Danfoss VLT AutomationDrive FC 302, Instruction Manual

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Symptom Possible cause Test Solution
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 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
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 imbalanced leg follows the wire,
it is a power problem. Check line
power supply
Problem with the adjustable
frequency drive Rotate input power leads into the
adjustable frequency drive one
position: A to B, B to C, C to A If imbalance 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 imbalanced leg follows the wire,
the problem is in the motor or
motor wiring. Check motor and
motor wiring
Problem with the adjustable
frequency drives Rotate output motor leads one
position: U to V, V to W, W to U If imbalance leg stays on same
output terminal, it is a problem
with the unit. Contact the supplier
Acoustic noise or vibration
(e.g., a fan blade is making
noise or vibrations at
certain frequencies)
Resonances, e.g., 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
14-03 Overmodulation
Change switching pattern and
frequency in parameter group
14-0* Inverter Switching
Increase Resonance Dampening in
1-64 Resonance Dampening
Table 10.1 Troubleshooting
Basic Start-up Troubleshoot... Instruction Manual
148 Danfoss A/S © Rev. 2014-02-07 All rights reserved. MG37A222
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