Danfoss VLT Midi Drive FC 280 Instruction Manual page 49

Maintenance, Diagnostics an...
Symptom
Possible incorrect settings in the
Motor does not
brake parameters. Possible too short
brake
ramp-down times.
Phase-to-phase short
Open power fuses
or circuit breaker
Motor overload
trip
Loose connections
Problem with line power (See Alarm
4, Mains phase loss description)
Line power current
imbalance greater
than 3%
Problem with the adjustable
frequency drive unit
Problem with motor or motor wiring
Motor current
imbalance greater
than 3%
Problem with the adjustable
frequency drive unit
Acoustic noise or
vibration (for
example, a fan
Resonances, for example, in the
blade is making
motor/fan system
noise or vibrations
at certain
frequencies)
Table 8.2 Troubleshooting
MG07A122
Instruction Manual
Possible cause
Check brake parameters. Check ramp
time settings.
Motor or panel has a short phase-to-
phase. Check motor and panel phase
for shorts.
Motor is overloaded for the
application.
Perform pre-start-up check for loose
connections.
Rotate input power leads into the
adjustable frequency drive one
position: A to B, B to C, C to A.
Rotate input power leads into the
adjustable frequency drive one
position: A to B, B to C, C to A.
Rotate output motor leads one
position: U to V, V to W, W to U.
Rotate output motor leads one
position: U to V, V to W, W to U.
Bypass critical frequencies by using
parameters in parameter group 4-6*
Speed Bypass.
Turn off overmodulation in
parameter 14-03 Overmodulation.
Increase resonance damping in
parameter 1-64 Resonance Dampening.
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Test
Check parameter group 2-0* DC brake
and 3-0* Reference limits.
Eliminate any shorts detected.
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.
Tighten loose connections.
If the imbalanced leg follows the
wire, it is a power problem. Check
line power supply.
If the imbalanced leg stays on same
input terminal, it is a problem with
the unit. Contact the supplier.
If the imbalanced leg follows the
wire, the problem is in the motor or
motor wiring. Check motor and
motor wiring.
If the imbalanced leg stays on same
output terminal, it is a problem with
the unit. Contact the supplier.
Check if noise and/or vibration have
been reduced to an acceptable limit.
Solution
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47
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