Question: 10 year old Campbell Hausefield 5HP 120v on a dedicated ckt. Has run flawlessly since new. I occasionally leave it turned on when I'm using it alot, so I don't have to wait for it to pump up. Now this Campbell Hausfeld compressor trips breaker.
Went out yesterday to pump up a tire and had no air pressure and breaker was tripped.
Reset brkr., it ran for about 4 sec slowly, then tripped brkr again...repeatedly.
Removed drive belt and started again...motor ran normal speed, but then tripped breaker after 4 sec with no load. What do you think?
Response: Dave, that's a good one. Good that you pulled the belt to check, as for me, that pretty much identifies the motor circuit as the source of the problem.
See the page on this site on checking your capacitors, as that would be the first thing I would check if my compressor was exhibiting your symptoms.
Comment It turns out that I had a bad run capacitor in the motor. It was visibly swollen and shorted. $27.50 for a new cap from my local motor shop and I'm back in business. Thanks for all the suggestions.
Response: Edwin, the sound of air rushing from the pressure switch is, I suspect, that of the UNLOADER VALVE working.
The unloader valve opens when the pressure switch trips the power off, shutting off the compressor motor.
When the pressure switch trips on at low pressure cut in, that closes the pressure switch, while the air compressor is running.
That yours dumps air again after trying to start suggests to me that it is your pressure switch that is failing, and when trying to start the air compressor, shorts the power, blowing the breaker, and tripping the pressure switch back off. I think! :-)
Comment: Bill, I have really come up on a mystery. I have disconnected the motor from the compressor and direct wired it to an outlet wired directly off the outside power supply. What I am saying is this, the only wire between the motor and the power is the cord of about three feet long, a temporary outlet and a breaker. I plug it in and it blows the breaker! I took motor to an electric shop and the fellow there replaced the run capacitor it runs on his power supply? I took it back home it blows the breaker immediately even with the new capacitor. Pretty frustrated now since the electric fellow can run without a problem. OK, so I am really scratching my head now?_____________________
If it runs at the repair shop, suggesting that the capacitor and the motor are fine, then the only variable is your power supply. You may have only a short cord to the motor, but what else is on the same circuit that is pulling power as your compressor motor is trying to run?
Comment: slow motor 1/2 speed indicates wrong motor voltage. Dual Voltage Motor, may be wired for high voltage 220 volts or may be 3 phase motor not single phase. Check motor plate for correct voltage and wiring. it iks common for factories to ship motors wired to higher voltage. You must set to voltage being used. Motor plate or spec sheet will state min. fusing required and maxium fuse allowed
Comment: Thanks Bill however that didn't work either. It will run slower than usual like a half power then trip circuit breaker after about 5 seconds. It appears as though it simply can't pull enough power but I am certain it has plenty for its rating. Thank you. What can I look at next?______________________
If there is no mechanical reason, the one reason that the fuse blows is that the motor is overloaded, or, and I think now this is more likely, the capacitor is failing. Time for a capacitor / motor check, I suspect.