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Forum Index : Windmills : F&P low rpm tests.
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I did a little test today. I set up a 100 series ( 1mm copper ) motor and spun it at low speed, about 60 rpm, or one revolution per second. The stator was not modified, it was factory wired. My multimeter showed 15vac across one phase. Converted to DC this would be about 21volts ( DC volts = AC volts X 1.414 after full wave rectification, if I remember my AC theory correctly ). Thats enough to charge a 12 volt battery. Maxium current may only be 3 to 4 amps, or about 50 watts max. But thats still 50 watts. A lazy old oil drum VAWT will easily drive the F&P, uncogged, at 60 and more RPM. While there is a lot of discussion about spinning the F&P as fast as possible to get 500 watts and more, maybe we are missing the point. You can pick up a F&P for anything from $0 to $100, add a bit of scrap steel, an oil drum or plastic bin cut in half, and you have a 50 watt generator that would start in light wind. You could build the thing for less than $200 tops. A 50watt solar panel would cost you many times that. My main windmill spends most of its day doing nothing. Its well designed high speed blades dont have the grunt to get past the first cog in the F&P untill the wind picks up. Once its going its great, but in low winds the windmill is doing nothing. A drum type VAWT could be clunking away, pumping a couple of amps in the light breeze. I think its worth while putting one together so see how it runs. The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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Chris Senior Member  Joined: 12/09/2005 Location: AustraliaPosts: 146 |
For decogging, i was thinking... Build one of the mini mills to charge some double AA batteries. Then build a simple circuit that detects when the windmill is at 0 rpm, then it sends a pulse from these batteries to one of the phases or each of the phases one after the other just to give it a push start. Then if it still detects 0 rpm, it waits say 30 or so seconds and does it again. Just an idea. |
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| Guests Guest  Joined: 01/10/2003 Location: Posts: 52 |
..hmmm. Me thinks my rantings on F&P's has tickled a nerve ..could you use the original hall sensor to provide the pulse? BTW, I've rewired my 80 series as per your method - just testing it as a STAR gennie to start with. At a 60rpm hand spin, I can hold a constant 15v.rectified DC current. (yet to test amps) Trying to get my hands on a cheap AC motor so I can get some data at contant rpm's. I plan to slip a star/delta switch in and I need to work out the optimum rpm to switch at. Scored a 100 series today too ! Greg |
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ozetrade Regular Member  Joined: 15/10/2005 Location: AustraliaPosts: 59 |
...above reply by ozetrade(Greg)...I did login Greg Just North of Brisbane in Redcliffe OZeTrade.net |
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| Chris Senior Member Joined: 12/09/2005 Location: AustraliaPosts: 146 |
Where do you guys score these motors from, i only have 1... I got it for 60 dollars off ebay. Ive tried finding them and theres not many u find lying on the side of the road. Washing machine servicers want like 300 dollars for them! rip off! |
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| ozetrade Regular Member Joined: 15/10/2005 Location: AustraliaPosts: 59 |
Hi Chris, Scrap metal yards is my primary source - $10-$15, You could try the dump, but they usually want let you scavange anymore. Another place is retail whitegoods stores, the ones that take tradein's. Your looking for any F&P smatdrive washing machine, dead or alive. eBay is still a place to look, but dont look for a motor, look for dead washing mashines - most are local pickup only. Greg Greg Just North of Brisbane in Redcliffe OZeTrade.net |
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