KEB COMBIVERT F5 Reference Manual page 300

Diagnostics and Troubleshooting
Problem
(Voltage) Modulation Grade
limit Reached
Motor tur ns in the wrong
direction (both directions)
Clunk at end of run after brake
sets
High peak current at either
start or stop
Erratic / glitching behavior of
keypad or drive
300
Cause/Solution/Troubleshoot
Verify correct wiring of the motor, in particular with motors which
have multiple voltage winding arrangements (eg. dual rated 230/460V
motors, wye-star/delta)
For IM motor, reduce the Field-Weakening Corner LM24 to 60% of
synchronous speed (720-480 rpm for 6-pole/60 Hz motor). A setting
of 45% of synchronous speed should be used as the practical lower
limit of this parameter.
For IM motor, try reducing Field Weakening Speed LM25 in steps of
100RPM.
For PM motor, check the current, particularly the peak current during
acceleration. Refer to Motor Draws High Current for additional
troubleshooting.
Reduce the acceleration and jerk rates into high speed.
Verify there is not excessive sag of the DC bus during acceleration.
Perform Encoder Synchronization procedure.
Inverter directions via LE03. Note, do not change A-B settings
(Not inverted/Swap A-B) to invert direction.
For PM motors, do not change (U,V,W) motor phasing !
Verify drive enable input is not being dropped prematurely while drive
is still outputting torque to motor.
Adjust LT12 Current Hold and/or LT13 Current Ramp Down timers.
Check the brake timing such that the motor is not starting against the
brake and that the brake is not stopping the load.
For digital input speed control, the Speed Start Delay LT03 can be
extended to prevent starting under the brake. For analog and serial
speed controls, this may need adjustment on the controller.
Ensure the keypad is securely connected to the drive. Press on the
keypad until a click or snap is heard.
Load US05 - write configuration to the drive.