Symptom
Possible cause
Test
Solution
Motor
running in
wrong
direction
Motor rotation limit.
Check that
parameter 4-10 Motor Speed
Direction
is programmed correctly.
Program correct settings.
Active reversing signal.
Check if a reversing command is programmed
for the terminal in
parameter group 5-1*
Digital inputs
.
Deactivate reversing signal.
Wrong motor phase
connection.
–
See
chapter 6.5.1 Warning - Motor Start
.
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
.
Maintenance, Diagnostics, a...
Operating Guide
MG16P222
Danfoss A/S © 04/2018 All rights reserved.
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