SINAMICS G120 F30001 instantly at power-on, r0949=1: what to check?
My SINAMICS G120 is tripping F30001 instantly at power-on, and r0949 shows a value of 1. What should I check first?
Fault F30001 on a SINAMICS G120 indicates an overcurrent detected by the Power Module, causing an OFF2 trip. The fault value r0949 helps identify the phase involved, with bit 0 corresponding to phase U. An instant trip at power-on, especially with a specific phase identified, often points to issues with the motor or its cabling.
Likely causes and checks
1Short circuit or ground fault in motor or power cables
- Points to it
- An instant trip at power-on, even with no load, and r0949 indicating a specific phase (like bit 0 for phase U), strongly suggests a short circuit or ground fault in the motor or its power cables.
- Check
- Lock out the system, disconnect the motor cable at the converter, and perform an insulation test on the motor and cable, phase-to-phase and to ground.
2Motor data or connection wrong
- Points to it
- Incorrect motor data or an improper star/delta connection can lead to overcurrents, especially if the fault appeared after commissioning, a motor swap, or a Power Module change.
- Check
- Verify the motor data against its rating plate and confirm the star/delta connection. If necessary, repeat the commissioning process.
3Motor current much larger than Power Module rating
- Points to it
- If the motor's rated current significantly exceeds the Power Module's rating, it can cause overcurrent trips, particularly if the motor is larger than the converter.
- Check
- Compare the motor's rated current with the Power Module's rated current (r0207).
4Line side issues: missing line reactor, interrupted phase, poor supply quality
- Points to it
- Problems on the line side, such as a missing line reactor, an interrupted phase, or poor supply quality, can cause overcurrents, especially if the fault occurs on power-on or after supply dips.
- Check
- Check the line reactor connection, inspect all line phases, and assess the quality of the line supply.
Next check: Given the instant trip at power-on and r0949=1 (phase U), the most critical next step is to check for a short circuit or ground fault in the motor or its power cables. Lock out the system, disconnect the motor cable at the converter, and insulation-test the motor and cable phase-to-phase and to ground.
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