F30027Fault · Power unit (Motor Module)Usually repairable
SINAMICS S120 F30027: Power Unit Precharging DC Link Time Monitoring
What F30027 means
The DC link did not charge up to its working voltage within the allowed time at power-on.
Symptoms
The drive never reaches 'ready' after switch-on.
Is it repairable?
Yes: precharge circuits and DC link capacitors are standard repairs.
Common causes
- Failed precharge resistor or relay
- Missing supply phase
- Short on the DC link (failed capacitor or IGBT)
- Too many modules on one infeed
Safe checks
- 1Check all three supply phases
- 2Disconnect modules one at a time to find a short on the DC link (power off first)
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