Active Pitchcontrol

[midwoud1]

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

and other uploads Midwoud1 on YouTube

Regards Frans.

[bj]

   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

[fabricator]

That is absolutely beautiful, it would be nice to see some video if the back side with the pitch control working.

[midwoud1]

http://www.youtube.com/user/midwoud1?gl=NL&hl=nl#p/u/7/xOqan-okQ40

[fixitguy]

so simple..the pitch controller.

[SparWeb]

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!

[midwoud1]

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

[Flux]

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

[TomW]

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

[Dave B]

 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.

[kitestrings]

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

[SparWeb]

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.

[midwoud1]

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.

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

[kitestrings]

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

[Perry1]

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

[prasadbodas2000]

amazing setup, hats off to you.... thanks a lot for sharing

[midwoud1]

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.

[windy]

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

[midwoud1]

   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

[kitestrings]

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

[midwoud1]

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.

[fabricator]

You are not gonna smoke an alternator in eight seconds.

[TomW]

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..

[fabricator]

Well, you can never say never, but plenty of gravity furling machines have been smoked that were supposedly fool proof.

[klsmurf]

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.

[midwoud1]

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

[Antero]

This is the best I have seen for a long time  

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

[Antero]

This solution will change everything in small windpower.

Antero Rantanen
Finland

[Antero]

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  

-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  

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

[Antero]

Can you make small windpower any better than this ?

Antero

[TomW]

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

[Volvo farmer]

Can you make small windpower any better than this ?

Antero

I can make it more reliable.  Is more reliable better or not?

[Flux]

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