Symptom
Possible cause
Test
Solution
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 group
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.
Line power current
imbalance greater
than 3%
Problem with line power (See
Alarm
4, Mains phase loss
description)
Rotate input power leads into the
adjustable frequency drive one
position: A to B, B to C, C to A.
If the imbalanced leg follows the
wire, it is a power problem. Check
line power supply.
Problem with the adjustable
frequency drive unit
Rotate input power leads into the
adjustable frequency drive one
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 one
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 adjustable
frequency drive unit
Rotate output motor leads one
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 8.2 Troubleshooting
Maintenance, Diagnostics an...
Instruction Manual
MG07A122
Danfoss A/S © 11/2015 All rights reserved.
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