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can an ordinary fan motor be used as a dynomo in a wind mill generator ? Answered


Generally no - presuming your fan is an AC motor.  It needs a loading (self-exciting) capacitor to charge the coils so that the motor sees any magnetic field to generate power with...

If its a DC permanent magnet motor then of course, just turn it and it will produce power :D

+1 ...and the things only really work at their original shaft speed ...

A lot of sources online say you need to go about 10% faster than original speed to compensate for the time it takes for the magnetic field to collapse...another point against using this for wind generation :(

Its more to do with slip speed - the difference between synchronous speed and the actual speed that the motor is doing. In a motoring situation, slip speed is negative. A motor runnning on 60hz whose synchronous speed is 3600 RPM will run at 3500 RPM. Generating, slip speed is +ve, and you'll have the opposite situation, to extract energy, you'll have to turn it at 3700 RPM to get 60Hz back out.

Wasn't it that if you turned it at a lower speed (1000 RPM instead of 3000) you would still get power, only at a much lower frequency?

I never knew that!  I thought the mechanical relationship between the coils would result in an exact requirement for input>output correlation, like cogs in a machine.

I are learned stuff.

No slip - no torque.

I've forgotten a lot - I did a LOT of electric machine theory when I did my degree in electrical and electronic engineering - looking at your profile, about when you were born.

Motors and alternators have a lot of surprises in them.