F30021Fault · Power unit (Motor Module)Usually repairable
SINAMICS S120 F30021: Power Unit Ground Fault
What F30021 means
The drive detected current leaking to earth (ground fault) on the motor side.
Symptoms
Trips immediately when the axis is enabled; can also trip a breaker.
Is it repairable?
Yes: motor insulation and winding repair, or drive power stage repair.
Common causes
- Damaged motor cable insulation
- Coolant or water inside the motor or its connector
- Winding insulation breakdown
- Failed IGBT or current sensor
Safe checks
- 1Disconnect the motor at the drive and megger the motor and cable to ground
- 2Inspect connectors for coolant or oil
Drives hold dangerous voltage after power-off. Checks should only be done by qualified personnel, with power isolated and the DC link discharged.
Reviewed by AutomIQ repair technicians. Code and name from the SINAMICS S120/S150 List Manual.
Related SINAMICS S120 faults
- F07011Motor overtemperature
- F07900Motor blocked/speed controller at its limit
- F30001Overcurrent
- F30002DC link voltage overvoltage
- F30003DC link voltage undervoltage
- F30004Overtemperature heat sink AC inverter