Siemens SINAMICS PERFECT HARMONY GH180 Function Manual page 453

Fault display
Thermal OT Rollback
IOC
Under load alarm
Under load fault
Output phase imbal
NXGPro+ Control Manual
Operating Manual, A5E50491925A
Type Enable Potential causes and corrective actions
A Parame‐ Cause
ter
When enabled (Min Rollback Level, ID 7171 below 100%) and either two
cell OT alarms are active or the Transformer OT alarm is active, a torque
rollback is calculated. When this rollback affects the torque output, this
alarm will become active.
Action
1. Check cooling system for clogged filters or reduced airflow
2. Check ambient air temperature.
3. Check wiring of transformer OT switch.
F Fixed Cause
Drive instantaneous over-current (IOC) faults result when the signal from
test point IOC on the system interface board exceeds the level set by the
drive IOC setpoint (7110) parameter in the input protect menu (7000).
Action
1. Verify that the motor current rating (1050) is below the Drive IOC
setpoint (7110) in the drive protect menu (7).
2. Verify that parameter Output current scaler (3440) is set to a number
that is close to 1.0.
3. Verify that the signals on test points IMB and IMC on the NXGpro test
point board match the percentage of full-scale signals.
A SOP Cause
The torque producing current of the drive has dropped below a preset
value set by the user.
Action
This alarm usually indicates a loss of load condition. If this not the case,
verify the setting of parameter I underload (1182) in the limits menu
(1120).
F Menu Cause
This fault usually indicates a loss of load condition when the torque pro‐
ducing current of the drive has dropped below a preset value set by the
user for the specified amount of time.
Action
If this is not an unexpected condition, verify the setting of parameter I
underload (1182) and parameter Underload timeout (1186) in the limits
menu (1120).
A Fixed Cause
The software has detected an imbalance in the motor currents. This alarm
may be in conjunction with a neutral current path or ground fault condi‐
tion, or may be due to shorted windings in the motor.
Action
Verify proper symmetry of the motor currents on test points VMA, VMB,
VMC, IMA, IMB, and IMC on the test point board. If the currents are
unsymmetrical, verify if the burden resistors for the Hall effect transducers
are connected correctly.
Troubleshooting Faults and Alarms
11.5 Drive Faults and Alarms Motor/Output Related
451