MOTOR PHASE
ABB · ACS800
What does FF56 mean?
One of the motor phases has been lost, causing an imbalance in the motor current. This can be due to a fault in the motor, motor cable, external thermal relay, or an internal drive issue. This protection is linked to programmable Fault Function 30.16.
Common Causes
- An open circuit or high resistance connection in one of the motor phases (U, V, or W) due to a cable fault or loose terminal.
- Internal winding fault (e.g., open circuit) within the motor.
- A tripped or faulty external thermal relay in the motor circuit, if used.
- An internal fault within the ACS800 drive's output stage.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Check motor windings and motor cables for open circuits or high resistance using a multimeter (ohmmeter).
- 2
Verify all motor cable connections are secure and tightened to specification at both the drive output terminals and the motor terminals.
- 3
Inspect and test the thermal relay (if used) for proper operation and correct wiring; ensure its contacts are clean and making good connection.
- 4
Check parameter 30.16 (MOTOR PHASE LOSS) setting. If protection is temporarily not desired (e.g., during specific test cases), consider disabling it with caution and appropriate safety measures.