Switch Smoke


G K
 

Working on the SB9 tonight, and smelled a little burn.  Flipped the switch off. looked around and saw no issues.  Flipped it back on and pop goes the breaker, and smoke from the switch.  I believe the switch is the original (1942) drum switch.  Unplugged it, and took the cover off the switch, and the jumper was fried.  No idea why.  I'm not an electrician, but can use a voltmeter.  Suggested troubleshoot? 

120 volt circuit. Furmas R44, 6-terminal switch, Dayton 3/4 hp motor.

I'm planning on pulling it apart tomorrow and look for any additional burned wires, but I do not believe I will find any from a cursory look.  Then I'll wire a receptacle directly onto the motor to see if there are any issues there.  If were good there, I will re-wire the switch and see what happens.  Maybe some chips got inside and caused a short.  Not sure.  Any chance capacitor went back and caused the short?  The only burn smell is in the proximity of the switch, but that could be where the smallest gauge wire (jumper) is located.

Thanks,

Greg

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