Danfoss VLT FC 102 Operating Instructions Manual page 84

Diagnostics and Troubleshoo...
Symptom
Motor is not reaching
maximum speed
Motor speed unstable
7 7
Motor runs rough
Motor does not brake
Open power fuses or circuit
breaker trip
Mains current imbalance
greater than 3%
Motor current imbalance
greater than 3%
82
®
VLT HVAC Drive FC 102 Low Harmonic Drive
Possible cause
Frequency limits set wrong.
Reference input signal not scaled
correctly.
Possible incorrect parameter
settings.
Possible overmagnetisation.
Possible incorrect settings in the
brake parameters. Possible too
short ramp down times.
Phase-to-phase shortcircuit.
Motor overload.
Loose connections.
Problem with mains power (See
Alarm 4 Mains phase loss
description).
Problem with the frequency
converter.
Problem with motor or motor
wiring.
Problem with the frequency
converters.
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Test
Check output limits in:
•
Parameter 4-13 Motor Speed
High Limit [RPM].
•
Parameter 4-14 Motor Speed
High Limit [Hz].
•
Parameter 4-19 Max Output
Frequency.
Check reference input signal scaling
in 6-0* Analog I/O Mode and
parameter group 3-1* References.
Reference limits in parameter group
3-0* Reference Limit.
Check the settings of all motor
parameters, including all motor
compensation settings. For closed-
loop operation, check PID settings.
Check for incorrect motor settings
in all motor parameters.
Check brake parameters. Check
ramp time settings.
Motor or panel has a short phase-
to-phase. Check motor and panel
phase for shortcircuits.
Motor is overloaded for the
application.
Perform pre-startup check for loose
connections.
Rotate input power leads into the
frequency converter one position: A
to B, B to C, C to A.
Rotate input power leads into the
frequency converter 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.
Solution
Program correct limits.
Program correct settings.
Check settings in parameter group
1-6* Load Depen. Setting. For
closed-loop operation, check
settings in parameter group 20-0*
Feedback.
Check motor settings in parameter
groups 1-2* Motor Data, 1-3* Adv
Motor Data, and 1-5* Load Indep.
Setting.
Check parameter group 2-0* DC
Brake and 3-0* Reference Limits.
Eliminate any shortcircuits
detected.
Perform start-up test and verify
that the motor current is within
specifications. 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 mains
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.
MG16I302