Siemens SINAMICS G120 fault F30001: Power unit: Overcurrent
Fault F30001 on a SINAMICS G120 means the Power Module detected an overcurrent and switched off with OFF2 (motor coasts). The fault value r0949 shows which phase tripped: bit 0 = U, bit 1 = V, bit 2 = W, bit 3 = DC link; 0 means the phase was not identified.
Diagnose this with AI
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
- Instantly at power-on or the first ON command
- During acceleration in U/f operation
- On a load step or jam
- After a line supply interruption (recharge current)
Likely causes and checks
1Short circuit or ground fault in motor or power cables
- Points to it
- Trips the instant the motor is switched on, even unloaded; r0949 often names one phase.
- Check
- Lock out, disconnect the motor cable at the converter and insulation-test motor and cable phase-to-phase and to ground.
2Motor data or connection wrong
- Points to it
- Trips after commissioning, a motor swap or a Power Module change.
- Check
- Check the motor data against the rating plate and the star/delta connection; repeat commissioning if needed.
3Ramp-up too short in U/f operation
- Points to it
- Trips partway through acceleration; heavier loads trip sooner.
- Check
- Increase p1120 (ramp-up time) and compare.
4Motor current much larger than the Power Module rating
- Points to it
- Motor is larger than the converter.
- Check
- Compare the motor rated current with the Power Module rated current.
5Line side: missing line reactor, interrupted phase, poor supply quality
- Points to it
- Trips on power-on or after supply dips.
- Check
- Check the line reactor connection, the line phases and the supply quality.
6Motor cable too long or Power Module defective
- Points to it
- All other checks pass.
- Check
- Check cable length against the Power Module limits; replace the Power Module if the fault persists.
Telling it apart
- F30001 comes from the Power Module hardware. F07801 is the Control Unit’s motor overcurrent limit (p0640-based) and points more to settings and load; F30021 is a ground fault.
- Use r0949: a single phase bit points to that phase’s cable or winding; bit 3 (DC link) points to the line side and recharge currents.
- Instant trip at switch-on points to cables, motor or line reactor. A trip during the ramp points to p1120, load or motor data.
Relevant parameters
| Parameter | Name | Why it matters |
|---|---|---|
| p1120 | Ramp-function generator ramp-up time | Factory setting 10 s. Siemens’ remedy for U/f operation is a longer ramp. |
| r0949 | Fault value | Bits 0–3 identify phase U, V, W or DC link. |
Evidence to collect
- r0945/r0949 values for F30001
- Insulation results with the motor disconnected
- Motor data and rating plate
- p1120 ramp-up time and control mode (U/f or vector)
- Motor cable length and whether a line reactor is fitted
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