From: soon lee <psln@CYBERWAY.COM.SG>

> Hi    guys
> got a question here
> is there a standard for the value of PWM frequency for motors and how you
> determind it??
>
> thanks
> regards

I'm not too sure, but one factor to consider is the audible noise that
comes from motor at the freq you drive the PWM at. Does a motor
resonate at a particular freq, like a speaker ? If so, is this affected
by the number of poles, or whether a motor is electro- or permanent
magnet type ?

I noted Russell McMahon's comments about the rotor losing touch
with the magnetic fields as the frequency is increased. This would
seem to imply that there's an optimum range of driving conditions.

Jinx