Trouble wiring a PSC motor, maybe a ground leak.

[S. Heslop]

I'm making a disc sander using a YYH-30A22 motor from a broken bread machine, the sort that were all the rage a few years ago. http://zs-maida.com/en/bread.htm It's in the upper left on this website.

One thing that's kinda spooking me is that when I grounded the case the motor started making alot more noise. There was even a spark when I re-attached the ground while it was running when trying to figure out the problem. One of those mains test screwdrivers also glowed when I touched pretty much any part of the motor, even the plywood it was mounted through. I can't detect any continuity to ground/ the case with a multimeter with it unplugged though so i'm wondering if it's something strange like induction. I can't remember if the motor was grounded when it was in the bread machine.

Being something I clearly don't understand I figured it'd probably be best to ask about it than risk electrocution or a fire.

[Jonfb64]

Sounds like the insulation is breaking down at higher voltages, test with PAT tester if you know someone with a tester or as it makes a noise when grounded it could be the starting capacitor windings. Try taking the end casings off and have a look for shorts.
What voltage have you got between ground and the motor case?

Best of luck

Jon

[S. Heslop]

End casings as in those of the motor? I forgot to say that I'd already done that and poked around, mostly becuase I first suspected I might have driven the mounting screws too far in and into the windings. Didn't see any visual damage and the insulation on the windings seemed good as far as my rubbish multimeter could tell.

It's a shame I'm not so friendly any more with the electrician I used to know.


I've just tested the voltage between the case and ground and was getting barely anything readable on this cheap analogue multi meter. In 50, 250, and 500 modes the needle moved about the same tiny amount. I don't trust this meter much at all but I took a reading of mains voltage direct to test it and it read at about 240, or at least the needle went over to the high end of the scale.