I have an air compressor. 6 horse, 30 gallon, always dependable.
Lately, it shuts down on me now and then. Well, trips its breaker in the panel, actually. It always sounds different just before it trips, so I got thinking it’s something in the compression area. I disassembled the head, letting the piston ride freely in its cylinder so there’s no load on the motor, but no dice.
Even removing the piston from the shaft and just turning on the motor doesn’t work. The motor starts and runs for 2-3 seconds, then trips the breaker.
Thinking I’m too far from the panel, and regular Romex isn’t carrying sufficient amps, I moved it next to the panel and plugged it in to the closest outlet. Still dies.
This last time, though, I noticed a wisp of smoke wafted from the motor when it tripped the breaker.
So. Is something repairable shorting out, or does this guy have the right idea?
It’s not working, so tearing into it won’t hurt anything. I’ll look at the actuator, but I’m still all ears.
A mechanical overload will make the motor draw more current and can cause the breaker to trip. Since you disassembled the head there shouldn’t be any fault in the compressor that’s causing an excessive load. That only leaves the motor itself, which would be something like a problem with the bearings inside the motor. Can you spin the motor freely by hand when it’s turned off? Bearings usually make some rather obnoxious noises when they start to fail, and you did say that it sounds different when it trips.
The other thing that comes to my mind is a fault in the motor windings. This would certainly make smoke. A mechanical problem that prevents the motor from turning freely can also cause the windings to overheat and fail, so you may actually end up with both problems.
I don’t know how easy your particular motor is to take apart so can’t give much more advice than that.
This doesn’t sound like a motor-start issue (since you said that the motor was running before it tripped the breaker). Sounds like a shorted winding to me. There are motor-rebuilders that might be able to fix this cheaper than buying a new one.
The motor spins freely by hand, no crunching/grinding sounds like a bearing on its way out.
The link I found sounds plausible regarding the start/run process. It starts, but then pulls too many amps obviously. Could a thorough spring cleaning help at all, before I disassemble #5 here?