looking at new ways.
Flux
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Neat videos, Be interested in how you did it. A reversible drill seems the perfect drive arrangement. Lots of them around and many cordless units get junked for want of a battery pack that costs more than a fresh drill with batteries.
Thanks for the share.
Tom
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Fantastic job ! Great creativity focused on a goal and you have succeeded with that and with time you will continue with more improvements. You will always receive the critics opinions here on the board because it's easier for them once the work is done and posted to tell you how they would do it or this should be that or thiis that etc. etc. There could be good points in with the mix and history shows those will come from the movers and shakers out there who are actually building machines and have logged years of flying time to back up their comments.
I hope you continue to update us with your projects, successes and failures. There is no right way or wrong way, only different ways to do things for different designs depending on the goal. That is really great work and thanks for posting. Dave B.
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Frans,
Nice work. It looks like you've been at it for some time, or you work much faster than most of us (exceptions noted: Dave B, Chris, ...).
Having worked on a number of machines over the years with passive, centrifugal pitch mechanisms (Quirks/Dunlite, Jacobs), I would say they simultaneously solve one set of problems while creating another, different set. The nose cone is a good addition. I think if you can keep it operating as designed - without long term effects of the elements, wear-and-tear, icing, etc. coming in to play - with regular maitenance it will serve you well.
All told very impressive. Thanks much for sharing, and do continue with your experiences.
regards,
~kitestrings
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The controller is a RPM counter with a trigger command at 330 Rpm ( can be set to any Rpm)
And is there a low-speed trigger too? Something to provoke the blades to pitch -2 degrees?
Wow a cordless drill - a great idea!
The basic circuit I found at Hugh's homepage navigation.Very simple circuit . There is a chip that counts pulses on 1 phase of the generator,the output is a variable Dc voltage.
In my case between 0 and 2.5 volt . As soon as there is 2.5 volt I have 330 Rpm . Than a trigger commands a relay and there is 10 volt on the actuator for half a second and the blade angle is changing about 2 degrees.
An op-amp comparator, maybe?
If there is another windgust this will repeat .
These 2 degrees give an immediate response on the prop revs
The actuator is an old cordless handdrill ( Makita ) ,I can run it fore- and backwards with a switch in my shack manually .
Position 2 is automatic control by rpm counter
All the electronics and switch relays are in the shack . On the film you see also a digtal readout but that is not necessary.
I used it for callibration.
The feather movement is commanded with the trigger relay. The Makita has a Threaded rod M6 with a travelling nut, distance 90 mm, and it also has limit switches to stop at end positions. The actuator has a freerunnig bearing connected with a push pull rod 6 mm inside the hollow mainshaft ,at the end it is connected with a lever system that commands the blade-angle ,possible 90 degrees. Mainshaft is 25 mm dia. The propeller root-shafts are 20 mm . Their bearings are sort of nylon ( POM ) anti wearout .
There is no electronics in the nacelle , just 2 microswitches end stop actuator
Scale-up to more power and larger blades must be possible.
It is quite a bit of work but it is a challenge. New videos will be soon here.
Regards Frans
Thanks again.
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Hi SparWeb.
Yes the cordless drill is very powerful .It can do 2 meter blades easy. A low-speed trigger not yet ,I was thinking of it startingup at 225 rpm. The Opamp comparator is a uA 741.
I think the electronica is reliable , we have it in our cars ,laundry-machines ... etc.
[attachment=1]
On the photo the control-board on the right with the analog meter ( ex VU meter )
On the left the digital Rpm counter without command function.
There was a question about a fail-safe backup. I case of ...I can use the manual switch and the electrical brake.
midwould1; hope you don't mind! I inserted the photo where its visible :0. Bruce S
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There was a question about a fail-safe backup. I case of ...I can use the manual switch and the electrical brake.
Unfortunately, this is only a fail-safe if you are there to save it when the strom hits. Just something to consider.
~kitestrings
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Hello Frans,
I don't post here much anymore but this thread really got my attention. So many people come to the forums wanting to build a pitch control machine, talk about it for a while, then go away. I know I sure did.
It looks like you have made something really unique here and I congratulate you.
Perry
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amazing setup, hats off to you.... thanks a lot for sharing
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One of the reasons to make this prototype , not only to park it in a safe position in highwind and storm .
But also to find a good match between rotor blades and generator in changing wind speeds.
At the moment 6 - 7 Bft . Feathered prop , Batteries are full , free energy for led lights ,Pc ,and TV.
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midwoud1,
In your pictures, it looks like you don't have any offset built into your generator. Are you planning to use pitch control as the only means of speed control? I'm thinking that 8 seconds may not be fast to keep the speed from going critical. Around here, when thunderstorms move through, the wind speeds from downbursts can go from 30 to 80+ mph in a matter of seconds. Just a thought!
I do like your design, though. Simple and effective.
windy
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Another video Pitchcontrol 3.
On the picture of the controlboard ,we can see on the leftside the blue transformer where the inputsignal comes in.
Than we have the frequency / voltage converter and the trigger.The triggersignal goes to a timer switchboard on the right.
With a 3 position selector-switch I can activate the command relay for 1/2 sec...3 sec...or 8 seconds.
The output of the timer relay goes to the actuator.....ect.
There is also a small adjustable potmeter ,here can I set the maximum Rpm. ( 330 Rpm ) can be higher or lower.
If I leave home to go shopping and storm is expected , I put the timer select-switch on 8 seconds.
With steps of 1/2 a second it also works ,but that takes longer time.
Normally the batteries are recharged in 1 hour.
Untill now all this is working correct.
http://www.youtube.com/user/midwoud1?gl=NL&hl=nl#p/a/u/0/aCBM-J7Ie-Y
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frans,
Looks like a quite a bit of tail-wagging going on. Perhaps a bit of imbalance, or maybe a undesirable natural frequency in the twoer that scould be improved by changing the size, location or tension in the guys?
Nice work non-the-less. Best of luck with it.
~kitestrings
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Hi Kitestrings.
I know . I have balanced the rotorhead ( vertical line ) .A pitch is more difficult to balance .And the rotor discs also ( was done on a car tyre balance machine) ,must check it again.
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You are not gonna smoke an alternator in eight seconds.
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You are not gonna smoke an alternator in eight seconds.
Maybe not but how about overspeed to destruction?
Depending on rotor size a LOT can happen in 70 MPH wind in 8 seconds
Just saying..
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Well, you can never say never, but plenty of gravity furling machines have been smoked that were supposedly fool proof.
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just thinking out loud here....
By the time you have consistent 35-40mph winds, you're already feathering back quite a bit. Right? So your 8 seconds is no longer 8, but more like 4 or even 2 depending how much you have safely set your rpm's.
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klsmurf has right. With upcoming wind feathering is already done step by step.
It can be half track and the prop will never speed up.
Yesterday we had 6 Bft and it worked like that.
We dont have here sudden windspeeds that pickup to 80 Mph. Netherlands.
Rgds Frans
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This is the best I have seen for a long time :D
You could mount oversize blades, or blades with special good shape for a low wind areas , to get get power and stil you have certainty that there is no danzer for overspeed etc
I have tested special thin blades with high efficiency, but they ovespeeded very easily and
sounded like a helicopter near you, with this overspeed protection, you can use any blades and get max power.
This gives you numerous possibilities !
This is good.
I have seen and been testing several units with pitch control with weights, but its not anywhere... near for its possibilities, with this ;)
OK
PS. In BIG wind farms they have laser or other devices to measure incoming wind from 1-2 miles. The pitch is always in the right position to produce maximum power for
every gust.
In small wind power its ok to get max power with this system and with for example oversized blades.
Antero Rantanen
Finland
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This solution will change everything in small windpower.
Antero Rantanen
Finland
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I do not understand.. that there is not more attention or comments for this ???
This is THE one, which can really make everything possible, in small wind.
-Free parameters, to solve everything :D
-You do not need charge conrtroller of any kind ! If battteries full, blades go to Zero position, or keep the wanted voltage, for maintenance etc
-You do not need anykindof electronic clipper etc etc to on grid solution, to protect from overvoltage.
-Storm protection solved. You can have downwind, which I have foud very efficient, or with tail, no matter !
-You can adjust the pitch, if you want silent running..
-BEST ;)
You can mount anykindof blades.
I have tested several extra thin with very high efficiency and oversized but gets
overspeed easily and noisy.
Now.. you can have max power all the time and in all conditions !
Etc
This solution could really make possible to have max power.
Are you speaking here just, to warm up.. or what.. ?
This is a really simple solution, after all, compared that robots have made us cars and electronics for centuries..
If we really want to make this wind power to happen, in our lifetime ?
Industrial made pitch control unit ?
That is a piece of cake.
Should cost a trillion part of a.., compared to anything :D
Lets start NOW !
Ps. I know.. next question is, what if..
It can be be solved.
If everything fails, there is a safety pin or other.. that will release the blades to zero position and it is released when electronics or power to the
pitch control unit is lost etc
Or with pitch conrol lose, or electronic controller lose, connects all the phases to short circuit.
Antero Rantanen
Finland
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Can you make small windpower any better than this ?
Antero
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Antero;
I am confused. You seem to be carrying on a one sided conversation here the last few posts anyway?
Probably a language barrier but I am just not tracking your point? I agree this is an interesting idea but not convinced it solves all of the issues.
It blows K.I.S.S. out of the water. At least for DIY folks but I am not sure you are even talking about DIY level systems?
Tom
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Can you make small windpower any better than this ?
Antero
I can make it more reliable. Is more reliable better or not?
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Yes this does open up interesting possibilities. I didn't see much interest in it when Samoa power gave details of his scheme a few years ago, possibly because it didn't have a lot of videos for people to understand what it was about.
There is nothing new about the concept, it just takes someone with the courage to try it. I tried altering the pitch of blades on one of my machines to see what effect it had on the performance. it was a laborious process of moving the blades manually and I really didn't see any very drastic improvement, in the end i left them in the position that gave the best compromise between start up and running.
If I had a servo pitch control it woul'd have been quick and easy and the end conclusion may have been different. It certainly is a very useful tool for experimenting and has much in favour of it. Some will benefit from it and some won't.
It would be nice to see a lot of data on how the prop and alternator match can be improved by this method at various wind speeds especially with different alternator and blade combinations.
The reliability of electronics is not really in question but the reliability of the whole scheme may be questionable unless built to a very high standard and maintained properly. Things go wrong with the simplest wind turbines that never look as though they would in the design stage, any added complexity needs even more thought.
For some this may be a revolutionary way forward, just as neo was, for others it may be an interesting diversion for a while before returning to more basic methods.
There are so many people here with different levels of experience and facilities that there is no one solution fits all. New ideas will come and give new found freedome for some and offer others a route that is beyond their capability for others.
It's nice to see all sensible ideas explored and every so often the desireable thing of the time changes and things move on ( and sometimes move back again as it may do with neo).
I look forward to seeing more results from this method and from passive pitch control and even to more ideas on conventional furling, which works well for some and fail for others.
Flux
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Can you make small windpower any better than this ?
This solution will change everything in small windpower.
Doubtful. I mean no disrespect to Frans - this is cool post, and I appreciate both his efforts and his willingness to share experiences here - but, for this control scheme to work long-term alot of things have to work in sync without a cough. There are condsiderable challenges structurally in having a rotor that can both resist fully loaded conditions at a good site and also pivot at will. Add to the mix, corrosion, icing, wear, lubrication/dirt, component failure (count how many are componnents there are; I'll wait...) lightning and three moving parts like many of the axials starts to look pretty convincing. Unlike the industrial comparisons, there is usually no crew on site monitoring the health of things and doing preventive maintenance.
And, to eliminate a charge controller or diversion controller, it would not only have to respond, but anticipate changes in the wind.
It's a welcome alternative perspective/approach. The homebuilders will never have one-size-fits-all. For the mass market wind ahs some broader challenges, such as siting, competing with PV, cost to name a few...
~kitestrings
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I realize that things have to be improved , f.i the hub baseplate and the blade-root bearingblocks, can be made of aluminum.
The blockbearings with deepgroove sealed ballbearings if carried out with a larger rotordiameter.
But this is all lightweight with nylon bushings ( waterproof ) The most work was to make the hub mechanism play-free
to avoid flutter . There is no flutter even in highwind.
For the time now I am testing the windmills behavior .....Doing good.
Also worked with another system : Moving 90 degrees tail rudder. That was retrackting for 3 seconds by increasing windspeed.
Controlled by an Rpm counter.
Repeating at another gust. It had a little problem ....There was no furling tail .Had to reset it manual.
Regards Frans.
http://www.youtube.com/user/midwoud1?gl=NL&hl=nl#p/u/4/wwHYQd3iadA
http://www.youtube.com/user/midwoud1?gl=NL&hl=nl#p/u/5/-QRK0nMsbf8
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Frans,
Pretty cool. What is the mechanism (motor actuator, hydraulic)?
We're planning a manual furling over-ride, for say an "anticipated event" - like the one we just had 'Tropical Storm Irene'. If I thought I could trust a remotely operated device I'd consider it. Otherwise, let'em run and keep them loaded seems to be our mode of operation.
~kitestrings
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I for one was very excited to see this project, and I still am. There's no point making absolute pronouncements of superiority, IMHO, but in comparison to the "standard" projects seen here and elsewhere, this is a step in a new and fun direction. At least, I haven't seen it before, but I certainly don't see everything. Poke holes in the design? Sure, but we can do that to anybody, if we wanted.
Furling: Alternatives to the folding tail abound. Powered yaw, for example. That's not "simple" or passive, but it's a good protection mechanism for those who like that kind of project. I like what Frans has come up with because it does something well, even if it's not super-simple. Who really cares if it's simple, when it's being done purely for the joy of exploring an interesting idea.
So I'm keen to see more!
I had an idea Frans... Have you considered a clutch in the actuator shaft? When there is a control system failure, power is lost, or an error condition is detected, the clutch opens on the pitch shaft. If you had a spring on each blade, they would turn to a feathered position, immediately stopping the turbine. Normal operation would require a small amount of power to operate the clutch. Note I'm not implying that the driven power shaft should have a clutch, just a small one on the rod that pushes out the pitch control "spider".
Making the bearing pillowblocks from aluminum will improve their resilience to weather if you intend to operate the turbine over the winter. With the right combination of shoulders and bearing sizes, you can combine a deep-groove ball bearing and a tapered roller bearing, or double them up like a trailer axle. By the looks of it you would have already thought of these things, just haven't had a chance to try them yet!
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Also worked with another system : Moving 90 degrees tail rudder. That was retrackting for 3 seconds by increasing windspeed.
Controlled by an Rpm counter.
Repeating at another gust. It had a little problem ....There was no furling tail .Had to reset it manual.
Rather than move the whole tail, would there not be a better mechanical advantage if only the tail fin was rotated about an axis just in front of its centre line. The boom is then fixed but the tail 'tacks' away from the flow rather than being directly downwind.
I think I might try a model of that idea to see how it works (it won't move up to 90 degrees but maybe enough to have an rpm controlled furl in a closed loop).
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Thank you, for your attention to this !
If I would win from lottery, all the money, I would put on this.
I could write write several pages about all this, but I only say;
Why ?
I really know, that it is easy to get your own power with wind.
I have lived with own power several years and been testing etc (private retiried person)
Best I know, is that my children come to my place and there is a winter storm(and its very dark here 6 months) and all the power
is coming from wind..
What we would need now, is just this.
It could really get attention, if we take a big jump forward with this solution.
Attention we need.
Think about this.
Antero Rantanen
Finland
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Hi windmill-friends
Just an idea.
There is another way to make a pitch system without electronics.
It works as a stall-brake and very use-full in case of storm...
Make the push-pull rod springloaded in working windrotor position.
Bring a 4 mm stranded steelwire down in the mast .
Down the mast ,with a handle ,the blades can be feathered .
Or push-pull with a servo
Regards Frans.
[attachment=1]
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Just a thought Frans--you could combine both ideas with a sleeve over the push shaft. Electronic control, with a
manual "lock out". Just a thought.
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I don't see how to integrate it with your motorized control rod, which also runs through the center of the alternator shaft.
But maybe you mean that this is "another way entirely"
Your idea can be made into an "override", where the internal shaft is not just a simple rod, but also made to contain the motor and rod that pitches the blades. When the Override is pulled, then they all move together, no matter what position the pitch motor is in, to the feathered position.
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Hi .
For the next project.
There are very good industial actuators (servo''s ) Linak Denmark.
They are compact , adjustable stroke and end stops , possible with feedback .
Perfect for longtime use. [attachment=1]
[attachment=2]
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Measuring RPM of your windgenerator.
A simple way to make an RPM counter. Even my mother in law can make it !
It consists of one chip LM 2917 and a few components . I made the circuit on Vero-board .
Connections are soldered with telephone wire ( solid core wires from house telephone-cable )
The input is picked up from one phase of the generator .
The read-out is an analog VU meter from an old tape-deck recorder ( 85 x 65 mm )
With an adjustable potmeter fine tuning can be done. ( R 4 )
Cost only a few dollars
I made a scan of the original Vu-meter scale ,than convert it by Paint into a Rpm scale and paste it carefully over the
Vu meter scale.
[attachment=1][attachment=2]
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Edit :[attachment=1]Electronical circuit
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Edit:
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You seem to have left out the limit resistor between the output of your transformer and the clamp diodes that limit the input volts to the 2917 chip.
Otherwise everything looks ok.
Flux
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Hi Flux.
You are right .I have to insert one . At very low rpm the needle swings a bit. I will put one in. When it goes over 60 rpm it's OK.
Frans
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During Worldwar 2 there has a B17 bomber crashed in our village .It came back from Germany in feb.45 and was hit by enemy fire AAA.The pilot was the only surviver and he is still a friend of us . Living in Illinois. My friend has a private museum at home with the parts of the plane we digged up 35 years ago .
Those parts are cleaned with care and are exposed and seen by many visitors from all over.
One of the parts is the Hamilton propeller pitch control and that inspired me a lot .
I have not copied this system because it is a hydraulic system .But it gave me an idea how it works.
The pitch on my windmill it still running ok.
Regards Frans.
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Glad it's still functioning well Frans. My guess is that because the mill is protected from the nasty weather (overspeed etc.)
it will function for quite a while. It will be interesting to see, when the day comes, which piece was the first to need replacement/repair.
Makes it easier to decide what to change for next time. (if anything that is)
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Hey Frans
In using active pitchcontol there is always the problem of the blade suspension.
Living in the southwest of the Netherlands I invite you and all windmillbuilding friends at my place
to have a brainstorm session about that turbine component.
Regards Rinus.
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Hi Rinus .... Blade suspension.
My idea is to start with a disc baseplate 12 mm alu . Make pillow-blocks on it .The outher bearings with rubber seals.
Blade root shafts 25 mm diam. Depends on the length of your blade .Secure with lock retainers.
Make lever and spider , connected with a push/pull rod. As shown on the image.
Rgds Frans
[attachment=1]
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Unless you are able to put the rotation axis on the neutral pitch moment line of the airfoils, there are going to be some pitching forces trying to rotate that hex shaped block in the middle and change the pitch. Unless that is going through a hex shaped bushing (you could make from a socket) then the only thing preventing this is the "bearings" (looks like just bolts in photo) and stiffness of the links (pushrods) which connect to the bell cranks on the blades. Since those are of thin plate, they don't have much stiffness.
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Hi Kevbo.
Yes I know. The most important thing with pitch is to avoid flutter of the blades in high wind .
For that reason I improved the mechanism with conical gear-wheels . It has a free running sunwheel
and 3 planet wheels on the root shafts . It's abolute free of play ,and no flutter in high winds.
But it is a bit more difficult to balance the prop. and find the c/g.
I do that later spending more time on it.
All the best . Frans.[attachment=1][attachment=2]
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Wow!, did you have those gears custom cut?
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No , on the shelf . I was surprised myself . Module 2 - 3 on stock. Custom is possible but more expensive f.i. hypoÃdal.
Rgds . F.
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Hmmmmm............What if you had one of these on the other side instead of the electronics? http://demonstrations.wolfram.com/WattSpeedGovernor/
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fabricator,
Thats the exact idea I was going for on my big one I am working on, I think it would work great. With the combination of different springs and maybe adjustable weights I think it could be tuned in pretty good.
Matt
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I'm sure it could be with a little tuning and experimenting.
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Though I don't like the idea of electric pitch contro on a machine of this size, I have to say your design looks very nice. And it also seems to perform well for you. I have just seen too many DIY built machine with servo pitch control fail miserably :). Let's hope this is an exception to that rule..
If you were ever to build a bigger machine the servo control would make more sense, as then engineering the required backups and safeguards would not be so big deal compared to the overall complexity of the project.
If you want to go with the mechanical governor, instead of mounting it to the rear of the main shaft, it makes more sense to build it all to the hub. The flyweights can be attached to the blades and the synchronizing mechanism built into the center of the hub. That way you won't need to have a hollow main shaft for the adjusting rod, nor separate rods for the flyweights.
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Some projects I made before : Pasive and Active control[attachment=1][attachment=2][attachment=3][attachment=4][attachment=5][attachment=6][attachment=7]
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That is one beautiful machine.
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I would be concerned with water getting on the gears and freezing during the winter.
windy
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I see Janne's album .He has done a whole lot of work ,with a big machine and had result.
It's many times a job with ups and downs . But as long as it works it's OK.
Have here made some designs with passive pitch ,and that made good sense from start to run rpm.
Good pick-up start in low windspeed.
My design is still a proto-type and I like the pitch wich is quick reacting for a few degrees in let's say 4 Bft.
And the prop is not exceeding 330 rpm.
Another benefit is the possibility to set full feathering during storm.
The electronics are looking a bit complex ,but it is not.
Maybe it is not a holy solution . For the time now I can keep max. volt for the batteries in hand. Without dumpload.
And also avoid overvolt shutdown of my inverter .
Scale up can be done later .
Hope sometime other windmill-technician will try it as well.
Rgds . Frans
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Yup Janne probably has more DIY experience than the rest of us on this site.
His projects, and his father's, are a great way to learn how to scale up the pitch control systems you have.
Janne has posted many photos and videos of large turbines. They include detailed discussion about pitch control (mostly of the passive variety). Also, you may take an interest in the member "Menelaos" who also experiments with these.
In case you haven't found the feature on the forum, you can examine each member's previous postings by clicking on their name, then searching for "previous posts by this member".
Funny, I just realized that you and the other two members I mentioned are European... How come none of us in the Americas aren't all making pitch-control systems? Eh? ???
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A good windmill friend in the Netherlands is making pitch rotorblades for many years.
He is now working on a model from a big mill ,(Enercon) according to his own technic.
It's a different design compared to mine , and he worked succesful before.
The project is in progress ,and we hope to see soon some new pictures of it.[attachment=1][attachment=2][attachment=3][attachment=4]
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Two blade passive pitch . Generator 12 volt 800 watt[attachment=1]
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Windmill friends
Pitch control has many advantages also for small turbines.
Lets exchange ideas to improve designs for DIY
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very goos design, but there are a lot of parts to keep working smoothly. where i am i get a lo of salt spray. next the the sea more or less. i cant help thinking there is a more robust way to do this using pneumatics. what i am thinking is something like the system used for manipulating models used in special effects. basicly a rolled up tube like a borden gauge made of silicon rubber. pneumatics are used in hostile environments like food processing where they get steam cleaned every day, so are by design rugged to start with. cant think of the how right now but just another thing to throw in the mix.
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I live also close to the sea , the electric actuator is no problem . The spider system is protected by a spinner ( nose cone) The thruster bearing between actuator and push-rod is OK .A critical point can be the outer nylon bushings of the blade-root-shafts . If it is I make seals on it. Pneumatics is an idea ,but on the other hand , a 12 volt actuator is easy to control with a simple electronic circuit and a relay. I work 10 years with an actuator moving tail without trouble. The blade pitch is doing very good for 4 months now.
Rgds . F.
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... Add to the mix, corrosion, icing, wear, lubrication/dirt, component failure...
Here in Wyoming where there's a lot of wind (dust) and brutal winter weather these factors are something to consider.
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That's why we want to think about a design where components like blade suspensions are neatly closed in.
e.g. a polyester double layers sealed nosecone/rotorhead in which the blades are attached.
See professional turbines like Enercon, Darwind etc.
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Spinner constuction.
I start to make a stack of plywood-discs 18mm in the tapered shape of a cone .
Put them together with an M8 threaded rod on a rotary-table . Primer coating. Fixed a template with the exact cone-form on the machine-bed. Polyester putty on the cone and turn the rotary-table around . Finish with fine emery-paper.The result is a good positive model of the spinner.
2) Made a negative mould of 7 layers of 160gram fiber and polyester . On top of the cone a 6mm x 50mm tubing to take the mould off the model with water pressure . Inside the mould I made the real spinner with 7 layers 160 gr fiber . Primer 2 comp polyester paint .Final mat black.[attachment=1][attachment=2][attachment=3]
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Midwoud,
That's a great system. Years ago I had a similar project, but made it much more difficult for myself than that.
When using "water pressure" to separate the plug and mold, do you mean that you only had to fit a water hose to the hole at the bottom of the plug - presumably the hole that was for the long threaded rod in earlier stages to bond the stack of plywood?
What about the template bar in the upper photo - is it metal? To make a metal part that matches the elliptical contour would require a CNC, but using more wood to make that template would require nothing but a coping saw. So I'm curious about the way that template came to be.
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Hi SparWeb
The piece of tubing is embedded on top of the negative mould . Separate by home-water pressure 3 bar. Before I already made a drawing of the elliptical line . Bring it over on a 2mm metal sheet with a cardboard template and cut it with a coping saw .The plywood discs were also made with the coping saw on the needed angle according to my drawing. The elliptical line on the drawing was made with a steel 1mm wire supported on the ends and at several points between. Draw with a pencil. And a needle on the template. No CNC needed.
On the wooden model there was no extra material to remove, because it had already its form.
Rgds . F.
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What about the template bar in the upper photo - is it metal? To make a metal part that matches the elliptical contour would require a CNC, but using more wood to make that template would require nothing but a coping saw. So I'm curious about the way that template came to be.
You don't NEED CNC, all you need is a template from anything, cardboard, thin aluminum etc, and a band saw or a plasma cutter. Folks were building spinners LONG before CNC was even dreamed of.
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Great work,
I use a similar process for a solid nose cone which could be used for making a mold as well. I use many layers of solid foam insulation just the same as your plywood. This is glued and stacked the same way and mounted on a round disk of plywood as a base. A center bolt is mounted in this base plate and the whole assembly is then chucked and turned on a lathe or chucked in a drill press and turned to shape with a rasp. After that I finish it with typical cloth and fiberglass and finish sand back on the lathe or drill press. It's time consuming but to me it's well worth the effort with a machine that looks finished. Fot my template I just drew it in Auto Cad then tile printed it, taped it together on a piece of cardboard and cut it out, later I made a more permanent template from plexiglass. Dave B.
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That is gonna be one of the best looking machines ever on this forum.
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Wow I must have the settings all wrong on my other computer screen. Now I'm sitting at another computer and the picture CLEARLY shows a simple sheet of steel. Thin enough I could snip it with hand shears.
Now I feel silly about the "metal bar" question. :P Looks even better now though!
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Making a plug ,we can use a pottery turntable with a template as well. Many people have one. But I wont bother them.
An other method is the way churchbell makers do. With a swinging around compass of plywood. I used this method to make
satellite dish-antennas with 2 meters diameter. The plug was made with a soft core (sand) and a cement skin.
The template parabolic line is math calculated.
Rgds : F .
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The template parabolic line is math calculated.
Rgds : F .
I have seen a method to do this with a square, a string, pencil with a thumbtack. Simple, hillbilly tech!
Here is an example:
http://www.sciences.univ-nantes.fr/sites/genevieve_tulloue/conics/drawing/para_string.html (http://www.sciences.univ-nantes.fr/sites/genevieve_tulloue/conics/drawing/para_string.html)
Just because I thought it was nifty.
Tom
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Generator.
Rotor-discs 2x 12 magnets epoxy + glass-bubbles + polyester coating
Stator 24 volt epoxy + glass-bubbles + coating
Lamp test 24volt cut-in 180 Rpm
Bearing Volvo rear wheel 544[attachment=1][attachment=2][attachment=3]
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There was a little problem , the push-pull bearing housing was sliding in the actuator bracket.
A security-screw was gone out 2 turns , Its solved with lock-tite. Not a big event ,lost temporary full feathering.
Had to bring the mill down for general inspection .
All OK. Full batteries . To day storm 8 Bf . As soon as it slacks off , fly again.
F.[attachment=1][attachment=2]
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[attachment=1]
http://www.youtube.com/watch?v=fOAdzbS16Jc
Happy Newyear Frans en Teresa
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Happy New Year to you as well Frans. May 2012 be a year of much happiness.
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To Frans and all windenergy-enthousiastics:
Happy New Year
Let's keep trying to improve our wind energy generating systems
Regards Rinus
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Certainly have upped the anny with DYI wind power. Im completely inspired now and am already planning another project with yours in mind. Fantastic build!!!
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Upped the ante.
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Improvement rotorhead with sealed angular contactbearings
Before it was carried out with POM bushings , worked good for 6 months but at the end there was corrosion on the shafts.
Its free of slob ,ridgid and it is very light running.
As soon as the weatherconditions are better it will be tested. Snow ,- 5 C
Frans [attachment=1][attachment=2]
http://www.youtube.com/watch?v=RiQiqi5jzVs&feature=plcp&context=C3936b8bUDOEgsToPDskLnYBe2bic7bVfqgq-CzQYT
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Very nice ;)
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A true work of art.
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Rotorhead test .
Pitchcontrol with sealed bearings . Light running and reliable in low temp. - 5 deg. C . Wind 6 m/sec.
http://www.youtube.com/watch?v=9jaz3soqXLo&feature=youtu.be
- Frans -
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I thought this was cool, so Im going to use the recent youtube feature, if anyone has a questions on how to do this in there posts with projects they have on youtube, let me know.
JW
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Hi JW , Thank you for the insert
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Frans,
Really nice work. Thanks for the on-going progress updates. Inspirational.
Just how do you get three more blades to poke out as it is spinng? ;) And to make them go backwards...
~kitestrings
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Hi Kitestrings.
There is an actuator with a push-pull rod . That is connected with a spider ,moving the blade angle .
You can see it on previous images .
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Frans,
I follow you. I was joking actually. In the video, which is fascinating to watch, there is the illusion of it having more blades as it gets to the 'strobe effect' speed, then they appear to reverse direction, like the wheels of stage coach in an old western movie.
~ks
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It is cold here , snow ,ice, low temperature ,so the best place is working in the shop 18 deg C.
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Fabulous work. Its cold here too. I like shops.
Cheers!
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I like it. That pitch control works a lot faster than I thought it would.
Steve Trumann
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Hey Franz:
It's been quite a while since I have visited the Fieldlines forum and, perusing the various topics, I was especially interested to read the thread on your efforts with active pitch control. As it turns out, I worked on a v similar project a few years ago, similar in fact to the point of using a Makita cordless drill (looks like the same model you used), threaded rod/nut, a push/pull rod through the main shaft and a "spider" mechanism to keep the blades synchronized. I only proceeded however to a bench operational prototype (and crude compared to your device) but then came to the conclusion that I was not confident of building something sufficiently robust and reliable to put into actual operation - just too many potential failure modes I guess.
My project did differ from yours in that I utilized a micro-controller for the control function. It was the "PicAxe" type, a readily available, inexpensive and quite easy to program device (programmed in a type of Basic language). Although my motor control was simply full on/off, forwards or backwards via an "H bridge", the processor is easily capable of servo and PWM so would IMO would be ideal for this type of application. It would also offer good capability for things such as load control (MPPT?) and I'm now BTW working on a Picaxe based load control for my turbine.
Anyhow, I then turned attention to a passive type of pitch control using basically the same mechanicals as before but with fly weights attached to the blade shafts (with spring return) as the actuation mechanism (it's a 12 foot rotor BTW). I use 1" ball bearing pillowblocks for the blade shafts (two per shaft) with 1 1/2"ers for the main shaft. I have about a year now of cumulative operation and it has worked very well in all kinds of weather. I especially like the ability to run even unloaded without problems and the fact it does not slow down or stop in strong winds like a furling system would (and of course it is inherently more reliable than an active system).
I've read comments here that pitch control mechanisms are problematical in that a lot of maintenance is required but I have found no particular issues. I tend to build the stuff heavy (the pole top assembly is about 300 lbs total) and spray everything thoroughly with roller chain lube to avoid corrosion. I have no weather enclosure on the pitch control hardware and was afraid the bearings might seize or corrode but have not found it to be a problem, at least so far.
I also thought about using bevel gears as you did for the blade syncing but was unable to find anything suitable at decent cost (I think that's the better way of doing it). Would appreciate any ideas on a good NA source for such gears.
OK, enough for now but let me finish by saying what a great effort you have made, in both design and construction - certainly something to be proud of.
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Hey NoSmoke,
Glad to see you work with pitchcontrol , Active pitch is a lot of work because few people make it.
So you have to find out yourself.
I had to make several improvements to have something reliable .
The PIC-axe is an excellent controller to keep it on track. Here I have an LM2917 Frequency-voltage inverter as
an Rpm programmable switch. It is set on 330Rpm max.
Bevel gears or (Tapered roller bearings) you can find it in the catalogues of SKF and Nachi etc. (32000 series.)
I dont know your machines Lathe and Mill . And that bearing should be made as a pillowblock.
Aluminum block is good.
Only the inner blocks to hold centrifugal rotor forces.
Good luck .
- F -
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Frans, thanks for the bevel gear sourcing info. That's a very nice looking control hub you have there but I wonder why both a spider and bevel gears are included (at least that's how it looks to me from the image). Anyhow, that setup could be easily changed to passive (if active doesn't work out for you ;)) by adding a fly weight and torsion spring to each shaft.
I don't myself have a lathe or mill - stick & mig welder, abrasive cutoff saw, bench & angle grinder and a drill press only so my construction capabilities are somewhat limited and, I buy a lot off-the-shelf as available (such as pillow block bearings). I'm also pretty cheap so try the minimalist approach whenever practical. One example is using cold rolled shafts instead of ground - I've found they make a surprising smooth & tight fit with the bearings and cost about 1/2 as much.
BTW, I've also experimented quite a bit with roller chain "gear ups" (driving a 3ph motor conversion). This has also worked well.
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The spider connects the gears, and keeps everything in sync.
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Without the bevel gear there was a problem to move the blades synchronuously.
It would have caused flutter. I was lucky it was in the local transmission shop.
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Hey,
Ich well believe that withe the gear, the synchronisation is far better...but now it is some kind of double synchronisation, isn't it? What is the spider still useful for if the gear does the job now? Or did I miss something?
Max
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miwoud1,
Very nice project and I have followed your progress for some time. I know you've studied various connectivity variations and the blade drive combinations.
Question: In the interest of simplicity at driving(controlling) the blades, If the spider were to be replaced by another bevel gear(connected to a rod coming thru the hole in the sungear), wouldn't the mechanism moving the blades be simplified using the rotary motion, vice having the drills rotary motion changed to a linear in/out motion to move the spider (hence the blades)?
Just asking, I'm certainly not criticising.
Bill
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It could be even simpler than that, you only need one sun gear, the existing sun gear moves the pinions if it is driven.
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Hi.
Moving the sun gear rotation left and right to change blade-angle.
Now we have two rotations 1) the mainshaft 2) the sungear independent
of the mainshaft making 45 deg left and right.
Looks to me a bit more difficult.
The push-pull rod and spider will do good when more rigid, and free of slob .
That can do without bevel gear
The actuator with spindle is fine ( choice of speed ) and high torque.
Good to control with electronics.
In the near future with a microcontroller.
- Frans -
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Personally I think you are right.
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Frans, yes I can see the gears give good sync. I too was concerned about flutter when I constructed my spider so I took care to make the linkages tight and low friction. There may be a small amount of flutter but it is not apparent from the ground at least.
I also agree that the push-rod control with gears would give the best results over gear control alone.
I'm wondering, is there such a thing available as a suitable linear servo actuator (something to replace the drill & threaded rod)?
What type of micro-controller will you be using?
I'd like to try the gear method but those suckers aren't cheap - looks to me over $200 for four. Maybe a transmission rebuild shop could supply some used ones(?).
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NoSmoke. We can find 4 bevel gear wheels inside a car dif. on the scrap yard.
From the type of a Pickup truck cardan .
Think these are hardened steel so we must anneal to work on it.
A suitable lineair actuator can be found in our adjustable bed mattress.
Or the window opener servo in our car. ( Scrap yard )
On Mobile scooters that disabled people use.
The type of micro-controller , I still have to find out , need more info about it.
Think a PIC 16f877 will do , I have to learn about programming language
( Basic , JAL )
- Frans -
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Yes, the 3a, 3b, 9a & 9b gears ought to do it. Does anyone know exactly what they are called so if I call an auto wrecker I will know what to ask for? Would those four mesh together or would gear 10 also be required for the "centre" gear?
To anneal them would one just place them in a hot oven for a while?
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"spider gears"
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(https://www.fieldlines.com/index.php?action=dlattach;topic=145925.0;attach=4990;image)
It looks like only one gear, but the other may have been removed for the picture- would be interesting to know if the bevel gear is gounded to the assy, or freely rotates, im sure backlash is a proplem with the design.
JW
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Thanks RP.
JW, the sun gear has to float otherwise the blades could not rotate with respect to the assy.
There might be a little backlash if the gears aren't tight but I doubt it would be noticeable.
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What concerns me is, its a single axle design. I understand planetary gear clusters. With 2 bevel gears, the assy would be much more solid. Could the common shaft for the bevel gears intesect, most likely yes.
This would attempt to nullify, the torque spread out on the surface area of each blade, into the gear cluster. I agree that backlash sread between both gears would be easier to control, overtime, and constant duration of use. It comes down to the surface area of the gear mesh being doubled, with 2 gears over one. I think only one gear as illustrated in the photo, is a bad idea. But thats only my opinion.
JW
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would be interesting to know if the bevel gear is gounded to the assy, or freely rotates, im sure backlash is a proplem with the design.
If the bevel gear was "grounded" (presume you mean firmly attached, unable to turn) - surely the other gears in mesh with it, couldn't turn then either?
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Actually if you put a second bevel gear in front, it could be attached to the rear one by a bearing/bushing and shaft and the pair of them could "float" without being tied to the frame at all.
I don't see an advantage to doing that but it may allow some more choices or eliminate some headaches.
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Gentlemen . Dont worry about backlash. All the parts are machined precisely and adjustable . The bearing housings are very tight-fit ,that will never move out by centrifugal forces . There is an extra ring to hold against axial force.
The sun gearwheel is free running around a hollow POM shaft.
The blade-pitch is running light , you can move it with your finger tips.
If anything goes wrong I'll report it.
http://www.youtube.com/watch?v=RiQiqi5jzVs&list=UUhmCD9VGJTBJsh0tCDHsHbw&index=2&feature=plcp
- F -
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I want to say I think this an really good example of innovation. I like this machine...
Yes RP there is an existing bevel gear below, but not one on top, I think the arrangement with both bevel's would be simular in action of a open differential (link a car has).
The primary drive bevel gear will regulate the outer bevel gear using the blade gears. So it would effectively float(outer gear), and having a common shaft for the bevel (pinion) gears, would assist in eliminating wear on all the gears, depending how strong you want it to be you could use a thrust bearing(outer pinion gear shaft). The pinion's shaft would be in parallel to the turbine axle.
This an excellent project. And it will work fine the way it is.
JW
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Frans, are all four gears alike (sun gear same as blade shaft gears)?
Has anyone actually bought these "spider" gears from an auto wrecker? Do they typically sell them separately or would one have to buy the entire differential and disassemble it?
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You're gonna have to buy and likely remove the diff from the car, you want the large sun gear and the small planetaries, although you will only be using three of the small gears.
I would think finding something small enough would be problematic with auto parts, the smallest sun gear in an automotive application would likely be at least six inches in diameter.
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I want to say I think this an really good example of innovation. I like this machine...
Yes RP there is an existing bevel gear below, but not one on top, I think the arrangement with both bevel's would be simular in action of a open differential (link a car has).
The primary drive bevel gear will regulate the outer bevel gear using the blade gears. So it would effectively float(outer gear), and having a common shaft for the bevel (pinion) gears, would assist in eliminating wear on all the gears, depending how strong you want it to be you could use a thrust bearing(outer pinion gear shaft). The pinion's shaft would be in parallel to the turbine axle.
This an excellent project. And it will work fine the way it is.
JW
KISS, in this case is very appropriate on several levels.
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You're gonna have to buy and likely remove the diff from the car, you want the large sun gear and the small planetaries, although you will only be using three of the small gears.
I would think finding something small enough would be problematic with auto parts, the smallest sun gear in an automotive application would likely be at least six inches in diameter.
OK but I wonder if four planetaries would mesh (one as the sun gear)? That's what it looks like in Frans' pics.
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It depends on the size of the planetaries 2 inch will do
Important is the sequence of working.
If I work with differential compoments I would reduce dia. partly of the blade shaft
equal to length of the planetary gear hole. Clean it with alcohol . Glue the components with Loctite HD . That will never walk away. Make a well locked retainer ( with a tension dowel, sorry I dont know the english word for it ).
Or 3 sinked centers in the shaft with high quality internal hex screws
On the retainer can the spider-linkage-arm be fixed.
After the retainer there is the inner blade shaft bearing.
The distance between the inner and outer bearing , I have 70 mm.
After the outer bearing another retainer with 2 normal hex. screws fixed.
Keep enough shaft length for blade fixation.
Lay these component on the table with the sunwheel meshed in.
Now you can determine the radius and dia. of the rotor disc.
Make the height of the bladeshaft above the the disc, and the length of the linkage arm , so you can move freely 45 degrees up and down from horizontal position.
Will be continued ,
- F -
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I think this video Midwoud made is really cool... Great job!
http://www.youtube.com/watch?v=RiQiqi5jzVs
JW
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Under construction
Blade pitchcontrol by a microcontroller they are available for a few euros.
And they have enough analog and digital inputs to control Rpm .
In my case between 210 and 350. Programmable whatever you want.
Shutdown at windspeed 17 m/sec (signal anemometer )
Measuring Volt and Amps of the battery bank .
Stator temperature , vibration control ( ice one the blades )
Option with LCD readout display.
- Frans -
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Frans, what micro and language are you using?
Any plans to do MPPT?
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Hi .
Microcontroller AVR-Atmel or Arduino. Language in C.
Windpower compared with Battery demand and consumption with dumpload and waterheater is the task of a controller.
First I concern on Rpm and MPPT later.
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Micro-controller.
I think the microcontroller can be a good assistant to control our windmills.
One of the ancestors is the organ you see playing at the canalstreets in Amsterdam where the lovely ladies also are.
Turning on a wheel and a perforated tape feed in and the whole orchestra is playing for you.
Another example is the teddy bear ,if you squeez his ear , or push on his belly he starts grumming or sing a song for you . I see students who hack that for another appliance.
There is even a book how to do that.
The controller can be used for run our mills safe and it costs only 20 dollars.
Connecting the hardware is a peace of cake.
Write a very simple program with your PC with your wishes and download it in the controller .
The program language is in - C -. Thats a bit complicated for a beginner.
Ask a friend software engineer to assist .
I think No-smoke can do that . Those programs can even be send by email .
We have the behaviour of the mill better in hand .
There are books on kid level to learn it.( Getting started with Arduino ) and we can find everything about it on internet.
A basic programme can be used for all of us .
We only have to feed in our data like Rpm , Bat.volt and Amps , Stator temp.
And Bob is your uncle.
I know that some people will say it's not KISS, But my laundry machine is working already 12 years with it.
- Frans -
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Frans, that's a nice looking controller and I think I will take a look at them. Still think however that a PicAxe & Basic would be easier for a beginner rather than C (not saying you are a beginner :)). I've looked at C at bit and don't find it very easy or intuitive.
Anyhow, I would be v interested in updates to your project. Maybe post some of the C code here?
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Check out something called DUINOMITE MINI.
It is a very small 25$ 2" x 2" 5V PIC-computer using basic.
I bought one.
/Piglet
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Check out something called DUINOMITE MINI.
It is a very small 25$ 2" x 2" 5V PIC-computer using basic.
I bought one.
/Piglet
Piglet, also very nice micro-computers (no PC needed to program or provide keyboard & monitor functions) but, looking through the instruction set I see nothing for pulse count, PWM or servo. Are they available as library functions and if so, where would I find them?
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Check this:
http://www.olimex.com/dev/DUINO/DUINOMITE/DuinoMite-UM-1-03.pdf
and this:
http://geoffg.net/Downloads/Maximite/MMBasic%20Language%20Manual%20V3.1.pdf
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Check this:
http://www.olimex.com/dev/DUINO/DUINOMITE/DuinoMite-UM-1-03.pdf
and this:
http://geoffg.net/Downloads/Maximite/MMBasic%20Language%20Manual%20V3.1.pdf
OK, it appears to have PWM - out of the audio port.
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Check this:
http://www.olimex.com/dev/DUINO/DUINOMITE/DuinoMite-UM-1-03.pdf
and this:
http://geoffg.net/Downloads/Maximite/MMBasic%20Language%20Manual%20V3.1.pdf
OK, it appears to have PWM - out of the audio port.
Yes, and if You want to use other pins for that, also the instruction "PULSE pin, width".
Will generate a pulse on 'pin' with duration of 'width' mS.
'width' can be a fraction. For example, 0.01 is equal to 10 μS.
For a pulse of less than 1 mS the accuracy is ± 1 μS.
For a pulse of 1 mS or more the accuracy is ± 0.5 mS.
Extremely easy to program tough little PIC32 computer, especially if You are familiar with Basic. :)
It has also built-in flash memory, this works as drive A:, also any micro-SD card will work as drive B:
/Piglet
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The Arduino controller is connected with the windgenerator. (working good )
Start feathering 350 Rpm .....unfeather at 200 Rpm .
Variable input sensor volt , delay time. An interface is made to protect the controller input max. 5 volt. Gate A-0.
The digital outputs 12 and 11 are connected with a relay card.
The relays are switching the pitch actuator in and out.
I have no experience with Language - C - other than the Arduino starter manual.
Have had professional assistance.
Looking for a good book.
Nosmoke and Piglet2 . The Duinomite looks good , I think you can things made moving.
And you know Basic .
I see similarity with the UNO .
Are you planning to let it work with pitch-control too ?
In the near future we can make our own MPPT controller with Lcd display
- Frans -
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Look, this basic is so easy to use that You will learn it in one hour. Or two!
Please check the earlier links, there is the manual.
The small PIC32 computer can also use C.
/Piglet
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Piglet, the thing with PWM is that it should run continuously in the background (same as a servo function) and is thusly implemented in hardware as I understand it on the PIC micros. Using pulse output would not do that would it, unless running in a background program but I don't know if the Duinomite Basic does that. Surely the Duinomite processor does support PWM at the hardware level (and with multiple PWM capability I would guess) so it seems odd that Duinomite Basic does not seem to support it directly at the output pin level(?).
Frans, I would be interested in seeing your C code if you could post it.
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Blade pitch with a microcontroller and a water heater , It's not a dumpload but to make coffee and tea.
Arduino Uno , C code will follow.
http://www.youtube.com/user/midwoud1?gl=NL&hl=nl
- F -
-
Hallo Frans,
What do you think about making new coils to get 220 or 380 volts?
Regards Rinus
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Hi Rinus.
I know you have a 4,5 mtr turbine under construction . In Hugh's Recipe book I found the number of coils and windings page 38 .
Wire diam 0,95mm ,windings 250 . That gives an output of 140 - 350 volts ,suitable with a Windy Boy inverter for grid tie. Or heating elements .
You also have Pitchcontrol and with a micro-controller you can keep your output volts between the limits and avoid overspeed .
Marijn Innotech has the same idea with a 24 volt windturbine. Looks proffesional.
- Frans -
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Hallo Frans,
Many windmillfriends are eager to use active pitchcontrol.
How can we simplify the hardware e.g. avoiding the bevel gears?
Regards Rinus
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You are not gonna smoke an alternator in eight seconds.
Maybe not but how about overspeed to destruction?
Depending on rotor size a LOT can happen in 70 MPH wind in 8 seconds
Just saying..
Here in Wyoming we can get gusts up to 50 MPH from the West when the weather changes. A microprocessor would be good to control it because you could tie in other input like barometric pressure. When you're expecting high winds you can tell it to be careful when seeking higher tsr's.
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It can be simplyfied to leave the bevel gears away , In my first design I made it that way but it did not work I wanted . If we make the push-pull rod better fit in the hollow shaft with a bronze bushing easy sliding we will have a good result. I think the Innotech collegues make like that. In a couple of weeks we can see their results . Keep the spider in the center line.
- Frans -
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Sunbelt 57
The actuator moves in 9 steps . The blades make 10 degrees a step . Between the steps there is a dalay of 4 seconds that works good in a normal situation . I have a direct respons on the propellerspeed . There is an anemometer signal on a second input of the m-controller
In a gust a signal commands 9 seconds and turn the blades in full feather at once.
Another fact , we have no sudden increasing windspeed here ,so no danger of destruction.
It can be 9 Bft and the propeller is already safely in parking position.
- Frans -
-
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Hey Frans,
You have made your turbine with tree blades.
Now it is known that with less blades you can generate more energy out of the wind.
I wonder: have you ever thought of using two blades, ore one?
Regards Rinus
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One has been tried by lots of people, they are very problematic as far as balance and vibration go, two is almost as bad, three is the generally accepted trade off because they are easier to balance and the vibration problems are easier to deal with.
-
Just an impression of the size of the spinner.
Windmill Enercon E 126 under construction in my place .
- Frans -
-
Wow, I'll bet they got REALLY big battery drill to pitch those blades!
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Frans:
After watching the video enough times I think I can buy or build the pieces. I'm not quite sure how the rest of it works. Does the rod that pushes that hexagonal plate out have to be on bearings or does it spin with the blades?
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Hi Sunbelt57.
The pushrod is fixed on the hexagonal plate , and has a bearing in a housing on the
actuator . The actuator rod stroke , I have 80 mm . 10 mm / sec.
Attention the actuator rod may not turn. I made a guiding.
Many factory actuators can rotate.
If you have any questions feel free to ask.
- Frans -
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They've broken the 100 meter barrier!
More for those who like BIG: http://www.astroman.com.pl/?mod=magazine&a=read&id=900
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Awesome, now they are "wind energy converters" not turbines anymore, you see how they broke the barrier, they extended the blade mounts, looks like maybe 50 feet. Damn, they are building power plants in the sky.
-
I see they are using direct drive alternators (I though the v big turbines always used gear-ups). I wonder what type of magnets they use? Maybe that's one reason the price of neos has increased so much.
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As far as I know they use neos in those things, thousands of pounds of them.
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As far as I know they use neos in those things, thousands of pounds of them.
I'm thinking probably NOT :o
IF so those guys working on them could not even the slightest iron based metal even close.
More likely they use an induction or something similar to the car alternators that use an exciter type of system.
Just a guess on my part too, would really like to know by seeing one in person :)
Cheers;
Bruce S
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They use electric coil magnets ,with that you can regulate magnetic field and output .
Like our car alternators.
Neos of 100 kilos each and lets say 150 of them is a disaster.
All tools hammers spanners screwdrivers and even your wallet will attract to it ,
Putting the rotor on the stator is impossible ,Look at the force of our mini rotor-discs.
Enercon makes directdrive ,Rotorspeed 9 - 11 Rpm ,generator diam 12 meters.
They dont like gearboxes . ( maintenance )
- Frans -
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I'm waiting to see even the Next Gen ones were they start using super-conductors.
:-)
-
Mounting the generator and the blades.
Rgds . - F -
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OK, I stand corrected, SOB those things are awesome, absolutely majestic, I wish they would put one in my backyard, the sheer size of everything is incredible, you would think they would start putting elevators in these monsters.
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Fabricator:
Actually, you are correct. Many of the new style turbines are direct drive with neo magnets. Enercon uses electric coil magnets and that is what you are looking at. Goldwind, Siemens, even the new 2.5 MW GE is neo magnet with direct drive.
Gearboxes are on the way out on the commercial machines. It's just a matter of time.
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Even if they were to use Neo's they would still have to wrap copper around them anyway to provide for flux weakening at the high rpm end of the curve.
I would not be surprised if they are running 1.7 to 1.8T field strengths on those coils, and the cores are probably built up using structured grain oriented steel, running as close to zero air gap as they can get. (structured as in the teeth are pressed into a "V" punched into the back iron. (there's probably some kind of a notch they make in the "V" to lock the tooth into the core.) The back iron itself being made from say 24 pieces to complete the 16? foot diameter core.
midwoud1 do you know what topology they are using for the inverters, and what the switches are made from?
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Fabricator:
Actually, you are correct. Many of the new style turbines are direct drive with neo magnets. Enercon uses electric coil magnets and that is what you are looking at. Goldwind, Siemens, even the new 2.5 MW GE is neo magnet with direct drive.
Gearboxes are on the way out on the commercial machines. It's just a matter of time.
Ok, I stand uncorrected or semi uncorrected.............
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Interesting Enercon factory vid. Inside factory starts after 5 minutes.
Rgds - F -
http://www.youtube.com/watch?v=NngywATy2ys
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All you can say is awesome, those things are magnificent examples of what humans are capable of.
-
Here' here
I say we embed a youtube video here.
I remember years ago (probably more than 6) where the Dan's were granted a tour of these type of 'Mega Turbines'
JW
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Lineair Actuator with adjustable stroke .
Motor 24Vdc 1000N ( electric wheelchair junkyard )
Speed 10 mm / sec.
I made micro-switches on it as end stops.
Easy to change the stroke by sliding the m-switches.
Switch circuit forward - back by polarity change relay 12 Vdc .
Easy to connect with voltage Rpm sensor and micro-controller
Rgds - Frans -
http://www.youtube.com/watch?v=T0igWBX-r5E&list=UUhmCD9VGJTBJsh0tCDHsHbw&index=1&feature=plcp[attach=1]
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Cool, that one looks pretty big though, I can see you are not going to stop until you have the perfect machine. :)
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Its a bit big to build in ,I plan it for a mill larger blades.
The actuator runs very reliable , I had all the components in my workshop.
So it was cheap to make , only time.
JW . Sorry I cant embed the youtube starting image , I tried it several times.
Rgds . - F -
-edit-JW
Hi Frans sorry for the late action on this I was out of town, there is a trick you have to use the url of just the video playing once. If the url autoplays several videos then it wont embed. the first time you see the & charictor in the url, delete everthing after that and it should solve the problem for you-
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Hey Frans,
Looking at your drawing on page 2 , reply 39 of your topic:
Bringing the actuator down in the mast.
The size of the actuator is no problem.
Regards Rinus
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Hallo Frans,
Do already you have new pictures of the progress of the Enercon 126
or haven't you been on the building site lately?
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I just noticed something, in the picture with the crane and the spinner, there is a turbine in the background, does it only have two blades or is it just an optical illusion?
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Fabricator; Its an optical illusion, near as I can tell there are 3 blades there-
[attach=1]
JW
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Yeah I guess when you study it enough it looks like the sun is on it just right to make it the same color as the sky.
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Windmillfriends,
The Enercon is impressive.
Nearby stands the Darwind D115 and the Lagerwey L 93
Rinus
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Pitchcontrol design 2
Lineair actuator stroke 80 mm ,time 8 seconds , 0 - 90 degrees
PVC pipe 40 mm with keyholes . ( Later stainless Steel )
No bevel gear . Easier to make ,less time .
- Frans -
make sure the "youtube" tags are before and after the youtube url -JW
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Absolutely beautiful, it's extremely cool watching this evolve, seems like it's pretty close to the simplest possible form.
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Nice work.
Keep improving
Rgds. Do
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Nice ideas. How does the gear assembly maintain lubrication?
Dennis
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Dennis.
The propeller rootshafts have sealed angular contact-bearings (lubricated)
The gear system is low friction with Ptfe teflon grease.
Checked every 6 months.
- Frans -
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There is no gear assembly in the new design.
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Windmillfriends,
Probably we are in a fair way to a perfect working active pitchcontrol.
regards Rinus
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I like it a lot, my only problem is with all the electronics, it seems like a very simple fly ball governor could be used in place of the linear actuator, the balls fly out push on the rod the blades furl all in a completely linear fashion, there would of course be some testing to do with fly ball weight and fly ball spring tension, although the springs could be mounted on the pins that run in the slots on the blade hub.
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I have had fly weights in front of the propeller and my experience was the prop still had high rpm in strong winds.
It was searching a balance between Rpm and centrifugal force .
I had the same story like JLT , People heared the sound of a runaway and had to run.
So I was looking for a way where I could feather the blades by an actuator, with the benefit to full feather and stop in case of storm ( 10 Bft ) and full charged batteries ,
And no load on the tower.
The electronics are not complex and quite easy to make on vero board .
If anybody is interested I can send the schematic diagram.
Would be nice to find someone who knows how to connect the Microcontroller .Let a friend do the soldering .
Two months ago I knew nothing about Controllers
But after 3 hours help with software programming I was able to upload it.
And the machine is running like a watch.
- Frans -
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Windmillfriends,
In our test drafts we always use a governor which overrules the electronics if necessary.
That's no problem.
Besides we see perfect active pitchcontrol on the professional windturbines all around us.
What we need is cooperation with electronic discipline to low budget simplify things.
Like Frans does.
Cooperation between hobby windmillbuilders is the key.
Rinus.
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Rinus
So you make the mechanical parts for my small turbine, and I
deliver you all the electronics you need.
This is a serious offer.
Agreed?
Do
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Frans, I understand, it is a fantastic system, it would be perfect if somebody could come up with a little black plug and play box with adjustable parameters, for us electronically challenged people. :)
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Do you're welcome.
Let's get in touch.
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I have given some thought to the fly ball issue and it appears to me that dynamic balance might become an issue. From what I know about wheel balancing, weights are placed on both sides of the rim to eliminate this issue of essentially having the center of mass rotating in a plane not perpendicular to the rotational axes.
Keep up the good work, it is fascinating.
Dennis
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Windmillfriends,
The intention of the "Gewiekste" is cooperation.
Bringing together knowledge of windmillbuilding enthusiasts.
Via testarrangements we want to go on forming components, striving
to translate the latest turbine techniques to our compositions.
Low budget and on hobby basis to real good working models of professional windturbines.
rds. Rinus
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Lifting the nacelle and ring-generator. Enercon 7,5 Mwatt
Look at the multi rotor flying video - foto camera .
- Frans -
Not a valid youtube URL
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http://www.rtvhk.nl/2012/04/24/film-item-300-ton-zware-turbine-geinstaleerd-in-windmolen-de-ambtenaar/
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It appears from the video of their factory that their towers are concrete sections, do you know if that's right?
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Yes the tower is buildup with concrete ring sections . The sections are fixed with special glue.
Inside the section walls there are channels from top to bottom with steel rods under tension .
Rgds - F -
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Excellent, thank you.
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Frans,
Congratulations on your engineering. Active control is a challenge to us DIY people without lathes but with big hammers in lieu and left hands. The Jacobs idea of passive control is simple with the centrifugal force of the props pulling against springs and turning the prop. The engineering challenge there is to mill a spiral into a hollow shaft to achieve the correct pitch with the pull from the props.
The Jacobs certainly had a reputation for longevity and they are still spinning to this day.
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I don't think they had a spiral cut tube, the early ones had a pin that rode up a ramp as the blades were pulled out, the new system uses a spider and ball links
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It would be nice if we could get a wiki like book/site/section together that started to summarize these ideas along with drawings. There have been some very clever ideas here over the years and it is very difficult to find them and put them to use.
Histories of what has worked, how long, where it failed, when it failed could avoid a great deal of duplicated effort.
The original ideas seem to work until they don't. I do miss the Dans' reports of spectacular failures, the evenings of song, etc.
Then again, perhaps after the basic idea, more is not better just more.
Dennis
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There are drawings of the Jacobs passive pitch on internet.
I have seen a centrifugal system and a special gear ,crown and pinion to change blade angle.
Without a spiral gunbarrel shaft.
The active pitch reliability depends on the use of a good actuator (Linak) and ball bearings on the blade root-shafts.
I have it succesful for 8 months.
Another 2 designs are under construction, Marijn and Mbouwer in the Netherlands.
Working with nowadays technic .
If something fails in my design I will report it.
Rgds. - Frans -
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by the way...
There is this guy on youtube that has built some really nice machines...
He now seems to experiment with passive pitch as well...and I wanted to post it as it refers to the topic...
http://www.youtube.com/watch?v=3vO5hzFMW14&feature=channel&list=UL
Max
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Hi Max.
Thanks for the link . That must be in Spain or Portugal.
Looks good , he has his own ideas . ( multi slip-rings )
Curiuos to know how he made control : auto - manual ?
Pitty he closed answering on YouTube to have more info.
Maybe language.
How are your doing with your design ? And blade manufacturing.
Rgds - Frans -
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Hello Frans,
So far I have made some sets for testing and I have purchased a chainsaw but bought the wrong thing...
I have made up a few designs for various diameters of props for laminated wood beam dimensions that are common over here so noone has to bother with surface planing line I did.
Here are some pictures that I have made in solid works. First I carve them on my computer, then in my work shop ;-)
But I do not want to get too much off topic...I wonder that this topic got out of fashion so quickly...but for some reason it is still on top of the list...wonder why
Max
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Frans's design has that thing beat all to hell and gone, the link system is similar to the Jacobs passive design.
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Frans,
I like your new design, a little bit reminds me of this one that I found about a year ago:
Max
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Windmillfriends,
Because it's very beneficial, more and more big turbines have a single main bearing construction.
We are trying to make a small ( e.g. 30 cm diameter ) good and simple light version of such a bearing.
Also installing active pitch control becomes a lot easier then.
Regards Rinus
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Rotorhead design 2.
Without gear . Mockup prototype.
To find measurements.
The generator will be between the flanges.
Propeller diam. 10 - 12 foot.
Actuator Linak 10 mm / sec.
Control : Microcontroller Arduino and software .
- Frans -
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That is fantastic, it's amazing how the design process works, one question, where will your main shaft bearings be?
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Hi Fab.
Don't worry .The permanent mainshaft is a 30 mm diam. C45 hollow shaft ( 10 mm ).
200 mm lenght behind the rotorhead flange, enough for the bearings.
I'm making an extended drill for it and go to a mechanical friend who has a lathe with a bigger chuck
Rgds - Frans -
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Beautiful, do you have gunsmiths over there? They drill stuff like that all the time.
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Pitch-controlled H-bird .
Hollow mainshaft . 300 x 30 x 10 mm
Modified actuator , adjustable stroke .
Pillowblocks 25 mm hub , 30 mm mainshaft.
Bearing push-pull in spider piston.
Adjustable flanges 120 x 6 mm fixation rotorblades .
- Frans -
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Cool, that actuator setup is kind of.......not to elegant though, no offense intended, check out this line of actuators, could you see one of these mounted directly to your shaft, I'm not sure how much they cost, probably a lot but you could have one made for your specific length, and it sounds like the actuator could communicate with a simple plc or your micro controller.
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Hi Fab.
Right . I know those programmable actuators ( with signals for endstop and feedback indicator) but I had an actuator laying for a long time for free.
I have made a plug and play connection on the microcontroller relay board to run every actuator.
Have made a new spinner . Separated from the mold with garden-hose pressure.
- Frans -
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That spinner is beautiful.
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It'll be interesting to see what paint scheme you select. ;) for the spinner.
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Bruce,
Sandpaper waterproof 240 , Polyester laquer 2 component ( Double Coat ) , sandpaper WP 240,
Synthetic paint ( mat black ) white spirit based .
Rgds - Frans -
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Pitchcontrolled blades 3,22 m diam.
The noise is from an unstabilized powersupply 24 dc .
Mu- controller holds Rpm between 200 - 360 . Autostop and manual in highwind.
- Frans -
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http://www.youtube.com/watch?v=FzRJQuWEcPg&feature=youtu.be
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As us rednecks in America say that is fandamntastic, there is nothing more beautiful than beautiful mechanical mechanism working perfectly, Frans you are a World class Journeyman in multiple trades.
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JW. Thanks for embedding the video. My computer still refuse it.
All people who have a bit experience with metal have the same good feeling with results.
Sometimes it is blood and sweat.
If you see my lathe you start laughing : center to bed is 7 cm , between centers 25 cm.
Bigger discs are made with a mill and a rotary table , all conventional.
My next rotor discs are made waterjet or laser.
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Exactly, that is the definition of a true journeyman, you can do pretty much anything with nothing. ;)
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@TomW.
Thanks . The project is going on. Still some work to do.
Rgds . - Frans -
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Exactly, that is the definition of a true journeyman, you can do pretty much anything with nothing. ;)
back in the day when I had a time card job in used to have a plaque on my tool cabinet
We the unwilling
led by the unknowing '
are expected to to the impossible for the ungrateful.
we have now done so much with so little for so long
we are fully qualified to do practically anything with nothing.
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The first shop I worked in when dinosaurs walked the earth had that on the front wall on a poster about 3 feet by four feet.
Right next to the one that read " Your lack of planning is in no way an emergency for me" LOL.
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You are good and I like the vice grips. :D
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If it were not for visegrips civilization as we know it would not be possible ;) I've often used vise grips to hold vise grips in place. LOL
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One of my old beater trucks from the days I was super poor went down the road with a brake line vice gripped shut :o got me 3 month until I could afford to fix it ;D braked a little funny but what the heck.
-
MaryAlana
We are glad you'r still here. ;D
-JW edit- use ; D (without the space to make that smiley)
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The first shop I worked in when dinosaurs walked the earth had that on the front wall on a poster about 3 feet by four feet.
Right next to the one that read " Your lack of planning is in no way an emergency for me" LOL.
I don't remember seeing too many dinosaurs around the blacksmith shop where I took my apprenticeship but we did have an old model "A" ford engine powering the overhead flat belt shaft system this ran the grinder the trip hammer the drill press & the lathe though and we had a carbide generator we used once in a while if we ran out of acetylene,
I started there then I was 11 sweeping up and cranking the blower for the forge by the time I was13 I was re tipping and beating out plow sheers. before I was 15 i had my 6G and could do a bell hole weld with a mirror if need be.
come to think of it there was 1 dinosaur a Lincoln upright welding machine we called it the Coffee pot
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Those Lincolns were called coffee grinders, you still see em at auctions and estate sales, the first sheet metal shop I worked at had an over head jack shaft, EVERYTHING ran off that shaft, the one half inch by ten foot shear the 12 foot press break that would put a 90 in 12 feet of 1/4' mild steel, you might have to jump on the pedal a couple times but it would do it.
all the drill presses, everything but the welders,( I remember when they came around with the first wire welders it was ten years before anybody trusted the welds they made) IIRC the main motor was about 15 or 20 HP and it was a huge old thing, it had an open frame and had lots of oiling points, that was the apprentices job (me).
I also got to fix belts, at least two a day broke or came apart, nothing was shut down, i just got the belt length, put on the laces, put it over the shafts and fed it on the pulleys, there were NO guards anywhere, a contemporary OSHA inspector would have a stroke and die right on the spot.
I remember a furniture shop we used to do a lot of blow pipe work in had and actual stationary steam engine that ran the whole plant, the plant had about five floors, you want to talk about a LOT of jack shafts and belts, a lot of the jack shaft bearings were just greased wood pillow blocks.
It mad a lot of sense for them because they could run the plant in saw dust, shavings and scrap they made, the engine even had a dynamo on one end that made electricity for the plant too. I got caught a lot of times just standing there watching that engine run. ;D
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I have seen several plant with those type of belt drives and some water wheel driven.
My dad would not let me out of his sight when we were there. I love that stuff.
I grew up on a farm and we worked the land, gathered corn, cotton and fed our live stock( cows, pigs and goats). We had vegetable gardens of 5 acres for our use. A smoke house for our meat and salt box for our bacon and hams.
When I got my first job as a machinist I knew nothing other than the farm and hard work.
Engine lathe, turret lathe, surface grinder and milling machine.
For three years I saw four walls and no sun light. I am no engineer but a worker who did not know I would miss the sun, grass and non-conditioned air.
Several years later(37) I have readied myself for retirement and love wind( I remember an old water pumping wind mill I could see from my bus ride to school), Solar and Hydro power-Thanks "The Mother Earth News- Handbook Of Homemade Power") .
I think Fabricator You are slightly above my experience level but you know the secret of happiness. The ability to function effectively with and around complicated machinery. And function effectively without it.
I learned to burn a stick with a Lincoln buzz box. Boy was that a thrill to join two pieces of metal and have it stay together- Ag shop 1971.
Kenneth
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nice....
i build with wood also...never had a problem -even in high winds..
but why did you make your rotor from wood ?[blade mounts]..most stresstfull..?
just curious sence it looks like the rest is all made from metal.........
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Some may wonder what old jack shaft shops has to do with this thread
.
Yea we Hijacked it big time LOL
however many principals of this man's active pitch control could be found in those old shops.
the block bearings ans stub shafts.
the linkages& fulcrum arms would have been seen through out the machinery.
. Back to the hijack anytime you see an 11 year know how to take a broken broom handle to the side of a running belt then knock it off the pulley to stop a machine that is trying to eat the 70 year old operator alive then reach with his hand and toss the reversing belt over another pulley and then take his broom handle to nudge the belt onto the lower pulley just enough to cause the machine to back up enough to allow the man to free himself you have got to appreciate the apprenticeships of by-gone days. I worked at that blacksmith-shop for 5 short years left there in 1970 but was there long enough to help convert the whole shop to electric motors on each machine 42 years later some of my fondest memories are of the hard work I put in there.
Fab you are right it may have been called the coffee grinder
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Hiker.
It is under construction and I use wood to find measurements ,
Not to f...k up an aluminum disc I am waiting for.
A friend of mine is looking for it in the scrapbox of a shipyard where they make luxury sail-yachts.
That will be permanent. With an extra ring on the pillow block tops .
A sort of sandwich to make it extra strong . I did that before succesful.
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Frank, Kensue, Fab,
That was history leatherbelts with cram and pin connection , reverse with a halftwist belt.
Pedal and fork switch . hahaha. '' the good old days''
A resin block in hand was used to make extra grip in case of slip.
I remember a Lincoln welding machine as a rocketmodel with iron wheels AC motor -> DC generator with handwheel to adjust amps . I did my 6G with it.
We had this till end 60's because after the war there was a lack of everything.
With Marshal help, tractors came here like JohnDeere ,Allis-Chalmers , Ford and Ferguson.
Caterpillar and first hydraulic.
Dinky-toys If you see it now.
A frontwheel of a todays tractor is bigger than a rearwheel of the old-ones.
The industry who worked soon with electric motors on their machines ,lathe,mill ,drill were airplane- car- and arms-factories
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Frans, thanks for being so gracious on our blatant hijack of your thread. ;)
-
Most of the best machines are used by arms-factories.
We digged this up years ago . A Browning 0.30 from a shot down Wellington in 1942.
It is visible that the parts are made high class and with precision.
I made a new heat protector for it .
We found other-ones which are still operation ,they were well protected in the ground.
-
That's cool Frans, I don't know country flags from spit, what country are you in? Germany? Holland?
-
Fab, Hover over the flag.
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I never knew that, thanks KS.
-
The Netherlands .
The 0.30 is a part of our WW2 airplane museum . All guns are not operational.
People from all over visited the museum .
There are parts of B-17 , Beaufighter , Spitfire, Focke-Wulf , Wellington.
A pilot from Springfield ILL. USA came over several times , he is a good friend .
-
Pitchcontrol system B-17 WW2 Wright Cyclone 1000 Hp Radial.
We have one in our museum. That inspired me a lot.
-
Long time ago in 1991 we made a plan for a windturbine for a friend 10 miles from here.
I made an ''impressive'' sketch and calculations on a half A4.
Than we delivered the plan to the council inspector.
They knew nothing about a windturbines because it was an upcoming technical phenomenon.
So one of the inspectors came on the location and we told him it was a hi-tech scientific project supported by the Dutch Technical University.
Later to be used in 3rd World-Countries like Africa , India , and China ..... duh ???
In a week time we had permission to start.....big fun.
Today the rules and knowledgement are a bit changed.
- Frans -
-
Hallo Frans,
Aare you also going to visit Aeolus Windpowered Vehicles Race 22 - 25 august in Den Helder?
It is quite nearby where you live and perhaps we can meet some windmillbuilding friends.
Regards Rinus
-
...
They knew nothing about a windturbines because it was an upcoming technical phenomenon.
So one of the inspectors came on the location and we told him it was a hi-tech scientific project supported by the Dutch Technical University.
Later to be used in 3rd World-Countries like Africa , India , and China ..... duh ???
In a week time we had permission to start.....big fun.
Today the rules and knowledgement are a bit changed.
- Frans -
They'd never believe me with that story today! Good for you for trying. ;D
-
It's about real safe windmills in places with quite undisturbed windstream.
I would like to make a solemn appeal to our d.i.y. windmillbuilding friends for more cooperation.
Several disciplines finding each other in translating the latest techniques to our working models.
Regard Rinus
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....
Several disciplines finding each other in translating the latest techniques to our working models.
Regard Rinus
Rinus,
Here is something I translated from Finnish (Suomen) last year:
www.sparweb.ca/Forum/Tuulivoima_ABC.pdf (http://www.sparweb.ca/Forum/Tuulivoima_ABC.pdf)
This is from the Finnish Wind Power Association, their Home-Builder's Guide. (Suomen Tuulivoimayhdistys ry, Tuulivoimaharrastajan Opas)
The scale of wind turbines represented in the Guide are much larger and more complex than the ones seen on this website.
I found the checklist of safety and design requirements very worthy of translation and being shared on this website, even if the majority of Fieldlines members will never consider overspeed brakes or blade pitch.
I hope you and Frans will find it useful.
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Hi Sparweb.
Thank you for the translation of the Fin info .
Interesting to see they talk about " Home Build '' with that size of mills.
The safety rules are equal to the professionals.
We as DIY are working in The Netherlands with blade diameters max. 4,25 meters.
2 projects are in progress with active blade pitch .
I have a 2,9 mtr diam succesfully operational , a 3,25 m is under construction.
Rgds - Frans -
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I don't see how the design Frans has come up with could be improved upon, the only thing I have been thinking about is a rotary actuator with a cam shaped disc on the shaft to push the furling rod, things could probably be lightened and made a little smaller.
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I don't see how the design Frans has come up with could be improved upon...
Fabricator,
Many ways to skin a cat. Frans has worked out a nice system, especially suited for the scale of turbine he has built. I expect it to be reliable for him, too, as long as he replaces some of his fasteners to better resist vibration.
But consider this alternative, also from the Finnish builder's handbook:
Mr Vilho Salmela was using a hydraulic system to operate his pitch control. Push rod through the bore of the shaft, like Frans is doing with his mechanical actuator. In 1994. The valves could allow the system to auto-feather the blades in the event of a system failure (though I don't actually see that feature in his simplified system schematic).
Frans,
You are welcome!
I hope it can give you inspiration or ideas.
In fact, there is more in the documents, perhaps you may find it useful, too, if I send it to you.
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Un my design that I have been working on I have considered a pitch control that is both active and passive. actually it is quite similar to Franz's design in many ways,
the system I have been drawing uses the pressure of the wind against the blades via linkages that are controlled by a very stiff spring or even could be a hydraulic cylinder connected to an accumulator. the end of the plunger would have a thrust bearing that would have an actuator pushing against it the actuator would be controlled by a wind speed indicator, The anemometer would send a signal to the actuator to maintain a maximum blade angle set according to wind speed. For gust of higher wind speeds the heavy spring and plunger would allow the blade angles to to change even further.
Now the RPMs of the turbine could be held to a near perfect setting for the operation of the generator.
[attach=1]
[attach=2]
[attach=3]
more can be found on my thread
http://www.fieldlines.com/index.php/topic,146738.msg1006757.html#msg1006757
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Last week very warm weather 40 deg.C.
Fortunately we have a free energy fan cooler.
http://www.youtube.com/watch?v=_vSf_wV7VE0&list=UUhmCD9VGJTBJsh0tCDHsHbw&index=1&feature=plcp
My apology if the embedding fails.
Sparweb.
Thanks for your offer. If you have a link of the site ,I can translate the pages and I select the worthful chapters out of it .
Frank.
That's a great design . I like the spindle actuator with spline ( compact )
Good presentation with Solid Works ?
Bring it in production and we start a Kuwait , USA , Dutch joint venture.
Production in China is riskfuly lol.
- Frans -
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Sparweb.
Thanks for your offer. If you have a link of the site ,I can translate the pages and I select the worthful chapters out of it .
Sure. I will send you a PM (private message) and e-mail the file to you.
If you don't know how to use the private message system on Fieldlines, I can explain.
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Hi SparWeb.
Thanks for the links .I've tried to answer by PM but it seems it did work on my dino PC.
Rgds - F -
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windmill friends
About Johnathans topic: My Windturbine with active pitch control
We think it's a real nice design, but his remark:
" I'm not sure why at the time I decided not to use the method with a linear actuator as that's bound to be easier than my method" ,
looks very important to us.
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I got your replies Frans,
You are welcome.
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Aluminum rotorhead baseplate with fillets under the pilowblocks.
More rigid and better line-out of the blades.
Took a bit of time to make but it's worth of doing so.
- Frans -
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Beautiful Frans.
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Hi Fabricator,
Nice to read that you can make your own bearings.
We also try to do so to get a single main bearing design.
Can you tell what kind of material you use, and how we can harden it.
Regards Rinus
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I use water hardened W1 tool steel, it is the easiest to machine tool steel that can be hardened in water.
You simply machine your part then you heat the steel up until it becomes non magnetic, that is usually a dull cherry red, then quickly quench it in a pot filled with a lot of ice cubes and water.
Be sure all your machining is done though because it gets HARD, it has a very hard outer shell and the interior is also quite hard, it's often user to make hammers.
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Hi Fabricator,
Thanks for telling us about your method.
Also I am impressed by the bearing Frank S shows.
We are trying to make a light weight single main bearing ( diameter 30 cm ) because our goal is a working model of the Enercon.
In hardening afterwards we thought it would give deformation.
Thats why we first hardened the ring. About in the way you discribe.
After that we made the race way for the balls by grinding.
Between the balls is a steel ring to keep them in place.
We now want to improve.
Regards Rinus
(http://)
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Hey Rinus. What is the diameter of the balls, and where did you get them?
Rgds. Do
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Hi Do,
The diameter of the balls is 15 mm, and we took them out of other used bearings.
We would like to improve the making technique of our bearing and besides that use ceramic balls. But where to get them low budget?
Rgds Rinus
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bearing houses should carry an assortment of balls
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You can order different types of balls from McMaster Carr, although shipping over seas would probably be costly.
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Thanks Frank S and Fabricator,
At this moment we have enough used bearings to provide the balls for the new single main bearing.
But it would be nice if we could find low priced ceramic balls.
And instead of steel bearingrings what to think of composite?
Then once we have made a mould, we could provide other windmillfriends with a single main bearing.
The application of active pitchcontrol becomes a lot easier then.
Rgds Rinus
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At a place in FT Worth Tx called Bearings INC I used to buy nylon, Rubber, Silicone, Ceramic Steel, brass, & balls made out of UHMW for various applications some forbearing use others for valves
here is a link for steel & ceramic
http://www.vxb.com/page/bearings/CTGY/Bearing Balls the 2nd page has larger sizes
if you are using the mon a turbine the only reason I can see to use ceramic would be lubrication
one note ceramic balls do not like high impact forces without perfect race radius contours
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Hi Frank S,
Thank you for your referring.
Here in Holland where almost everyone is connected to the grid, our intention is to build a small real profitable turbine.
Profitable means that we have a few issues that we must avoid.
High expenses is one of them. Weight is another.
So its impossible to BUY that bearing diameter of 300 mm diameter
What we need is creativity from several disciplines working together to create components,
like constructing a ridgid light weight single main bearing.
Rgds Rinus
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Why do you need a 300 mm main bearing?
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Hi Rinus;
Machining the upper and lower bearing races is no big deal in the 300 to 350 mm dia range
you can either do it like Fab dit with a rotort table and a ball mill on his Bridgeport mill.
ir like we do for the jib cranes I build on a lathe any good medium carbon machinable steel will work for the races and can be flash hardened quite easily in an induction furnace or by torch. You do not need to get them super hard if it will be a Yaw bearing since it will never be rotating at speed. A turbine bearing is a little more involved and should be precision ground after hardening
[attach=1] here is one that is just about 300 mm in diameter 20mm balls I didn't even bother to harden the races just used them as machined 50kips steel and was used in a 2 ton jib crane 5 meter beam length almost all of the bearings we do are angular contact.
the nice thing about doing your own is you can design them the way you want them. the Jib crane has been in service since 2004 and has been relocated to 3 different buildings so far.
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Very nice work, how would they be ground for speed?
Dennis
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one way would be to have a rotating profile tool holder mounted to the tool post with a grinder like a do-more
another way would be to mount a grinding stick that had been ground to the correct radius in the holder
however if a custom ground piece of tooling stock had been used to machine the grove and finished off with high Rpm low cut feed little if any grinding would need to be done just polishing after hardening
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Thanks for the reply.
In making the gooves for the ball bearings, do you use an off the shelf tool with a given radius?
Again, nice work.
Dennis
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Why do you need a 300 mm main bearing?
Hi Fabricator,
We are vey impressed by the professional turbines like Darwind, Enercon, Siemens..........
and want to make small working models of them, using the latest modern windmill techniques.
As well as we are working on other components, we try to construct and improve a light and ridgid single main bearing.
Cooperation with other windmillfriends is what we nead.
Rgds Rinus
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since none of my lathes at the shop are CNC and off the shelf inserts are expensive in this country plus being very limited in sizes or shapes hand ground tooling is mostly what we use for any custom shapes.
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Why do you need a 300 mm main bearing?
Hi Fabricator,
We are vey impressed by the professional turbines like Darwind, Enercon, Siemens..........
and want to make small working models of them, using the latest modern windmill techniques.
As well as we are working on other components, we try to construct and improve a light and ridgid single main bearing.
Cooperation with other windmillfriends is what we nead.
Rgds Rinus
If you want cooperation we need to know where this bearing is located on the machine, is it the yaw bearing?
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Impressive job of hand ground tooling. Old school. It really did the job and still does.
Dennis
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In my experience at least I can never get the finish on a part with store bought inserts, than I can get with a good old fashioned hand ground piece of HSS.
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In my experience at least I can never get the finish on a part with store bought inserts, than I can get with a good old fashioned hand ground piece of HSS.
good analogy
for high speed production where I can allow myself to really plunge into the work piece I'll chose the inserts any day of the week.
for most other things I silver braze an old insert on to a piece of tool bar then grind to suit
for still other where I really need to get down and dirty so to speak with the shapes or finish a chunk of HSS gets to meet the rock then very carefully finished off with a ceramic honing stone like you would use to sharpen a surgeon's scalpel or your best fillet knife
The yellow titanium oxide coated inserts are great for speed if you flood with coolant oil like lubrisol but their main advantage is the made in chip breaker , to over come this with HSS or carbide I either have to grind in my own or adjust the rake angle
Tools are made to serve man not the other way around
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To fabricator and other windmillfriends this quick sketch
rgds Rinus
[/img]
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Unless there is something that I am not seeing you are trying to use a single bearing to support your blades.
What you are trying to do is to create a bearing like is used on a slewing ring of a crane or an excavator
[attach=1] [attach=2]
these bearings are normally very low RPM or intermittent rotation
here is a catalog
http://www.kaydonbearings.com/downloads/catalog390/Kaydon_Catalog_390.pdf
search page 64 for the MT series
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if I were going to think about doing this the bearing design I would go with does not exist
so I would make the races a 1 piece outer and a 2 piece inner the inner races would be held together by the mounting bolts this way you can load the balls or replace them otherwise to load the balls in a regular slew bearing you must shrink the inner and expand the outer
note the drawing I made
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actually this would be better since it interlocks the 2 inner races
[attach=1]
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Exactly, a bearing like in the drawing would have to be pressed together in a large press with a lot lf pressure.
I would venture to bet that the bearing Frank drew is very close to what the big boys use, they certainly would not use a single two piece bearing.
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Fab; as I see it using a 3 piece race design allows for easier rebuild closer fit & finish between the inner and outer races without the need to have a loading hole which would have to have a precision fit plug
also would be cheaper to make even with having to fit the 2 inner races together before the ball grove was cut.
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No question about it.
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with a turbine there are more than 2 forces at work though while a single row 3 point contact slewing bearing as I drew would work in theory since it can withstand thrust and radial to an extent Moment as well however this severely limits the speed at which it can rotate continuously.
To have speed we must have a couple more factors clearances being one of these
. if the bearing is made with too much then it cannot hold true rotational direction it would either wobble or vibrate causing still more problems one of these would be impact loading
The best way to reduce this would be what is called preload for a 2 point contact preload is easy to accomplish.
not so with a 4 point contact since this causes friction and wear
so the way around this most use taper roller bearings facing opposite of each other now radial , thrust and moment are reasonably controlled . But there is a problem tapered bearings of large internal and external diameters are also very thick and heavy
There are ultra slim tapered bearings and they are 100 times the price of a much smaller set of bearings which would have the design capacity for the turbine to run on
Angular contact ball bearings share many of the same design qualities of taper bearings it takes 2.
Ford and Nash were among the last car makers to switch from angular contact ball bearings to taper roller bearings in the front wheels
So this brings us to thrust ball bearings it takes 2 to control thrust and moment but they do not do well with radial
What we need is a bearing that exhibits the capacity to handle thrust both positive and negative angular moments and radial loads all at the same time
we could either just use 2 angular contact bearings or 3 thrust bearings plus a radial bearing or 2 taper roller bearings Or the one single row slew bearing similar to what I have previously posted and be satisfied. All of these have their merits and short comings
In the contemplated design the designer has shown that he wishes to have a large internal diameter he has his reasons for this.
The complicated and tedious machining to make ultra slim taper roller bearings and the fact that 2 would be required NIX's this one
The need for 3 bearings 2+1 for thrust & radial NIX's this one
leaving angular contact meaning 2 NIX!
or the slew bearing, Viable but with issues.
It seams we are out of options or one might think they were.
Never fear back in 1947 a company in Sweden used to build radial arm drill presses in their Quill there was a single bearing that could handle thrust in 2 directions and radial loads. I know this because I used to own one of those drill presses the problem was the 50 year old quill bearing finally failed and I could not find a replacement so I did what any Texas redneck would do I machined out the Quill and installed 2 thrust and a radial bearing in its place.
When what I should have done was to machine a new bearing housing and buy replacement balls
the drawing below is a rendition in much larger form of that bearing
[attach=1]
it consists of a single outer race which could be press fit into a housing or machined large enough to be drilled for mounting bolts. 3 rows of balls 2 will take thrust and some radial plus handle any angular moment loading the center row of smaller balls would take care of any radial loading. due to the contact angles no ball receives more than a 2 point contact friction and wear is greatly reduced allowing for higher RPMs
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In the reactions of Frank S and Fabricator I learned a lot.
With all the knowledge shown, I would like to ask to keep thinking along with us.
More and more the big boys use single main bearings on their turbines.
The weight, number of parts, cost etc. become reduced.
Those bearings are very complicated because of the fantastic forces that have to be withstanded.
For our small turbines ( e.g. diameter 5 meter ) the load is rather low and calculable,
We think for us it would also be an improvement to use single main bearings.
It is not really simple to make a leight weight low budget design, but in cooperation there is a good chance we will succeed.
Rinus
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Dumb question.
In the slewing bearings, how do you get the balls in place? The inner and outer races appear to be one piece.
In the drawing with the 3 sets of bearings, how do you keep them from falling out when assembling?
Dennis
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Dumb question.
In the slewing bearings, how do you get the balls in place? The inner and outer races appear to be one piece.
In the drawing with the 3 sets of bearings, how do you keep them from falling out when assembling?
Dennis
In my drawings on posts 284 & 285 the inner race is 2 pieces in assembly of anything with ball bearings there is a thing called grease that is impossible to get by without some of the very tedious micro precision instrument bearings are assembled in their factories by using a low level electromagnetic current applied to a race just enough current to aid in holding things in place but not enough to cause any residual magnetism in the race or the balls when non magnetic materials and in many cases where they are a special tool that is on the end of a robotic arm plunges into a tub of balls and one ball is picked up for each hole that the disc has using vacuum.
in the cases of a slew bearing the inner and outer races have very little gap between them then either there is a loading hole located in one race or the other and a fitted plug with an end profile that matches the race is inserted to fill the hole Or one race is shrunk using cold while the other is warmed by heat contracting the diameter of the inner while expanding the diameter of the outer another method that is next to impossible to detect is the outer race has a cut across it allowing it to expand like a woman's bracelet or a magicians set of magic rings. Bearing makers have more secrets to their methods than the CIA ever had.
When I was installing a conveyor system at PTC Components INC a division of link belt they warned me that if I heard one of their large bearing races hit the floor not to look around to see what was happening but to duck and cover as if an atom bomb was going off because the wedge that was holding the ends of a race separated could shoot out at mach 5
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I that case you wouldn't hear the race hit the floor if the wedge got you. ;)
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Travelling in Poland .
I see the item big mainbearing.(Hub suspension)
Another reason that Rinus is talking about a big mainbearing as I understand .
To bring the pitch actuator in front of the hub as far as possible.
Being compact fit and short linked in the Enercon model nacelle.
- Frans -
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Franz it can do another thing as well having a big through hole affords an easier way to add gearing however
redesign of the rotor placing a large thin bearing on the turbine side and one on the back side would serve even better
I'll draw up a double axial stator with a triple rotor as a case scenario to show my perspective tomorrow.
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I don't see the need for such a thing in a small turbine, you could take Frans's design and simply use a larger main shaft, say 3" chrome moly steel and drastically shorten the distance between the main bearing pillow blocks and use a shorter actuator mounted under the pillow blocks as a pull instead of a push.
You could shorten Fran's nacell by half at least, not that there is anything wrong with it as it is now.
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Windmillfriends,
Turbine engineers often have tried to start with available parts.
After years of searching for improvement came the design of the large diameter direct drive generator.
Besides that: The larger the diameter of the wings the more energy you can generate.
I would like to point the following question:
Isn't it logical enlarging the diameter of the bearing, and use a single main bearing ?
rgds Rinus
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I'l answer that one often times what appears to be logical on paper or even table talk does not always equate to the most economical nor the most suitable for a given situation . it boils down to a matter of choice which road do I wish to travel on the one that has long gentle sloping hills and straight a ways and gentle large radius turns or the one in which has constant switch backs steep ups and downs, if I choose the former I will need something to keep me awake with the latter I will be too busy to fall asleep However the road with the switch backs and steep hills is 5 times shorter. Can I arrive sooner taking the longer road or the shorter more difficult one.
it is the same way with wind turbines or wind generators. the 2 are neither the same thing nor are they much different in the end.
A large single bearing may look inviting and ultimately could turn out to be a reasonable choice.
doing it with one single row of balls may not be the solution doing it with 2 or 3 rows may not either it may be found that balls should not be used at all but rather sue short rollers with a diameter the same as their length Size the bearing so that an equal number may be placed at 90degree angles to one another now you have a single double row bearing that functions like a pair of tapered roller bearings back to back the groves now "V"s and have 2 flat surfaces by which the rollers roll upon.
we think OMG we have come up with the perfect bearing design it can take care of radial thrust and angular moment loading all at the same time and could have much tighter tolerances. BUT does IT?
is it just yet another road to travel upon?
I have seen a few slew bearings designed just that way used on some huge equipment. Had I had the opportunity to ask the designing engineer who came up with the idea. I would have asked what about the interference angles between the squareness of the rollers and the surface of the "V" groves
was this a another trade off? there wold have been only one possible answer Yes.
all bearings have at least 3 things in common they are a trade off compromise solution, they function better in one plane than another, they work better when in pairs
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Another thing a builder can do in the design of their turbine is to make a "V" grove outer race then make a mated pair of inner races with the piloting boss like one of the bearing drawings I showed use a stack of shim stock to space the inner race then use round balls remove or add shims until the tightest fit is accomplished but still loose enough to rotate freely. the balls are only going to touch in 4 points no matter if the grove is round or "V" and a ball is just as happy rolling in a "V" as it is in a radius.
This way you may be able to hold costs of machining down Hardening a flat surface is easy to see and check the results as the groves wear shims can be removed to hold tolerance
There are any number of different way to look at a problem and equally as many way to solve them.
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Windmillfriends,
To show in what direction we want to look " out of the box " we made this lightweight ajustable two rows angular contactbearing. ( 2 x 24 balls )
But we think two rows is not really an improvement of the bearing we showed in reply #263 of this topic.
Rgds. Rinus
(http://)
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That looks nice, is it heavy enough to take the beating though?
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Hi Fabricator,
The version in reply #300 was only intended to show in what direction we think to construct a leight weight single main bearing.
Our intention is to find windmill builders who think along.
rgds Rinus
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I'm done we have hijacked Franz thread long enough none of this bearing talk has anything to do with his or anyone else's active pitch control.
this discussion has strayed into another realm even though it still has subject matter relative to wind generators
any more contemplation of design for bearings should be in a thread about bearings unless it is about bearings for the blade mounting
I apologize to Franz and others for contributing to the wayward stray of this thread
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Frank and Rinus.
There is no problem of hijacking the topic.
You are welcome.
I'm interested in all inovation and improvements of our windturbines.
The big bearing might be a long prayer but on a day there is a solution.
Rgds. - Frans -
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Franz what I was thinking of is future seekers of info might be searching for a how to or an alternative to use for their main bearings
the large diameter one has some merits in that it allows the through hole to be what ever you design in
the car hub style with the small bearings has its limitations but affords the use of recycled scrap car parts
should someone be just a little industrious and use the assembly from a front wheel drive vehicle this has 2several merits of its own. First it would have a hollow hub by which an activation plunger could pass through the hole where the axle would have been
another is it has larger bearings offering a better angular moment control it will withstand thrust as well and obviously radial
next it is off the shelf technology easily replaceable.
the added plus just like the regular trailer type hub it can be found as scrap
Let's carry this one step further and use a hub from a rear end of a light truck with a full floating axle
right away we can see more benefits here in that the housing tube can be mounting member just weld a vertical pipe to it and you now have a full unit for both the yaw mount and the turbine mount.
the hub has generally from 6 to 10 strong studs depending on size. a very large plate can be mounted for the blades or the generator
if we get into the really large truck hubs like the Mercedes with the planetary we can use the hub the housing tube and with a little modification even use the axle by mounting a bearing in the opposite end of the tube then mount the rotor on the axle to give us a gear up now we have about a 1 to 2 speed increase the planet plate can be changed a secondary gear set could be used with lighter duty gears allowing enough room in the hub to make it a double gear set possibly going to 1 to 5 or more Of course using that set up kills a plunger driven active pitch control unless a hollow axle was used.
as I have said before there are as many ways to design the main bearing assembly as there are folks who chose to build turbines.
I like the double bearing pic of Rimus I question its strength without knowing the scale or thickness of materials
When i see something that looks like stamped plate with small stay rods for supports I have to think of an item being on the extreme end of being optimized for weight.
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Hi Fabricator,
The version in reply #300 was only intended to show in what direction we think to construct a leight weight single main bearing.
Our intention is to find windmill builders who think along.
rgds Rinus
Rinus, if you are looking for enough home DIY windmill people to make it worth having some actual bearing manufacturer build those bearings it would take a half million or so to make it worth while for a manufacturer.
IMHO you are going to have to use an existing bearing or have a machine shop build them for you.
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Hi Frank S,
We really appriciate your explanation, and we share the same thoughts about a frontwheel drive hub.
Mainly the limitations of the small diameter of the hollow hub hinder us.
rgds Rinus
(http://)
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yes well this would largely depend on the make or models some are larger than others and the splines can be machined out as well allowing the bores to be increased in some instances as much as double the original diameters.
A plunger shaft strong enough to operate a ptich control system such as Franz's unit needs to be only about 1" in diameter
A 5/8" 70KSI rod 25" long can achieve 1000Lb thrust before buckling a 1" can be 60" long for 1000lb or 25" long for 6000lbs
Step it up to 2" and we are talking close to 50,000 at 35" long
if you designed a pitch control to be in the pull mode then those figures would be re calculated to sectional area times tensile of the material
loads are meant to represent approximate values and are not to be considered as relative absolutes, eccentric loading reduces values.
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I think Frans is only using something like a 1/4" push rod, that hub could be annealed and bored to twice that inside diameter.
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Sometimes on these long threads it is well worth going all the way back to the beginning and take a look see at the pics or read some of the posts
Lots of evolution and info in them
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The pushrod of the 10 footer is 6 mm dia. x length 450 mm ( brass )
The 12 footer design has 8 mm x 450 mm ( C 45 )
It's very light running back and forward even at high speed prop.
The blade shafts in the center of gravity point of the blade profile.
I don't know the figures but increasing current draw is hardly to see on the actuator power-supply.
- Frans -
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Windmillfriends,
After the Gewiekste kick off meeting to start building a working model of a modern professional turbine, we started making a console out of old iron to place the top part of the mast on.
Intention: exchange parts, information and ideas.
Rgds Rinus
(http://)
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My question is why? Is this machine meant to produce power or just be a model? If it is meant to be a real working turbine why does it matter that it looks like a professional turbine, Frans turbine is producing power every day and can be built at a fraction of the cost of your proposed model. Take Chris Olsons geared machines for example, the don't look like the big machines but they produce kWh every day.
I guess I just don't see it as practicle to design for form instead of function.
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Hi fabricator,
Via our site and in conversations, we become more and more firm believers that people in Holland get inspired by the impressive windturbines they see around them.
If they live in the countryside and have undisturbed wind stream, some would like a small turbine on their domain.
It has to be safe, easily controllable (active pitch), dependable and they like "high tech"
If I see the pictures of the turbine you have so nicely composed I can put myself in your place.
Although we look in a somewhat other direction I think we have much in common too.
Rgds Rinus
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Fair enough, good luck.
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windmillfriends,
We made the mast upperpart and fitted it on the console.
with 12 bolts M 5 ( stc 120)
If anyone in our region, wo has no facility to weld, would like to build along with us we can take care of the welding.
rgds Rinus.
(http://)
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Windmillfriends,
We want to continue describing this working together windmillbuildingproject on the Dutch forum:
http://www.ecologieforum.eu/viewforum.php?f=23&sid=1e32a820f5db9a164fb31be66cf97049
In cooperation with www.gewiekste.nl
Language is Dutch. Ask us if you want a translation.
Regards Rinus.
(http://)
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Windtunnel test Piggott windgenerator 1,80mtr at OJF (OpenJetFacility) TU Delft.
Netherlands
http://vimeo.com/33005718
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I most liked the part of the video with it furling. Tail still mostly downwind, blade disk furled back about 45 degrees.
-
25-Nov-2012
Storm 7-8 Bft, Gusts 9 Bft.
Blades feathered .
Fully charged battery bank.
No smoke.
- Frans -
-
That thing is really cool Frans, very nicely done.
-
In airplane-talk, we call that "fully-feathered".
Excellent.
-
Hey Frans,
We really are curious after your 2013 improvements.
Regards Rinus
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What is the best blade airfoil ?
I'm working many years with Clark-Y ,but I see different ones good working as well.
The Clark-Y is low noise in normal working condition with a sharp trailing edge.
But in higher wind 15 m/sec.with auto-blade pitch 8 deg. there is stall-effect and noise at 350 rpm.
Wondering if other airfoils have that more or less.
Rgds. Frans.
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"Don't get me started" (that's a common english phrase that may not translate well. It means that you will provoke much heated debate, just for asking!)
I've often said that too much importance is put upon selecting the perfect airfoil, but for small backyard projects such as ours the result is hard to detect. Using the Clark Y or the NACA is perfectly fine. These are tried-and-true airfoils, easy to make, and have thick cross-sections for strength. You make your life complicated with the cambered airfoils, unless you are also ready to commit to making them in a somewhat complicated way (though if you do have a table saw or a router table available, then don't let this stop you.
In your case, Frans, you have electronics that monitor the turbine, and a pitch control system that responds to wind speed, so you are in a much better position than usual to measure and check these assumptions.
I believe the effort of making complex blade airfoils such as the SERI types is a total waste on a home-built wind turbine. Second, the only airfoil types to seriously consider are the ones designed to be effective at low Reynold's numbers (that aerodynamic terminology for "small scale"). Other than that, you have other things to do that are more important than the airfoil shape.
I usually see, in photos on this site, variations in profile that can add up to several millimeters, or in other words many % of the airfoil chord. In comparison, the difference between the Clary Y and NACA 4412 is also just a few % of the chord, in scale. To me, that means that the airfoils often used are not highly accurate reproductions of the "perfect" shape. The builder may have good things to say about the blades, but the airfoil isn't as true as he thinks.
Another fact is that the aerodynamic smoothness of the airfoil, which you should be sanding and finishing with paint or other protection, will be the strongest factor in the air drag. Since drag steals torque from the blades, any effort at reducing drag will pay handsomely in efficiency. Since sanding and painting should take about an hour or two of work, I would venture that the value of that time spent is worth 10 times the value of selecting a "perfect" airfoil. That task can take days, and the benefit will be smaller.
Those are just my general opinions about what's important to me, when making blades. Back to your problem:
Have you tried adjusting the pitch angle?
Is it the 12-foot or 10-foot blades that are giving you this trouble? Stalling always makes noise.
Is the "stall-effect" you mention an abrupt, cyclical one, or does it just rob power away? Shouldn't the blades be feathering at that wind speed? Have you compared the pitch of the blade to the inflow angle of the wind to find an approximate angle of attack?
-
SparWeb.
Thank you for the info. Most of us have Clark-Y (Hugh) ,NACA 4412, GOE 222 airfoils(Royalwdg)
I think Chris has S 809 . I red in previous posts that stall resonance can cause damage to the generator construction. There is no flutter, so no problem. All working fine.Balance and track.
Have a blade set of 12 foot (model Piggott with a streamlined trailing edge).
and a blade set 10 foot with half the root thickness wich is running now.
At 350 Rpm the blade-pitch is activated 1 step 0,5sec , with increasing wind another step and that's the moment of stall. 1 step is about 6 degrees.
With decreasing wind below 250 Rpm its going the otherway.
In storm or full batteries there is auto or manual full feathered prop.
There is a slight resonance in the generator at 200 Rpm ,but that disappears at higher Rpm ,I think most us have it.
Rgds. - Frans -
-
Thank you for the info. Most of us have Clark-Y (Hugh) ,NACA 4412, GOE 222 airfoils(Royalwdg)
I think Chris has S 809
I am flying a set of S809's at present but they are very noisy. The turbine that has them will be getting a new set of NACA 4415's in the next couple of weeks.
--
Chris
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I am at 40' now and my turbine acts exactly like yours. 40' doesn't even get over my small trees.
cheers
gww
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The only NACA 4415 I have is the wing of my WW2 Spitfire.
Good flying performance.
Rgds -Frans-
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I just set up my blade carving machine to carve that airfoil and it works good. I can sand it down to a 4412 but the 4415 seems to have a bit better torque and I can make the blades run a bit slower in the midrange and still get the power from it, then let them speed up as the wind speed increases.
I carve them with just about no pitch at the tip (maybe 1/2 degree) and about 8 degrees at the root. They run plenty fast enough.
That's a nice Spitfire. Now all you need is a scale model working V-12 Rolls-Merlin for it ;D
--
Chris
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found this on youtube today...
I like his work, its worth looking at his other videos as well...
I also use car hubs made by BMW for my bigger designs of active pitch control.
Might be some inspiration...at least another nice approach :-)
Max
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I don't know how I put my above post on this thread.
gww
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found this on youtube today...
I like his work, its worth looking at his other videos as well...
I also use car hubs made by BMW for my bigger designs of active pitch control.
Might be some inspiration...at least another nice approach :-)
Max
His pitch control works nicebut I would hope that when he puts the turbine up for use he would use nylock nuts or double lock nuts or safety-wire or loktite or some means to prevent any bolting hardware for coming loose
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Found on YouTube
Another active pitch windmill with faster actuator response.
Istanbul . Turkeya
http://www.youtube.com/watch?v=MWz87YH9yz4
http://www.youtube.com/watch?v=8tozBPjSpuw
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Nice design...but I do not like those Pedestal block bearings, also in your setup. Ball Bearings are not made for axial forces to widthstand the centrifugal forces of the blades when they spin with higher RPM. Furthermore they only have one single point of contact with the ball housing. They will wear out quickly, especially when there are additional vibration issues and the bearings hold up in one and the same position most of the time.
In my opinion, the only things that will last for a long time will be roller bearings or cylindrical roller bearings as they are made for axial forces as well and have much more contakct surface. Roller bearings in addition have the advantage that the can be lined up in case of tolerances...also slide bearings are good or a combination of them
Max
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In my opinion, the only things that will last for a long time will be roller bearings or cylindrical roller bearings as they are made for axial forces as well and have much more contakct surface.
Max - not totally accurate. Roller bearings will hammer out (brinnell) due to the fact that they are required to have the rollers turning to keep them lubricated. When they sit in one spot the lubrication "cushion" that protects the rollers from metal to metal contact with the races is not renewed and they fail prematurely.
Tapered roller bearings are the worst choice for axial loading in an application where the bearing does not turn in its design speed range.
The best choice for axial load is bronze thrust washers or bearings with thrust flanges. The second best choice is angular contact ball bearings. Svenska Kullagerfabriken AB (SKF) in Sweden invented them. Sven Wingqvist's 1907 Swedish patent for the multi-row angular contact ball bearing forever changed how combination radial and axial loads are handled in machines.
--
Chris
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Ok Chris, so you think that my blade bearing will hammer out as well...as it contains taper roller bearings...it is a common car hub. The turbine is not finished yet but it will turn the blades once a day to grease the rollers...
I like this setup as it is easy to build without lathe and cheap to get.
Slide bearings are probably the best choice, IGUS makes some great stuff over here and they are cheap but there are tight tolerances to keep and without a lathe the shafts will not be cheap to make which is why I did not mention them...
"The best choice for axial load is bronze thrust washers or bearings with thrust flanges."
I am not sure what you mean...google translate makes probelems here as well. Could you post a picture of an example or even of the complete setup on how you would construct the blade shaft bearing section?
Max
edit.
I think you mean this with the angular contact ball bearings...?:
http://www.ebay.de/itm/1x-Schragkugellager-3001-2RS-12x28x12-mm-NEU-/140898605990?pt=Wälz_Kugel_Rollenlager&hash=item20ce361ba6#ht_1776wt_732 (http://www.ebay.de/itm/1x-Schragkugellager-3001-2RS-12x28x12-mm-NEU-/140898605990?pt=Wälz_Kugel_Rollenlager&hash=item20ce361ba6#ht_1776wt_732)
If so, I think I could get replacements for my hubs or choose a different make. Some trailer hubs have those inside them but usually those are the ones that are rated for 250 or 750 Kg axles...so I am not sure if they could hold up with a blade length of 3m.
I cannot quite remember the numbers exactly but I once calculated for a given set of laminated blades that the centrifugal force of a 6m prop was something like more than 500 KG of axial force on higher rpm for something like 50 mph and I like having some room for safety...
I am not sure if such a trailler hub can handle that...
-
A constant speed propeller hub cutaway - Hamilton aircraft propeller:
[attach=1]
This is a hydraulic hub, operated by engine oil pressure that comes from the prop governor on the engine case and is fed to the pitch control piston thru a port in the end of the crankshaft. While not shown in the cutaway, the root bearings are bronze (sleeve) bushings. The oil seals are standard lip type. The thrust bearings are angular contact ball.
Tapered roller bearings have been proven to fail in aircraft propeller hubs, although many companies have tried them.
--
Chris
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chris, did u see the "edit" part in my last post?
Max
-
Max.
Chris gave already a clear explaination , a combination of a thrust bearing and bronze sleeve bushing.
You can find all the thrust and radial loads in the bearing catalogues like SKF, Nachi, etc.
As you know the weight of your blade and max. Rpm. You can calculate the centrifugal force.
I have angular contact and deepgroove bearings in my flying windmill, it is a light weight 3 meter diam. prop. Running perfect.
Keep going good luck.
Rgds - Frans -
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I have angular contact and deepgroove bearings in my flying windmill, it is a light weight 3 meter diam. prop.
The bearing shown in your top picture there, Frans, is a called a deep groove angular contact ball bearing. They are rated for 100% axial loading and radial loading. They come in single row (show in the photo) and dual row, as well as self-aligning type (covered by Sven Wingqvist's 1907 Swedish patent). They are the absolute best choice for a blade hub where both axial and radial loading is applied to the bearing assembly. That type of bearing is just about the only type used anymore in front-wheel-drive cars for the cartridge type wheel bearings.
The only way to make it stronger and more durable yet would be to use the bronze sleeve bushings and angular contact ball thrust bearings shown in my photo of the Hamilton aircraft prop hub.
--
Chris
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Since this thread has drifted from Frans' question about pitch settings to the ball bearings, how about I make it worse and link up this this (similar) thread:
http://www.greenpowertalk.org/showthread.php?t=15544
...
Anyway, back to your pitch control Frans, it sounds like the 6-degree increment of pitch is enough to trigger the moment of oscillation, as I understand it now.
That represents a change in lift-coefficient by +/-0.5 or in other words about +/-30% torque if the blades are already at or near stalling.
I thought your mechanism moved the blade pitch in a progressive way, not in steps. Perhaps I didn't understand your reply yesterday, so I'll look through your old postings about the turbine to get this straight.
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Well that didn't take long to find :)
You described the pitch controller to me in your earliest posts. It's just my memory at fault.
At that time the pitch would change in 2-degree increments. Have you changed this?
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I have several things I can adjust.
Switch trigger at max. and low rpm. (350 - 250 )
Actuator speed.by variable voltage supply.
Active time of acuator ( 1/10th sec - 60 sec ) set by software Arduino controller.
I call 1sec.time one step maybe a wrong expression.That is an progressive increment pitch of 6 degrees for now.
Depends on the active actuator time I have an angle set.
Combination of time and speed
At 12 degr.pitch ,Stall begins ,
Still have 60% of power.
Blade tip angle almost zero degrees in normal working condition.
Rgds -Frans -
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Images : Variable blades small windturbines
https://www.google.nl/search?q=variable+blade&hl=en&tbo=u&qscrl=1&rlz=1T4MERD_enNL505NL505&tbm=isch&source=univ&sa=X&ei=wdACUa7QCYSi0QWVlYDYBA&sqi=2&ved=0CGIQsAQ&biw=1024&bih=498#hl=en&tbo=d&qscrl=1&rlz=1T4MERD_enNL505NL505&tbm=isch&sa=1&q=variable+blade+smallwindturbine&oq=variable+blade+smallwindturbine&gs_l=img.12...160662.172396.0.176824.17.17.0.0.0.0.134.1252.16j1.17.0...0.0...1c.1.x6mZeZCxdyE&bav=on.2,or.r_gc.r_pw.r_qf.&bvm=bv.41524429,d.d2k&fp=215b751541b43c69&biw=1024&bih=498&imgrc=h8jZBObHUNfp3M%3A%3BtQznG0favleqmM%3Bhttp%253A%252F%252Fwww.inforse.org%252Feurope%252Fdieret%252FWind%252Fwair.jpg%3Bhttp%253A%252F%252Fwww.inforse.org%252Feurope%252Fdieret%252FWind%252Fwind.html%3B578%3B397
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Hey Frans,
In the park nearby we can see that in the past days big pieces of ice have been thrown off te wings.
How is the situation at your site?
Regards Rinus
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Windgenerator in high wind 12 - 15 m/sec.
Automatic feather and unfeather .
Max. Rpm. 350
Arduino controller .
Rgds. - Frans -
http://www.youtube.com/watch?v=F9AN1TdJz1A
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@midwoud,
Nice engineering,
Maybe in this way in Holland more interest in building small windturbines arises.
Regards Rinus
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Blade pitch mechanism.
Lineair actuator (adjustable stroke )
Manual switch forward / reverse
- Frans -
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Yearly check up windturbine 11-04-2013.
Mechanical and electrical.
All looking good.
A little paint on the blades.
Teflon spray oil on the gear.
Minor adjustment gear-wheels.
- Frans -
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Lineair actuator 3 test. Variable blade pitch.
It has a cordless drillmotor 12 VDC with a planetary gear ,two stage 36 : 1
Gear has hi-grade plastic satellite wheels (China ??) all the low voltage drills have it.
Output shaft 550 Rpm ,threaded rod M8 increment 1,25 mm p. turn
Stroke 100 mm / 10 sec. with adjustable end switches.
Cheap and strong system.
- Frans -
http://www.youtube.com/watch?v=rckwnQrHtOs
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midwoud,
do you think it's possible to make things more compact?
rgds Rinus
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Rinus.
It is a test setup , total lenght is 480 mm
Can be made compact to 330 mm with 1/2 inch timingbelt.
Rgds - Frans -
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Yaw drive.
Test set-up.
Cordless drill-motor , wormgear 100 : 1 ,Chain sprocket 3,5 : 1 .
360 degr. in 60 seconds. Windvane micro switch activate.
- Frans -
http://www.youtube.com/watch?v=ga6yLKOq608
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i admire the way you re purpose and re task commonly available mechanisms for your your enhancements
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just replacing the tail by a servo-actuating mechanism.
nice development.
rgds Rinus
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Cordless drill for other use. -Frans-
http://www.youtube.com/watch?v=sIdtLK6fldw&feature=player_embedded#!
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Windturbine Cam Blade-pitch.
200 Rpm , 6 Amp , 24 Vdc , 4 m/sec.
- Frans -
http://www.youtube.com/watch?v=69HZD4rG__U
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Fantastic, Frans,
Thank you for doing so much work to make such a fun video.
And such a clear demonstration of your effective system.
That must be your house, showing off those PV panels!
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Sparweb thanks. I made the video with a very cheap carcam € 29 incl.shipping.
Had to have special weather conditions : not to much wind ( noisy microphone )
Not to much sun ( over exposure )
The advantage of a carcam , it starts as soon as you put 12 volt on it.
SD card memory 16 Mb 8 hours.
Tower lower and raise 30 minutes.
The house with the solar panels is my neighbors (grid tied)
More will follow.
- Frans -
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...More will follow.
- Frans -
And looking forward to it!
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frans,
Very cool! I like the camera angle on this one. it's like riding the thing (without the risk). Thanks for sharing.
~kitestrings
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Hi Frans,
Great Work,
For my project I bought one of those:
http://www.voelkner.de/products/267950/Transmotec-DC-Linear-Motor-DLA-DLA-12-10-A-100-POT-IP65-16012112CR-12-V-DC-Hub-Laenge-100-mm-Schuble.html?WT.mc_id=googlebase&utm_source=google&utm_medium=base&utm_campaign=Q09809&gclid=COqLsvOGl7gCFTHJtAodBAIArw&WT.mc_id=googlebase
I make very slow progress as I have other priorities at the moment but it slowly gets where I want it ;-)
By the way, on tuesday I start a pedal bike tour from my place near Bremen to Amsterdam, if your place is not far off my route I would really like to meet you and see your turbine working. Would be nice if you send me your address ( probabaly better in the german discussion board...)
Max
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Max
Trying Not to Hijack this thread too much.
However, knowing the country side of both areas, (I was stationed in Hanau for about 3 years) how are you ever going to make it with all that beautiful scenery to stop and enjoy?
Happy Trails!
Bruce
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I planned our route along the islands, Texel, Vlieland etc...there are really nice spots over here and over there, We will do our best to see as much as we can, including wind turbines of course ;-)
Max
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Max (Menelaos) was here by bike with his girlfriend and dog.
They made a trip of 340 km.
We had a nice conversation .
Almost no wind but still spinning blades.
Thanks for visiting us.
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It was a nice trip, 700 km all together. That girl by the way is my best friend, not my girlfriend. We left our partners home... ;-)
Thanks Frans for the nice hours. It really is a nice pitch system you created. But of course, whenever there is somebody comming by to see the turbine there is no wind, it probably came back directly after we were leaving your place :-D
Max
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Hy guys,
Joust thinking. Would be possible to make pitch drive with electromagnet. The larger the current the stronger the force of an electromagnet.
-
Linear solenoids are notoriously inefficient. With any conventional type of electromagnet you will run into trouble with the inverse square law ( or something near). I doubt that you will build a stable mechanism.
Flux
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Thank Flux. In my head was too easy (good) to be effective (true). Also a friend - electrician advised me that a system with solenoid will not work.
I'll go back to the drawing board:)
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Lineair solenoïds are used to stop diesel engines .
Lineair actuators ,car window motors and cordless drill are better (with endstops).
I have good results with a speed of 8 - 10 mm per second.
Publication of the mechanical system is soon on the forum.
Looking forward to your new design.
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I have some experiences with linear motors, these had a close stop point, and a adjustable open stop point. The biasing element was a spring. The spike from the extended stop would generate one hell of a back voltage spike. I solved the problem with mosfet and a ziener diode.
One thing that peculiar is that, after the first use the reluctor becomes polarized , so if the reverse the feed dc input was used the back emf became uncontrollable. The steel I used for the parts of the actuator were not magnetized until the actuation. At that point you could never reverse power input polarity or it would fry the solid-state array.
Why not use a worm gear linier actuator, im sure that's not needed for high speed use, for what your doing.
JW
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Drawing of the mechanical control system, not on scale.
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Here is another idea for activ/passiv pitch sistem.
a - pitch rod
b - main shaft bearing
c - main shaft
d - spiral spring
e - fan rotor
f - external pitch brake
g - generator
At low RPM, the fan rotor (e) with nut, there would be no great resistance. When the rotor RPM increases, resistance of the fan becomes larger, causing retardation behind main shaft, pitch rod then move. When RPM is reduced, spiral spring (d) returns the fan rotor to its original position. Any coments?[/img]
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acme12
It took a wile to understand the design.
You are using the vector difference of the bladehub and the mainshaft.
Problem is the long track you need with twisted springs back and forward ,to get movement and stroke of the pitchrod.
I am a fan of a control with a few components ,I have good results with the airplane-like control.
Looks complex but working okay.
Keep going on ,on the drawingboard .
Rgds. Frans
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Tip of the day ;D; passiv pitch sistem. This one should work.
a - pitch rod
b - main shaft bearing
c - main shaft
d - chain gear
e - chain
f - spring
g - generator
h - rail
i - wagon+weight
j - chain
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Nope, not yet, they all have to be connected together you can't any of the blades at different pitches.
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Good morning fabricator.
All wagons on rails are conected via chain to pitch rod. Rotor blades are ment to be on the left side, not seen in sketch.
Now I need to go to sleep. It's pretty dark here.
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A very good design for passive pitch control is JACOBS .
If I make a passive pitch I think on this :
http://www.youtube.com/watch?v=B7gndP6mgTU
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Yep, tried and true for around 100 years, they are not shown there but there are large springs that hold the blades in and as the rpms increase the centrifugal force overcomes the springs and increases the pitch of the blades.
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Right. Large springs and sweep . Atleast 6 meters.
acme12 can make it on a smaller scale 3 meters.
Reliable and not to much parts.
This basic system can be made for active control too ,if you know the way.
- Frans -
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Drawing metric mils . Active Pitchcontrol mechanism.
- Frans -
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Windmillfriends
Am I right Pitch Control in small windturbines is booming?
Greetings Do
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Do,
That's quite logical. See the professionals.
And how many years it took them before they were convinced.
Regards Rinus
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Rinus.
I dont think its booming soon.
The drawings can be a support for technicians who intend to make one.
Its designed for a 3 meter dia prop and a 9 coil and 2x 12 magnet PMG.
Most of the parts can be made with hand-tools. Mainshaft .. machine shop.
Working good here for 2 years.
Should be nice to interchange experience mechanical and electronics.
Rgds. Frans.
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Frans,
I've enjoyed following this thread pretty much from the beginning, and I'd echoe electrodaddy's comment a page back; you're creative and persistent in your approach(es). Nice to see folks looking at different ideas. Regarding centrifugal/mechanically hubs, I wonder if you ever seen a Dunlite/Quirks machine. I always thought they had a nice hub design, though the machine itself had some other short-comings (blades, tail support, earlier models had inaccessible diodes up on the tower).
I also wondered if you have considered or tried an actuator that operated the furling mechanism on a folding tail design. It is an idea that I've toyed with.
regards, ~kitestrings
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Kitestrings thanks.
I didnt know much about Dunlite/Quirks ,it was an Australian windturbine with passive pitch in the 70's. There is a very good topic on The Backshed , where they recondition them. 5 pages.
There is told about the short-comings too.
http://www.thebackshed.com/forum/forum_posts.asp?TID=2378&PN=0&TPN=1
[attach=1]
I had a folding actuator tail on a previous windturbine design 3 years ago.
http://www.youtube.com/watch?v=wwHYQd3iadA
But the blade pitch works more instant with a micro-controller.
Regards -Frans -
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The Dunlites brings back memories. They were god-awful heavy I remember that part.
And, I do remember seeing your post on the folding actuator tail now. Was it hard-wired to the controls? or remote? I'd be interested in any details that you recall. I was actually not thinking of it for governing, but just to allow the machine to be shut down, as an alternative to mechanical means (or without braking electrically via shorting). Many designs, like the Dunlite, Sencenbaugh had a manual furling cable, but they are a pain to deal with and not have influence the normal furling mechanics.
~ks
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Actuator fold tail.
Hard-wired to the switchpanel. (2 wires). A Rpm counter triggered a relay for 3 seconds at max. 340 rpm propeller speed. Repeat with extra wind.
Manual switch to start and stop.
The actuator is a LINAK LA 12
- Frans -
-
Thanks Frans,
It's helpful to see how it is set up.
What I don't like about this is that it is always tied to the tail, and likely is too slow in fluctuating winds. The beauty of folding tail, IMO, is that it is simple and doesn't rely on electronics, or in this case the motor actuator to work.
What I was was considering, however, was an actuator where say the cylinder simply pushes on the tailboom, but when retracted does not interfere with the normal gravity/thrust balance act that is going on with a furling design. If it could be wireless, which I think it can, I'd like it even better.
Best,
~kS
-
Oh, and thanks for allowing me to diverge slightly from your main topic.
-
Okay welcome.
Its late here , zzzz . Tomorrow a sketch on the drawing board.
-Frans -
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Tailfold actuator and gravity furling.
Push-Pull quarter segment.
Pulled in , the tail has free movement.
Wireless operation like garage-door opener.
Probably a car window opener can be usefully.
Rgds - Frans -
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Frans,
Yes, that's closer to what I was thinking. Oh course the devil is in the details. This would take lots of force without getting out further from the hinge-point, and it is not a linear path (as shown). Perhaps hydraulic over electric. The cylinder retracts under pressure, but stays clear of the mechanism otherwise.
I was initially thinking something simpler still... If there was a ratchet/pawl that could be engaged remotely, you could just let the wind furl it (at some point, perhaps not exactly when you'd like), but not allow it to open until after the inspection, repair, maintenance. This mechanism would take very little force to engage it.
What I do like about all of these strategies - i.e. furling tail, pitching blades, motorized yaw - is that they are generally passive, controlled. Comparatively, the brake-shorting method puts a pretty abrupt hit on things. And, if the alternator is in trouble to begin with...well, a run-away is a frightening thing.
~ks
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Kitestrings,
Ratchet and pawl like a handbrake in our cars. But how to lock and unlock...solenoid(s) ?
Because it is a complex handling.
On Backshed a goodlooking system (Deneema line ) of Phillm.
No actuators , relays , electronics on top.
http://www.thebackshed.com/windmill/blog.asp?blog=1
The builders of the old wooden windmills spend also long hours around the table to solv and improve their systems centuries ago , and it is still working . hi.
Regards - Frans -
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Nice looking build form the BackShed site.
The manual furling is pretty much what we've had with our Sencenbaugh. On ours it is a piece of amour-flex conduit that houses the cable. The problem with this design is two parts: 1) the weight of the cable - not insignificant on a ~100' tower - will affect the operation of the furling, and 2) the cable has to either slide very freely thru the cable guide or it will loop if there is enough slack. The latter should be easy, but think about an old brake cable on your truck. The effects of lubrication/dirt, ice, corrosion can be a factor.
I'd wondered if the ratchet could just be operated from a pull on the SO cord?
The builders of the old wooden windmills spend also long hours around the table to solv and improve their systems centuries ago , and it is still working
Yes, and the table's expanded now thru internet.
~ks
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Kitestrings.
Is it for your new windturbine 15' and 100' tower ?
With new design stator.
Rgds. - Frans -
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Yes. I probably should have taken this to a separate post. My apologies, but I thought the overall themes that you are exploring were relevant - namely having control of the thing from the ground in some fashion. ~ks
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KS.
Free furling tail and actuator parking system.
Rgds. F.
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Kitestrings,
We read about your nice new developments in the making of coils.
But we are wondering: why not thinking about active pitchcontrol?
Regards Rinus
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Frans,
It appears to be a rod sliding in a tube at the end of the piston's rod...
Very interesting idea: the tail can be forced to furl when the rod extends, but when the rod is retracted, the tail can extend or furl depending on wind loads, so a gravity-furling design will function.
Thanks! I wonder if I can incorporate that into the unfinished WT chassis I have on my workbench.
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SparWeb.
Detail of the actuator with flatbar slider. Free furling
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midwoud1,
Interesting possibilities. If an actuator is employed I'm still wondering if it would be better to have it simply push the tail off the lower stop - possibly mounted to, or near, the stop with the piston pushing thru the mount to the tail-boom. When retracted it has no contact, or effect on furling.
A window or skylight type of chain drive operator is another thought, but to get enough force, length and durability in an exterior location all complicate a seemingly simple scheme.
In any event thanks for your input, drawings and ideas.
mbouwer,
But we are wondering: why not thinking about active pitchcontrol?
I admire the work you and Frans have put together on this strategy, but honestly I'm not sure as it is the most reliable or fail-safe of all options. Or perhaps said another way, it both solves and at the same time creates challenges to be considered.
Many of the earlier units (like the Dunlite) that we worked on had blade failure or worse problems over time. Admittedly that may have biased my thinking.
On my own unit I also had a fixed piece hub plate available, and overall good long-term experience with 'tail-waggers'. I've departed from the norm quite a bit on the alternator design. I fear if I change too many features at once I won't know what to fix (or point to when it fails).
Best, ~kitestrings
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Windmillfriends,
Around us we see all the professional turbines equipped with electric driven yaw and pitch control.
That's why we think more and more selfbuilders want it in their creations.
On Ecologieforum http://www.ecologieforum.eu/viewtopic.php?f=23&t=2566&start=240 ::) we show our progress.
We think it's important to exchange designs and expieriences.
Regards Rinus
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Should be nice to make a replica of a professional windturbine
I have a pitchcontrolled windmill ,that gives every day energy, led lamps ,Coffee pot, Laptop, TV , fridge . The best people who understand it is on the forum.
Not yet a copy example,pitch and yaw control,maybe later. I'm sure there are mechanical technicians who can make it.
But the combination knowledge of , metal , woodcarving, electric ,electronics , software, polyester working ,rigging makes it a bit complex.
Never the less I see inovative ideas and projects on the forum. Very interesting.
And a place with a good average windspeed ,and permission for a tower.
- Frans -
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On Ecologieforum
Rinus,
Thanks for sharing. I love the tail vane on the photo at sunset (France). Is there someway to translate?
I agree with Frans it is a wide mix of disciplines, talents and experiences that keep this interesting.
~ks
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Kitestrings,
Maybe you could use http://www.vertalen.nu/zinnen/ to translate.
Regards Rinus
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Google translater .Some words are not correct , but good to read.
Tekst block translate by copy and paste . Like Rinus his proposal.
-Frans -
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dank je vrienden
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Windmillfriends,
On the basis of Frans' design:
let's concentrate on improving hardware and software of the active pitch control.
Regards Rinus
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Electronic circuit for Active Pitchcontrol
High voltage input connected to one phase of the generator.
Polarity switch connected to the lineair actuator.
Propeller Rpm trigger , angle step time of feather and unfeather , Time between steps , can be adjusted by C - programmed software
- Frans -
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Frans,
Perhaps people with electronic expertise like to react.
But your scheme is hard to read.
regards Rinus
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Rinus right.
It is composition of several images and it ended up at 302 Kb . To much so I minmized it .
I'll upload it in readable format.
- Frans -
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Schematic circuit pitchcontrol actuator, detailled[attach=1][attach=2][attach=3][attach=4][attach=5]
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Frans,
Again a nice step in the development of small DIY mills.
Regards Rinus
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Rinus.
Can be an idea to make it in kit form.
- Frans -
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Frans,
Is it possible to approximate give us an idea what all components in your scheme together cost?
Rinus
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Electronic components , Trafo, Tacho chip , Arduino controller , Relays, Polarity switch, Resistors , Caps,
Estimate Euro 50. Know how to use the solder-iron. It's a perfect circuit for blade-pitch.
- Frans -
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Frans,
We are now making a test setup so we can apply your electronic cicuit for Active Pitchcontrol.
(http://)
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Test setup : Automatic Active blade pitchcontrol.
Constant speed system.
The electronic circuit is connected parallel with my consisting windgenerator.
The actuator is pulling back in decreasing windspeed.
In high wind above 330 propeller Rpm it's going the other way.
Controlled by an Aruino MC. And software programma.
- Frans -
http://www.youtube.com/watch?v=xGMj90mXcwI
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Frans, you should seriously think about putting all that in one package and selling them or licensing somebody to build and sell them, maybe a complete package with the hub and blade grips and the whole ball of wax.
I'd but one to play with for someone like me that does not have a background in electronics it might as well all be in Latin. ;)
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Hi Fabricator. If there is a demand for it I can make it.I have the gear with UV light and acid bath.This circuit is made on Veroboard and that's not proffesional.Spaghetti wiring on the backside. Should make an etched PCB. Saves a lot of time. This circuit is for mbouwer. He is making his own mechanical design based on the 3 meter prop diam Piggott.
Menelaos is also making one. For the time now it is experimental .
We wish you and all Fieldliners a Happy New Year.
- Frans -
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Cool, it will be good to have several working models to get all the bugs worked out. Happy New Years to all you fieldliners across the pond too. :D
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Fabricator, you are right.
We're working on it.
(http://)
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Good luck and happy new year.
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Control board functions
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Wincharger modified blade pitch DIY
With implementation of the Rural Electrification Act in 1936, however, the wind-powered battery charger's days were numbered. Even the most remote farms had access to electricity by the mid-1950s, ending the need for the wind generator and a free energy source. Many utility companies refused to provide power to farms with working wind generators, and more than a few Winchargers were deliberately disabled by high-powered rifles.
- F -
Read more: http://www.farmcollector.com/equipment/charged-by-the-wind.aspx#ixzz2zMcxQZ3O
https://www.google.nl/search?q=wincharger&hl=en&qscrl=1&rlz=1T4MERD_enNL505NL505&tbm=isch&tbo=u&source=univ&sa=X&ei=KUZSU5HPLY6sOvzWgUA&sqi=2&ved=0CCgQsAQ&biw=1041&bih=489#facrc=_&imgdii=_&imgrc=1EXxr4ri1Uh7QM%253A%3Bxx6_jTySe9I-0M%3Bhttp%253A%252F%252Fwww.antiqueradio.com%252Fimages%252FMar02-Russell-Wind-Fig3.jpg%3Bhttp%253A%252F%252Fwww.antiqueradio.com%252FMar02_Russell_Windradio.html%3B400%3B530
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I got a 6V Wincharger Airline Deluxe but it needs a new blade. Every farm back in the 1920's - 1930's had one of these too:
(https://www.fieldlines.com/proxy.php?request=http%3A%2F%2Fwww.eldensengines.com%2FDelco%2FDelco%2520003.jpg&hash=cbf3810e682c682cb45d10b5b1ae059bd6603d5c)
That one is a 32V Delco Light Plant. But they also made them in 6V. There was all sorts of 32VDC appliances back then, including light bulbs, clothes washing machines, sewing machines, clothes irons, and even shop tools like drills and saws.
The REA was basically a government subsidy for electric companies to build distribution lines to rural areas.
My dad was 16 years old when they came to my grandpa's farm to run the powerlines there. My grandpa had bought the Wincharger in 1931 when my dad was 10, and he refused the new electric service. That Wincharger ran on our home farm until 1968 when the blade broke on it. I have the Wincharger and the Zenith tube radio that came with it, and the radio still works. My grandpa paid $10 for it.
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Wondering for what price you can buy a remanufactured Wincharger nowadays.
Rinus
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Thinking of a real good design:
The new 20 pole, 15 coil CAD with active pitch control.
Greetings Do
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looks expensive ;D
http://www.northeastwindenergy.com/Tipod_Frame_Turbine.html
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Active pitchcontrolled blades
https://www.youtube.com/watch?v=fI5-DxQx7x8&feature=youtu.be
Works like the big windmills . Reliable 3 years now.
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This is a fantastic design, the options for control are endless with the right circuitry.
Kudos.
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Can we say active pitchcontrol is booming?
(http://)
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A lot of progress in the development of active pitchcontrol.
Variable pitch propellers and micro-controllers.
You can create an invasion with a 1000 drone squadron.
The technical application we use to control our windmills is simple.
Can be booming.
https://www.youtube.com/watch?v=NRL_1ozDQCA&feature=youtu.be
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We would like to find out if implementing the drone pitchcontrol on our windmills is possible.
Regards Rinus
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There are RC servos that can do the job.
Torque : 12,8 kg / cm 6volt . metal gear and ballbearings, compact dims.
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Hi All.
I am living in Northwest Holland . Average wind 5-5.5 m/sec . Building windgenerators several years .
Have some experience with making blades ( fixed- and passive pitch and active pitchcontrol )
I see that some of you ( Menelaos ) and other friends on Fieldlines are thinking about pitchcontrolled blades .
For the time of 3 months I have running a DIY active pitch controlled windgenerator.
Must say I am very content about it .
It is controlled by an actuator wich can be switched automatic and manual.
Blade angle from zero to 90 degrees in 8 seconds.
Propeller diam. 290 cm .
Controllable max speed 330 rpm . (adjustable)
Feathering and electrical brake in case of storm.
Generator disc type ( Hugh Piggott design ) 9 coils and 2x 12 neo magnets. 24 volt.
I see some advantages : Never overspeed , No overheat stator, No dumpload , No overload of batteries , controllable voltage and amps for inverters for batteries and grid tied ones. No material stress. With extra sensors No voltage controller.
http://www.youtube.com/user/midwoud1?gl=NL&hl=nl#p/a/u/1/csr2BLBQ6rc (http://www.youtube.com/user/midwoud1?gl=NL&hl=nl#p/a/u/1/csr2BLBQ6rc)
and other uploads Midwoud1 on YouTube
Regards Frans.
(Attachment Link)
(Attachment Link)
Wow! this truly is a labor of love. Midwoud1, what can you not do? and to the people pitching in, you guys are awesome. Thank you for sharing this thread. This is an inspiration to me. Will be looking forward to following this thread.
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and we are sure the best is yet to come
Lancewlksn343,
What are your plans to go build?
Regards Rinus
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Hi Lance.
Welcome to the forum.
Please some info about what you intend to do .
Battery charging or grid tie ?
Start with a basic design , or active bladepitch ?
Regards Frans ( midwoud1 )
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Merry Christmas to all people on the forum.
Frans & Teresa
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Happy Holidays Frans & family. ~ks
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Windmillfriends,
Trying to make an elektically driven yaw bearing.
Regards Rinus
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Just found a discarded bearing of which we can use the balls
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We want to use a simple worm gear drive.
Here is the welded wormweel.
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Rinus,
Is the goal to optimize tracking of the wind, or to provide a means of turning the turbine out of the wind for regulation? And, if the latter, are you thinking this would be in lieu of variable pitch blades, or in addition to it? ~ks
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Kitestrings,
We are searching for a simple implementation of a low weight, steered yaw bearing.
And we always want to be able to master the turbine so we think we need pitch control.
Regards Rinus
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After this ballbearing we would also like to make a slide bearing implementation.
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We have made the base ring for the slide yawbearing. Worm wheel is part of the construction now.
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The slide ring we again made in lattice to reduce the weight and have a good stiffness.
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The slide yaw bearing completed with locking ring.
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A new setup.
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The corresponding pivot.
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On the mast it looks like this.
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Rinus,
That is some impressive heavy metal.
I am looking forward to the result.
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Windvane yaw control.
Reed contacts , Polarity forward - Reverse relay , Windshield wiper motor.
Rgds Fbm.
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Very cool. What is a the size of this? It's hard to tell from the pictures. Regards, ~ks
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The diameter of the top of the mast is about 100 mm ( 4 inches )
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Almost all the professionals use it.
Diy turbines with active pitchcontrol are hard to find.
How come?
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Hi: I have a few questions. I must say this is a very clever idea. Thank you for sharing.
1. Why do you limit the rpm from 180 to 350? I was thinking Scoraig Wind (Hugh) in one of his textbooks said that the maximum rpm for an axial is 3 times the cut in rpm. So that could be give or take 600 rpm. It could make a lot more power but maybe not as reliable.
2. I've only read about six pages of the thread so maybe someone has mentioned this but does the Sun Gear need to have a tooth count diviisonable by 3?
My understanding ( only a personal opinion) is that the the reason side facing is used on the axial flux is because they need speed. The machine you have probably only has 12lbs of copper whereas the Jacobs had maybe 30lbs so it could turn at a maximum of 300rpm and make full power. Thank you. Arch. Ps. I couldn't do the electronics (progaming) anyway but I might try the rpm counting
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Smitson,
The electronics for the steering of Midwouds turbine is also on this topic.
And real good functioning for years now.
Greetings Rinus
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Hi Arch.
Between 180 - 350 Rpm it's running safe. No high centrifugal forces. 600 Rpm is dangerous.
The amount of sunwheel teeth here is 37 to keep the hub compact. Disc diam. is 280 mm.
More or less teeth gives the same result to move the blades synchronous.
The generator here has 5 kg copper 9 coils and 2x 12 magnets to make 800 watt ( Hugh Piggott 3 meter windmill )
With a microcontroller you can switch easy to change the behavior with software, of rpm and charge power.
But it is not a must . The Rpm counter has a variable voltage output ,use that as a switch command trigger between the desired Rpms.
Tension level active.
The actuator makes steps of 0,5 seconds.
Rgds. Frans.
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To all Fieldliners Merry Christmas and a happy NewYear
Frans.
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Merry Christmas Frans. ~ks
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Frans,
We heard that some guys want to go further on the basis of your prototype.
That's good news.
Regards Rinus
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Blade suspension for the new mock up.
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Blade suspencion completed.
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In 2011 this Midwoud topic began and sometimes there were enthusiastic reactions.
I wonder if other windmill builders have gone further with this concept of active pitch.
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There was some criticism on the actuator control system.
Imagine if something fails in wiring or powersupply , Does the blade-angle follow a sudden windgust ?
It all worked perfect as a prototype.
I think its time for a bigger windmill.
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Exchange of ideas could improve the design.
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Now I am trying to make a radial direct-drive generator. Starting with this package
with outside diameter 364 mm
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14 inch rotor..neos or ceramic mags ? looks like a good start..made one useing a exersize bike flywheel..glued down some cheap ceramic mags to that--made a stator from a couple pieces of plywood-with a metal curved flatbar for the coils--metal insert in each coil hole...20-15 3phase 55winds two in hand #17 wire..maxed out close to 400 watts with currant gearing...
whats your layout ?
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In my report KD 437 of 2010 I describe a pitch control system for the 2-bladed rotor of VIRYA-15 wind turbine. I have made certain choises resulting in a design for which the mechanism is shown in figure 7 of KD 437. Other starting conditions will result in a different design. In chapter 6 of KD 437 I give some arguments for certain choises and these arguments may be of help if someone wants to design his own system. KD 437 can be copied for free from my website: www.kdwindturbines.nl at the menu KD-reports.
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To start I would like to make a small low-speed synchronius generator with separate exitation.
The laminations are now modified and have 96 poles.
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Why did you cut off the outer edge of the ring??? :(
The available flux path is now cut by 1/4.
You will increase saturation, and self-heating, and have less steel to absorb the heat through.
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The intention is to make a small scale Enercon generator. (http://www.enercon.de)
Later on I want to grind the lamination core to the inner diameter of 295 mm
Now I have made a fixed axle pin.
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I don't see how cutting down the teeth ID will help. You have choked the MMF to 1/3 or 1/4 of its original capability, by increasing the magnetic path resistance.
The power curve will flatten out very early. The medium range power will suffer from low efficiency and the high end will run hot.
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So your going for field coils on the rotor not mags ? Once it's started should power it self like a car alt.
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I have had contact on a Dutch forum with Mr. Brouwer about his generator. The original stator stamping has 48 grooves and is ment for an 8-pole asynchronous motor. Mr. Brouwer has not reduced the outer diameter but removed the original 48 grooves completely and replaced them by 96 much smaller grooves. So he has increased the inner diameter. He will make a 32-pole armature with 32 separate electro magnets. For a 32-pole armature, the pole pitch is 11.25 degrees. For an optimal coil, there are three stator spokes within each coil. Half of the magnetic flux flowing through these three spokes bends to the left and half bends to the right when the flux arrives at the bridges in between the bottom of a groove and the outside diameter. The width of a bridge must be at least a factor 1.5 times the width of a stator spoke to prevent that the steel at the bridge is saturated earlier than the steel at the spokes. In the photo it seems to me that the bridge is wide enough.
If the original stamping with 48 grooves would have been used for a 16-pole generator, it would be allowed to reduce the outer diameter such that the bridge has half the original width. Then you get the same strength of the magnetic flux in the bridge as for the original stamping and an 8-pole generator.
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Now after this mock-up,
how to make a better start trying to make a real nice small Enercon-like generator?
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Thank you for the explanation Adriaan! I did not realize that he had done that.
Yes I see now that there is adequate flux path when the pole count is increased to 32.
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On the Dutch Ecologieforum http://www.ecologieforum.eu/viewtopic.php?f=40&t=2566&start=1095
there are more photos.
Also many Enercon turbines around here.
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What kind of draw will all those field coil have ?
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Hiker,
I would like to ask people with expertise: please respond to this question.
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To find the knowledge for a design and to make a small direct-drive synchronius generator with separate exitation is going to take some time.
In the meantime I modificated a ceiling fan to a small generator.
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Small size. Fun to do.
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To all windmillfriends,
Merry Christmas and a lot of energy for the coming year
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AND a VERY MERRY Christmas to you as well.
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More details of this test setup on Ecoforum http://www.ecologieforum.eu/viewtopic.php?f=40&t=2566&start=1140
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https://www.youtube.com/watch?v=kSqNOVECurc just a vid of my radial bike alt...mag powered ..
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Nice device. I guess you used iron in your coils and can you tell something about that?
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just a on going hobby with me....its a 20-15 3 phase alt..coils two in hand #17 wire..hit 400 watts at 28v ..briefly ! Using a 400 watt aircraft landing light..coils are mounted to a iron band..with iron inserts in the coil holes...mags are ceramic .with small neos glued to the top of the neos as well..mounted a auto rad. Fan ..just for a load..works great for that..hits up to 8 or 9 amps at around 20v..plus it keeps you cool as well..coils are a bit over kill at two in hand...makes a good batt. Charger as well..chugs along at 5 amps 13v fairly easy...grandkids like to work out on it..makin Sparks fly..or breaking water down into gas..HHo...💥
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Mags are ceramic with neos glued to the top !
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The ceiling fan generator is back on the test stand.
If I drive it now with another motor. Does power come off it?
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Hi Rinus.
Do have power with motordrive on your celingfan generator?
On Youtube there are several ceilingfans converted to generators.
Rgds: Midwoud1,
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The ceilingfan motor is in its original state. I only have made a new axle in it.
I would like to find a way to use it as a generator. ( without neodymium )
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Cheap ceramic mags...output will be low...rewired one of mine...with some heavy wire..mounted next to a small gas engine..hit 15-20 amps output...if your going with small stuff..just use a car or truck alt...you can play around with the field coil power input to get the power output you want...treadmill motors are another way....motor conversions ........lot of options......
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The point of going with permanent magnets is that the excitation field costs you a lump sum at initial construction. With a wound field the excitation costs you an ongoing drain on your produced (or stored) energy. This is worst when the incoming wind is low, and not just in proportion: The slower you're spinning, the more excitation power you need to get a given output voltage.
In addition to eating much of your production (and the most when you need it the most because wind is low), wound-field excitation has the effect of raising your cutin wind speed (by eating all of your output at otherwise usable low speeds) and thus drastically reducing the fraction of the year your mill actually generates anything useful. While wound-field generators are usable, they need a larger turbine and oversized generator, compared to a permanent magnet alternator, to deliver something useful.
Ferrite is pretty wimpy, as are most other non-rare-earth magnets, so you don't get much out of your converted fan motor's stator's already low power flux guides and windings. Neodymium magnets were the breakthrough that took us to really practical home-brew microgeneration mills. In a motor conversion they are strong enough to saturate the transformer iron laminates, which gets as much power out of the windings on them as it is possible to get.
If you don't want to buy some neos, see if you can find some scrapped computer disk drives and pull the neo magnets from their head actuators.
DON'T break them to fit: Neos are plated to protect them from corrosion and will rapidly rot away if the plating is compromised.
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It is possible to get a strong magnetic field in the air gap if ferrite magnets are used but only if the magnetic flux is concentrated. Concentration is only possible for radial positioning of the magnets. To prevent a strong fluctuation of the clogging torque, the magnet grooves have to be inclined with the correct angle with respect to the generator axis. One of my first PM-generators was made this way from a 12-pole car generator and it reached an open DC voltage of 12 V at a rotational speed of 900 rpm, so at about the same rotational speed as for the original generator with an electromagnetic armature for the maximum armature current. This PM-generator is described in chapter 3 of my free public report KD-341.
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This is the ceiling-fan motor with its original stator and rotor.
Only thing I did was to make a hollow ( pitch control) shaft with heavier ball bearings in it to attach the blades.
Now if you drive it above its nominal number of revolutions per minute:
Will there be a chance then that it starts functioning as a generator?
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mbouwer;
IF that ring that I'm seeing is in fact magnets, then YES you will see voltage.
From shaky memory cells, you will actually begin to see a voltage when you begin to spin it.
The voltages will probably be high with a low current abilities.
Best would be to start spinning the motor with known speeds and a volt-meter to find beginning of voltages and highest out.
Once there, you can go further if you wish.
OF course; your current limits are going to be a function of the wire sizes.
Cheers;
Bruce S
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This is the ceiling-fan motor with its original stator and rotor.
Only thing I did was to make a hollow ( pitch control) shaft with heavier ball bearings in it to attach the blades.
Now if you drive it above its nominal number of revolutions per minute:
Will there be a chance then that it starts functioning as a generator?
It has a two-phase winding.
The ring looks like a "squirrel cage" - a conductive component dragged around by the magnetic field from the coil/laminate assembly and the magnetiztion from the eddy currents that field generates within it.
If you connect a capacator across ONE of the phases to make a resonant circuit (leaving it otherwise unconnected), leave the other unloaded at low voltages (for instance, by hooking it to a rectifier and battery, which won't pull appreciable current until the voltage gets to the battery voltage plus two diode drops), and the rotor has a bit of residual magnetiztion to get things started, when you spin it up to where it's going a tad faster than the RPM corresponding to the resonance, you should start pumping energy into the "ringing" of the tuned circuit - up to the point where the core is saturating. It will start "fighting back" to try to keep itself from spinning appreciably above that RPM.
At that point the magnetic lines that are "nearly pinned" by the eddy currents in the rotor will also be dragging through the other phase's winding, generating a voltage and transforming shaft HP into electrical energy you can harvest.
There are substantial downsides to this approach - among them that (like a wound field) you have copper losses, both in the resonant winding and the rotor, and that it only works at a narrow range of RPM. Nevertheless, it can give you nontrivial generation without further conversion of the rotating electrical machine to add either magnets or a field coil to the rotor.
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It is a FRAMEWAY AC~ CEILING FAN MODEL: FW 48 230 V~ 50 HZ 60 W 310 rpm
Can you tell me how to start to get those 60 Watts out of it?
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Made a few ceiling fan gens...toss the ring...super glue mags on the inner side of a case cover..use spacers if you have to ..to get a close air gap ...on your motor it looks like ..the mags would have to overhang a bit..sence your case is split down the middle of the motor ? Should still work..just glue down well...I like to use epoxy stick..to fill in the gap between the mags..drys rock hard..then just resemble the motor...tah dah....your done...just give a spin...and light up some l.e.d.s....yours is a high voltage motor...not sure what it would do...ide rewire for 12v use if that's what want...easy to do on these little motors....have fun...
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Ps..the amount of mags are determined by the number of coils you have..on the outer ends of the lams..looks like ..14-16.?.. That's the number of mags you need..glue the mags down..north south north south..all the way around..just hold a mag in your hand.. Put near a case mounted mag..it should pull your hand down..next case mounted mag should push your hand away..then next mag will of course pull your hand down...and around you go....simple...
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Now if you want to rewire for 3 phase....its a whole different story..
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My goal is: -- not to use neodymium ( or ceramic magnets )
-- participate in a team to design and make a real nice direct drive generator.
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Try a cap. Across the lead out wires..hit it with a few volts while its spinning..Should only take a secound..then disconnect power..if that worked..you should have power output on the lead out wires..check with a voltage meter...then try a small load....won't get much with that motor...if you get no power out....then you will have to make some small field coils for each output coil..not sure if that would work on such a low output motor.gen...of course you will have to hit it with a few volts to get things started..done this with car alts..once going the alt powers the field coil......
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I understand that this is a wrong way trying to make a generator. It wo'nt work.
Hiker,
You mentioned rewiring for 3 phase. Is that an option?
The outer ring is 14 coils. The inner ring 7 coils.
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Not so many wind turbine builders here in the Netherlands. But I always want to come in contact with them.
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I like the blades!
You do know that once you put up a 'mill there's normally 3 days of no wind ;).
Cheers;
Bruce
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The turbine is from the Danish Technical University
Cheers Rinus
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IF you don't mind me asking> Where are you located?
There used to be a good dozen of the home built units on the way to Amsterdam from Brussels.
Not every large tho, only around 2 meters tip to tip. 3-bladed units that were right along side the beautiful 4-bladed grinding mills. This was back in 2007 - 2009
Cheers
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...
You do know that once you put up a 'mill there's normally 3 days of no wind ;).
That's not just Murphy's law.
In the poleward part of the temperate zones the weather systems tend to come by roughly periodically, several days apart. It has to do with downwind propagation of waves in the boundary between the (ant)arctic and temperate zone regions. Three-ish calm days, or a bit more, is typical.
When you're installing a mill you wait for calm and dry weather, so you're not working in the rain or wrestling with big airfoils in strong or gusty winds.
So you put it up at the beginning of a calm period. Then, when you've got it up, and are waiting with bated breath for some wind to make it spin, you get to wait out the remaining days of the calm period before you get to see whether your new mill actually works. B-)
Or at least that's the case if you don't have something that gives you a daily "lake effect" cycle. (Like northern San Jose CA, where the "lake" is S.F. Bay and the "island" is the valleys to the south. Or Altamont Pass in CA, where the "lake" is the Pacific Ocean, the "island" is the Central Valley, and the pass is the notch in a wall of mountains between them. Or my ranch, where the "lake" is Tahoe and the ice caps on the Sierra Nevada mountains, the "island" is the desert portion of Nevada, and Monitor Pass forms the funnel throat.)
In lake effect situations a windmill is the power takeoff on a solar heat engine the size of an appreciable fraction of a continent. B-)
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Bruce,
It is in the South, not so far from the coast where I live.
And I would like to form a team with others who want to use windenergy.
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ULR;
During my short stay in the south eastern region of MI there was the lake effect of Lake MI too, the bad part, it was most noticeable during the winter (AND still is according to kin that still lives in that area).
mbouwer ;
You should have NO problems finding fellow 'mill DIYers . Once they see your mill I'm certain they will be stopping by.
Best of Luck
Bruce S
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On the photo above is a working model that we made in 1990 of the Stork Newecs 45
We had a club here then: the Gewiekste.
The mill and also the club do'nt exist anymore. Always seeking new windmillfriends.
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ULR;
During my short stay in the south eastern region of MI there was the lake effect of Lake MI too, the bad part, it was most noticeable during the winter (AND still is according to kin that still lives in that area).
Where were you there? (I was born in Grand Rapids and raised in Ann Arbor and Milan before eventually moving west.)
Ann Arbor and Milan were far enough from the great lakes that the daily cycle lake effect winds were absent, or at least not particularly noticeable compared to the prevailing and weather-system winds. (We left G.R. before I was old enough to remember much, but I understand they also have a related phenomenon of the same name there - where the humid wind off the lake onto the cold land dumps LOTS of snow and silverthaw ice in the winter onto the first tenish miles inland from the western coast. B-b )
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We also made this water turbine. With pitchable blades.
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Living in Northwest Holland . Average wind 5m/sec .40 Miles north of Amsterdam.
Classic waterpumping windmills fixed pitch .
Those mills were used to create new land from sea and lakes.
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ULR;
During my short stay in the south eastern region of MI there was the lake effect of Lake MI too, the bad part, it was most noticeable during the winter (AND still is according to kin that still lives in that area).
Where were you there? (I was born in Grand Rapids and raised in Ann Arbor and Milan before eventually moving west.)
Ann Arbor and Milan were far enough from the great lakes that the daily cycle lake effect winds were absent, or at least not particularly noticeable compared to the prevailing and weather-system winds. (We left G.R. before I was old enough to remember much, but I understand they also have a related phenomenon of the same name there - where the humid wind off the lake onto the cold land dumps LOTS of snow and silverthaw ice in the winter onto the first tenish miles inland from the western coast. B-b )
ULR, sorry for the late response. Work got in the way for several days ;-(.
There is a small town on the south east area of the lake "Baroda " The high school I went to name is LakeShore high. Great time. At the time they had no such thing as snow days, even while the snow was being measured in feet not inches. Everyone was expected to won a snowmobile or tractor. Moved up there for family reasons; worked a 7 acres of Welsh's grape farm in early 70s moved back to Missouri so I could graduate both high-school and Automotive school. The refuse collector hired me for winter work, he and I found enough cast-off stuff to build two stills. He was slightly amassed a teenage could "teach" him something.
I learned that I knew more about farming that I learned while still a kid, than I realized.
It's pretty cool to figure out, all the while we were playing out in the hay bales, milking cows, gutting chickens, turkeys and rabbits as kids; we were also learning.
Most people here in MO have no clue about driving in REAL snow. In 73 it was so #$@!% COLD! my coffee got stone cold before I could clean the snow off the windows.
Great Times ;-D
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Living in Northwest Holland . Average wind 5m/sec .40 Miles north of Amsterdam.
Classic waterpumping windmills fixed pitch .
Those mills were used to create new land from sea and lakes.
Last fall I spent a week in the Netherlands on business with GE Wind Turbine division. Great place for wind and enjoyed the history of how the windmills were used to perform many different mechanical work loads. My great grandparents are from the region, we're all very tall, 6 foot [1.83 meters] or more so I felt right at home with all of the "giant" people.
Can't wait to return, it's a great piece of the world.
CM
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CraigM,
Can you tell us something about GE Wind Turbine Division and their turbines?
Regards Rinus
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Rinus,
Sorry, not much I can share that isn't already out on the internet. Our company is contracted by GE to manage their inventory requirement for small fabrications, small electrical and fasteners. As a contractor we are required to sign non-disclosure and proprietary information documents. We are also not allowed to carry phones or camera devises inside their manufacturing facility.
What I can tell you, and further information is available on the internet, is their primary platform for on-shore wind is call the DFIG (Dual Fed Induction Generator) in 1.6MW to 2.85MW. The last PMG model was made around 2012 and I believe it was 3.2MW.
Hope this helped a little.
CM
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Thank you for your reply.
It must be very enjoyable to be dealing with modern wind technology.
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What is the problem for self builders to use this DFIG-system in a small generator?
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What is the problem for self builders to use this DFIG-system in a small generator?
Complicated electronics (amounting to a three-phase inverter / speed control - somewhat more complicated than an inverter and necessary for the machine to deliver power). It has to match the electrical machine, too.
The generator has three-phase windings on both the stator and on the rotor, the latter with a set of slip rings. It's more complicated to build - and far harder than a motor conversion to build right. And it's a specialized piece of equipment that you won't find lying about. Doing a motor conversion would get you a stator, but then you'd have to build the wound rotor (with silicon-steel laminated flux path) and slip ring assembly (which would require an expanded bell housing on one end. You MIGHT find such a device lying around. But they're orders of magnitude more rare than induction motors.
PMAs are drastically simpler. They're also far more forgiving on tolerances, making them ideal for home-brew.
= = = =
For a giant commercial mill they make a lot of sense. They match the line frequency despite the arbitrary RPM of the shaft. The electronics doing the frequency conversion does it for only one of the two sets of windings, so it's smaller than one to convert wild-frequency AC carrying ALL the energy of the mill to the line. It also does the excitation, so you don't need a second "field coil" controller. Power is pulled out on BOTH sets of windings, so the mill has a similar advantage over a wound-field generator to that of a PMA: You don't pay a lot of energy for excitation. Splitting the output between the two sets of windings means the currents in each are lower. Since the resistive losses go with the SQUARE of the current density the double-wound electrical machine is more efficient than a single-wound.
But there's enough equipment and engineering involved that it only makes sense in a wind farm full of big machines. For a small home-brew operation KISS is the word. (Or buy one designed by a big operation with a farm of engineers.)
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three problems:
Slip rings.
Low efficiency of small induction motors.
Difficulty and or expense of finding someone or the tooling to wind a doubly fed induction motor.
Secondly: you need a vfd to supply the difference in frequency to the rotating or stationary coils.
The energy needed to be supplied to the machine is proportional to the torque, multiplied by the difference in frequency.
So the usual industry standard is the vfd is about one third the capacity of the generator and that covers the usual range of 40-80hz operation into (or out of) a 60hz grid.
that's a 2:1 speed control, for which constant torque is available.
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ULR and Joestue thank you for your reply.
I see this as a search for a self build suitable radial direct drive generator.
Without the use of the controversial neodymium.
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mbouwer;
Have a search look at some of Chris O's stuff . He's built some very mills using ceramic magnets.
His posts should help you on you quest. You might also PM him, he's sure to answer. He doesn't post much while getting the farm ready for planting.
Cheers
Bruce S
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I see this as a search for a self build suitable radial direct drive generator.
Without the use of the controversial neodymium.
What's controversial about neo?
The toxics from mining it in China? Weaker magnets, more copper, and copper mining in the developing world isn't all that clean either. Copper is quite toxic (in amounts above the traces needed for good nutrition).
If you're concerned about that, consider using stacks of recycled magnets from older disk drives. Then the toxic side-effects have already occurred, and you're actually preventing a bit more from the recycling operation.
Is there some other issue?
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ULR,
I can see what you mean.
But I read so much about it and I would like to avoid it.
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will it be a dual rotor air core radial alternator mbouwer?
or will you involve iron?
it will be a challenge to cast and position a stator for a dual rotor air core alternator.
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mbouwer;
What speeds are you looking at ? I went back a few pages , but could not find the listing.
I am curious where you are with this so far
Cheers;
Bruce
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I see this forum as R&D.
As a hobby I want to become part of a team designing and building small windmills and exchange ideas and parts.
No matter if the team members live in my neighbourhood or worldwide.
Cheers Rinus
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The ideas on the forum to make your own gearbox inspire me, and I searched in my collection.
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understood.
You might try getting in touch with gnadt1990. His posts are about gaining insight to future RE stuff, but he's aslo located in Germany and might be able to assist with finding people with the same interests.
I like your website, it pushes my German/Dutch translation to it's limits ( That's a Good thing :-D) but google translate is also my friend.
There is also a thread : http://www.fieldlines.com/index.php/topic,149203.msg1040229/topicseen.html#msg1040229 you might want to follow.
gearing can be a double edge sworn , while you can gear up easily enough there could be startup problems.
Cheers
Bruce S
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... I read so much about it and I would like to avoid it.
What have you read that makes you want to avoid neos? I haven't read anything that makes ME want to avoid them.
Some of the stuff I've read makes me want to be careful with them (so I don't get "pinched by an elephant" or "hit by a flying tool" while assembling some powerful machine or otherwise handling the very strong magnets, shatter one and have flying particles, or disrupt their coating and have them rot away). But I have yet to see anything that makes me think I should avoid them.
Gennies built with weaker permanent magnets still have very strong forces involved and must still be handled carefully to avoid accidents.
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ULR,
I see what you mean.
On their website Enercon writes:
... excited annular generator, there is no need for the use of permanent magnets that are manufactured from highly controversial neodymium (rare earths).
How you interpret that?
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mbouwer
Personally I see that statement as an opinion; unless they quantify the "highly controversial " portion.
I can saw with all due respect, if you assemble a brake hub with ceramic mags such as Chris O did (mine were only 1/2 the size) you will quickly see how those forces can be just as dangerous.
I stayed away from Noes due to the cost involved when I started learning & my ceramics came to me free. The ones salvaged from HDD are crazy strong and I now regularly use them behind the ceramics. I cannot build full sized 'mills due to urban living and safety laws. But the coffee can mills are great little backups to solar lawn light panels.
Hope this helps too
Bruce S
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It would be nice to meet someone on the forum who is building the 2- or 3F from Hugh.
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Like the recipe book the 2F is valueable as well.
I learned alot with Hugh's construction books and info at internet.
It is the base of my succesful active pitchcontrol windturbine run for many years.
Using ferites which are good embedded in epoxy or polyester will hold at higher rpms .
Rgds Fbm.
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On their website Enercon writes:
... excited annular generator, there is no need for the use of permanent magnets that are manufactured from highly controversial neodymium (rare earths).
How you interpret that?
"Controversial" doesn't mean "bad". "Controversial" means "some people are talking about it and have differing opinions".
Usually it's uninformed newsies regurgitating the handouts of somebody with a competing product that is impacted by whatever they're slamming. (The newsies do this because they need something to print to get their next paycheck. Edit: My wife points out that "They also do that because six major corporations own just about all of the media in the US and some of them have very diversified holdings - possibly including a competing product.")
Any windmills at all are "controversial". "Oh NO! They KILL THE POOR BIRDIES!" Note that this meme started showing up right after a plan was announced to build offshore windmills that would have been visible from the Kennedy compound on Martha's Vinyard. All of a sudden windmills went from earth-saving carbon-replacing green tech to sky-mowers cutting down migrating flocks and hunting raptors.
(Hint: Birds die where they live. The area around a wind farm is a prime hunting ground for raptors, so guess where their corpses end up. As for migrating birds, wind farms are a drop in the bucket compared to glass skyscrapers and moving vehicles. {Have YOU ever seen a goose corpse in one of those open grassy fields?} Hunting license numbers are adjusted to keep the flocks at a healthy population, so even if giant windfarms DID kill a significant number, rather than maybe an occasional bird, the relevant states' fish-and-game departments would cut the number of licenses and at least the gamebirds would be unaffected.)
If all you are worried about is "controversial" you're worried about nothing but where a particular news fad went. Look for the truth, if any, behind the controversy. But don't expect to find any substance: If they had anything real, they'd have used it instead of trolling with "controversial".
But if you still think "controversial" means "significantly bad", why are you making a windmill at all?
Avoiding controversy means becoming a conformist, being herded, and having your life (and death) controlled, by the people who run the media or are skilled at applying social pressure.
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ULR,
What you are writing is quite clear to me.
My point is that I find the making of a safe reliable windmill rather complicated.
And I think it would become easier in cooperation with other disciplines.
Just like in a company.
So the intention is to make contact with windmillfriends and exchange ideas and parts.
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ULR,
What you are writing is quite clear to me.
My point is that I find the making of a safe reliable windmill rather complicated.
And I think it would become easier in cooperation with other disciplines.
Just like in a company.
So the intention is to make contact with windmillfriends and exchange ideas and parts.
Then you've come to the right place. B-)
By the way: If I sounded annoyed, it's because I am. But not with you. I'm annoyed by people who use social pressure judo like the "controversial" trick, and that they'd use it on one of our newer people, with the possible result of misguiding him into making a less effective mill. (I've had far too much of this stuff lately, thanks to the recent political season going into overtime. B-b )
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Hi mbouwer,
As I have said, your are welcome to pop down the road, (but you might have to come through Belguim!), for a couple of days and examine and talk about my 3.7m, 12 footers, Hugh Piggott design Wind Turbine farm.
How many do you need to be a farm, three ?.
Hughs design is Simple, and Robust. Yes there are areas for improvement, but considering one of mine is getting on for nearly 10 years of flying, with just one tail jumping, the modifications are pretty minimal.
And where one of mine has failed its normally due to my new fiberglass blades being twice the weight of Cedar blades. Yes I stick to Cedar now, because I have a local source.
Note to 'Damon' with 'Bruce' hiding behind, (what a sight that would be hehe). .... No 2 shed a blade when one delaminated the two halves at the root, a weak point for fiberglass blades. And throws it about 200 meters across the road.
midwoulds pitchcontrol is fascinating and I enjoy reading his posts.
Just about to re-balance my No3 after its modifications and re-launch. James a RE guy from the UK is here helping me around the place for a couple of weeks on a Cultural Exchange, WORKAWAY arrangement. As he was part of a team that built a HP at V3 near Nottingham UK. Its real nice to talk to folk who love there Wind Turbines.
Dead Birds.. In Nearly 10 years, I have only seen one starling at the foot of my No 1, but considering it was being eaten by one of the local cats when I found it, that might not be a fair conclusion of a Turbine strike.
I find Fish at the base of my No 3, In a half eaten state...... I think one of my cats Mr 'Puosoin Rouge' likes the new non moss covered concrete base as eating surface. Very odd staring at the depths of a 100,000 litre pond to see a black and white cat swimming up towards you with a Gold fish in its mouth. !
Sorry rambled of topic.
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How many do you need to be a farm, three ?.
1 in the limiting case, or 0 if you are still in 'research' phase.
3 is luxury!
Rgds
Damon
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Nowadays with internet and sending parcels all over the world,
for me I think it's much more fun to contribute to mills of friends,
than work on my own all the time in my backshed.
Think of all the possibilities of new materials, electronics, new windmill techniques.
It's only a question of disciplines finding each other.
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And just like Kitestrings and Clockman show us:
All that matters is a good team.
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In: http://www.windstuffnow.com/main/poured_stator.htm
I read about a poured stator.
Is someone on this forum doing so?
And where to find the right kind of iron powder?
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Machine shop....should be able to get some cut offs or grinding waste their....home or lowes depot sell a product called epoxy stick...one brand has steel in it..would cost a pretty penny for enough for a full size stator..coffee can size..?
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Machine shop....should be able to get some cut offs or grinding waste their....home or lowes depot sell a product called epoxy stick...one brand has steel in it..would cost a pretty penny for enough for a full size stator..coffee can size..?
Ordinary steel will eat a lot of power and turn it into heat, due to hysteresis. You need powdered transformer iron or (better yet) the powder that they use to cast "ferrite" transformer toroid and cup inductor "cores" for circuit boards. (NOT the kind they use for ferrite beads, which in some cases may also be deliberately "lossy".)
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Perhaps if I could find the powered transformer iron at a reasonable price I could make a stator mould.
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magnetite powder http://shop.chemicalstore.com/navigation/detail.asp?MySessionID=101-974522690&id=FE3O4M1
transformer powder http://shop.chemicalstore.com/navigation/detail.asp?MySessionID=74-125314844&CatID=21&id=SM1001
Other types here along with other metals if you want to make a blend http://shop.chemicalstore.com/navigation/categorylist.asp?MySessionID=74-125314844&CatID=21
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the whole point of using a core is so that you don't have to shove magnetic flux through air, which costs you nothing if its from a magnet, except for the one time expense of a bigger magnet. due to the resistance of copper, it is not practically possible to make an electromagnet air core motor. btw, the core has an additional benefit: the flux lines don't go through the conductors, they go through the core, as such the coils don't have near as much eddy current losses, but in an axial flux machine that's probably not a problem unless you exceed 60 to 300 hz at 1T flux densities, and its practical to use fine wire. but if you want to get 100,000 rpm on an 8 pole machine, you will probably have to use 30 gauge wire or finer (yes, somewhere i have a document on this, experimental flywheel energy storage iirc).
But the air gap flux densities that you're dealing with in an axial flux neodymium machine exceed practical flux limits of cheap powdered iron cores. you could have a powdered core made that could handle 1T flux densities, but it's cost would exceed the wire or sink EDM cost of cutting slots into a toroidal transformer core. -water jet cutting them would be better. but finding a place that can cut 2 inch thick steel may be difficult. also the coil would probably have to be unwound, then re-wound with epoxy between the layers to make sure the metal doesn't shift during the process. the coil would have to be set up on a rotary table with some kind of deflector i would imagine to due to the topology.
practical flux densities for ferrite is .4T, and they compress the powder to tens of thousands of psi to get the density required. you can't just mix it up with epoxy. look at the cost of those ferrite cores. at the low frequencies involved here ferrite bead material will work just fine though, and you could probably buy bricks of it and then cut and fit them together to make a core. this would be practical for a ferrite magnet motor, but with neodymium it would be of no practical assistance.
radial flux machines are more efficient than axial flux anyways, why not just make a motor conversion? once you add a core to an axial flux machine its not much lighter than a radial machine
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Ran across this site a while back that is promoting sinter and powdered metallurgy for motor design. I've have never seen a motor core done in this way.
http://www.gkngroup.com/sintermetals/products/mechatronics/radial-flux-motor-and-generator-components/Pages/default.aspx
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Joestue,
You say:"The powdered iron has to be compressed. You can't just mix it with epoxy".
But suppose I organize the coils in a mould and pour the flued in. In a short time the stator is ready.
Do you think less efficiency will be a big problem then?
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If you do use iron powder, then it can help.
Ferrite powder has a maximum flux density of .4T, as such it will be no help in a neodymium system.
To get reasonable permeabilities with iron powder, then yes it has to be compressed. by reasonable i mean more than like, 10.
But with an air core system any improvement is better than nothing since your magnets are already sized for no core at all.
The frequency is fairly low, the hysteresis losses may not be significant, I believe the bulk of any efficiency loss would be eddy currents. you may want to bake the iron powder to get a uniform coating of oxide on the surface.
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posted this awhile back;;bike alt......coils mounted to a flat steel band...coils have stacked steel inserts in the coil holes....steel inserts made out of steel cutoffs from a length of flat steel..these were super glued together ..then glued down to the steel band...coils mounted over them....mags are ceramic with neos glued on top for some extra kick...mags are glued down to the flywheel...with epoxy stick around each mag....thought their might be a lot of cogging..but it spins over with my finger...some drag thou..because the wheel has a slight drag to it....so far its worked out great as a exersize bike...max 60v with currant gearing...lights up a 400w-28v. aircraft landing light.....to 25v..best i could do at the time...fun stuff
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not sure why two picts..loaded.. heres a vid. link...if it works ? https://www.youtube.com/watch?v=yl2OGvOoTj0 https://www.youtube.com/watch?v=kSqNOVECurc
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But what would be the result if you ( instead of the steel inserts) poured the right kind of iron powder+epoxy in the coils?
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less drag--and less output.? works great as is...next one--use only one strand of wire for coils..maybe a 200v single phase setup..? need to hit 110 at a low rpm.reason for 200v...i do have a belt driven ..220v dc treadmill motor..that ive hooked to a pedgen...runs a 6amp sawsall easy enough..plus a ac motor conversion as well....works great for watching a vcr movie..powers the tv and vcr....easy to pedal... just wanted a more compact setup---trouble with making a slow speed gen---is the drag you get from the windings in the coils..you need more winds per coil = extra drag.....just a hobby-fun to mess with...
https://www.youtube.com/watch?v=AwX0nmOh__U
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Looking at this successful design. How to make a small version of it?
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It seems to me the best to start with the axis (with mounting points for the stator and the suspension)
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Hub. The front ring is for attaching the blades. The rear ring for the generator rotor.
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btw, the core has an additional benefit: the flux lines don't go through the conductors, they go through the core, as such the coils don't have near as much eddy current losses,
Actually that's not true. The lines DO cut the copper as they move from one core pole to another. If they didn't you wouldn't get any output. B-)
So you still get the full eddy current loses from the copper. (Maybe more, if you've increased the flux by putting a core in there in place of an air gap.) Any hysteresis or eddy current losses in the core are extra. (The rest of the post is right on.)
In a powdered core the eddy current losses will be negligible but the hysteresis losses may be significant - which is why you use steel (soft iron) rather than ferrite.
A core must also be shaped right or you get cogging - eliminating one of the primary advantages of the air-core axial flux machine and maybe keeping your mill from starting in less than a hurricane. So why not (as joestue suggested) use bigger magnets and forego the core, or do a motor conversion?
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posted this awhile back;;bike alt......coils mounted to a flat steel band...coils have stacked steel inserts in the coil holes....steel inserts made out of steel cutoffs from a length of flat steel..these were super glued together ..then glued down to the steel band... ...some drag thou..because the wheel has a slight drag to it
Is the "flat steel band" a solid piece of steel, or a stack of thin steel sheets, edge-on to the magnets, with the edges aligned along the motion of the wheel?
Are the punchings for the pole pieces inside the coil stacked so the face of each stack is presented to the magnets, or are the edges presented to them (preferably also arets are presented to the magnets and with the edges aligned along the motion of the wheel?
If either of them are the first case mentioned, a lot of your drag is eddy currents in the steel.
(Some of your drag is also hysteresis losses, unless the steel is transformer steel or other (magnetically) "soft iron".
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A small amount of the flux does pass through the copper according to the saturation of the core, the width of the slot opening, and the permiability of the core.
99% of the flux lines go through the core, not the conductor.
Answer me this: why do superconducting coils work in a transformer or motor if no flux can pass through the conductors
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Just worked with what I had...yes the flat bar is solid..and the coil steel inserts are laid flat..coils are laid wrong also...couldent have built it more wrong if I tried !...I new I would be fighting the steel as well as the coils..with all that metal..and extra windings...surprised it doesent really cogg that bad..thought it would with the metal in the coils...never thought it would work as good as it does or last as long as it has...being that the mags and coils plus inserts are glued down...was just going to be a quick project..its held up great..next one will be built right ! .......when ??
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Ps..I do ride it dang near daily..good way to start the day..mostly use the fan for a load..up to 10amps at 20v...little higher if I try..or a couple of 12v 50watt headlights..give a good workout..fan is great to keep cool...works great to get a pre workout before I headout on my studded tired mountain bike..snow and ice here......
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Ps..I do ride it dang near daily..good way to start the day..mostly use the fan for a load..up to 10amps at 20v...little higher if I try..or a couple of 12v 50watt headlights..give a good workout..fan is great to keep cool...works great to get a pre workout before I headout on my studded tired mountain bike..snow and ice here......
Ride it in shorts and point the fan at your upper legs to cool them. That lets you do a LOT more work and burn a LOT more calories than if you didn't cool your muscles with forced air.
That's why moving bicycles are such good exercise - and why some stationary exercise bicycles have a little squirrel-cage centrifugal fan driven by the wheel and pointing at the upper legs, i.e. to let them be as good as a moving bike.
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A small amount of the flux does pass through the copper according to the saturation of the core, the width of the slot opening, and the permiability of the core.
99% of the flux lines go through the core, not the conductor.
At any given moment the bulk of the lines go through the core. But when you move a magnet from one pole to the next the lines don't break at one pole and re-form at the next. They move through the gap - and thus through the copper conductors.
Lines of force don't break. They are loops that come into being at the atomic scale and expand, or contract to a point and disappear.
The closest they come to breaking is when they "reconnect", where fields going different ways in a plasma bump into each other and reconfigure into a lower energy configuration, dumping the energy difference from their relaxation into the plasma. That is a very energetic process - the origin of solar flares, where they kick the plasma out to interplanetary distances at an appreciable fraction of the speed of light. But even then, at no point does a field line disappear in one place and reappear in another. They are ALWAYS continuous.
Answer me this: why do superconducting coils work in a transformer or motor if no flux can pass through the conductors
Because flux CAN pass through superconductors - in two different ways (both of which involve losing superconductivity in one way or another).
In type I superconductors, a strong enough magnetic field makes the superconductor stop superconducting. Then the field passes through the resistive region just fine. But the overall wire (or other conducting structure) starts exhibiting resistance again. (There are superconducting switches built on this principle. They have been used both to close superconducting loops (after they've been pumped up to carry a ring current to create a magnetic field) and to make logic gates.
In type II superconductors there's also an easier way: Flux impinging on the edge of the conductor creates a small resistive region and an eddy current resisting its further encroachment, just like with type I. But in a type II superconductor the current is free to bend. So (rather than just keeping the field out of more than a microscopic surface region) the eddy current curves and squeezes a bundle of flux down into a tight core. The flux in the tight core is enough to make THAT part of the superconductor go resistive (though the average field before the squeeze-down is far too weak to do it), but the eddy current is in the still-superconducting part and doesn't decay. The field penetrates into the superconductor and the eddy current closes into a loop around it, much like an amoeba surrounding a bit of food. If the size of the loop is smaller than the width of the conductor (and it's microscopic - a quantum phenomenon - so it generally is), and the number of them is small enough that they don't fill the conductor from side to side, the flux bottled up in the eddy current tubes can cross the conductor just fine (carrying the tubes with them to the opposite edge, where they open up and eject the field), while the overall conductor still carries current (around the little whirlpools) with zero resistance.
Type II superconductors are useful because they can carry AC with zero resistance.
Again, because magnetic fields come into being as loops expanding from a point, when you go from a superconducting ring with no current to one with a current and a resulting (extra) magnetic field through its center, field lines MUST cross the superconductor.
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No, the flux lines do not have to pass through the conductor. Watch this animation here https://www.google.com/url?sa=t&source=web&rct=j&url=https://m.youtube.com/watch%3Fv%3D_uMuswyBw20&ved=0ahUKEwigmdLf-ubSAhUQyWMKHZwfAB4QtwIISTAM&usg=AFQjCNGeDACe5VaSXqOl7-R90yjvszaYR
The lines dont break, in the sense that they are imaginary, a better analogy is water flowing like a river. As the magnet passes by the teeth, the flow stops and starts flowing through another channel. But if the core had infinite permiability there would be no leakage flux through the conductor.
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Try watching it frame by frame.
The lines go through the coil very quickly in the animation. So you usually don't see them in the coil space, because they're on one side in one frame and the other side in the next. But occasionally you do see a frame where the line is in the coil space on its way from one pole to another.
Flux lines are "imaginary" only in the sense that each is an abstraction representing a given amount of flux. The flux they represent doesn't "stop flowing" in one path and start in another. The "path" propagates from one position to another at no more than the speed of light.
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If the flux lines have to pass through the conductor why does the presense of the core practically eliminate eddy current losses in the conductor?
From a certain perspective, yea the magnetic flux stops flowing through one path and starts flowing in another, instantly. Its like water flowing through multiple pipes each with its own valve. If one valve opens another shuts. If synchronzation isnt perfect u get cogging torque, not much different than water hammer. The lines of flux are just visualizations of the field strength or portion of flux in that area. They can indeed disappear and reappear somewhere else as quicky as conditions change. If the air gap was zero, and the permiability of the core infinite, no flux at all would travel through the area where the coils go, regardless if current was flowing in the coil or not.
Tl;dr yes lines of flux disappear and reappear instantly somewhere else as the magnet passes by the teeth. The total number of them doesnt even have to remain the same, but the rate at which they change is equal to the voltage potential generated. For neodymium magnets there is often considerable eddy currents induced inside the magnet by the varing air gap inductance which is what causes cogging torque.
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Interesting discussion. Today I have made the rotor.
My plan is to attach 64 neodymium magnets.
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So for what its worth there are actually a lot of people who refuse to believe that magnetic materials do in fact shield so to speak, a conductor from magnetic flux "lines" (whatever those lines are btw, the lines you see in a simulation are just representations of the flux's concentration, location, etc)
here's one such person. . The mathematics of induction are clear. It requires a changing magnetic flux - WITHIN THE AREA BOUNDED BY THE LOOP - and NOT ANYTHING AT THE LOCATION OF THE LOOP ITSELF OR THE ELECTRONS WITHIN IT. When it comes to understanding why electrons are forced around a secondary loop you must accept some "spooky interaction at a distance" without any local field at the electrons location to explain it. I have more than a bit of a problem with that.
you can find the discussion here, i believe its worth reading. http://www.practicalmachinist.com/vb/transformers-phase-converters-and-vfd/true-3-phase-transformer-how-does-really-work-how-can-i-test-310120/
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After mounting the axle and rotor.
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If the flux lines have to pass through the conductor why does the presense of the core practically eliminate eddy current losses in the conductor?
It doesn't. (But unless the conductors are quite broad the eddy current losses there are swamped by the added ones in the core.)
From a certain perspective, yea the magnetic flux stops flowing through one path and starts flowing in another, instantly.
No, it doesn't.
It snaps across the gap between the pole pieces of a generator, or the core paths of a transformer (as "leakage flux") at nearly the speed of light. (If it weren't slowed by the eddy currents from its passage through the conductors of the coils, or the refractive index of the air, insulators, and other non-conductors in the gap, it would be at the speed of light.) In the core it only needs to penetrate half the width in a quarter-cycle, which is glacial by comparison.
Because the field density in flux in the core is something about 1500 times that of the gap, and the animation you referenced shows only four lines per pole piece plus gap, the poles about three times the gap, and five gaps, you have about a one-in-300 chance of seeing a line in a gap in any given frame. The lines appear to disappear on one side and reappear on the other.
Nevertheless, there's one frame (in second :33) that clearly shows a simulated field line nearly centered in the second gap and "cutting" the coils.
Tl;dr
THAT post was too long for you to read it? Then you certainly won't want to bother studying http://web.archive.org/web/20031002111405/http://www.itee.uq.edu.au/~aupec/aupec00/edwards00.pdf until you understand poynting vectors. But take a look at 1.4 (a)-(b).
It's about transformers. But you can view a generator as the secondary half of a transformer where the field is varied by splitting off and moving a DC excited primary half (or other magnet), rather than changing its magnetization by supplying it with AC.
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Did you read section 2.2.2 in that paper you just linked to?
Yes i understand generators are like transformers with a rotating airgap.
Take a generator and fill the teeth with solid bars of copper. Measure the drag with and without them. Now remove the core and replace it with plastic. Rinse and repeat and you can measure the effect. Btw you will need to keep the airgap flux the same for both with and without the core for this to work as a demonstration of why electric motors have cores.
Place for example a one turn loop within the conductor fill of a motor, make the loop as wide as you can and move it around, rotate it 90 degrees.. Let me know how much voltage you get. Now remove the core and place the coil in the same place, let us know what you get. Best to do this with a concentrated pole motor so you can ignore harmonics. I think youll be forces to realize that the magnetic flux lines can indeed be confined to the core and push the electrons around without passing through or even nearby them.
Imagine the Magnetic field lines are like photons, imagine the rotor is a light source, and the core a series of optical fibers that send the light back to the rotor. This analogy isnt a good one but it should help you understand that ideally if the slot opening were zero, the light wiuld never cross through the conductor. Of course the slot opening is finite and the magnetic core is similar to a piece of stained glass, so some of the flux goes through the path of highest resistance.
But try maiking an axial flux generator with half inch solid copper. It would be practical with a core, and the same airgap flux density.
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You must be able to understand that if you slide a neodymium magnet into a bar of steel, the flux in the magnet is now about 1.3t instead of one. Pull it out and its back to one. You just created and destroyed a whole bunch of magnetic flux lines. Simulate it yourself and ask where did they go?
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Your knowledge is very wellcome specially now that I try to make this radial generator.
64 magnets. 48 coils?
And what configuration will I apply? Is it better to lay the coils on each other like roof tiles?
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the best configuration is similar to what is in any car alternator.
three phases that overlap each other. the cross section is approximately 50% copper and 50% steel as viewed from the rotor, but the slot teeth cover the opening to capture all that leakage flux we don't want crossing through the conductors. if you don't have any steel teeth sticking through, then you can double the amount of copper you shove through the air gap. so your coils are about 1cm wide, 2 cm inside diameter and 4cm outside diameter. mashed through the middle of the 2 cm wide inside diameter of one coil is two other coils.
when dealing with overlapping coils you have to press the coils together so that the cross section looks like this https://motoredbikes.com/attachments/cross-section-png.26611/
if you do not mash the coils together and fit them in the same air gap as what you can get from a single layer coil structure like this: 000 then you get no improvement, no increased copper density. compared to a single layer coil. and this should be easy to understand why. its like trying to fit washers in a box, there is a fundamental limit that you can't break through without bending them to fit inside each other.
here is a very creative way of achieving a fairly high copper fill density.
http://johansense.com/bulk/dayton90v34hp.JPG
i have no idea how they did that, other than to say they wound all the coils at the same time.
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The 64 magnets I have are 20-10 mm and 3 mm thick with a hole.
Attaching them with a normal steel screw and then a layer of epoxy over it?
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counter sunk hole on every north (or south) pole?
what a mess. it may be possible for you to screw only the countersunk magnets down and epoxy the others. if you put a screw in there it sticks up above the magnet and that's where you really do not want anything to be.
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You are right. I am going to buy new magnets without a hole.
But then I can also take the size 20-4 so I can place 160 magnets
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still good mags--screw down half...make tight fitting gap..between mags..so it will help keep the glued down mags secure..looks great..
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Making the mast and the yaw bearing now I have a lot of questions about the design of the stator.
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Yaw slide bearing. Later I can make grooves in it to get a ball bearing.
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The stuff mounted.
64 magnets 20x10x2 are in order.
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Wire 0.5 mm
Now there is the shape and configuration of the coils.
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Is it going to be wave wound ...like a car alt ? what kind of voltage and amps are you looking for..? Is the stator going to have lams built in as well..iron ? Looks great ....
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Thank you for your interest. The goal is a model of the Enercon.
So I would like the blades a low number of r.p.m. and yet a high voltage.
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What phase number are you looking at ? Low speed alt equals high number of winds per coil..but then again a high number of coils could equal lower turns....looks like a great project...
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If you could get another set of magnets that match the flat side dimensions but have minimal height then you could simply add them as caps, right? You have to seal the magnets regardless.
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There are many things about the generator I would like to discuss as for example the number and shape of the magnets.
On the circumference of the generator-ring I could mount 160 magnets of 4 mm wide.
In the meantime I can make the other components like the blade suspension.
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Blade suspension mounted (+ 4 magnets 20 x 10 x 2 )
Now the blade yaw bearings.
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mbouwer,
Are these 3D printed components or am I looking at modeled drawings?
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CraigM,
The professional windturbines around inspire me. http://www.enercon.de/en/products/ep-4/e-126-ep4/
So I would like to have a model in my garden and use the generated energy.
Always seeking windmillfriends for cooperation.
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CraigM;
I'm pretty certain those are actual metal parts he's using.
The magnet ring is metal with holes ( I think) to receive countersink stainless steel screws.
Mbouwer ;
Is that assembly ALL metal? or are you 3-D printing parts too?
Thanks
Bruce S
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Bruce S,
The assembly is ALL metal.
But is'nt welding a bit like 3-D printing?
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Bruce S,
The assembly is ALL metal.
But is'nt welding a bit like 3-D printing?
Sorta , BUT way cooler in my book ;D.
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That is some sweet machining! WOW!
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mbouwer,
How did you make all of these components? The hub, rotor and other pieces don't appear to be repurposed from something else but look to be made from castings. Are these just bits of other objects that you're fabricating and welding together?
Very nice fabrication work!
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It looks like poured metal. Maybe it's steel. You could more easily pour aluminum. Hopefully it's not cheap scraps thrown together. We used to call scraps mixed together pot metal.
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It is steel.The welding is poured metal of course.
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mbouwer;
Is that 6mm steel? IF those are welds , those are an order of magnitude better than mine.
IF the welds are even molten steel poured onto steel rings,,, that is still awesome workmanship .
Bruce S
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Bruce S,
The three rings for the blade suspension are made of 10 mm square steel.
After welding, grinding and a bit of paint you also get this result.
Now busy with the yaw bearing for the blades. I would like them to be light and solid and easy to make.
I thought of integrating them them in the blade.
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My intention is to support the blade on two places which have distance from each other.
The slide bearing and the threaded rod.
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Nice. Maybe I missed it, but what is the material(s) that you are planning for the blades? Great stuff. ~ks
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Polyester. I want to gain more experience with it because the stuff gives the ability to make all sorts of shapes.
I like reading about your actuator project.
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The pivots with a filling of cardboard and tape around them to shape the polyester blade hubs.
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The polyester hubs which I want to fasten in the blades.
The bronze filing is mixed in the inner layer of polyester.
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After shaping the blades in PUR foam I have fixated the hubs.
Now I want to strengten and cover the blades with glass reinforced polyester.
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The polyestering and sanding of the blades take a few days.
On the outer contour of the generator ring I can glue 160 magnets ( 20 x 4 x 2 mm / holding force 1,2 kg )
The intention is a slowly rotating turbine of about 60 rotations per minute.
Maximum power 100 Watts.
I would like to discuss this design of the 3 phase generator.
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I assume the stator coils mount off the three supports at 120 degrees just behind the magnet rotor? Are they radially mounted above the magnets?...or flat?
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60 rpm....voltage ?
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coils radially mounted around the rotor just like the added photo.
about 230 / 380 volt
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The blades mounted.
While I try to collect more information about the configuration of the generator,
I can make the mechanism for the blade pitch.
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What dia. are the blades?
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Perhaps next time I can try carbon fibre.
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Nice! Wondered how big this was going to end up.
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Bigger than I'd pictured. Can't wait to see it all assembled. Great stuff. ~ks
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Thanks for your response. I just want to make a test set up to get more contacts with windmillfriends and to exchange ideas and parts.
I think the blade suspension can be made more simple and easyer to do.
Making the generator I find more difficult.
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For a few days I was on the section Hydro. Perhaps I can meet likeminded people there who have interest in making a water turbine.
But now it comes back on making the generator.
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A lot of simularity between a water- and a windturbine. For example the blade pitch.
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It would be nice to meet someone on this forum who also is interested in making the generator.
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On the circumference of this generator rotor-ring I can glue 64 neodymium magnets ( 20 x10 x 2 )
What then is the best arrangement for the coils?
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In this coil configuration. Do I also take the ratio 4 magnets on 3 coils?
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http://www.fieldlines.com/index.php?topic=146957.0
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In this coil configuration. Do I also take the ratio 4 magnets on 3 coils?
The blue coils would be positioned over the north pole of the magnets, with the south poles in between them.
As shown, each of the coils would be wound in the same direction. O O O O
If you wind the coils like this OOOO then every other coil is reversed (you will also have twice as many of them), and you also have two coils in each slot. usually they are wound this way because the end turns are slightly shorter, but it may be harder to get the wires into the slot.
I suggest you try a 66 slot machine. the wiring diagram can be found here:
https://www.emetor.com/edit/windings/
you may be able to wind the coils over the top of a laminated metal backing plate without using any slots cut in the metal. the frequency you get out of this thing is going to be very high. you may need to use fine wire due to eddy currents in the wire. (you will have to anyway because the coils will hardly be 1cm in width)
In my opinion a more reasonable option is to make a 32 pole machine, which might get you more torque due to less leakage flux. the magnet poles would be square in cross section which is more ideal, you just arrange the 64 magnets like this: nnssnnssnnss.
a 32 pole machine can't use a 33 slot stator unless its a two layer winding which is more complicated to make, but a 30 tooth stator is a good fit and the least common multiple is still rather high at 480, much better than a 96 slot stator which would have an lcm of.. 96. but not nearly as good as the lcm of 2112 for the 64 pole, 66 slot machine. higher LCM= less cogging torque.
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Can we say that working further with this ring and these magnets is not going to bring a nice generator?
The metal work is no problem for me.
How to make a new start?
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whats the problem ?
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Its just a challenge of how to build the stator.
If you can take steel pallet banding strap and anneal it in a furnace, you maybe able to wind it edge wise around a cylinder, then use it as a backing plate to glue the coils to.
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Remember seeing this posted by oztules
"Yes, I was going to suggest the iron wire technique. I did a story on the Seeley conversion here." http://www.otherpower.com/images/scimages/5171/seely.html, and one of the photo's clearly shows the iron wire backing like this:
.... may help?
CM - Use a soft, very low carbon wire.
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Another option if you can find it is to use the "I" section of an E transformer, tape them end to end and wind a toroid core. Your flux lines will enter the flat side of the laminate instead of the edge... not sure how much loss this will incur.
I was able to find packages of silicon steel "I" sections at the local scrapyard. Have a bunch of this stuff and not sure what to do with it.
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how thin are those laminations?
if they are .010" or less i can use them to make inductors for sine wave filters for vfds, but i'm not sure i'll use them either..
He could wind a toroidal core with those strips of metal, but... he has a radial machine, not an axial one, the laminations need to be oriented 90 degrees to the induced voltage.
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The metal work is no problem for me.
But I think that does not mean that I am capable to make a generator on my own.
Can we start to talk about a design that others also want to make. Perhaps cooperation is possible.
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if you re-orient the magnets so you have two of them facing each other, an inside and outside cylinder, you can make a radial air core design.
another alternative is use the outside of a large motor core as a slotless core.
there is a photo here of the method.
http://www.fieldlines.com/index.php?topic=143518.0
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It's a pleasure to read all your comments.
Only with your support I'm going to manage to make a radial generator
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you seem to do very nice metal fabrication.
i don't understand if you have 64 mags with mounting holes and another 64 mags without mounting holes .
why would you not build a dual rotor radial alternator with an air core stator and avoid all the coggeing?
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That's what I will do. Air core stator with 1 layer of coils.
36 magnets and 27 coils.
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The coil winder for the coils with inside measure 20 x 10 mm
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Coils 100 and 50 windings / wire 0,5 mm
Mounted with the rotor at 100 rounds per minute the biggest coil shows 0,05 volt.
Bigger magnets and coils, thinner wire.....?
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If you use a stator without steel lamination in it, you should use rather thick magnets other wise the magnetic resistance of the air loop wil be rather high with respect to the magnetic resistance of the magnet itself. This will result in a rather low magnet flux flowing through the coils. In my recent report KD 631, I describe an axial flux PM-generator with no iron in the coils and even with 15 mm thick magnets there is a large reduction of the magnetic flux in the coils (see calculations in chapter 3). The same theory can also be used for a radial flux generator.
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dual rotor required
add another rotor on the outside of your present one with another 32 magnets.
cast a 2 phase stator with overlapping coils
a total of 64 coils and 64 magnets
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......
:....==coils
:
mag:rotor
:
:.....
:.....==coils
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Something like this?
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yes, just like that.
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But then I would prefer to make an axial dual rotor type first.
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i always build dual rotor axial flux machines .
with out a second rotor to draw out the magnetic flux you will need iron behind your coils. otherwise the magnetic flux is traveling sideways from one magnet to the next and not through the coils at 90 degrees.
from discussions here on other power i have come away with the understanding that the least cogging type metal backing can be created using mild steel wire wound in several layers behind the coils.
you have displayed good metal working skill so you could create a support bracket that could contain the coils and the wire backing . good luck
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Your idea about using mild steel in several layers apeals to me.
I made these support rings for the magnets.(dual rotor) Perhaps next time I could use thinner layers.
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in the photo posted on reply no.365 you will see wire backing behind copper coils
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Reply 635 of Craig M.? But does'nt this steel wire become magnetic then?
How about a poured stator from one of the shops Mary B showed in Reply 554
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Mbouwer,
I'm amazed how quickly you can fabricate something like your latest support rings. Maintaining concentricity from inner ring to outer ring doesn't look easy.
I believe a point you may be missing is the need for a closed loop magnetic circuit. In your original radial design you have a ring with magnets on the ring placed N-S-N-S. The metal ring allows the magnetic field to pass through the metal from N pole to S pole. This is one half of the magnetic circuit. The second half (to close the loop) is on the top of the magnet. With your design there isn't a closed loop. The best it can do is for the magnetic field to jump sideways to the adjacent magnet. If you place a coil over the magnet you will get very little flux passing through the coil.
To correct this you need to have a magnetic conductor directly above the magnets. You want to sandwich your coil between the magnet and the conductor with as little air gap as possible.
You can't simple attached your coils to a solid metal plate or ring. this would complete the magnetic circuit however the problem is as you sweep the magnetic field through a thick metal plate you'll induce eddy currents which result in heat. Others here can elaborate on eddy currents.
Electric motors use laminated steel cores. The laminations are very thin and the steel used is specialized to reduce eddy currents.
If you have access to silicon electrical steel you might be able to find someone to punch out a laminated core that fits the rotor you already made. You may be able to find a steel core from a motor but would then need to remake you rotor to match. Other option is to build your stator to match the rotor dimension and then wrap low carbon wire around the back side.
Think of the magnetic field needing to complete a looped circuit with the coils placed in the middle of the circuit.
Steel core (wire or lamination)
| Coil |
Magnet N , Magnet S
Magnetic field loops from N to S or S to N. Flux jumps the air gap with coil and then travels through the steel core and returns to the opposite magnet.
Thanks CM
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Building small windmills is a worldwide activity and I enjoy making parts. Also for windmillfriends.
Until now the generator is a bit of a struggle for me. Mainly because I would like max. 100 rounds per minute and a high voltage.
Now, making a dual axial generator whith air core, what to say about the closed loop magnetic circuit?
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i would say yes .
a dual rotor axial flux is very forgiving mechanism
with adjusting screws on one of the rotors you can make up for short comings in your construction abilities.
with a radial layout (no adjustment) clearances are set and must be perfect.
i don't recall anyone building a radial alternator on this site over the last 12 years
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Idea for making the shaft. I took 2 mm sandwich suspension plates for stiffeness.
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you only need laminated plates when the magnetic field is moving relative to the plate.
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If you think the laminated magnetrings are a problem I can make new ones.
The hub with the two bearings. I tried to shape it light and robust.
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laminated or not, no problem
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New magnet backing rings.
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Fastening.
More space now for the overhanging coils.
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Rear magnet backing ring on the hub. It is possible to also ajust this ring on behalf of the air gap.
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Ajustment. For the final assembly I think it's better to use lock nuts.
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Now to go on with the generator at eye level I need a tripod and a yaw bearing.
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There is another reason why a 3-phase winding is more favourable than a 1-phase winding and that's that you can get more power out of the generator at a certain rpm for the same armature.
This really appeals to me.
Now I have to decide about the number of magnets and coils.
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This yaw bearing is easier to make than the one of Reply #590
Also, in the event that I could make one for a windmillfriend.
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The stuff is on the test stand and now I can shape the wooden mould for the stator.
The magnet backing rings are diam. 300/256 and 4 mm thick.
How to determine the optimal number of magnets and coils?
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were the magnets you have 10mm wide? if so if you place 64 magnets on each disk you have 14mm for each magnet on the outer diameter for each magnet, on the inside diameter you have 12.56mm available.
this is fairly reasonable.
as far as the number of coils you have a lot of options. did you intend to move to wider magnets?
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The backing rings are 4 mm so I think I have to buy new magnets thickness 4 mm.
A suggestion for my setup:
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Lots of great information on this forum about designing a generator.
My rough cut moulds.
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https://www.windgenkits.com/pages/test-page-with-tech-stuff
One of the best videos to make an Axial Flux PMA for HAWT and VAWT
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Much knowledge and great craftsmanship over there.
Maybe it's a good idea to ask them to put together my 3-layer stator.
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Determining the shape of my new coil winder.
So the starting point is 64 magnets and 48 coils. This means 192 coil legs?
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The coil heads must be bended out to cross each other.
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Modified coil winder.
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Make sure not to pull the wire too tightly. If the coils are very tight, they will also be stiff and hard to lay on top of each other.
They also change shape as you bend them, of course, so keeping the straight sides to stay straight also requires "persuasion".
It will help a lot to leave some space between the coil legs so that they can be massaged as needed, to make them lie flat.
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A few test coils on the mould. To give the coilheads more space to bend they should be shaped a little longer.
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should be fine as long as the hole is the size of the mag...more dead wire will just add more resistance
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New inside measurements of the coils 46 mm / 10 mm / 8 mm
Coil legs: wide 4 mm / thickness 5 mm
Added a brake to hold the coil in position if neaded.
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Determining the shape of my new coil winder.
So the starting point is 64 magnets and 48 coils. This means 192 coil legs?
I don't understand this sentence and the following pictures. If you have 64 magnets, I suppose that you have 64 armature poles. If you make a 3-phase, 1-layer winding, you will have 3/4 * 64 = 48 coils. But in this case there are no crossing coil heads. The sequence of the coils is U1, V1, W1, U2, V2, W2 and so on. You only get crossing coil heads if you use 96 coils and a 2-layers winding.
This option for doubling the number of coils is explained in chapter 11 of my report KD 596 for a 12-pole axial flux PM-generator. Figure 8 out of KD 596 gives a picture of the winding. The first winding is lying at the bottom and the second winding is lying at the top. For a 1-layer winding, you only have the bottom layer. For an axial flux generator, one coil has two legs with radial positioning, one short inner coil head and one long outer coil head. For a radial flux generator, the coil pattern is identical but the coils heads have the same length. The coil heads of the first layer are bent to the outside to make the grooves free for the coils of the second layer.
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Correct me if I am wrong but it seemes to me that I am now using the method like it is also in chapter 11 fig. 8
96 coils / 2-layers winding / 192 coil legs.
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SparWeb,
A little persuasion will do now.
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Persuasion indeed!
Might want a system to keep track of all the wires. More than just "in and out"...
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4 test coils out of the mould.
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At a 100 r.p.m. with 2 mm magnets one coil shows 0,1 volt.
Now trying coils with 0,3 mm wire.
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2mm magnets?
I must have missed something earlier. Why are your magnets so small?
I was guessing your magnets should be at least 10mm thick...
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The thougt is: first make a properly functioning design, and then scale up.
At a 100 r.p.m. the coil with the 0,3 mm wire gives 0,2 volt.
What about thinner wire?
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100 Rpm and 0,3 mm coil-wire there is no power.
With extra windings and extra Rpm you can increase voltage.
0,3 mm wire is no amps . Stator overheat.
Better make a Piggott generator with a gearbox and large pitch controlled blades .
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on posting #650 you will see the proper ratio between the thickness of the magnets and the thickness of the stator coils.
with thicker magnets the magnetic flux is projected a greater distance from the surface
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Midwoud,
It's my striving to use less heavy magnets.
But if I would meet someone who wants to build a Piggott design like yours I would ask for cooperation.
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Going right down to basics... very basic...
You need to maximize "Electromotive force" and minimize the resistance. I think the need to reduce resistance in the coils of wire is obvious, but there's a trade-off when going to larger wire, which you're aware of. There are things you can do to make it work out. It is a balancing act.
If you haven't dealt with the expression EMF, Electromotive force (or its equivalent in Dutch "Elektromotorische kracht" ) then take a moment to read up on it, because it will help you balance the need for a strong magnetic field with your budget to spend on magnets. I'm really not the best person to explain it, but I was exposed to the concept in college, and it has helped me a lot when I was building my own generators.
I think I can also point you to some online calculator webpages that will help you try various combinations of magnet size. That may help you see what thickness of magnet you really need. I stated my guess earlier (about 10 mm) but you could find a combination of 8mm magnets or maybe thinner, depending on what you want to do.
Gearing a turbine adds cost and complexity, so the money saved on magnets at the cost of gearing can easily be penny-wise-and-pound-foolish.
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In this case the magnet width is greater than the gap so the situation is reasonable.
In this particular case i would configure the magnets for 32 poles so that the cross sectional area of the magnet appears to be a 1:1 ratio, but this could be argued later.
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At professional wind turbine manufacturiers many disciplines work together. There is a continuous development.
That's also what homebuilders need. We can make it happen on a forum like this.
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missed out...back in 04 it was a everyday new build dam near...tons of picts and talk of builds.....guess i better hit the shop !!
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Hiker,
Many of us have noticed.
Popularity and dropping cost of solar is one factor, but I am not sure what is really behind it.
Maybe it is just that Facebook sucked most of our supply of new members away.
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We are talking about generating energy. A big advantage is that solar and wind energy can complement each other.
But it is not that easy to get a good and safe and reliable device on your yard.
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but now, at least you can talk about a vertical mill without being insulted called a Charlatan or insane.
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After rereading lots of information on this and other topics it seems to me it's better to focus on radial+lamination core.
Found: Outer diam. 364 mm / inner diam. 234 mm / 48 slots
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Nice find....
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do you have the rest of it?
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This is what I have. It is a good starting point?
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Then I guess: internal size of the coil about 40 mm
inner width of the coil 14 mm + what is needed to bend out the coil heads
magnets 40 x 15 mm
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I just put a couple of pegs in the middle slots...that stick out aways...wind the coils right on the stator..wave wind or separate coils..or make a jig..then transfer the coils to the slots..
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Adapter kit to slide in the two middle slots to wind the coils on the stator. Both sides extend 21 mm from the lamination core.
Next item: wire thickness.
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you can use a concentrated pole design that uses your existing 10 wide magnets.
every other tooth gets its own coil. no overlapping coils, rather high pole count, nearly no cogging, etc.
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But does'nt it bring many advantages applying overlapping coils?
I also want to buy new magnet sizes.
Today I would like to get started with the suspension of the lamination core.
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Supporting ring of the lamination core.
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Beside the core I took a space of 14 mm for the bent out coilheads.
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But does'nt it bring many advantages applying overlapping coils?
I also want to buy new magnet sizes.
All that matters is that the coils be electrically useful. for air core coils, as i have explained, you need to overlap the coils and by doing so you can fit basically twice as much copper in your machine.
once you add a magnetic core, all that matters is that the coils be electrically useful and you fit as much copper as possible in the core.
anyhow, due to the aspect ratio of your core i think a concentrated pole design will be more efficient, due to the reduced end turn length.
if you go with the regular 3 tooth 1 magnet ratio, your end turns are three times the length of the active winding. basically 75% of the copper is wasted.
with a concentrated pole design, only half of the copper isn't doing anything, if you wind every other tooth.
if you wind every tooth, your end turn length will be somewhat but you'll have twice as many coils to wind.
(that's why i asked what did you do with the rest of the core)
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It is clear that the dimensions of the core are not really suitable. But I think the material is o.k.
So what about adjusting the core.
Like cutting the teeth and in the remaining bridge 144 new slots.
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i don't know why you want to stick with the traditional three slots for every magnet (pole)
there really isn't any reason to do so in my opinion. it cogs badly unless the magnets are skewed across two teeth, which reduces the voltage.
anyhow the core you have is fine for a concentrated flux machine, given the 10mm wide magnets you already have. the number of magnets isn't critical, but there are combinations that are much better than others, such as two less or two more magnets than the number of slots. for some combinations of magnets and teeth, winding every tooth is about 5% better than winding every other tooth, but for some of them its electrically the same so do whatever is convenient.
cutting any laminate core destroys the baked on insulation and iron oxide coating and leaves a burr that cuts through to the other plate which makes an electrical path for eddy currents to flow through. eddy current is approximately proportional to the square of the thickness of the steel, that's why it makes a big difference.
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Spokes 14 x 4 mm. Heads of the spokes 14 x 12 mm.
Slots 8 - 10 mm wide. Depth 30 mm.
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I don't see the logic of a coil around each stator pole. This only works for a 1-phase winding if the number of armature poles is identical to the number of stator poles but in this case the winding direction must alternate from left hand to right hand and you will get an extremely high peak on the clogging torque.
In my multi-pole generators, I have a coil around half of the stator poles but all grooves are completely filled with copper. All coils of the 3-phase winding have the same winding direction. The number of armature poles must be two more or two less than the number of stator poles and this neutralises almost all fluctuation of the clogging torque. There are several public reports on my website www.kdwindturbines.nl about multi-pole PM-generators with different pole numbers of which the most recent is KD 632 for a 26-pole generator. But there are also reports about a 34-pole generator (KD 622, KD 580 and KD 560) and about a 46-pole generator (KD 624). It depends on the number of grooves (or poles) of the stator stamping which you have chosen, which of my reports is most relevant to you.
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For some combinations of teeth and pole count winding each or half of the teeth is slightly more efficient than the other, and the end turn length is slightly reduced. And more surface area for cooling.
Anyhow you can find the winding factors and wiring diagrams on the emetor website.
30 poles 36 slots works good as well, you don't have to stick to the +/-2 rule, but below a ratio of 5 poles for 6 slots the winding factor drops off and copper losses skyrocket
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What is said about a coil around each stator pole is right but I think that lying the double amount of coils is more work and you must be very alert that the winding direction of adjacent coils alternate. The advantage of a slightly shorter length of the coil heads is only relevant if the length of the stator stamping is short.
If you have 34 armature poles and 36 stator poles, the number of preference positions per revolution is 34 * 36 / 2 = 612. If you have 32 armature poles and 36 stator poles, the number of preference positions per revolution is 32 * 36 / 4 = 288 which is much smaller. The fluctuation of the clogging torque increases for decreasing number of preference positions per revolution, so I think that taking a difference of only 2 in between the number of armature pooles and stator poles is the best option.
Another point is the configuration of the coils. If you have 36 stator poles and 34 armature poles you can lay 18 full coils, so 6 full coils per phase. The coil sequence is: three coils U1, three coils V1, three coils W1, three coils U2, three coils V2 and three coils W2. If the north poles are about opposite to coils U1, the south poles will be about opposite to coils U2. So the three coils U1 must be connected such to the three coils U2 that the voltage of both coil bundles are strengthening each other.
If you have 32 armature poles and 36 stator poles you will get four coil bundles of each 1 1/2 full coils per phase positioned under 90 degrees. In this case you are forced to use three half coils per coil bundle. It is possible but I prefere the option with three full coils per coil bundel.
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Lamination cores in the professional turbines have another shape.
If I cut my 28 laminations like that, polish them and give them a new insulation layer.
Would'nt that bring me advantages?
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For big direct drive professional turbines, the rotational speed is very low. To generate a sufficient high frequency, therefore one needs a stator stamping with much more slots than for a normal asynchronous motor. For a small wind turbine the rotational speed is much higher and therefore you can use a stamping with 24, 36 or 48 grooves and stil have a sufficiently high frequency.
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Thinking of a safe quiet spinning workpiece in my garden.
With somewhat larger diameter.
Already full power at low wind speed.
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mbouwer;
As many before me have said, you'll need to decide what "low wind speed" you're trying to work with.
Most notably anything below 7 mph (3.12 m/s?) does not have nearly enough usable energy.
Others have designed their mills down in the 5 mph (2.23 m/s?) , however I couldn't find anything posted that had usable results. The VAWTs regularly shoot for lower speeds because of their wonderful ability to be self-limiting.
Hope this helps
Bruce S
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Imagine a direct-drive generator of max. power 500 Watt
Diameter of the blades 5 m ( active pitch)
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It just depends on what you like you have on your yard: a high speed nervous propeller or quiet turning somewhat larger blades.
The suspension ring for the lamination core.
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There must be more people on this forum who are inspired by the energy-generating professional wind turbines around.
Ajustable suspension bracket. Now working on axle and hub.
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Suppose I cut off the teeth and enlarge the inside diameter I get a nice backing ring for the coils.
Assembly:
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Teeth removed. Now it looks more similar to a lamination for a direct drive.
I am now going for 144 new slots.
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Idea: Drilling 144 holes ( dia 4 mm ) on pitch circle 321 mm ( pitch 7 mm )
+ on the rotor 321 magnets 20 x 3 x 2
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you don't have to stick to the +/-2 rule, but below a ratio of 5 poles for 6 slots the winding factor drops off and copper losses skyrocket
How should I apply it in this configuration?
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The number of stator poles must be dividable by twelf, so that is correct for 144 stator poles. So you can use 142 or 146 armature poles if you follow my rule that the number of armature poles is two more or two less than the number of stator poles. If you have 144 stator poles, 72 full coils can be laid. So 24 coils for each phase. The coil sequence then is: 12 coils U1, 12 coils V1, 12 coils W1, 12 coils U2, 12 coils V2 and 12 coils W2. All 12 coils of one coil bundle have the same winding direction and are connected in series. Be alert that the 12 coils of coil bundle U1 is connected such to the 12 coils of coil bundle U2 that the voltages of both coil bundles are strengthening each other.
If you don't follow my rule, so if you take for instance 140 or 148 armature poles you will get the coil sequence: 6 coils U1, 6 coils V1, six coils W1, six coils U2, six coils V2, six coils W2, six coils U3, six coils V3, six coils W3, six coils U4, six coils V4 and six coils W4. If you take 138 or 150 armature poles, you will have three coils in a coil bundle and you will have eight coils bundles for each phase.
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you don't have to stick to the +/-2 rule, but below a ratio of 5 poles for 6 slots the winding factor drops off and copper losses skyrocket
How should I apply it in this configuration?
by deciding to cut your new 144 slots, the only reason i can understand why you decided to do so, was because you wanted to stick to the traditional 3 slots per 1 pole, or 48 magnets.
but you can do anything between 128 and 142 magnets, as well as 146 to 160. you can go as high as 176 magnets (magnets means poles in this context) before the winding factor drops below .9
110 to 124 is also possible but the winding factor is .9 to .93. not super good, but still reasonable.
note that some of the wiring possibilities are rather complicated.
https://www.emetor.com/edit/windings/
because you've decided to cut your own slots i would make the magnet pole count as low as practical to keep the frequency low, due to eddy current losses in the laminations.
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I also don't understand why you removed the existing stator poles and want to go to 144 slots. The remaining width of the stator is rather small and there is only little space for making of the 144 slots. So there will be only a little space for the copper of the winding and therefore the maximum power you will get out of the generator at a certain rpm will be much lower than for the original stator stamping. Mounting of the winding will also be more work. The winding may look more like a scaled down version of the winding of a big windmill but I expect that the power you get out of this generator will be disapointing.
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Before I start drilling I definetely like to discuss more options.
Joestue,
You think I better drill 48 slots diam. 8 mm / pitch 21,3 mm and tooth wide 13 mm?
Adriaan,
Why not give every tooth a coil?
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Have just completed and painted the axle. Now making a matching hub.
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Before I start drilling I definetely like to discuss more options.
Joestue,
You think I better drill 48 slots diam. 8 mm / pitch 21,3 mm and tooth wide 13 mm?
Adriaan,
Why not give every tooth a coil?
If you give every tooth a coil, you have the wires of two adjacent coils in one groove. So a coil can contain only half the amount of copper than for the option of a full coil around only half of the teeth. The power generated in two half coils is the same as the power generated in one full coil so I see no reason to favour the double number of half coils.
If you have a coil around half of the teeth, and if one coil is opposite a north pole, the adjacent coils are also about opposite to north poles. So all coils of one coil bundle have the same winding direction. If you have a half coil around each tooth and if one coil is opposite a north pole, the adjacent coil is about opposite a south pole. So adjacent coils must have a different winding direction.
I suppose that all coils of one coil bundle are wound outside the generator and will therefore have the same winding direction during winding. So if the coils are mounted, you have the turn half of the coils 180 degrees to realise an altenating winding direction. This is rather complicated, especially if you have a lot of coils in one coil bundle.
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Is'nt it an advantage the coils fit better winding them on the tooth? (instead of using a coilwinder)
The hub.
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Winding of the coils outside the generator is the general practice for asynchronous motors. I think that the main reason to do so is that the winding thorn can rotate very fast and that all wires are good in parallel to each other which results in the maximum amount of copper in a groove. Asynchronous motors use rather thin wires and have many turns per coil so the coils are very flexible and even round coils can easily be mounted in straight grooves. But for certain low voltage generators with thick wires, one sometimes uses winding robots which lay the winding directly in the stator stamping.
Lying of the winding directly in the stator stamping has the following disadvantages if it is done by hand:
1) The stamping is rather sharp and the wires can easily be damaged at the edges of the stamping.
2) The wire will not be straight in the groove and the wires will cross each other so the copper density will not be very high.
3) One can very easily make a mistake if one counts the number of turns per coil.
4) It takes a very long time to lay a full winding.
But it is possible and I have laid the winding of my first 12-pole PM-generator made from an asynchronous motor this way. But I made two special brass parts with which the coil heads were guided from one groove to another. It took me more than a complete day to lay the winding of a 12-pole PM-generator frame size 112. Your stator stamping is very short and may be winding by hand is then an option if you have enough time.
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Just wrap a little tape around each tooth..toss a peg in the empty slots that sticks out aways ...only need one or two pegs..for what ever size the hole in the coil is...then just wrap the wire around..as even as you can...pull pegs when done with that coil then do same with next....if your wave winding..then of course you will need more pegs...practice with a piece of string or old wire....really dosent take vary long to knock one out.....made a few truck alt conversions in that way....
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at this point, i would say wind every other tooth for a concentrated pole winding. its half the complexity, and you can probably get more copper in it than winding every tooth. also there is less chance of a short between two coils or between two phases.
because you have to start over with cutting slots, the number doesn't really matter. pick the number of magnets you can place on the rotor for the most number of magnets, ideally the ones you already have. if they are 10mm wide, then go with that number, 15, etc, 20mm, etc. or if you have imperial magnets, 3/8th, 1/2", 3/4" or 1" wide magnets. pack them close together and use that number.
once you have the maximum number of magnets on the rotor for a practical and available width of magnet (that is, use what you already have, and or use the magnets that are cheaper per cubic inch), then choose the slot count that makes sense.
if you go back to that site i link to repeatedly, you need to choose a pole count and a slot count that makes sense. winding factor should be as high as possible. so should the least common multiple, higher = less cogging torque. also, avoid the choices that force you to use a 2 layer winding. on that website, 2 layers for concentrated pole motors means you have to wind every tooth.
I still tend to think that the magnet length to width should be approximately 1:1. meaning if your lamination stack is 20mm deep, then use 20mm wide magnets. this dimentionless ratio seems to hold across a lot of different types of machines, but we see exceptions everywhere.
for example, the 100MW direct drive hydro turbine generators that are 20meter/60foot diameter. the poles are a foot wide, all 120 of them, (or whatever number it is) and 4 feet deep/thick. perhaps in an ideal world the generator might be made to be 40meter/120foot diameter, and the poles 2 feet wide and 2 feet deep. the air gap would be the same 4 square feet, but the electrical length of the copper windings would be reduced from 10 feet to 8 feet. diminishing returns at this point. clearly they can't make the generator that large diameter, so you make it deeper instead. the weight would be the same, but the air gap velocity would be double, so you would multiply the windage losses by 8, but divide by two for the reduction in depth. so windage losses would be 4 times higher, for 20% less copper losses.
so, i'd use whatever magnets you already have. i don't think the pole count is significant until you discover what your eddy and hysteresis losses actually are.
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Windmillfriends,
Trying to build this generator it is very nice to be guided by people who are more knowledgeable than me.
I wonder what I can do for others who also want to use windenergy.
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To easely work on the generator, and because I have to make it anyway, I want to create a setup on a yaw bearing.
The hole is to mount the drive of the bearing.
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Pivot.
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update: 4 leg lattice test set up.
now I want to shape the basic generator rotor ring.
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Basis for the rotor magnet backing ring.
The outer diameter is going to depend on the magnet thickness.
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The lamination after drilling the 10 mm. slots.
Now I have to polish them en replace the coating.
I wonder what kind of coating I can use here.
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It's a bit of a struggle and a lot of ancillary material is needed.
But how else can I get a suitable lamination core?
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Made a testcoil ( 0,5 mm ø / 6 m. lenght )
Now I want to ream the inside diameter of the lamination core.
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stone the burs down with a coarse oil stone, bake the laminations at 500F/300C till they have an oxide layer.
its not critical to reduce the air gap to zero, the 48 sided polygon (i presume that's what you have) is close enough to a circle..
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By letting rotate the core on this test stand I wil try to become a nice inner diameter surface.
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Blades flange is now bolted to the stand.
The core can rotate freely to polish a nice and even inside diameter.
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Flattening the surface and machining the inside diameter nicely circular shaped.
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need some plastic inserts for each hole...I lucked out on some motor conversions and was able to reuse the original ones...when I ran short I made a few from plastic place mats...
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Make the inserts a bit longer then the slots..so when you bend the wire around it won't rub on the sharp ends of the lams...test each coil after winding for shorts to the lams..nothing worse then to have wound a stator..only to find out a coil is shorted out..!
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Thought of setting up a test rig now.
1 coil and a dummy rotor with 2 magnets ( thickness 10 mm )
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In addition to the 3 adjustable spokes I now also have added 3 fixed spokes.
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Ajustable dummy rotor to fasten and test various types of magnets.
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Test with 2 coils: wire 0,5 mm lenght 6 meter
wire 0,14 mm lenght 2 meter
With the three stacked magnets thickness 6 mm I get 0,1 volt at 100 r.p.m.
With the round magnets thickness 10 mm both coils show 0,5 volt.
How to proceed?
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for a concentrated pole design you need all of the magnets installed to get volts/hz out of a single coil without using a spectrum analyzer to isolate just a single frequency's magnitude.
and since they aren't all in phase, you will need to multiply the voltage you get out of a single coil, by the winding factor, which for a 40,44,46 magnet, 48 slot machine is 0.96 to 0.95
your 2mm thick magnets are about half as wide as they need to be, so you can take them and arrange them nn ss nn ss nn ss. a 2mm thick layer of magnets may be enough, 4 would probably be better. do you have enough magnets on hand for a 2 mm layer arranged nnssnnss? for a 40, 44 or 46 pole machine you would need 80,88 or 92 magnets.
they do need to be radially aligned perfectly far as i know. probably doesn't matter if one is out of place, but if half of them are a degree or two bunched together, you could have a lot of cogging torque.
you don't have near enough room for copper to effectively utilize the 10mm thick round magnets, doesn't mean you can't use them, its like installing a 400hp engine in a geometro. it doesn't weigh enough to effectively use the hp, but you can still burn the wheels out. but so would a 100 hp engine.
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48 slots.
So I can buy 46 magnets 20 x 18 x 5
They fit on the outer diameter of the rotor.
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2 mm layer arranged nnssnnss....... I would like to apply. Enough magnets.
But nn and ss are repelling.
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Super glue..slide the two together and hold in place for 10-20 seconds ...small mags..super glue alone should be more than enough...made a few small mills with nothing but super glue holding the mags..they still work great...on my larger mills I used super glue and epoxy stick in the gaps between the mags to hold the mags in place..great product..shock proof..hard as rock...easy to apply..
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I highly suggest you get it working with the magnets you already have. 2mm thick may be enough. Yes they repel each other but if you put a spacer between the nn and SS magnets, they will be forced to remain where they are supposed to. You could also machine the 46 slots you need for the magnets to sit in. The slot only needs to be .005" deep for the magnet to be stuck radially. It could however decide to stick to the stator instead so you still need some glue.
I don't recommend superglue.
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It seems a good idea to me to first enlarge the slots.
Then I can dispose more copper and use a coilwinder to shape the coils.
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It seems too late to say anything, but I wish you hadn't done that.
Opening up the slots makes it easier to insert the coils, but it also makes it easy for the coils to dislodge, striking the magnet rotor as it goes by.
It also removes much of the surface material that the magnet rotor passes, causing a stronger cogging effect.
Lastly, the machining of the laminations together causes them to re-connect electrically, because you've cut through the oxide barrier that separated them (even if it's just in the area you machined). This could add a large number of eddy-current short-circuits that will just drag down the whole machine.
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Thanks for your comments. New options: take apart the laminations to polish and paint.
locking up the coils with epoxy
search for a lamination core that is obtainable.
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the coils are attracted to the mags as they pass over...so be sure theirs no loose strands of wire that can dislodge...no fun having to rewire...been their !
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Found a new lamination package and that opens up new possibilities.
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motor shop find ? Nice...deeper slots as well..
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At a firm that overhauls electric motors.
To become a larger inside diameter I want to cut away the teeth and make new slots. Now 1 sheet at a time.
Then polishing, painting and assembling.
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The 0,5 mm sheets are vulnerable and slack. I need a ridgid ring to fasten them.
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Cutting the teeth down marginally reduces leakage flux and increases the peak torque available from the machine, at the expense of increasing copper losses, however in your case you cut the tooth and your slot opening doubles or triples, probably negating any benefit.
anyhow, i made a concentrated, 30 pole 36 slot machine from a 1/6th hp induction motor using 1/8th inch thick magnets that were 2 inches long and 1/4th inch wide.
the air gap was fairly small, and the flux generated in the tooth by the magnets was on the order of 1.5T, which is mostly saturated. the machine could generate about 1/2 hp at about 75% efficiency, at 800 rpm and around 200hz, not bad in my opinion for 1.875 cubic inches of magnets. it had a 36 position cog because the air gap was not identical all the way around the rotor, and because one of the coils had a shorted turn, and because one of the magnets was 1.6 inches long instead of 2 inches.
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The professional direct drives give great inspiration.
Many slots, low speed, large inner diameter.
Until finding a suitable lamination core ( at a reasonable price) I think I need to shape it myself.
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It's fine the way it is.
Cutting the teeth down to increase peaks torque levels doesn't matter anyway because you can't operate it at that torque level for more than a few moments or the copper overheats.
read here
www.mdpi.com/2075-1702/4/1/2/pdf
So it is good to have wide open teeth, the reason why is because there is less leakage flux between the teeth. The problem is, it significantly increases eddy currents in the magnets. depending on what rpm and torque you intend to get, this may or may not be significant.
from https://www.comsol.com/paper/download/199803/giacometti_paper.pdf you can find approximately the ideal ratio of slot tooth width to slot width. its about 1:1.6 to 2. the ratio you find in traditional induction motors is about 1:1, or 1:1.5, but its not that bad. in a ceramic magnet motor, 10 poles, 12 slots, i found the ratio was about 2-3:1 (i could go measure it, but you're using neodymium, not ceramic magnets). there's basically twice the volume of copper as there is volume of teeth.
far as i know, ideally the depth of the slot is ideally the same as the width of the slot. but its not that much of a hit to stick with the traditional 2 or 3:1 depth to width ratio of the slot. basically you want to keep the magnetic flux lines away from the coil, and a good way to do that is fit all the copper in a 1:1 cross section. traditional machines have deep slots because the coils span several slots. when you look at the entire coil, the coil takes up a 1:1 cross section, but its spread out across at least 3 slots, each with a 3:1 cross section ratio.
I see no reason to increase the magnets beyond the number of slots, because the increased eddy current losses scale with the square of the frequency.. this is why its so much of a hit to cut the laminations.
some magnet to slot ratios are much worse than others at air gap harmonics. the 24 magnet 36 slot has much less eddy current losses in the core as compared to the 30 pole 36 slot, but the winding factor is .86 instead of .96. so its rarely a good choice.
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So I will use the lamation core in the form as it is now.
Made a new supporting ring.
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Only 3 spokes is conveniently because of the space needed to shape the coils. But the innerring should be more robust compared to the whole.
I want to try to make an improved version.
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The new supporting ring must be stiff but not too heavy and so I want a hollow composition.
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After welding I've got a ridgid inner ring.
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Supporting ring enhanced version.
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Now I have 2 supporting rings + lamination core. After drilling and bolting the small one
I want to remove the laminations and polish them.
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The burrs are polished and the laminations feature a layer of varnish.
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Looks great...with bigger coils..its possible to weaken your mags with to large of a load..or shorting out gen ...coils put out a reverse field under load and will weaken the mags if not sized for the coils.. My Pedgen has thin neo mags glued on top of ceramic mags..I've noticed overtime and abuse they have lost a bit of strength...ceramics are still the same...
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The laminations bolted back on the supporting ring. Should I apply stainless bolts here?
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Looks like you used hot glue as well ? Stainless may be better..iron might cause a bit of cogging..but if their buried in the lams..Should work fine..what about the coils ? Glued down. ? Make sure the coil legs are good and covered...
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It is the choise: a normal steel bolt that turns magnetic itself
stainless steel that means less "good" iron in the core.
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Not sure on eddy currants...stainless if open to the elements..plastic liner around the bolt as well..keep it from shorting out the lams..?
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Original the package had thin weldings on a number of points.
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I'm not sure, but i still think the original lamination will be better, if you fill them completely full of copper.
The weld on the back side won't matter, because the flux density behind the teeth is a third or less of that in the tooth, where it matters the most.
as far as the bolts go, stainless or brass will probably be better than steel because the flux density in that area might be rather high, but i'm thinking it may not make a significant difference, simply because the frequency won't be that high.
in my 30 pole, 36 slot machine made from a 1/6th hp 6 pole induction motor, the iron losses at 1750 rpm or 400hz were about 100 watts
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The bolts can always be replaced by stainless steel bolts or also by a smaller size with plastic lining.
Modified suspension bracket of Reply #724
I will drill the holes after the axle is positioned exactly in the center of the lamination core.
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I would avoid ionic transition between dissimilar metals before I'd worry about flux. What good is weakening it's longevity for an insignificant gain?
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So in a subsequent test setup no bolts through the lamination core?
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with the bolts mounted to the lam rim...ide go with Iron bolts ..might have a slight decress in drag..with out bolts...and also a slight loss in power output..with stainless bolts you would still have the drag..and a slight loss in power..choise is yours...
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Back on the test stand. Moving the 3 magnets 20 x 10 x 2 above the coil shows 4 volt.
Now I want to make a rotor.
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What kind of voltage are you shooting for ? no dout it will be shocking !😜
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A coil with 0,5 mm wire gives 0,4 volt. So what is wise?
While I try to build a small mill it's the exchange of ideas, and if possible also of parts, I like most.
The material to put together the rotor.
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The rotor can be solid...or your just using what's available? Can't wait to see the finale build...the fun part is always the build..
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If laminated has no advantages next time I will make it solid.
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Regularly, also like today, I mow with my electric powered ride-on mower.
It would be nice to do that with energy generated by my own mill.
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Coils need the lams to help control the eddy currants...other wise you get a lot of extra drag..less output..looks great
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the rotor only deals with eddy currents according to the change in flux in the magnet, which is usually rather small.
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Solid rotor..lams for coils....guess I should have clarified..😜
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Well, whatever. Highspeed machines would benefit from laminated magnets.
Anyhow as I said before you need all of the magnets and one test coil, and then take 95% of that to get open circuit volts.
Alternatively you could setup.. a single magnet, or three of them. Fix the rotor to a pendulum and let it swing back and forth ( for 40 magnets) 18? degrees of travel. I suppose the volts you get out might be accurate... idk. Anyhow it will be rather low frequency so you'll have to rectify the output, charge up a capacitor and measure the dc volts with a high impedance volt meter.of course this assumes zero lost volts in the diodes
Anyhow I can't see how you can measure the volts from a single coil and a few magnets without an oscope and a spectrum analyzer.. if you do the pendulum gig, an oscope alone should suffice
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Because I might want to reduce the rotor outer diameter to use thicker magnets
I now have fastened the 46 magnets 20x10x2 with cellotape.
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At 60 rpm the 0,5 mm coil shows 1 volt and the 0,14 mm coil 10 volts.
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What wire thickness do I choose if I want to use the energy of the mill directly for heating?
Meanwhile I try to improve the yaw slide bearing of reply # 589
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What wire thickness do I choose if I want to use the energy of the mill directly for heating?
Meanwhile I try to improve the yaw slide bearing of reply # 589
Ultimately it doesn't matter. as long as the practical voltages and currents produced by the alternator are within reason.
amps below what wouldn't be cost effective to run the transmission line.. volts below what would kill you if you touch it.. if that's something you care about..
personally i'd wind it for a voltage that corresponds to the normally available resistances of standard heating elements.. in the range of 1500 watts for 120 volts, or 3500-4500 watts for 240v water heater elements.. according to the amount of wind power you can get.
what diameter of blades are you going for?
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As for the generator:
say 50 volts max?
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simplified welded yaw bearing sprocket.
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As for the generator:
say 50 volts max?
And how much power are you going to get from the blades at what rpm?
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With a gearbox and an asynchronous motor as generator we have made ( with varying degrees of success ) blades up to 6 m. diameter.
Max 60 rpm. With active pitchcontrol applied that is no problem.
With this generator, I don't know yet what output I can get.
Only then I can determine the blade diameter.
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The top of the mast as a pole for a new test stand.
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Yaw bearing hub.
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Nice...if your going for heat...ide go with the thicker mags..the thin mags lose their stringht under a large load...due to the coil having a reverse field when they pass over the coil..coils..
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My intention now is to make a well-arranged test stand and have, together with windmillfriends, a critical look at all components.
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Yaw axle. The heavier the nacelle the more reinforcement sheets I would like to add.
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Next issue: the yaw drive.
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As a side note:
How about shaping the lamination core out of disassembled transformer laminations?
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The yaw bearing should turn less than 1 rpm. I could use this cordless screwdriver motor ( 180 rpm ) with one more reduction.
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After mounting an extra planetary reduction of a cordless drill I have a good outgoing speed.
But I think the torque is overdone, in fact the motor could be much smaller and it's too complicated this way.
I want to search for a smaller engine with the proper reduction.
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I am really happy this thread is still in tacked.
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I agree...wating on latest progress report...😜
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As an aside relating to reply #796
I converted my electric powered ride on mower to a forklift like shape. The swing arm pivot of the power supply cable is attached to the top of the mast. Easier steering and riding around now.
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No doubt you get a lot of second looks in that rig.
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Lawn mower on steroids...with that you could trim the tops of hedges..or even give someOne..a flattop crew cut..😜
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You could tackle some REALLY long grass with that...
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Actually I like this way of mowing because it brings less damage to the environment.
My big goal is to be able to mow with the energy of my, in cooperation with windmillfriends built, small windturbine.
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I myself also would like to be involved in others who build a small mill.
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The slide yaw bearing of reply #810 I would like to change to a double row ball bearing.
2 outer raceways turned / grinded in the hub.
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Few years ago I made a yaw drive prototype.
Chain sprockets , Worm reduction , Cordless drill-motor.
Never used it in real situation .
Very content with the active pitchcontrol system.
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Really interesting project. Is it still available for home constructors for further build?
The "axle" of the yaw bearing.
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shortening the spacers = iserting more rollers = heavier load possible.
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This construction is derived from reply # 810 Weight: 1747 grams.
I would now like to make a simpler improved version with a slightly larger sprocket.
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I am quite good at working with metal ,but making a slew-bearing I am too young for it.
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Cooperation is the answer.
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Shaping the new light yaw bearing. Filling ring at the holes.
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Found these pinions ( 3 Euro ) Now I need to shape an appropriate sprocket on the yaw bearing.
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Welded teeth at the circumference. Following is the internal assembly.
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Inner ring+roller-raceways.
Thinking another and easier method might be to make the yaw bearing from composite material.
Or 3D printing.
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A base for continuing with the other components.
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First of all, back to the generator.
I would like to make a test rig of an axial generator with a lamination core between the two magnetrings.
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Axle and hub.
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Are you placing the coils on each side...two separate stators ? Looks great...!
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I thought at 1 stator, with a steel lamination in the coils, between 2 magnet rings.
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Try it both ways..without Steel in the coil holes...then other...might have a bit of cogging..with the steel in the coils...might see a few extra volts with the steel..cogging might take that advantage away..? Tried it once on a single phase alt..few years back....took a pipe wrench just to spin it around...on my 20-15 Three phase excersize bike alt..with steel in the coils..I can spin that with one finger....it's all in the design...good luck..
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Magnetrings+setting.
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For the generator I could shape the lamination core with the material of a scrap transformer.
Does anyone here have experience with that?
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Lamination core for the axial generator out of transformer sheets.
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New coilwinder. Magnets holding the core and two side plates to wind the coil.
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Nice...
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2 coils of 14 m wire / 10 layers. With inserted lamination core.
I wonder if it makes sense to add laminations in the space between the coils.
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Do a simple test...mount the coil..then run your mags by it...with and without lams..helped out on my pedgen...small amount of cogging..still able to spin with one finger...my coils are mounted to a steel band as well...the coils are fairly thick..so having the metal in the coil hole..helped to magnatize the entire coil...
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Energize the entire coil..might be a better way of saying it..😜
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Better use tapered shaped laminations, coils and magnets?
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Seeing the coils in the mould I think I'd better take another ratio of more and smaller coils and lam.core.
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Using iron coil cores will certainly increase the strength of the magnetic flux flowing through the coils as the air gap becomes much smaller. Therefore the voltage generated at a certain rotational speed will be much higher. However, iron cores may cause strong fluctuation of the clogging torque depending on the number of armature poles and stator coils. This fluctuation is maximal if the number of armature poles is equal to the number of stator coils. This fluctuation can be minimised if the number of armature poles is two more or two less than the number of stator coils but this requires a special winding (see public reports KD 560, KD 580 or KD 632).
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If I can use transformer sheets the shaping of a lamination core becomes easier.
Hub +rear magnet backing ring.
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The distance between the magnetrings I now can vary up till 34 mm.
Each ring 30 magnets 10 x 5 (thickness 4 mm.)?
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The lamination packages in the mould pressed on a polyester layer.
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Modified coilwinder.
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That looks like something I can turn my spare meat grinder into .
Thanks for the idea!
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Dummy stator + a few coils.
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Composing the basering for the stator mounting bracket.
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Stator bracket. Now first proceed with the stator.
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18 coils in the mould to shape the stator.
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On the photo I count only 18 stator coils (but 36 stator cores). How many magnets do you use? I would prefere 34 magnets.
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You're right. I have adjusted reply #862
I will buy 34 magnets. How would you connect the coils?
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Ready for packing the coils.
I want to have the start-and end wires outside of the mould.
Different circuits are possible than.
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Capturing the wires is depending on the way of connecting.
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Some measurements first.
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Looking good.
The oscilloscope finally give me some scale to judge the size!
How have they turned out?
May I ask if you are only testing resistance and continuity, or other parameters, too?
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Once this test set up is working properly I can scale up.
With the scope it is possible to measure characteristics like volts when I move a magnet over a coil.
Now organizing the wiring.
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Plan for connecting the coils and shaping a terminal block.
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Got 68 magnets + glue.
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The magnets glued to their backing rings.
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Stator terminal block in polyester.
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The thickness of the lamination core is 11 mm.
Now stacking magnets.
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When ordering extra magnets I can make stacks of 3, 4 or 5 pieces.
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Is this real state of the art axial flux technology?
https://www.youtube.com/watch?v=rGu7XDapR58&t=
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No design breakdown of how it is built... I smell snake oil...
Is this real state of the art axial flux technology?
https://www.youtube.com/watch?v=rGu7XDapR58&t=
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its been known for a very long time that axial flux machines have a higher torque density at the cost of efficiency.
the largest 5,7,10MW wind turbines are all radial flux, neodymium magnet machines. they also have generators in them that are larger than the 100MW hydro power generators. (which don't need any magnets to get the same "efficiency" )
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It is about whether this axial implementation on youtube, scaled down, can be a guidance for homebuilders.
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Turning at about 60 rpm it shows 1,5 volts.
Before scaling up what to do to improve this test set up?
Make a new thinner lamination core and thus less stacked magnets?
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My instinctive suggestion is to make each pole 4 magnets, two wide, instead of a stack of 5. To illustrate:
You have shown:
------------- (ROTOR)
N S
N S
N S
N S
N S
gap
~~~~~~~~~~ (STATOR)
gap
S N
S N
S N
S N
S N
------------- (ROTOR)
My recommendation:
------------- (ROTOR)
NN SS
NN SS
gap
~~~~~~~~~~ (STATOR)
gap
SS NN
SS NN
------------- (ROTOR)
This arrangement allows the flux path to be much shorter for all magnets, and is both thermally and structurally more stable.
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For your recommendation I need to buy extra magnets 10 x 4 x 2
To be able to apply your rated remarks I believe it's better to restart this test set up with a larger diameter.
Starting with new backing rings and magnets and new lamination core and coils.
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I'm building my turbine with a hub with a hollow center, and was wondering if any new developments on controls for variable pitch systems. I sadly never got into programing and was wondering if some one would sell a programed arduino with a copy of software so if it fails can just program a new one?
I have no shortage of linear actuators. But control systems not so much! I ordered a new breadboard so eventually I can prototype analog controller but need ideas.
I want to do as much of the work on paper possible to save allot of fab head aches!
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...Starting with new backing rings
???
You make me hesitant to reply.
It sounds like you are about to discard much of your work simply on my last hunch. I hope that is not true!
I was attempting to suggest an improvement to your magnet poles without requiring you to change any of your other components such as the rings.
But from this you take the message that you need new rings? I would expect a discussion, not a redesign.
From my point of view, I can see very little of your project as a whole.
Please do not overreact to my humble suggestions.
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Sparweb,
No problem at all. Wind energy excites me very much and all the comments of windmillfriends I find very valuable.
Regards Rinus
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mbower;
What Sparweb;
Posted makes sense to be .
From the days of early NEOs, I remember there being a pretty long discussion about stacking NEOS. Even stacking the hard drive NEOS on top of ceramic ones
The more you stack the less "Flux" depth comes to mind, so if you re-stack those sets you have, per Sparweb's illustration. You should see a similar voltage, not to mention each re-stack will net you spare magnets.
It is certainly worth a try, before ordering more magnets or at least try while waiting for the others to arrive.
Just a thought
Bruce S
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So if it is slightly possible no more stacking.
Modified hub of reply #839
New support of the magnet backing rings.
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i recall conversions about stacking magnets and experiments with stacking a second magnet on top of the first does not double flux density it only ads about 20 %. were as placing two mags side by side doubles the lines of flux a coil cuts through.
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Size backing rings is 10 x 5 mm.The idea is to make lamination packages of 10 x 4 mm ( thickness 8 mm )
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Hi Xeon Pony.
My blade pitch controlled windmill is a very nice working windmill.
If you have some technical experience its not difficult to make.
It is clearly explained in de topic.
Some additional information.
The wind turbine is a 10 feet Piggott 24 volt with variable blades , controlled by a lineair actuator and an Arduino Uno
programma in C language.
The software is custom tailored for max 350 rpm and min 260 rpm.
If you need other rpms it's easy to change the software ,I can send you by PM.
Rgds Midwoud1
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The blade system and actuator will be the easy part it is the control is the hard part for me! going to be exciting getting the real unit made! Vs the air X
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Suggestion:
Let us try first to improve the hardware parts for pitching.
And then show it to forum members with knowledge of control systems.
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New magnet backing rings.
-
It would be nice to have a dialogue about scaling up to 300 mm outer diameter.
e.g with 51 Lamination packages 20 x 8 x 8 ( 17 per fase )
and 49 magnets 20 x 10 ( thickness 5 )
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300 mm outer diameter magnet backing rings. Thickness 4 mm.
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To glue together the sheets ( 20 x 8 mm ) of the 51 lamination packages I now want to make a mold.
What do you think of the size 20 x 8 (thickness 8 mm) of the packages,
compared to magnets 20 x 10 x 5 mm?
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It is not so easy to figure out shape and size of the laminations, magnets and coils.
In the meantime, I would like to go on with a new axle and hub for the 300 mm. magnet backing rings.
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Is it me or is this thread getting derailed from this project, probably be better in its own thread?!
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My intention is to build on the Hugh Piggott design such as Midwoud showed in this topic (with active pitchcontrol)
And to get contacts and constuctive discussions with windmill friends.
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yes I understand this but there is way to much fluf with nothing to do with the topic building up in here, yours is a very nice project and think better served if it was given it's on thread then link to this one for the pitch control parts.
Nothing personal just I been looking over this for the topic and just so much more messy now then what it was.
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XeonPony,
Thanks for your comment. You're right.
Let us talk about active pitchcontrol in this topic.
Regards Rinus.
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To attach the pitch control system I have threaded holes M4 at the back of the shaft.
-
Pitch bracket for guiding the threaded M 12 steering rod.
-
Mounted bracked / steering rod / cable driven nut.
-
Now first I want to shape the blade suspension.
Base ring. Later on the holes need to be reamed to 6 mm.
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Now I need 3 bearing arrangements.
I'd like to integrate the bearings in the blades.
-
The pitch bearings for these small blades, I would like to perform as slide bearings.
Lightweight: polyester on steel and stainless steel nut on thread.
-
The polyester sleeves which have to be included in the blades.
-
Now it comes to guiding the movement of the pitching rod.
-
How can we come to a pitch control steering design for do-it-yourself builders such as applied on proffessional mills?
Pitch rod bearing.
-
Midwoud has made a steering unit for me. It's based on an Arduino and controls the number of blade revolutions of his Piggott 3 m.
Along with forum members I would like to try to customize and extend that arrangement.
The mold for the pitch steering guiding.
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Besides the speed of the blades it would be nice to monitor the power output, the vibration switch, the generator temperature etc.
Steering rod guidance frame.
-
Once a professional controller for our mills is developed, everyone of us can use it.
The blade push rod.
-
The blade ajustment.
For clarity I have covered the generator with paper.
-
Happy NewYear to all Fieldliners
-
Looking good. Thank you for keeping us up to date all year.
-
Especially at stormy weather pitch contol promotes a good night sleep.
How can we improve the components?
-
I'd be uncomfortable personally relying on pure friction to transmit torque to my blade, I'd use some sort of locking pin into the blade root my self.
-
You are right. Safety first.
Can we get in touch with forum members who can implement strength calculations?
-
Any system I build that requires torque transmission for control I use splined or keyed shaft, being the key runs same length as the shortest member, failing those two usually a couple grub screws or roll pin, just some sort of positive locking system.
As time goes vibration and water ingression can cause enough slippage for bad things to happen.
-
To twist the blade the necessary torque power is not that huge. Also because the blade itsself is suspended in the line of gravity.
Also see reply #907
-
Sealings around the blade root can prevent water ingression.
-
Isn't your wind direction incorrect in the 01/16 post? The wind normally is coming at the flat side of the blade, and due to the rotation of the blades the relative wind typically hits the airfoil at angle just a few degrees off the cord line at the tips.
-
Kitestrings,
You are right of course. But the drawing only served to support the question which I very much would like to talk about.
How can we improve the components?
-
It seems to me worthwhile to regard the pitch steering as used by Midwoud
-
The steering is based on the measuring of the voltage of one of the phases of his Piggott generator.
But I would rather like that he describes the circuitry.
-
What about other ways of measuring the rotations per minute,
and on that basis installing the angle of the blades?
-
It would also be nice if I could make a simple direct-drive motor to move the pitch steering rod.
-
On reflection I would like to first try an axial direct-drive motor.
It only must turn limited rpm.
How to make the control?
-
The pitch steering rod provides at the same time the axle for the hub with the magnet discs.
-
Number and thickness of the magnets is not determined yet.
-
The heart of the statormal is divisible to facilitate unloading.
-
Actuator test setup during high windgust at max windmill rpm.
https://www.youtube.com/watch?v=N3hPAq9e8gA
-
Is the actuator in your mill of the same type as this one?
-
lineair actuator active blade pitchcontrol. Reliable system.
Adjustable stroke / speed , forward and reverse , powerfull Cordless drill motor , Timing belt ,
threaded rod . Actuator activated by max and minimum prop rpm by an Arduino Controller.
-
So much closer to reality. You must be getting excited to see the hub mechanics come together.
-
Glad to see other hub mechanics .Hope we can interchange ideas, alot experience here.
-
When Midwoud started this topic there were lots of nice enthusiastic reactions, and I thought that windmill friends would pick up the design and go on with it and write about on the forum.
-
Maybe people who live on the countryside and want to do something with wind energy can tell what they are hiccups about.
We can then look at possibilities, for example through cooperation.
-
A windmill friend told me that I may have expressed myself wrong in Reply # 939
What I wanted to say:
Maybe people who live in the countryside, and want to do something with wind energy, can tell us what kind of windmill they want to build.
-
Hi mbouwer,
My concerns with a variable, powered-pitch mechanism like this are pretty much the same. To me, it adds quite a bit of complexity up on the tower. With this comes extra components & weight, wear points & maintenance and the potential for failure. For a small turbine it is just hard to justify.
Generally I've leaned toward passive designs like a furling tail. We have added a power furling unit at the base of the tower to shut things down either automatically or by manual intervention - say in the case of an imminent storm, but the normal furling happens all on its own. It is not dependent on a motor or actuator or control to function.
I'm in no way trying to discourage you, rather I've enjoyed the progress, and alternate approaches. It may, however, be one reason others haven't adopted this design. Other factors are quite simply that PV has far and away taken reign of much of the RE market. It has become lower cost, more predictable, modular... and comparatively easier to permit and get installed. I think there are just less of us wind enthusiasts still around now...
~ks
-
Hi Kitestrings,
With pleasure I always read what you show us about your turbine.
But do'nt you think active pitch control would be a real improvement also for you if it could be maded simpler and fail safe? Proper implementation may take a while, but that's a challenge and no problem.
The pitch drive can also be done from below the mast. Then it is always possible to control your turbine, and in a storm it can continue to run quietly. The load remaining low.
Wind mill enthusiasts are a little dreaded to build a heavy nervous windmill in their yard I think.
I would like to focus on nice creations, with slow speed, and always manageable.
And for which we can supply to each other the components.
Regards Rinus
-
But do'nt you think active pitch control would be a real improvement also for you if it could be maded simpler and fail safe? Proper implementation may take a while, but that's a challenge and no problem.
Actually, I don't...I guess this is my point. Having installed and maintained small turbines - we did mostly residential induction generators, but some eventually were scaled up to about 60 kW; and some off-grid installs - for a number of years, my bias is to have the simplest, most robust equipment on the tower. Electronics, rectification, regulation, monitoring, diversion, protection and controls can all be done on the ground, and under cover. To me this is preferred.
Our turbine, it is by no means perfect, but I like that fundamentally it has three moving parts on the tower. The rotor turns, the machine yaws, and the tail hinges, or furls to protect things. All this happens without any signals or sensors or wiring.
The power pitch mechanism that Frans designed is very elegant, clever, and precise. And, I only wish I had some of his skills. It does however, introduce a great deal of complexity, particularly on the tower. Where we live most turbines have to up 80-120' to work well. So, any added maintenance is an important consideration.
-
On that beautiful spot and with that background it is great that you can use wind energy in that way.
And I understand what you are saying.
Personally I like the complexity and the technique of modern windmills and that really appeals to me.
-
I really love what you guys have done and what you are doing with active pitch control. Keep doing what you are doing. There are lots of us quietly watching your progress.
I decided to build a side furling tail and fixed pitch prop for the reasons stated by kitestrings. Also, i would add that building a turbine is a daunting task and adding another layer of complexity probably makes it too big a project for most people.
My observations from the last two years running my 13' turbine would be that it works very nicely and would only gain a very small percentage from variable pitch.
We are off grid here, so we don't really have a use for the high storm wind type production. It is the slow, steady, 500w output that we really look for. For grid tied people, variable pitch might be more worthwhile.
If you guys are having fun tinkering with variable pitch, keep on doing it. I enjoy reading about it.
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I'm tempted to weigh in... but have little to add to the good points made here.
About 10 years ago (has it really been that long??) I teamed up for a while with a fellow who lives nearby, building DIY turbine projects together. His innovation was the pitch-control hub that he had developed. While I was fascinated by the way his hub worked, it needed a lot of tuning to get it to operate in the right wind speed. Each adjustment required a different torsion spring - adjusting the mass balance was not enough. For his part, he was not interested in wood carving as I am, nor doing the math to get the pitch and curve just so. He preferred to buy simple fiberglass blades, which undoubtedly is less expensive than what I do. It has taken me 3 generations of hand-carved cedar blades to get the right generator-blade match, which is not too different from his iterations of torsion springs needing trial-and-error.
Here I find the active pitch-control to be preferable to a passive one. It solves the tuning difficulties with a control system at ground level. Now the issue becomes reliability of a system distributed between an actuator motor in the nacelle, and electronic devices at ground level. Franz made it fail-safe so I call that a win. Anyone with the needed skill could go further and add redundancy and robustness to make it last a long time. This thread deserves all the attention it's received and I have referred to it many times over the years when the subject comes up.
-
There are wind energy enthusiasts on this forum who already have a turbine and use wind energy. That in itself is quite an achievement I think.
They are the ones who have experience and are now the ones who react in this discussion. Thanks for that.
But how can we focus on and involve builders who want to concentrate on inventing, designing and building active pitch control?
-
Active pitchcontrol can also make a small turbine quiet and safe.
This topic started here about 10 years ago, but it seems that it does not inspire anyone to apply it.
Or even to discuss methods on this forum.
But let's be in no hurry:
It also took the professional windmill builders a very long time before they all understood they needed ajustable blades.
-
Happy New Year to Midwoud and all other windmill friends.
And perhaps in 2021 we together will find simpler manufacturing techniques to apply pitch control.
-
Pitch control has been discussed in several of my public KD-reports. It is described in KD 437 of the VIRYA-15, starting at chapter 6, in KD 622 of the VIRYA-5 starting at chapter 9 or in KD 654 of the VIRYA-3.6PC starting at chapter 6.
-
Nice descriptions. And it would be nice to also consider the system, with external energy source to steer, as applied by Midwoud on his Piggott.
-
Active pitch control [attach=1]
-
Pitch control systems can be divided into two main categories A and B and each main category can be divided into several sub categories with each different mechanical constructions. Every category has certain advantages and disadvantages. As all pitch control systems result in a complicated hub construction, they are normally only used for rather big rotors.
Main category A
For this category, the movement of the blade around the blade axis is steered by the aerodynamic moment, by a moment caused by centrifugal weights or by a combination of both. Both moments increase with the square of the rotational speed. These moments are counter balanced by a moment caused by a spring and this spring moment keeps the blade in the normal working position up to a certain rotational speed. One can use positive pitch control for which the blade angle is increased or negative pitch control for which the blade angle is decreased. Negative pitch control is also called active stall. The aerodynamic moment around the quart-chord point has a direction such that the angle of attack is decreased and so the blade angle is increased. So the aerodynamic moment supports positive pitch control. The main advantage of this category is that it works automatically and that no external energy is needed to activate the system. The main disadvantage is that the pitch control system can't be used to turn the blades about 90° to the vane position for which the rotor stops. Another disadvantage is that the system works only nicely if the bearings of the blade rotation have only a little friction but as the bearing load is rather high, this is difficult to realize, especially if plain bearings are used.
Main category B
For this category, the movement of the blades is coupled mechanically such that there is a shaft in the center of the rotor which is moving forwards or backward. The movement of this shaft is activated by a hydraulic cylinder or by a linear electric motor. The movement of this shaft can be steered by any signal like the wind speed, the rotational speed, the power, the temperature of the winding of the generator, vibrations or whatever. A computer is required which transforms the signal into the right movement of the central shaft. The main advantage of this system is that any signal can be used to activate the pitch movement. The system can therefore also be used to stop the rotor if the blade can be turned about 90° to the vane position. This system can also be used to facilitate starting of the rotor at increased blade angles. The main disadvantage of this system is that some energy is needed to activate the central shaft and so the system isn't working automatically. So if something goes wrong with the computer or with the energy supply, the system is no longer active and the rotor stays in its normal working position. This may result in too high forces in the blades at very high wind speeds resulting in destroy of the rotor. This disadvantage can be cancelled if the blade is always pushed back by a spring to the vane position but this requires a rather strong hydraulic cylinder or linear electric motor to counter act the spring moment for the normal working position.
More information about this subject is given in chapters 6 - 14 of my public report KD 437.
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There are a couple of related influences, some discussed much earlier in this thread, but active pitch mechanisms usually result in a heavier rotor assemblies. As much of this weight is added closest to the plane of the blades, it may also require a more robust frame and/or yaw assembly to support it. It may require additional conductors and slip-ring poles.
Adriaan points to the idea that for the system (Category A) to work well depends on the blades having relatively low friction about their axes. I think this is true of both categories, and to achieve this depends not only on the selection of the bearings, and related components, but also on regular maintenance of those components and points of contact (cleaning, lubrication, removal of corrosion). We recently discussed some of the older Dunlite turbines. Although they were a very heavy, robust build (Cat. A type), they often had severe damage over time if they were not maintained.
I do agree that an advantage of the Category B designs is that you also have the added potential of shutting down the turbine. This feature is a significant advantage if there are hurricane force winds on the horizon, or say if there is icing, or a need to climb the tower for inspection or maintenance. In my experience this is one of the best ways to avoid problems; wait out the really rough stuff.
With either category, you will have introduced more complexity. Most of it up on the tower.
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Adriaan points to the idea that for the system (Category A) to work well depends on the blades having relatively low friction about their axes. I think this is true of both categories, and to achieve this depends not only on the selection of the bearings, and related components, but also on regular maintenance of those components and points of contact (cleaning, lubrication, removal of corrosion). We recently discussed some of the older Dunlite turbines. Although they were a very heavy, robust build (Cat. A type), they often had severe damage over time if they were not maintained.
With either category, you will have introduced more complexity. Most of it up on the tower.
In my calculations I have found that the aerodynamic moment is rather small. The moment of centrifugal weights will also be rather small if not very large weights are used. So the friction moment of the bearings must be low for category A systems if you don't want to have large hysteresis in the pitch movement. It is true that the friction moment may increase if the lubrication of the bearings becomes worse after certain time. It is therefore very important to use good seals for the bearings although seals give some extra friction.
Most safety systems of category B use hydraulics to activate the movement of the central shaft. Very high forces and therefore very high moments can be executed by hydraulic cylinders. So for category B, it isn't very important that the bearing friction is low.
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Yes, and it is not just the bearings to consider. The blades have to rotate in unison, so there is linkage between them. There is also the center shaft and slides of some sort that limit the range of motion. It may go without saying, but the entire mechanism needs to be protected from the elements, and even condensation can introduce corrosion or frost. I've had sliprings on my engine driven generator glaze over or stick the brushes momentarily, preventing output, when the wrong combination of humidity and and temperature drop have combined. (Stop and restart it, and all is good once a bit of heat is present).
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Frans;
There are quite a few new faces here.
Perhaps you could give us an update on these beauty?
https://www.youtube.com/watch?v=U9DdA5LWs08
Many Thanks
Bruce S
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Yes, and it is not just the bearings to consider. The blades have to rotate in unison, so there is linkage between them. There is also the center shaft and slides of some sort that limit the range of motion. It may go without saying, but the entire mechanism needs to be protected from the elements, and even condensation can introduce corrosion or frost. I've had sliprings on my engine driven generator glaze over or stick the brushes momentarily, preventing output, when the wrong combination of humidity and and temperature drop have combined. (Stop and restart it, and all is good once a bit of heat is present).
The blades have to be coupled mechanically to each other if the system contains centrifugal weights. This is because apart from the centrifugal force, also the own weight is acting on a centrifugal weight. The direction of the moment caused by the own weight depends on the position of the blade and so if it is positive for one position, it will be negative if the blade has rotated 180°. This fluctuating moment causes a torsional vibration in the blade. But if the blades are coupled mechanically, the resulting weight moment of all blades together is zero.
Some traditional Dutch windmills have air brakes at the blade tip of two opposite blades which are activated by a centrifugal weight and for which there is no mechanical coupling. I have observed a windmill with this system and it could be seen that the brake goes out for a certain position of the blade and goes in if the blade has rotated 180°. As traditional Dutch windmills have a rather low design tip speed ratio of about 2.5, the tip speed is rather low and the force because of the own weight of the centrifugal weight is therefore rather large with respect to the centrifugal force acting on the weight. The oscillating system must cause some variation of the balancing of opposite blades and some variation of the blade thrust but as the blades are very heavy and very stiff, this isn't hindering the functioning. The positive effect of automatic limitation of the maximum rotational speed is more important than the negative effect of the vibration.
If the blade movement is only activated by the aerodynamic moment, there is almost no torsional vibration as the aerodynamic moment is almost constant for every position of the blade. The aerodynamic moment is determined by the relative wind speed W which is mainly determined by the blade speed for the most important outer part of the blade where the blade speed is high (see formula 5.11 of report KD 35). So even if there is some variation of the wind speed in the rotor plane, this results in almost the same relative wind speed W for every position of the blade. Therefore mechanical coupling of the blades isn't necessary if the blade movement is only activated by the aerodynamic moment. But as the aerodynamic moment is rather small, the bearing friction must be low and every blade must have its own spring and its own stop for the working position. Cancelling of the coupling mechanism makes the system more simple, especially for a 2-bladed rotor. This system is described in detail for the VIRYA-5 rotor in chapter 9 of report KD 622.
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It sounds like there are more than two categoriess to control pitch. And it sounds like weight and the harmonics vary by choice. I'd argue that furling is a form of pitch control.
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It sounds like there are more than two categoriess to control pitch. And it sounds like weight and the harmonics vary by choice. I'd argue that furling is a form of pitch control.
It depends on the definition. I say that there are two main categories for pitch control systems but within each main category you have several sub categories. For pitch control, it is generally meant that the blade angle varies and so the blade can turn around the blade axis. Furling means that the whole rotor is turned out of the wind and if this is done, you can use a rotor with fixed blades. But there have been built windmills which have both pitch control and furling like the big Windcharger. For these windmills, the pitch control system is normally used to limit the rotational speed and thrust. The furling system is used to stop the rotor by turning the whole rotor 90° out of the wind if no power is needed, if a big storm is expected or if maintenance is required.
If the rotor is furled, it turns with a certain yaw angle delta in between the rotor axis and the wind direction. If the blade is followed during one revolution, you will see that the angle of attack alpha varies. However, the blade angle beta, which is the angle in between the neutral line of the airfoil and the rotor plane for a certain station, is constant and therefore furling is no form of pitch control.
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Yes, I'd also interpreted this discussion to be focused on blade pitch/pivoting strategies.
One additional consideration -
Most of the pivoting blade designs I've seen have the rotor mechanism enclosed (e.g. Dunlite, Jacobs). Some designs have the blades mounted to a flange-plate, so they are just thru-bolted to a pivoting assembly. Others, however, have a shaft that extends into the root of the blade. For this approach you have to consider carefully how the blades are mounted and removed. I've seen some where corrosion makes them a bear to remove. The pockets themselves are also a place where water can enter, be trapped, and cause imbalance over time.
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I wouldn't be surprised someone uses Arduino or Raspberry Pi to create an active pitch control mechanism on the wing tips.
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I wouldn't be surprised someone uses Arduino or Raspberry Pi to create an active pitch control mechanism on the wing tips.
In stead of turning the whole blade, it is also possible to turn only the blade tip. 3/4 of the power is generated by the outer half of the blade. So a relative small outer blade section can generate enough drag to consume all energy generated by the inner part of the blade. However, such a construction has some disadvantages. One is that the outer blade section can become rather noisy if it isn't streamed at the optimal angle of attack. Another disadvantage is that it is more difficult to connect the movement of the different blade tips as this requires a rod which is moving in the fixed inner part of each blade and a coupling mechanism at the center of the rotor.
About 30 years ago the University of Delft has tested a pitch control system of the blade tips on a 8 m diameter windmill which was using the rotor of a helicopter. They used a mechanism for which the blade tip moves outwards because of the centrifugal force and for which it rotated because of a helical twist in the blade shaft. What I remember was that the system worked nicely and I think that there was no mechanical coupling in between the blade tips.
About 40 years ago I have tested elastic air brakes on each tip of a 3-bladed windmill rotor with a diameter of 4 m. I have also tested a scale model in the wind tunnel and the air brakes were very effective in limitation of the rotational speed. There was no mechanical coupling in between the three air brakes. However, at high wind speeds, the noise production was enormous for the real windmill and therefore this idea was cancelled. Windcharger has made small 2-bladed rotors with air brakes at rods which make a 90° angle with the blades. But as the speed at the position of the air brakes is much lower than at the blade tip, you need much larger air brakes to get enough braking torque than for my rather small air brakes at the blade tip. The advantage of the lower speed is that the noise production is much lower.
So the advantage of turning the whole blade is that there is no part of the blade which generates a lot of energy which has to be destroyed by the outer part of the blade.
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An elastic airbrake was the basis to conclude active blade tips are noisy?
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For an elastic air brake at each of the blade tips, the whole blade is active, so the airbrake has to destroy all power generated by the rotor as the system has to work also for an unloaded generator. The field tests have been performed for an unloaded rotor. The blade speed is maximal at the blade tip so you need only a small air brake area to generate a lot of drag. The air brake was made out of 1 mm stainless spring steel and had a chord of 200 mm (the same as the blade) and a width of 150 mm. The air brake was connected to the blade at the front side and bent outwards due to the centrifugal force acting on it. It produced a very large tip vortex which sounded like a helicopter was coming over.
If you turn only the blade tip, a smaller remaining part of the blade is active than for an air brake at the blade tip but this active part of the blade will still generate a lot of power. This power can only be destroyed for a small blade tip if this blade tip is stalling. So you need negative pitch control for the blade tip. A stalling blade tip will also be very noisy, probably less noisy than my elastic air brakes but I won't chose this option if you have neighbours.
The advantage of positive pitch control of the whole blade is that the lift coefficient of the whole blade is reduced and so there is no part of the blade which generates a lot of energy which has to be destroyed by another part of the blade. Negative pitch control of the whole blade can also be rather noisy but it can be used for constant chord blades as for those blades, stalling starts at the blade root. This is because for those blades, the lift coefficient is low at the blade tip and high at the blade root.
In about 1980 there has been a France company (I can't remember the name) which supplied a windmill with a rather big 2-bladed rotor with negative pitch control. They used a clever pitch control mechanism with two springs in it with different stiffness. This made that the blade angle was large during starting and the weak spring was compressed already at low rpm which makes that the rotor was turning with the normal blade angle at moderate wind speeds. At high rotational speeds, so at high wind speeds, the strong spring was compressed and then the whole blade was stalling. So an advantage of negative pitch control is that you can have a large blade angle during starting if you use two springs with different stiffness.
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I wouldn't be surprised someone uses Arduino or Raspberry Pi to create an active pitch control mechanism on the wing tips.
In stead of turning the whole blade, it is also possible to turn only the blade tip. 3/4 of the power is generated by the outer half of the blade. So a relative small outer blade section can generate enough drag to consume all energy generated by the inner part of the blade. However, such a construction has some disadvantages. One is that the outer blade section can become rather noisy if it isn't streamed at the optimal angle of attack. Another disadvantage is that it is more difficult to connect the movement of the different blade tips as this requires a rod which is moving in the fixed inner part of each blade and a coupling mechanism at the center of the rotor.
About 30 years ago the University of Delft has tested a pitch control system of the blade tips on a 8 m diameter windmill which was using the rotor of a helicopter. They used a mechanism for which the blade tip moves outwards because of the centrifugal force and for which it rotated because of a helical twist in the blade shaft. What I remember was that the system worked nicely and I think that there was no mechanical coupling in between the blade tips.
About 40 years ago I have tested elastic air brakes on each tip of a 3-bladed windmill rotor with a diameter of 4 m. I have also tested a scale model in the wind tunnel and the air brakes were very effective in limitation of the rotational speed. There was no mechanical coupling in between the three air brakes. However, at high wind speeds, the noise production was enormous for the real windmill and therefore this idea was cancelled. Windcharger has made small 2-bladed rotors with air brakes at rods which make a 90° angle with the blades. But as the speed at the position of the air brakes is much lower than at the blade tip, you need much larger air brakes to get enough braking torque than for my rather small air brakes at the blade tip. The advantage of the lower speed is that the noise production is much lower.
So the advantage of turning the whole blade is that there is no part of the blade which generates a lot of energy which has to be destroyed by the outer part of the blade.
There is a commercial unit near me that uses blade tip brakes. Looks to be an induction type and has twin out swept tails(to make it track better?). No clue if it is functional still, has been up for 30+ years. See the tips rotated 90 degrees all the time...
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Pitchcontrol.
Rotorhead gear
[attach=1][attach=1]
https://youtu.be/MRVGYVrgsdc
electronic control tach
tacho-chip LM2917 > Arduino Uno software in C
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In the photo I see that the turning point is lying about at half the blade chord. This results in a large aerodynamic moment coefficient which has tendency to increase the angle of attack alpha and so to decrease the blade angle beta. The mechanism which turns the blades has to be that strong that it can over power the total moment of all three blades at high wind speeds. The influence of the position of the turning point is discussed in chapter 4 of public report KD 463 for the Gö 623 airfoil and in chapter 5 for the Gö 624 airfoil. The relation in between the moment coefficient Cm (-) and the Moment M (Nm) is given by formula 3.3 of public report KD 35.