Siemens SINAMICS G120 fault F30003: DC link voltage, undervoltage
Fault F30003 on a SINAMICS G120 means the Power Module detected undervoltage in the DC link and switched off. Siemens lists a line supply failure, line voltage below the permissible value and an interrupted line phase. The undervoltage threshold depends on p0210 (unit supply voltage).
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Try Free Drive Diagnostic Upload a keypad photo, the fault history or a parameter export from your Siemens SINAMICS G120. InduQT compares the evidence and suggests the next useful checks.
When it happens
- Running when the supply dips or fails
- During brownouts or when a phase is lost
- At power-down with an ON command still active
Likely causes and checks
1Supply failure or dip
- Points to it
- Trip matches a plant power event.
- Check
- Compare the fault time (r0948, r2130) with power-quality records.
2Line voltage below permissible value or p0210 set too high
- Points to it
- Trips under load on a weak supply; p0210 does not match the supply.
- Check
- Measure the line voltage under load and check p0210.
3Line phase interrupted
- Points to it
- Trips under load; F30011 (line phase failure) may also appear.
- Check
- With the supply isolated, check the input fuses and connections, then measure all three phases.
Telling it apart
- The converter’s automatic restart treats F30003 as a power failure: with p1210 set for restart, the drive switches the motor back on when the supply returns (the manual warns this can start the machine unexpectedly).
- F30011 is a line phase failure detected from DC link ripple or a ruptured fuse; Siemens notes it can also come from a phase failure in the motor feeder cable.
- F30027 (DC link pre-charging time monitoring) appears at power-on, not during running.
Relevant parameters
| Parameter | Name | Why it matters |
|---|---|---|
| p0210 | Unit supply voltage | Sets the undervoltage threshold; must match the supply. |
| p1210 | Automatic restart mode | Values above 1 restart the motor automatically after a power failure. |
Evidence to collect
- r0945/r0948 for F30003 and any F30011
- Measured line voltage on all phases
- p0210 setting
- Plant power events
- Automatic restart setting p1210
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