Troubleshooting Cell Over Temperature Faults - Siemens SINAMICS PERFECT HARMONY GH180 Function Manual

Handling VDC undervoltage faults
The undervoltage fault occurs when the voltage drops below the threshold of the detection
circuitry on the CCB. This can be the result of a low MV level coupled with a high current drainage
by the load, or simply as an excessive load that may give a momentary spike in current. It can also
occur if one of the AC power fuses fails under load.
Action
1. Check the cell fuses and check the historic log for line dips.
2. Correct the problem before continuing operation. A faulty CCB could also give a false
indication.
3. Replace defective or faulty parts.
Handling blocking failure faults
Blocking failures occur when IGBTs short due to perforation of their junction caused by excessive
current, i.e. high current density. This may be a result of out of saturation conditions and
frequent trips. The device will need to be replaced when the cell is removed for service. A
defective gate driver may be the root cause. A faulty CCB or bad data from the CCB could give a
faulty indication of this fault.
Action
Replace damaged or defective parts.
Handling switching failure faults
Switching failures occur when a device opens or fails to turn on. It could also be caused by a
defective gate driver or a damaged device. Also, a defective CCB or modulator could give a faulty
indication.
Repetitive OOS failures can degrade the device by reducing the conduction area. This would
result in higher current density, which could lead to eventual switching failure.
Action
Replace defective parts.
11.12.3

Troubleshooting Cell Over Temperature Faults

For water-cooled drives only, cell over temperature faults are typically caused by problems in the
coolant system. Use the following steps to troubleshoot this type of fault:
Course of action
1. Check the coolant system for proper flows and temperatures.
2. Inspect cell cooling paths for kinked hoses or major leaks.
3. Be sure all cell cabinet manifold valves are fully open.
NXGPro+ Control Manual
Operating Manual, A5E50491925A
Troubleshooting Faults and Alarms
11.12 Cell Faults and Alarms
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