ATS480 Tripping Breaker

Title

What are possible causes for the ATS480 soft start to trip the breaker?

Issue:

ATS48 soft start trips the main breaker.

Product Line:

ATS480, Altistart 480

Environment:

All models and serial numbers

Cause:

Possible causes:

1. The load is excessive

2. Shorted SCR

3. Shorting contactor is welded in the closed position

4. Incorrect settings on the breaker

Resolution:

If excessive load, you may need to upsize the motor and soft start. Try increasing the acceleration time. Decrease the load.

With the soft start powered down, perform static checks on the SCR's. If shorted SCR's, repair or replace.

If shorting contactor is welded, replace the shorting contactor.

Check SCRS of the soft start. Dial proper trip settings on the breaker if present.

Released for: Schneider Electric Canada