Siemens SINAMICS PERFECT HARMONY GH180 - Table 11-14 Diagnostic Cell Faults

Fault display Type Enable Potential causes and corrective actions
xx DC Bus Over Volt
xx = cell that is faulted
F Fixed Cause
The bus voltage in a cell has been detected over limit, i.e., the signal on the
VDC test point is > 8.0 VDC and is usually caused by a regeneration limit
that is too high, or improper tuning of the drive.
Action
Refer to the Operating Instructions manual.
xx DC Bus Under Volt
xx = cell that is faulted
F Fixed Cause
The DC bus voltage detected in a cell is abnormally low. The signal on test
point VDC on the CCB is <3.5 VDC. If this symptom is reported by more than
one cell, it is usually caused by a low primary voltage on the main trans‐
former T1.
Action
1. Check input line voltage.
2. Check for faults on other cells.
The following cell faults will occur only during the cell diagnostic mode immediately following
initialization or reset. All IGBTs in each cell are sequentially gated and checked for proper
operation, i.e. blocking or not blocking. See Table Diagnostic cell faults.
Note
Switching and blocking tests
Not every cell type has switching and blocking tests. Refer to the Operating Instructions manual.
Table 11-14 Diagnostic cell faults
Fault display Type Enable Potential causes and corrective actions
xx Blocking Qn
n = 1,2,3,4
xx = cell that is faulted
F Fixed Cause
During cell diagnostic mode, the drive checks the voltage across each IGBT
under "gate o󹪜" conditions. A blocking failure is reported if insu󹪟cient
voltage is detected when power transistors are o󹪜 (not gated). This may
indicate a damaged IGBT, or a malfunctioning gate driver board or CCB. No
subsequent switching test will be performed on the cell.
Action
Refer to the Operating Instructions manual.
xx Switching Qn
n = 1,2,3,4
xx = cell that is faulted
F Fixed Cause
During cell diagnostic mode, the drive turns each IGBT on one-by-one, and
veri󹪝es the collapse of voltage across the devices. A switching failure is
reported if a device is supporting voltage while it is gated on, i.e. voltages
on test points VT1 and VT2 on the CCB are > ±0.5 VDC when power tran‐
sistors Q1-Q4 are gated. Usually, this fault is caused by a malfunctioning
gate driver board, IGBT, or CCB.
Action
Refer to the Operating Instructions manual.
Troubleshooting Faults and Alarms
11.12 Cell Faults and Alarms
NXGPro+ Control Manual
472 Operating Manual, A5E50491925A