On 2019-04-28, Confused wrote:
replying to Wild Bill, Confused wrote:
Hi I have a bench grinder that I converted for polishing. Recently the thing
has lost power when I push against the polishing mop and I can even stop it
rotating if I grab hold, can anyone loll me whats up. Ive opened it up
and had a look, no debris or broken parts, no bearing wobble. Is it the
capacitor or is it toast?

Almost certainly the capacitor. And they are cheap, so get a
replacement and swap it in.

You probably cooked the capacitor when pushing too hard against
the mop and stalling it, which results in the start centrifugal switch
closing, and applying power to the capacitor for too long. They can
only take a very short application of the AC which drives the motor.

Get several spare caps, as you will probably be killing more of
them in this application.

Better if you have a three-phase motor and a VFD to drive it.
That can take the extra load a lot better than a cap-start motor.

Good Luck,
DoN.

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