Siemens SINAMICS PERFECT HARMONY GH180 Function Manual page 484

Troubleshooting Faults and Alarms
11.12 Cell Faults and Alarms
Action
1. Check the fuses and replace any that are blown, more than one could be blown.
2. Replace defective or damaged parts.
Handling control power faults
This fault is caused when one or more of the control fuses that supply power to the CCB are
blown. This is rarely seen because the CCB is supplied by 2 circuits: the control power supply
bridge and the DC link. If a control power fault is observed, the AC fuses might also be blown.
Action
Replace the defective or damaged parts.
Handling capacitor sharing faults
The cell capacitor bank is made up of from 2 to 3 series capacitor banks. Circuitry on the CCB
measures the voltage on each section and if the voltages are off by any amount, the fault is set.
This indicates that under load the capacitors are not sharing load evenly and could be the result
of faulty capacitors or loose connections.
Action
Fix or replace damaged or defective components.
Handling Q1-Q4 out of saturation (OOS) faults
Out of saturation faults occur when the transistor junction is depleted of charge carriers
resulting in a higher junction resistance. This in turn created a larger voltage drop and more
losses in the transistor which can lead to premature failure. The cause of the OOS can be a
defective gate driver board or a high di/dt transition on the device. The gate board is designed
with circuitry to detect the larger voltage drop when the device should be on, shutting down the
device in a fault condition. The fault can also be caused by a defective CCB.
Repetitive OOS faults on a device can shorten the life of the device. The damage to the device
can be cumulative.
Action
The exact cause needs to be determined before pulling a power cell out of service.
Handling faults when bypass failed
This fault results from the failure of a cell to go into bypass when faulted. The cause can be from
a defective modulator, bad link between the modulator and the MV bypass board, a defective MV
bypass board or supply, or a defective bypass contactor.
Action
Find and replace the faulty components.
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NXGPro+ Control Manual
Operating Manual, A5E50491925A