Breaker tripping and capacitor burning


I live in Japan and have an unnamed 10gal air compressor I purchased from a friend for $60 a couple years ago. It is rarely used, but I booted it up yesterday (with an extension cord), and magic smoke came from the wiring enclosure. A small capacitor had burnt up.. luckily exactly where the ratings and part# normally are, so I cannot tell what type it is. (This motor has another capacitor piggy-backing on the side of the case as well, but no smoke from it).

I have a slightly smaller motor laying around, and rewired the cap. (110vac 270-324MFD)I move the compressor from my work area, and plug it directly into the outlet. Runs fine for about 10-20 seconds, then trips the 15A breaker on the enclosure body. I let it cool down a bit, and after several re-tries, I notice the cap I replaced is extremely hot, and oil is starting to pool out of the top, and down the sides of it.

No inductive amp meter here.. only 10vdc for automotive use, so I cannot test the draw. The house breaker did not trip.. only the on-board 15A did.

Local power is 100vac/60Hz, and I've run the compressor before without issue on the same outlet. By size alone, I'd say the motor is 2hp. If it wasn't 100vac, I'd say it looks to be the size of a 5hp.

Any help would be appreciated.

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Dec 20, 2015
by: Doug in

You might use the tank for portable air - the pump might be worth something for spare parts.

Dec 18, 2015
Lucky me..
by: Anonymous

Thank you for the info. After mentioning my compressor had died, a coworker gave me a small 1 gallon Devilbiss compressor that just needed a little TLC.

A few days later, I lucked upon the same exact compressor for free! A little rusty, but works great. Just going to transplant the motor over to my cleaner pump/tank.

Any thoughts as to what I could do with the extra pump and tank?

Dec 01, 2015
Magic smoke
by: Doug in

Sounds like the extra low voltage due to the extension cord not only took out the cap but part of the motor winding, which may be causing the new cap to go on overvoltage.

If the cap isn't already gone, you could check the voltage across it. If it's much over 100V or so, you probably need a new motor, preferably designed for 100V.

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