F30003 fault in Siemens V70 Drive indicates a DC link undervoltage. This means the internal DC bus voltage dropped too low, caused by a failure or dip in the incoming AC line supply.
Cause: The power unit has detected an undervoltage condition in the DC link.
- Line supply failure.
- Line supply voltage below the permissible value.
- Line supply infeed failed or interrupted.
- Line phase interrupted.
Remedy:
- Check the line supply voltage.
- Check the line supply infeed and observe the fault messages relating to it (if there are any).
- Check the line supply phases.
- Check the line supply voltage setting.
