2hp compressor tripping breaker on 2kva generator

by Darryl
(Rockhampton Australia)

Hi Bill Compressor runs ok on mains power (240) and also fills from empty on genset. Cuts out OK and dumps at 120 psi However it won't cut back in at the low end and will trip the circuit on the generator.

I think the reason is and related to back pressure. As soon as the check valve on the main tank is cracked when the motor starts there is a surge of air that comes back from the tank to the compressor head that basically stops the piston.

I was considering fitting an accumulator type tank to give the motor time to build momentum or increasing the length (or diameter) of the line from the head to the tank. Any experience with this at all. I already know the system is undersized but space is at a premium on my 40' yacht. Mainly will be used for small sandblasting and needle gun.
Darryl, please advise as a comment here if, when the air compressor gets to cut out and shuts down, the compressor unloader valve is working.

Be good to know the make and model of compressor too.


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Mar 17, 2014
by: Doug in s.d.ca

You might be looking at a failing start cap.

I doubt that adding more air line between the head and the receiver would give your motor enough time to get started, but if you can do that conveniently it wouldn't hurt to try.

While it would be a pain operationally, a manual "unloader" valve might work. Taking that a step further (if it works), you might try a time-delay electric valve for hassle-free operation.

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