JVShermco
Electrical
- Jan 22, 2009
- 3
We have a star delta or Wye Delta starter on a 550 hp air compressor motor. We are tripping the 800 amp feeder breaker feeding the starter. It does not trip on every start. We have done inrush measurements (se attached pdf). The motor gets up to speed during the reduced voltage portion of the start. There is an approximate 1/4 second delay between low voltage and high voltage start. At the initiation of the delta contactor, the cuerrent spikes. This is when the breaker trips. Is there a timing issue with the transitional period between low and high voltage contactor closing? Is there a timng issue with the two Delta contactors? Is there a test to see if there is a contactor timing issue?