Symptom
Possible cause
Test
Solution
Open power
fuses or
circuit
breaker trip
Phase-to-phase short.
Motor or panel has a short phase-to-phase.
Check motor and panel phases for shorts.
Eliminate any shorts detected.
Motor overload.
Motor is overloaded for the application.
Perform start-up test and verify that
motor current is within specifications. If
motor current is exceeding the nameplate
full load current, the motor may run only
with reduced load. Review the specifi-
cations for the application.
Loose connections.
Perform pre-start-up check for loose
connections.
Tighten loose connections.
Mains current
imbalance
greater than
3%
Problem with mains power (see
Alarm 4, Mains phase loss
description).
Rotate input power leads into the 1 position:
A to B, B to C, C to A.
If imbalanced leg follows the wire, it is a
power problem. Check the mains supply.
Problem with the frequency
converter.
Rotate input power leads into the frequency
converter 1 position: A to B, B to C, C to A.
If imbalance leg stays on same input
terminal, it is a problem with the
frequency converter. Contact supplier.
Motor current
imbalance
greater than
3%
Problem with motor or motor
wiring.
Rotate output motor cables 1 position: U to V,
V to W, W to U.
If imbalanced leg follows the wire, the
problem is in the motor or motor wiring.
Check motor and motor wiring.
Problem with frequency
converter.
Rotate output motor cables 1 position: U to V,
V to W, W to U.
If imbalance leg stays on same output
terminal, it is a problem with the unit.
Contact supplier.
Frequency
converter
acceleration
problems
Motor data are entered
incorrectly.
If warnings or alarms occur, see
chapter 7.4 List of Warnings and Alarms
Check that motor data are entered 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
.
Frequency
converter
deceleration
problems
Motor data are entered
incorrectly.
If warnings or alarms occur, see
chapter 7.4 List of Warnings and Alarms
Check that motor data are entered correctly.
Increase the ramp-down time in
parameter 3-42 Ramp 1 Ramp Down Time
.
Enable overvoltage control in
parameter 2-17 Over-voltage Control
.
Table 7.5 Troubleshooting
Maintenance, Diagnostics, a...
Operating Instructions
MG33AQ02
Danfoss A/S © 07/2015 All rights reserved.
49
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Summary of Contents for VLT AutomationDrive FC 301
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