Siemens SINAMICS PERFECT HARMONY GH180 Function Manual page 449

Fault display
Input phase imbal
PreChrg M1 Contactor Flt
NXGPro+ Control Manual
Operating Manual, A5E50491925A
Type Enable Potential causes and corrective actions
F/A SOP Cause
Drive input line current imbalance is greater than the setting in the phase
imbalance limit parameter in the drive protection menu. This fault / alarm
may be in conjunction with a neutral current path or ground fault condi‐
tion, or may be due to shorted windings in the transformer.
Action
1. Use an oscilloscope and the NXGpro test point board to verify proper
symmetry of the input voltages and currents: VIA, VIB, VIC, IIB and IIC.
2. Check the values of the input attenuators.
Note: During pre-charge, if so equipped, it is normal for phases to be
imbalanced.
F Cause
This fault aborts pre-charge and the message is issued in lieu of the pre-
charge fault.
Possible causes include:
• No power to contactor coil.
• Incorrect wiring of contactor and auxiliary contact, and connection
with system interface board.
• Loose or defective cable between DCR and system interface board.
• Defective system interface board.
Action
1. Check for control power to contactor (customer side).
2. Check wiring; check connections to system interface board.
3. Check cable connection between DCR and system interface board.
4. Replace system interface board.
5. Replace DCR.
Troubleshooting Faults and Alarms
11.4 Drive Faults and Alarms Input Line Disturbance
447