# Turning a brushless AC motor into a generator



## SouthernThunder (Jun 3, 2004)

I have several brushless AC 3 phase motors rated at 3/4 horse and a few 1horse. What needs to be done to make these into generators in something like a windmill?


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## Guest (Oct 22, 2007)

otherpower.com They have all ya need to know.


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## ace admirer (Oct 5, 2005)

you'll have to turn them at around 115% of syncro speed. not really the best for a wind mill. those that have used them have highly modified them.


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## MELOC (Sep 26, 2005)

what is syncro speed?


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## artificer (Feb 26, 2007)

Not to be flippant, but the easiest way to convert them is to sell them, and then buy a generator.  

Synchronous speed is the theoretical speed the motor will run at with no load. For 60hz power it is typically 3600, 1800, 1200 rpm. The motors will actually run less than that. The speed is listed on the faceplate of the motor.

The long answer to the question is that yes, they can be used as a generator, but they need to be connected to a large power supply, like the grid. You then drive them faster than the synchronous speed. They still aren't that efficient. You would have to come up with a speed control system to keep the speed up, even with lower wind speed. Not an easy task... go to the otherpower site, and get a proper generator. If you want a challenging project and the bragging rights to go with it: go for it. If you really just want a generator, its not worth the hassle.

Michael


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## Jim-mi (May 15, 2002)

They'll make excelent boat anchors . . .fore and aft.



sorry . . . .couldn't resist that....


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