"PeterD" wrote in message
...
On Fri, 18 Apr 2008 08:28:08 -0700, Smitty Two
wrote:

Our air compressor at work is powered by a 5hp, single phase, 230 volt
motor. Often when the compressor tries to start again (triggered by
falling tank pressure) the breaker trips. By rotating the motor by hand
prior to resetting the breaker, the motor will then start. Since this
happens between two and five times per day, we're getting tired of it.

The nameplate says the motor draws 24 full load amps, so I had the
electrician (who was there for another job) pull the motor off the 20
amp breaker and put it on a 30 amp. (wire gauge sufficiency verified.)

Still trips, and not knowing what else to do, I replaced the motor
starting capacitors.

That didn't fix it. So, before taking this to a motor repair shop, or
replacing it, is there anything else an idiot could look at and possibly
fix? TIA.

Check your unloader valve.

Yeah, if you dont hear a 'hiss' when it shuts down it's very likely the
unloader valve needs attention.

--
Cheers ............. Rheilly