Danfoss VLT AQUA Drive FC 202 Installation Manual page 85

Diagnostics and Troubleshoo...
Symptom
Possible incorrect settings in the
Motor will not brake brake parameters. Possible too
short ramp-down times.
Phase-to-phase short
Motor overload
Open power fuses or circuit
breaker trip
Loose connections
Problem with line power (See
Alarm 4 Mains phase loss
Line power current description)
imbalance greater than 3% Problem with the adjustable
frequency drive
Problem with motor or motor
wiring
Motor current imbalance
greater than 3%
Problem with the adjustable
frequency drives
Acoustic noise or vibration
(e.g., a fan blade is making Resonances, e.g., in the motor/fan
noise or vibrations at system
certain frequencies)
Table 7.5 Troubleshooting
MG21B322
Installation 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
Change switching pattern and
frequency in parameter group
14-0* Inverter Switching
Increase Resonance Dampening in
parameter 1-64 Resonance Damping
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Test
Check parameter group 2-0* DC
Brake and 3-0* Reference Limits.
Eliminate any shorts detected
Perform start-up test and verify
motor current is within specifi-
cations. If motor current is
exceeding nameplate full load
current, motor may run only with
reduced load. Review the specifi-
cations for the application.
Tighten loose connections
If imbalanced leg follows the wire,
it is a power problem. Check line
power supply.
If imbalance leg stays on same
input terminal, it is a problem with
the unit. Contact the supplier.
If imbalanced leg follows the wire,
the problem is in the motor or
motor wiring. Check motor and
motor wiring.
If imbalance 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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