Jointer Motor Troubleshooting help

[Brian Loran]

My jointer motor shut down on me the other week and I am having trouble figuring out what is wrong. I was jointing away when I smelled that nice burnt electrical smell and then it shut down (breaker tripped). I re-set the breaker and it would start but then pop the breaker and shut down again. I called the tech line and they were very helpful. I checked the start cap and it looked ok. When looking at the centrifugal switch I noticed the set screw was loose and it turns out it was stripped and could not be tightened very well. I thought that must be it and ordered a new switch and contactor. I installed those last night, fired it up and it started for a little while, then sparks shot out of the switch/contactor area and the breaker popped. I'm stumped now. What could be wrong??

[Rod Sheridan]

Hi Brian, the centrifugal switch would be in the motor, however the contactor would be in an enclosure somewhere, or did you mean centrifugal switch and contacts?

It could be a centrifugal switch that doesn't open, or a failed winding in the motor.

That burned smell generally indicates a failed winding, do either of the windings look burned?

If so it's new motor time as it's not worth rewinding fractional HP motors..............Rod.

[Brian Loran]

Yes, I meant contacts. The thing the centrifugal switch hits and releases from. Should I pop open the enclosure and check the windings and contactor?? I was a little worried about disassembling that much of the motor. What are the sparks from? Too much current and then arcs out?? Man I don't want to have to buy a new motor :(

[Rod Sheridan]

Hi, the only items in your motor are the centrifugal switch and contacts.

When you operate the bobin on the shaft that opens the centrifugal switch, do the contacts open? If not the starting winding is always on and has probably burned out.

Sparks could be from a loose connection, a partially open centrifugal switch or a failed winding.

You're at the motor shop/replacement stage probably...................Regards, Rod.