Author Topic: Pitch Control  (Read 4662 times)

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Jamiel1997

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Pitch Control
« on: August 21, 2015, 09:01:28 PM »
Hi, I was wondering if there is a system that works like the opposite of a passive blade pitch. Where instead of the blade pitch being fine/low in normal operating wind conditions and then becoming course/high in high wind conditions it does the opposite so that the turbine starts easily in low winds because of the blade pitch is being high and as the speed of the turbine increases, the pitch of the blades becomes fine so that the turbine can gain some RPM's

(I'm asking this because I have a turbine that takes a lot of wind to get started because of its weight and the very low angle of attack that the blades has).

If there is a mechanism like what was explained above it will help in low wind startups and then the centrifugal force will make the blades become more fine so the turbine can produce more RPM's

mbouwer

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Re: Pitch Control
« Reply #1 on: August 22, 2015, 03:47:46 PM »
Jamiel,

Have you seen the small films on YouTube from Midwoud?


Greetings Rinus

midwoud1

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Re: Pitch Control
« Reply #2 on: August 22, 2015, 04:02:59 PM »
Active pitchcontrol.

Youtube  https://www.youtube.com/watch?v=rUcxmbLfu_U


Jamiel1997

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Re: Pitch Control
« Reply #3 on: August 25, 2015, 09:49:10 AM »
That's a nice design but I was thinking of something the does not require manual adjustments, for example: have some weights on the blades and when the wind picks up and the turbine begins to spin faster, the centrifugal force on the weights begins to decrease the angle of attack on the blades so it spins even more faster.

kitestrings

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Re: Pitch Control
« Reply #4 on: August 25, 2015, 12:27:10 PM »
Quote
I was thinking of something the does not require manual adjustments, for example: have some weights on the blades and when the wind picks up and the turbine begins to spin faster, the centrifugal force on the weights begins to decrease the angle of attack on the blades so it spins even more faster.

This has been done on a number of machines over the years with this feature, with varying results.  Examples are Dunlite, Jacobs, etc.https://www.google.com/search?q=dunlite+wind+turbine&rlz=1T4AURU_enUS501US501&biw=1536&bih=723&tbm=isch&tbo=u&source=univ&sa=X&ved=0CCoQsARqFQoTCLC8oe_RxMcCFYyXgAod_GQDnw

https://www.google.com/search?q=jacobs+wind+turbines&rlz=1T4AURU_enUS501US501&tbm=isch&tbo=u&source=univ&sa=X&ved=0CDoQsARqFQoTCOTe4Z7SxMcCFYzNgAodO5UFjA&biw=1536&bih=723

http://www.wincharger.com/

The later used "air-brakes" controller by centrifugal on the most commonly known units.

Smithson

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Re: Pitch Control
« Reply #5 on: August 26, 2015, 09:58:24 PM »
If you mean to have the blade set coarse (say 45 degrees at startup) then go normal as it comes up to speed, then back to coarse as it try's to over speed this was said to be incorporated in some of the machines of the 70's and early 80's.  I've lost all my literature on it but from what I can remember the blade was mounted on a tube spar with a crescent moon shaped cam cut in the base of each spar.  The rotor was 3 spokes with a roll pin near the base of each of the spokes.  The roll pin fit in the crescent moon shaped cam so as the blade pulled out with centrifugal force and speed the blade went from coarse to fine to coarse.  Springs held the blades in home position.   The problem was to keep the blades the same weight or vibration would wreck it.  If you could figure out how to link the three blades together it would be ideal.   Arch

midwoud1

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Re: Pitch Control
« Reply #6 on: August 27, 2015, 04:57:00 AM »
Blade synchron system for active- and passive propeller windgenerator

clockmanFRA

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Re: Pitch Control
« Reply #7 on: August 27, 2015, 05:46:19 AM »
midwoud1, I love the contents of that Van.

Good use of those Rose bearings/knukcle joints, but watch the bushes, I have seen some oriental manufactured ones with the bush loose and then pushing out.  ::)

But, your bolt heads look just big enough to cover the Rose bearing /knuckle joint casting body.
« Last Edit: August 27, 2015, 05:51:07 AM by clockmanFRA »
Everything is possible, just give me time.

OzInverter man. Normandy France.
http://www.bryanhorology.com/renewable-energy-creation.php

3 Hugh P's 3.7m Wind T's (12 years) .. 5kW PV on 3 Trackers, (8 yrs) .. 9kW PV AC coupled to OzInverter MINI Grid, back charging AC Coupling to 48v 1300ah battery

midwoud1

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Re: Pitch Control
« Reply #8 on: August 27, 2015, 09:41:47 AM »
CM.
The hub with the bushings is made by Janne ( Finland ) . I know him as a very good constructor .
The upper photo ,my own hub with bevel gears ,push pull rod and actuator. Good working.

kitestrings

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Re: Pitch Control
« Reply #9 on: August 27, 2015, 03:48:20 PM »
Great pics!  Is that second one as large as it appears - some ~3' in diameter?  Wow.

clockmanFRA

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Re: Pitch Control
« Reply #10 on: August 28, 2015, 03:47:37 AM »
KS, that passive control is so  ..........................  :P

Had to rush off and have several cold showers.......... ha ha!

Nice design.
« Last Edit: August 28, 2015, 03:53:50 AM by clockmanFRA »
Everything is possible, just give me time.

OzInverter man. Normandy France.
http://www.bryanhorology.com/renewable-energy-creation.php

3 Hugh P's 3.7m Wind T's (12 years) .. 5kW PV on 3 Trackers, (8 yrs) .. 9kW PV AC coupled to OzInverter MINI Grid, back charging AC Coupling to 48v 1300ah battery

kitestrings

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Re: Pitch Control
« Reply #11 on: August 28, 2015, 08:21:11 AM »
Yes.  Nearly a work of art just as it sets.

Historically passive pitch mechanisms have been mixed blessings.  They offer arguably better, smoother control than furling machines.  They do however, increase weight and complexity, and without proper maintenance the results can be disastrous.  Commercially the added complexity also adds costs.  Jacobs seemed to have solved the issue of having all the blades rotate in unison; a common problem with early designs.  What little experiences I had with them, I was impressed with the design and durability.

Don't know if anyone remembers the "Carter's"?  IIRC they produced a machine with some sort of passive torsional pitch in their blades.  It was interesting in concept, but I don't remember them holding up well over time.

The work that Frans & Rinus have been doing with active pitch control is pretty impressive, and seems to solve some of the weight and component count problems.  I think if I live long enough to do another one I'd be chatting with them.

~ks

midwoud1

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Re: Pitch Control
« Reply #12 on: August 28, 2015, 02:07:51 PM »


              http://www.eazwind.com/en/team-2/

Four young enthousiast men have a passive pitch farm windmill in production .
Propeller diam. 12 meter . 10 Kw . Grid tie .
I would like to see the system inside the hub , because there is the only way to protect in case of storm.
As far as we can see there is no furling tail. And it has survived several winter storms.
   

midwoud1

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Re: Pitch Control
« Reply #13 on: August 28, 2015, 02:37:17 PM »


  Ks.   The chatbox about active pitchcontrol is allways open.

midwoud1

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Re: Pitch Control
« Reply #14 on: August 28, 2015, 03:10:15 PM »

Boondocker

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Re: Pitch Control
« Reply #15 on: August 28, 2015, 03:43:35 PM »




Kestrel has a passive pitch design.

Hugh had some positive comments about it:

http://scoraigwind.co.uk/2011/11/kestrel-e400i-wind-turbine-on-scoraig/