Converting AC motors. Vikash?

[scuzzy]

I have an AC motor I pulled out of an old fan, good condition I believe. I'd love to be able to convert this into a DC motor, brushless or not - driven by 12 volts. can this be done?

is it feasible?

The purpose is to drive a small water pump to feed an AWIC setup.

just curious.

thanks.

[vrg3]

AC motors are very different from DC motors. They're a lot simpler because the power supply generates an alternating magnetic field to make things move. There's usually no commutator. In a way, they're simple brushless motors already, so all you have to do is drive them appropriately. The problem in this case is the voltage; rewinding it to use a different voltage is likely to be impractical.

So, if it's meant to run on 120 VAC and you want to run it on 12 VDC, your best bet is an off-the-shelf inverter. This will serve as the driver for the "brushless" motor and also as a level shifter to provide the appropriate voltage. For a steady-speed motor a modified-sine-wave inverter should do, but I'd say to avoid square wave inverters. In any case, a true sine wave inverter would be ideal.

If the motor's chassis is connected to either of its power rails (it shouldn't be though!) you'll want to make sure the inverter either grounds the same side or has its input and output isolated.

[scuzzy]

AC motors are very different from DC motors. They're a lot simpler because the power supply generates an alternating magnetic field to make things move. There's usually no commutator. In a way, they're simple brushless motors already, so all you have to do is drive them appropriately. The problem in this case is the voltage; rewinding it to use a different voltage is likely to be impractical.

So, if it's meant to run on 120 VAC and you want to run it on 12 VDC, your best bet is an off-the-shelf inverter. This will serve as the driver for the "brushless" motor and also as a level shifter to provide the appropriate voltage. For a steady-speed motor a modified-sine-wave inverter should do, but I'd say to avoid square wave inverters. In any case, a true sine wave inverter would be ideal.

If the motor's chassis is connected to either of its power rails (it shouldn't be though!) you'll want to make sure the inverter either grounds the same side or has its input and output isolated.

that's what I needed to know. thanks