Author Topic: Active Pitchcontrol  (Read 331828 times)

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kitestrings

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Re: Active Pitchcontrol
« Reply #33 on: October 11, 2011, 11:03:25 AM »
Quote
Can you make small windpower any better than this ?

Quote
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


midwoud1

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Re: Active Pitchcontrol
« Reply #34 on: October 11, 2011, 03:24:25 PM »
  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.
                   
 
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                                                 http://www.youtube.com/user/midwoud1?gl=NL&hl=nl#p/u/5/-QRK0nMsbf8

kitestrings

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Re: Active Pitchcontrol
« Reply #35 on: October 11, 2011, 04:31:14 PM »
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

SparWeb

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Re: Active Pitchcontrol
« Reply #36 on: October 12, 2011, 01:10:41 AM »
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!
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
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frackers

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Re: Active Pitchcontrol
« Reply #37 on: October 12, 2011, 04:01:21 AM »
                    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).

Robin Down Under (Or Are You Up Over)

Antero

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Re: Active Pitchcontrol
« Reply #38 on: October 12, 2011, 07:31:11 PM »
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


midwoud1

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Re: Active Pitchcontrol
« Reply #39 on: October 13, 2011, 01:03:10 PM »
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.

bj

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Re: Active Pitchcontrol
« Reply #40 on: October 13, 2011, 01:14:49 PM »
   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.
"Even a blind squirrel will find an acorn once in a while"
bj
Lamont AB Can.

SparWeb

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Re: Active Pitchcontrol
« Reply #41 on: October 13, 2011, 02:49:41 PM »
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.

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, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
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midwoud1

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Re: Active Pitchcontrol
« Reply #42 on: October 13, 2011, 04:53:14 PM »
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.                 4084-0
4085-1

midwoud1

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Re: Active Pitchcontrol
« Reply #43 on: October 14, 2011, 03:39:56 AM »
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.

4091-04092-1

midwoud1

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Re: Active Pitchcontrol
« Reply #44 on: October 14, 2011, 03:47:06 AM »
Edit :Electronical circuit

midwoud1

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Re: Active Pitchcontrol
« Reply #45 on: October 14, 2011, 04:22:12 AM »
Edit:
« Last Edit: October 14, 2011, 04:27:29 AM by midwoud1 »

Flux

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Re: Active Pitchcontrol
« Reply #46 on: October 14, 2011, 05:10:59 AM »
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

midwoud1

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Re: Active Pitchcontrol
« Reply #47 on: October 14, 2011, 05:33:00 AM »
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

midwoud1

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Re: Active Pitchcontrol
« Reply #48 on: October 21, 2011, 03:25:12 PM »
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.

bj

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Re: Active Pitchcontrol
« Reply #49 on: October 21, 2011, 04:49:49 PM »
   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)
"Even a blind squirrel will find an acorn once in a while"
bj
Lamont AB Can.

mbouwer

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Re: Active Pitchcontrol
« Reply #50 on: October 26, 2011, 02:13:48 PM »
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.

midwoud1

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Re: Active Pitchcontrol
« Reply #51 on: October 26, 2011, 04:15:55 PM »
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

kevbo

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Re: Active Pitchcontrol
« Reply #52 on: October 28, 2011, 02:02:37 PM »
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.


midwoud1

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Re: Active Pitchcontrol
« Reply #53 on: October 29, 2011, 03:22:54 AM »
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.

fabricator

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Re: Active Pitchcontrol
« Reply #54 on: October 29, 2011, 09:54:23 AM »
Wow!, did you have those gears custom cut?
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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Re: Active Pitchcontrol
« Reply #55 on: October 29, 2011, 02:53:12 PM »
No ,  on the shelf . I was surprised myself . Module 2 - 3  on stock. Custom is possible but more expensive  f.i. hypoídal.
  Rgds . F.

fabricator

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Re: Active Pitchcontrol
« Reply #56 on: October 29, 2011, 03:34:15 PM »
Hmmmmm............What if you had one of these on the other side instead of the electronics? http://demonstrations.wolfram.com/WattSpeedGovernor/
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.

methanolcat

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Re: Active Pitchcontrol
« Reply #57 on: October 29, 2011, 11:38:13 PM »
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

fabricator

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Re: Active Pitchcontrol
« Reply #58 on: October 30, 2011, 09:16:27 AM »
I'm sure it could be with a little tuning and experimenting.
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.

Janne

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Re: Active Pitchcontrol
« Reply #59 on: October 30, 2011, 11:01:49 AM »
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.
« Last Edit: October 30, 2011, 11:03:34 AM by Janne »
Nothing's as easy as drilling a hole in the wrong place

midwoud1

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Re: Active Pitchcontrol
« Reply #60 on: October 30, 2011, 01:07:31 PM »
Some projects I made before :  Pasive and Active control

fabricator

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Re: Active Pitchcontrol
« Reply #61 on: October 30, 2011, 01:39:04 PM »
That is one beautiful machine.
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.

windy

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Re: Active Pitchcontrol
« Reply #62 on: October 30, 2011, 11:02:23 PM »
I would be concerned with water getting on the gears and freezing during the winter.

windy
I don't claim to be an electrical engineer. I just know enough to keep from getting electrocuted.

midwoud1

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Re: Active Pitchcontrol
« Reply #63 on: October 31, 2011, 05:03:05 PM »
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

SparWeb

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Re: Active Pitchcontrol
« Reply #64 on: November 01, 2011, 02:14:48 PM »
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?   ???
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, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

midwoud1

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Re: Active Pitchcontrol
« Reply #65 on: November 02, 2011, 12:47:45 PM »
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.