F30003Fault · Power unit (Motor Module)Usually repairable
SINAMICS S120 F30003: Power Unit DC Link Voltage Undervoltage
What F30003 means
The DC link voltage dropped below the minimum the power unit needs to keep running.
Symptoms
Trips on supply dips, when several axes accelerate together, or right after switch-on; other axes on the same infeed may report it too.
Is it repairable?
Yes, when the infeed or power unit is the cause.
Common causes
- Missing phase, blown fuse or voltage dip on the supply
- Line Module (infeed) failing or not ready
- Loose DC link busbars
- Precharge or DC link capacitor problems
Safe checks
- 1Measure all three supply phases under load
- 2Check the fuses
- 3With power off, check the DC link busbar screws between modules
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
- F30004Overtemperature heat sink AC inverter
- F30005Overload I2t