"gtslabs" wrote in message
ups.com...
I picked up a 10 hp compressor, dual heads, 2 stage, 120 gallon tank.
The Pump has a centrifical unloader. The Motor is 3 phase 240 of which
I run on my 10hp rotary phase converter wired with 8-3 With Ground and
a 40 amp breaker.
The compressor starts fine but the breaker trips when the compressor is
near its top end around 160 psi. What are some causes for the breaker
to trip?
Thanks


I assume that you are you refering to a 40 amp single phase breaker on a
240 volt circuit that feeds the rotary converter.
The rotary converter isnt supplying perfect 3 phase.
Pumping at 160 PSI might be loading the compressor's motor to near its
max.
The 40 amp breaker is operating very close to the current where it is
designed to open.

If you want to experiment with this compressor current requirement, maybe
you can put a tachometer on the motor pulley. I suspect the motor is
turning at an RPM lower than its specified RPM at max power.

Jerry