Crane machine sparks near compressor

[MidStateVending]

I just acquired a Model 780D, in the hopes of fixing it. When I close the door, the compressor comes on for a couple of minutes. Everything sounds fine, then there is a major spark and it throws my breaker. Then there is a puff of smoke at the finally.

I can tell it sparks towards the rear of the machine.

I plug it back in and runs fine until it sparks again.

Anyone know where it is shorting out? I can't seem to find any burned wires or damage.

[AZVendor]

That is likely coming from inside the start relay cover.  Open it up and see if there are burned wires or if the overload is burned.  The fact that it runs for a short time though indicates you either have weak, burned overload, a start relay that is stuck and not dropping out of the circuit or, more likely, a bad compressor that pulls too much current as it runs and heats up which would mean you need a new compressor.

[orsd]

What AZ said.

The time delay tells me that it is related to heat. Too much current will create heat, which will make the compressor draw even more current, and the sparks may be from the overload trying but failing to shut it down.

At this point, I would throw on a 3 in 1 kit. Gives you a fresh start cap, relay and overload, May or may not help, but it's a lot cheaper than a new compressor. Also check and make sure that the condenser is not clogged or blocked.

While you are at it, if you have a multimeter you can check the compressor winding resistance, post the readings here (should be 3, start to run, run to common, common to start)

 

 

[MidStateVending]

After a few more 'sparks' I noticed that the wire to one of the compressor fans burned off. I got a new fan and ready to install. Hopefully that fixes it.