Bendt (Customer) asked a question.
How to size circuit for soft starter on compressor
I recently added the SR35 soft starter for a reciprocating air compressor motor, but now I'm experiencing circuit breaker trips due to the extended startup time and high current draw at startups. I have a 15HP 3 phase motor with FLA rating of 40 Amps on a 60 amp breaker. I suspect I need to upgrade the breaker, but looking for help on how to size that if so.
Sorry if I'm coming off pedantic:
Before changing the circuit breaker, are your wires big enough in gauge to handle a larger circuit breaker? But before you answer that, what model and what is your supply voltage? Also, was it working fine before with a motor starter? Another question: is your pressure relief valve on the load side operated by the pressure switch that turns on the starter or is it one operated centrifugally on the flywheel? I had a compressor where the centrifugal pressure relief valve stopped working. So, the compressor was attempting to run against a load at start leading to nuisance tripping.