Danfoss VLT AQUA Drive FC 202 Operating Instructions Manual page 77

Diagnostics and Troubleshoo...
Symptom
Frequency limits set wrong
Motor is not reaching
Reference input signal not scaled
maximum speed
correctly
Possible incorrect parameter
settings
Motor speed unstable
Possible overmagnetisation
Motor runs rough
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 mains power (See
Alarm 4 Mains phase loss
description)
Mains current imbalance
greater than 3%
Problem with the frequency
converter
Problem with motor or motor
wiring
Motor current imbalance
greater than 3%
Problem with the frequency
converters
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 7.9 Troubleshooting
MG21B202
Operating Instructions
Possible cause
Check output limits in 4-13 Motor
Speed High Limit [RPM], 4-14 Motor
Speed High Limit [Hz] and 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 shorts
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.
Bypass critical frequencies by using
parameters in parameter group
4-6* Speed Bypass
Turn off over-modulation in
14-03 Overmodulation
Change switching pattern and
frequency in parameter group
14-0* Inverter Switching
Increase Resonance Dampening in
1-64 Resonance Dampening
Danfoss A/S © Rev. 2014-01-22 All rights reserved.
Test
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 shorts detected
Perform startup 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 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.
Check if noise and/or vibration
have been reduced to an
acceptable limit
Solution
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75
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