Symptom
Possible cause
Test
Solution
Motor is not
reaching maximum
speed
Frequency limits are set incorrectly
Check output limits in
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-** Analog I/O mode
and
parameter group 3-1* References
.
Program correct settings.
Motor speed is
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 6-
** Analog I/O mode
.
Motor runs roughly 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. Possible too short
ramp-down times.
Check brake parameters. Check ramp
time settings.
Check
parameter groups 2-0* DC brake
and
3-0* Reference limits
.
Open power fuses
or circuit breaker
trip
Phase-to-phase short
Motor or panel has a short phase-to-
phase. Check motor and panel phase
for shorts.
Eliminate any shorts detected.
Motor overload
Motor is overloaded for the
application.
Perform the start-up test and verify
that motor current is within specifi-
cations. If motor current is exceeding
nameplate full load current, the
motor may run only with reduced
load. Review the specifications 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
frequency converter 1 position: A to B,
B to C, C to A.
If the imbalanced leg follows the
wire, it is a power problem. Check
mains supply.
Problem with the frequency
converter unit
Rotate input power leads into the
frequency converter 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 unit. Contact the supplier.
Motor current
imbalance greater
than 3%
Problem with motor or motor wiring
Rotate output motor leads 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 the frequency
converter unit
Rotate output motor leads 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 the supplier.
Acoustic noise or
vibration (for
example a fan blade
is making noise or
vibrations at certain
frequencies)
Resonances, for example, in the
motor/fan system
Bypass critical frequencies by using
parameters in
parameter group 4-6*
Speed Bypass
.
Check if noise and/or vibration have
been reduced to an acceptable limit.
Turn off overmodulation in
parameter 14-03 Overmodulation
.
Increase resonance damping in
parameter 1-64 Resonance Dampening
.
Table 7.4 Troubleshooting
Diagnostics and Troubleshoo...
VLT
®
AutomationDrive FC 360
52
Danfoss A/S © 03/2017 All rights reserved.
MG06A702
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