Danfoss VLT FC 103 Instruction Manual

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 Line 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*.
Check if noise and/or vibration
have been reduced to an
acceptable limit.
Turn off over-modulation in
14-03 Overmodulation.
Change switching pattern and
frequency in parameter group
14-0*.
Increase Resonance Dampening in
1-64 Resonance Dampening.
Table 9.1 Start-up and Operation
Basic Troubleshooting Instruction Manual
MG16E222 Danfoss A/S © Rev. 2014-02-10 All rights reserved. 75
9 9

Danfoss VLT FC 103 Specifications

General

Brand	Danfoss
Model	VLT FC 103
Category	DC Drives
Language	English