GE Industrial Solutions AF-600 FP High Power (460V_575V 150HP and above) - Manual (Page 50)

4.5.4 Incorrect Motor Operation
Occasionally, a fault can occur where the motor will continue to run, but not in the correct manner. The symptoms and causes may vary considerably. Many of
the possible problems are listed below by symptom along with recommended procedures for determining their causes.
Wrong speed/unit will not respond to command
Possible incorrect reference (speed command).
Ensure that the unit is programmed correctly according to the reference signal being used, and that all reference limits are set correctly as well. Perform Input
Terminal Signal Test (6.3.16) to check for faulty reference signals.
Motor speed unstable
Possible incorrect parameter settings, faulty current feedback circuit, loss of motor (output) phase.
Check the settings of all motor parameters, including all motor compensation settings (Slip Compensation, Load Compensation, etc.) For Closed Loop operation,
check PID settings. Perform Input Terminal Signal Test (6.3.16) to check for faulty reference signals. Perform the Output Imbalance of Supply Voltage Test (6.3.10)
to check for loss of motor phase.
Motor runs rough
Possible over-magnetization (incorrect motor settings), or an IGBT misfiring. Note: Motor may also stall when loaded or the frequency converter may trip occa-
sionally on Alarm 13.
Check setting of all motor parameters. Perform the Output Imbalance of Supply Voltage Test (6.3.10).
If output voltage is unbalanced, perform the Gate Drive Signal Test (6.3.11).
Motor draws high current but cannot start
Possible open winding in motor or open phase in connection to motor.
Perform the Output Imbalance of Supply Voltage Test (6.3.10) to ensure the frequency converter is providing correct output (see Motor Runs Rough above).
Run an auto tune to check the motor for open windings and unbalanced resistance. Inspect all motor wiring connections.
Motor will not brake
Possible fault in the brake circuit. Possible incorrect setting in the brake parameters. The ramp down time too short. Note: May be accompanied by an alarm or
warning message.
Check all brake parameters and ramp down time (parameters B-0#).
Perform Brake Check (6.3.13).
AF-650 GP and AF-600 FP High Power Service Manual
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