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11 KW - English WIND MILL


By Nando, Section Wind
Posted on Tue Apr 3rd, 2007 at 05:13:47 PM MST
11 KW - DRAWING AND POWER CURVES

For those interested.

In days past, I reported a wind mill prototype in made in England :
see in my user files:

prototype 10 KW turbine.pdf

In addition you may see the basic drawings of the pitch controlled hub

hub1.tif
hub2.tif

The initial power chart that Simon sent to me

power chart.tif

indicated that there was a discrepancy between RPM and power harvested, Simon checked the microprocessor and found that some registers were over flowing, and after correcting them he drew another power curve.

power curve 2.tif

Showing the improved results.

Comments are welcomed

Nando

11 KW - English WIND MILL | 9 comments (9 topical, 0 editorial)

Re: 11 KW - English WIND MILL (3.00 / 0) (#1)
by BullCreek on Tue Apr 3rd, 2007 at 01:52:19 PM MST
(User Info)

I've studied the pitch control pictures in the PDF quite a bit, and it all seems clever.  A few questions:
  1.  Is the all-thread going thru the spring in the picture for real or just for testing?  Seems like actually just threading the end of the shaft and protruding it all the way thru the end of the spring might be better than the all-thread assuming the ID of the spring was big enough.
  2.  What are the two smaller black bolts coming up thru the plate in the bottom picture for?
  3.  How was the offset of where the pitch shafts and boxes that hold the blade roots meet determined?
  4.  What if any special techniques are required to weld phosphor bronze to mild steel?
It will be interesting to see how the gearbox holds up over time.  Is there some sort of cover over it all to keep the elements out?  I've often thought this would be a much simpler way to build a larger machine, but it seems most people poo poo the gearbox.  Thanks for sharing and let us know how it holds up over time.  I thought the wind blew here - heck that guy is in wind heaven!



Re: 11 KW - English WIND MILL (3.00 / 0) (#2)
by hvirtane (hannu_markus_virtanen(at)yahoo(dot)com) on Tue Apr 3rd, 2007 at 02:36:15 PM MST
(User Info) http://web.archive.org/web/20050404022706/www.cc.jyu.fi/~hvirtane/cooker/

By a coincidence just a day ago happened to check about that mill. I think that I came to that website from 'builditsolar' website.

A really nice machine.

During a short look didn't understand exactly the pitch control system... Could you anyhow make some more drawings, how it works..?

- Hannu



Re: 11 KW - English WIND MILL (3.00 / 0) (#6)
by Nando (nando37-at-tx-dot-rr-dot-com Correct theanti-spam) on Wed Apr 4th, 2007 at 06:13:45 PM MST
(User Info)

Hannu:

You need to look to the blades holders since each one of them has a bar and a weight welded and offset from the axis of rotation of the pitch angle axis to act on the blades once the RPM has reached certain value and the generated force by the weights overcomes the large spring setting force against the low wind blade initial blade angle set by bolts.

Nando


[ Parent ]



Re: 11 KW - English WIND MILL (3.00 / 0) (#3)
by jmk on Tue Apr 3rd, 2007 at 05:52:33 PM MST
(User Info)

 I don't see the link to the pdf. Where are you guys looking at this?
jmk


Re: 11 KW - English WIND MILL (3.00 / 0) (#4)
by jmk on Tue Apr 3rd, 2007 at 05:54:09 PM MST
(User Info)

 oops! I see it's in your files.
jmk
[ Parent ]


Re: 11 KW - English WIND MILL (3.00 / 0) (#5)
by simonbrookes on Wed Apr 4th, 2007 at 10:35:24 AM MST
(User Info)

Hi. To reply to BullCreek comments. The treaded bar is used for two thinks. One to adjust the tension on the spring and the other to hold the nose cone on. The threaded bar screws into the end of the drive shaft and is only long enough for the travel of the triangular plate. This plate slides up and down the 40mm machined shaft on a linear bearing this is what controls the angle of the blades. The two black bolts that come thought the back plate (there are really three but the other is out of shot), are used to set the plate to the starting position and level so all blades are at the same angle.

The offset of the blade was done from drawings and a model. There is no dissimilar metal welding the bronze bushes are all interference fits into the bearing holders. The gearbox is a 24 7 industrial gearbox and it has been running for over a year with no signs of wear. I hope this helps Simon




Re: 11 KW - English WIND MILL (3.00 / 0) (#7)
by jacquesm (j@ww.com- I run a whitelist, add 'stjoes' to msg) on Sat Sep 15th, 2007 at 12:15:17 PM MST
(User Info) http://www.greenbits.com/

Hello there Nando,

I see that you have made a clone of my design. That's fine, of course, on the internet people rip each other off all the time without credit, and I'm sure that the fieldlines community is no different. Or is it...

Anyway, as a word of warning, in copying my design you have also copied some of its more subtle flaws, which I'm sure you are going to be finding out about if you do not do some original thinking.

For reference, in case you 'forgot' where you got all the goodies I figure you may want to get a little refresher from :

http://www.fieldlines.com/story/2004/11/10/172439/76

For one you misunderstood the forces involved (it shows in the shape of your weights) and you really need to radically alter that governor.

best regards,

 Jacques

www.greenbits.com



Re: 11 KW - English WIND MILL (3.00 / 0) (#8)
by Nando (nando37-at-tx-dot-rr-dot-com Correct theanti-spam) on Sat Sep 15th, 2007 at 02:55:55 PM MST
(User Info)

JACQUES:

No it is not a clone of your design and I did not design it at all.

Simon, the owner of the 11 KW wind mill, got the drawings from another source and he cut all the materials with a CNC he was upgrading or repairing ( cut the materials for the mill to test the machine) and I helped him to acquire the generator, which was free (not counting the shipping), my part was to teach him how to MPPT the available power.

Centrifugal Pitch Controlled designs are all over the world, I used to have at least 12 - 15 different designs ( this several decades ago), then you could go and search for patents to find many more designs.
Right now there are many more patents and quite a few of them have "died".

I went to your indicated files and saw the build, it looks good.

By the way, I do understand the forces involved and I can calculate them which are needed for a Torque Pitch Controlled Hub, or of course, for a centrifugal pitch controlled hub.

Nando

[ Parent ]



Re: 11 KW - English WIND MILL (3.00 / 0) (#9)
by jacquesm (j@ww.com- I run a whitelist, add 'stjoes' to msg) on Sat Sep 15th, 2007 at 03:30:46 PM MST
(User Info) http://www.greenbits.com/

the 'bar and weight' trick has been used on commercial machines, most notably on many designs that did not live past their first year in flight.

DanB once sold me one of the less fortunate ones :)

The reason for that is that the forces are not working just to move the blades but also to wrench the weights off the shafts. Which eventually succeeds... And even if it doesn't succeed directly it tends to fatigue the shafts.

Secondly, you have copied (accidentally or otherwise we'll leave to the observer, but let's just say the number of design details that exactly match mine which was arrived at after 18 months of experimenting) the biggest flaw that you could possibly have, which is that this design has a maximum speed until which the governor will work and then above that speed is will make things worse instead of better. The reason for this is the pitching moment, which gets larger very fast when the wind speeds go up, and which increases with decreased blade angle. You need to correct for that, and from the attachment point of the root of your blades it is evident that no such correction is in place.

Then there is the execution of the design, the welding to the base plate causes local hardening of the metal, you'll have to anneal the whole governor plate to get rid of that or the welds will fatigue. Also even the smallest flex of the base plate will eventually bind the bushings which will stop the governor from working.

A flat plate (like in my design, which you say you did not copy and which your friend has no knowledge off, oh, you stole it elsewhere, would you mind posting the link so we can go and have a look ?) is not a very good base for a windmill, no matter how thick you make it. A hollow 'cake' shaped box with inserts would already be a lot (make that a whole lot) better.

Then there is the issue of damping, again, you matched my errors 1:1, such coincidence. There is nothing there that stops the machine from going from flat to coarse pitch in 0.1 seconds. A mill that size going coarse pitch is like strapping an out of control aircraft engine to your mast, it will yank the tower forward with a tremendous force. In my case that force was enough to lift a barrel full of concrete clear out of its hole. Then this phenomenon will repeat itself because after the mill has expended its energy trying to throw the guy anchors into the neighboring fields it will flip rearwards again as the wind pushes it and will speed up again. This will happen over and over. Unless you add damping. Which if you had a look at a commercially designed variable pitch hub instead of my poor substitute for one you had known. And I didn't, because I really did design it from scratch.

You seem to be quite eager to associate yourself with the design, there must be a thousand different ways to make a variable pitch hub, I've seen plenty and no two of them look as much alike as your 'friends' design and mine, and you are a fieldlines member, the coincidences pile up quite high.

sayonara,

 Jacques.
www.greenbits.com
[ Parent ]



11 KW - English WIND MILL | 9 comments (9 topical, 0 editorial)
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