Author Topic: Active Pitchcontrol  (Read 240493 times)

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midwoud1

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Active Pitchcontrol
« on: October 04, 2011, 02:11:34 PM »
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.


« Last Edit: October 06, 2011, 07:50:27 PM by kurt »

bj

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Re: Active Pitchcontrol
« Reply #1 on: October 04, 2011, 02:29:47 PM »
   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 :)
"Even a blind squirrel will find an acorn once in a while"
bj
Lamont AB Can.

fabricator

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Re: Active Pitchcontrol
« Reply #2 on: October 04, 2011, 02:46:00 PM »
That is absolutely beautiful, it would be nice to see some video if the back side with the pitch control working. ;)
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

midwoud1

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« Last Edit: October 06, 2011, 07:50:51 PM by kurt »

fixitguy

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Re: Active Pitchcontrol
« Reply #4 on: October 04, 2011, 04:19:08 PM »
so simple..the pitch controller.

SparWeb

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Re: Active Pitchcontrol
« Reply #5 on: October 04, 2011, 11:15:14 PM »
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!
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

midwoud1

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Re: Active Pitchcontrol
« Reply #6 on: October 05, 2011, 01:03:47 AM »
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

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Re: Active Pitchcontrol
« Reply #7 on: October 05, 2011, 01:46:17 AM »
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

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Re: Active Pitchcontrol
« Reply #8 on: October 05, 2011, 06:28:02 AM »
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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Dave B

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Re: Active Pitchcontrol
« Reply #9 on: October 05, 2011, 09:24:30 AM »
 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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http://dcbenergy.com/

kitestrings

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« Reply #10 on: October 05, 2011, 09:57:49 AM »
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

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Re: Active Pitchcontrol
« Reply #11 on: October 05, 2011, 12:35:15 PM »
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.
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

midwoud1

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Re: Active Pitchcontrol
« Reply #12 on: October 05, 2011, 01:26:48 PM »
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
« Last Edit: October 05, 2011, 02:13:02 PM by Bruce S »

kitestrings

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Re: Active Pitchcontrol
« Reply #13 on: October 05, 2011, 02:10:09 PM »
Quote
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

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Re: Active Pitchcontrol
« Reply #14 on: October 05, 2011, 02:41:45 PM »
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

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Re: Active Pitchcontrol
« Reply #15 on: October 05, 2011, 11:15:14 PM »
amazing setup, hats off to you.... thanks a lot for sharing

midwoud1

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Re: Active Pitchcontrol
« Reply #16 on: October 06, 2011, 12:53:49 AM »
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

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Re: Active Pitchcontrol
« Reply #17 on: October 06, 2011, 09:26:01 PM »
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

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Re: Active Pitchcontrol
« Reply #18 on: October 07, 2011, 05:34:21 AM »

   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

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Re: Active Pitchcontrol
« Reply #19 on: October 07, 2011, 10:44:52 AM »
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

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Re: Active Pitchcontrol
« Reply #20 on: October 07, 2011, 12:01:20 PM »
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

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Re: Active Pitchcontrol
« Reply #21 on: October 07, 2011, 04:55:59 PM »
You are not gonna smoke an alternator in eight seconds.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

TomW

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Re: Active Pitchcontrol
« Reply #22 on: October 07, 2011, 05:33:11 PM »
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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fabricator

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Re: Active Pitchcontrol
« Reply #23 on: October 07, 2011, 06:02:17 PM »
Well, you can never say never, but plenty of gravity furling machines have been smoked that were supposedly fool proof.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

klsmurf

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Re: Active Pitchcontrol
« Reply #24 on: October 07, 2011, 07:53:32 PM »
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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midwoud1

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Re: Active Pitchcontrol
« Reply #25 on: October 08, 2011, 10:10:30 AM »
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

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Re: Active Pitchcontrol
« Reply #26 on: October 08, 2011, 01:46:58 PM »
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
« Last Edit: October 08, 2011, 02:09:51 PM by Antero »