Symptom Possible cause Test Solution
Motor current
imbalance
greater than 3%
Problem with motor or motor
wiring.
Rotate output motor cables 1 posi-
tion: U to V, V to W, W to U.
If the imbalanced leg follows the wire,
the problem is in the motor or motor
wiring. Check motor and motor wiring.
Problem with AC drive. Rotate output motor cables 1 posi-
tion: U to V, V to W, W to U.
If the imbalanced leg stays on same
output terminal, it is a problem with
the unit. Contact the supplier.
AC drive accel-
eration prob-
lems
Motor data are entered incor-
rectly.
If warnings or alarms occur, refer
to the Warnings and Alarms sec-
tion. Check that motor data are en-
tered correctly.
Increase the ramp-up time in parameter
3-41 Ramp 1 Ramp Up Time. Increase
current limit in parameter 4-18 Current
Limit. Increase torque limit in parameter
4-16 Torque Limit Motor Mode.
AC drive decel-
eration prob-
lems
Motor data are entered incor-
rectly.
If warnings or alarms occur, refer
to the Warnings and Alarms sec-
tion. Check that motor data are en-
tered correctly.
Increase the ramp-down time in param-
eter 3-42 Ramp 1 Ramp Down Time. Ena-
ble overvoltage control in parameter
2-17 Over-voltage Control.
Maintenance, Diagnostics, and
Troubleshooting
Operating Guide | VLT® Refrigeration Drive FC 103
AQ275652766279en-000101 / 130R0707
126 | Danfoss A/S © 2020.01