23 January 2021
Wondering what would cause the shunt trip breaker to trip on the Enclosed ATS46 and ATS48 soft starters on power up?
Shunt trip breaker
Circuit breaker disconnect is tripping on power up.
The fault relay has a timed on-delay contact that will power the breaker shunt trip coil if the Altistart R1 relay is not opened by the end of delay. The factory sets the delay to 2 sec. If the delay is set too short or the fault relay does not actuate, the shunt coil will energize and trip the breaker. Consult factory wiring schematics.
Consider increasing the delay time on the time delay relay.
If the relay circuits operate properly, consider that the thermal or magnetic elements of the breaker may be tripping it, rather than the shunt coil.