Search FAQs

What can cause a PHF (phase fault) on the ATS22 Soft Start?

Issue:
Display shows PHF on ATS22

Product Line:
ATS22, Altistart 22

Environment:
All models and serial numbers

Cause:
Loss of a line phase

Resolution:
1. Check the line voltage, the connection to the soft starter and any isolating devices located between the line and the soft starter (contactors, fuses, circuit breakers, etc.).
2. Check the motor connection and any isolating devices located between the soft starter and the motor (contactors, circuit breakers, etc.).
3. Check the motor state.
4. Verify that the run command to the ATS22 is applied AFTER the supply power is applied to L1, L2 and L3. If an isolation contactor coil is energized at the same time as a run command on LI2, expect that the run command will become active before the supply power is applied. The ATS22 will attempt to start, but see no amperage. The PHF fault will follow immediately.