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Forum Index : Windmills : NEWB question, Alternator for VAWT
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Jon Bennett Newbie ![]() Joined: 01/11/2007 Location: AustraliaPosts: 27 |
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 |
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Gizmo![]() Admin Group ![]() Joined: 05/06/2004 Location: AustraliaPosts: 5116 |
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 |
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Jon Bennett Newbie ![]() Joined: 01/11/2007 Location: AustraliaPosts: 27 |
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 |
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Gizmo![]() Admin Group ![]() Joined: 05/06/2004 Location: AustraliaPosts: 5116 |
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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