Symptom
Possible cause
Test
Solution
Motor is not
reaching
maximum
speed
Frequency limits set wrong.
Check output limits in
parameter 4-13 Motor
Speed High Limit [RPM]
,
parameter 4-14 Motor
Speed High Limit [Hz]
, and
parameter 4-19 Max
Output Frequency
Program correct limits.
Reference input signal not
scaled correctly.
Check reference input signal scaling in
parameter group 6-0* Analog I/O mode
and
parameter group 3-1* References.
Program correct settings.
Motor speed
unstable
Possible incorrect parameter
settings.
Check the settings of all motor parameters,
including all motor compensation settings.
For closed-loop operation, check PID settings.
Check settings in
parameter group 1-6*
Load Depen. Setting
. For closed-loop
operation, check settings in
parameter
group 20-0* Feedback.
Motor runs
rough
Possible overmagnetization.
Check for incorrect motor settings in all
motor parameters.
Check motor settings in
parameter groups
1-2* Motor data, 1-3* Adv Motor Data
, and
1-5* Load Indep. Setting.
Motor does
not brake
Possible incorrect settings in
the brake parameters. Ramp-
down times may be too short.
Check brake parameters. Check ramp time
settings.
Check
parameter groups
2-0* DC Brake
and
3-0* Reference Limits
.
Open power
fuses
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 can 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 AC drive.
Rotate input power leads into the AC drive 1
position: A to B, B to C, C to A.
If the imbalanced leg stays on same input
terminal, it is a problem with the AC
drive. 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 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 position: 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 supplier.
AC drive
acceleration
problems
Motor data are entered
incorrectly.
If warnings or alarms occur, see
chapter 8.5 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
.
AC drive
deceleration
problems
Motor data are entered
incorrectly.
If warnings or alarms occur, see
chapter 8.5 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 8.5 Troubleshooting
Maintenance, Diagnostics, a...
Operating Guide
MG16O102
Danfoss A/S © 01/2017 All rights reserved.
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