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Jon Bennett
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Joined: 01/11/2007
Location: Australia
Posts: 27

Posted: 11:11am 03 Nov 2007

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Hi.
Am new here, have been reading a bit and have a question.
Am going to attempt making a VAWT based on Ed Lenz's design 2.4m high by 1.3m dia.
On Windzone it looks like we have about 6m/s average wind speed here (Redcliffe qld).
Working on a TSR of 1.3:1 from Ed's posted data I am looking at 105-110rpm average.
With this low an rpm is a F&P unit viable or am I better of making an auxial flux alternator from scratch?
Still undecided on voltage to designs sytem for so any advice would be apreciated.

thanks
jon

Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5116

Posted: 11:18pm 03 Nov 2007

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Hi Jon

I had a 1.2 high by 1.3 wide Lenz with a F&P mounted on it. It worked ok, but I always wanted to make a bigger one. I did start work on a 2.4 meter by 2.1 meter diameter Lenz, but it never got finished.

The 1.2 by 1.3 Lenz made about 20 to 40 watts, I think the max speed I had was just over 100 RPM, it was held back by the F&P. I remember I always felt it was a little to small for the F&P. A 2.4 by 1.3 diameter Lenz should work very well I think.

Another problem I had was noise, there was a lot of "droning" from those big winds. I fixed this by using a de-cogged stator, and later a 7 phase conversion.

Go for it.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ

Jon Bennett
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Joined: 01/11/2007
Location: Australia
Posts: 27

Posted: 04:36am 04 Nov 2007

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Hi Glen
Had a look at your 1.2 X 1.3 lenz and the one under construction, both very nice.

Did the winglets make any noticeable difference? Was going to put a full top and almost full bottom (hole for support shaft) on mine to cut down on drag and to help tie it all together.

Do you thnka F&P will a be able to make full use of the torque developed at low revs by a 2.4 X 1.3 Lenz?
Working on Eds wind tunnel test efficiencies of 35% it should make about 150W @ 100 rpm in a 6m/s breeze.

If so what component/wiring configuration would you recomend as a starting point?

regards
jon

Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5116

Posted: 08:50am 04 Nov 2007

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Hi Jon

I didn't notice any improvement by adding the winglets, but I do think they would help, its only logical.

The F&P is good for 1 watt per rpm, so 100rpm would give 100 watts, under ideal conditions. To give more power, you could try a neo magnet conversion, or adding capacitors as Dennis has suggested. Or try a 1:2 step up drive ( belt or gear box ) to get the increased F&P rpm.

Sounds like a good sized windmill, keep us posted.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ

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