(Ok, I know this is a bit of a 'how long is a piece of string' question...)

I am currently designing a motor controller (on a voluntary basis) for a school's engineering project. It will be controlling a 24V PM motor rated at around 250W. I wondered if anyone here had any thoughts as to what sort of frequency the PWM should be running for this. In the past I've tended to run controllers at about 3kHz (just because that's the fastest I can generate with a 4MHz PIC) but having read a bit more about the subject I'm now wondering whether this is too fast? Or if a look somewhere else, too slow?

Any thoughts?

P.S. At the moment I'm only planning to use a single FET with a flyback diode.

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Andy Millar CEng MIET MCMI

http://www.linkedin.com/in/millarandy

Edited: 28 January 2010 at 01:33 PM by amillar