Re: [avr-chat] OT: Motor vibration due to PWM harmful?

[Clemens Koller]

Hello, Erik!

Erik Christiansen wrote:
> While fooling with FET drive for a 200 watt DC motor, there was a fair
> howl emanating from the motor when the PWM frequency passed through
> mechanical resonances. I've read of ruined bearings in large motors, due
> to arcing through the lubricant, due to voltage build-up on the rotor,
> apparently exacerbated by peaky drive, but the wear effects of
> continuous high frequency mechanical vibration doesn't seem to be
> mentioned much.

This is really OT.
I did some motion control with high-end motion controllers
from Delta Tau about two years ago. There are ton's of Amplifier Manufacturers
for DC Brushless motors i.e. (i.e. ELMO Flute) Check their design and you will
see that they have (sometimes) some pretty complex Filters mainly to improve
the loop stability, but also to reduce EMI.

You could also contact some Motor Manufacturers (i.e. Maxon) and ask them about
their opinion, but I guess they will just tell you that everything is fine,
as long as you use their motors. :-)

But please, that's too complex to be discussed here. Find a proper list for your
questions.

Best greets,

Clemens Koller
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