Danfoss VLT FC 103 Operating Manual page 127

Operating Guide | VLT® Refrigeration Drive FC 103
Symptom Possible cause
Motor running Motor rotation limit.
in wrong direc-
tion
Active reversing signal.
Wrong motor phase connec-
tion.
Motor is not Frequency limits set wrong.
reaching maxi-
mum speed
Reference input signal not
scaled correctly.
Motor speed Possible incorrect parameter
unstable settings.
Motor runs Possible overmagnetization.
rough
Motor does not Possible incorrect settings in
brake the brake parameters. Ramp-
down times may be too short.
Open power Phase-to-phase short.
fuses
Motor overload.
Loose connections.
Mains current Problem with mains power
imbalance (see Alarm 4, Mains phase loss
greater than 3% description).
Problem with the AC drive.
Danfoss A/S © 2020.01
Test
Check that parameter 4-10 Motor
Speed Direction is programmed
correctly.
Check if a reversing command is
programmed for the terminal in
parameter group 5-1* Digital inputs.
–
Check output limits in parameter
4-13 Motor Speed High Limit [RPM],
parameter 4-14 Motor Speed High
Limit [Hz], and parameter 4-19 Max
Output Frequency.
Check reference input signal scal-
ing in parameter group 6-0* Analog
I/O mode and parameter group 3-1*
References.
Check the settings of all motor pa-
rameters, including all motor com-
pensation 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
phases for shorts.
Motor is overloaded for the appli-
cation.
Perform pre-start-up check for
loose connections.
Rotate input power leads into the
1 position: A to B, B to C, C to A.
Rotate input power leads into the
AC drive 1 position: A to B, B to C, C
to A.
Maintenance, Diagnostics, and
Troubleshooting
Solution
Program correct settings.
Deactivate reversing signal.
Correct motor phase connection, or set
parameter 1-06 Clockwise Direction to [1]
Inverse.
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 groups 2-0* DC Brake
and 3-0* Reference Limits.
Eliminate any shorts detected.
Perform start-up test and verify that
motor current is within specifications. If
motor current is exceeding the name-
plate full load current, the motor can
run only with reduced load. Review the
specifications for the application.
Tighten loose connections.
If imbalanced leg follows the wire, it is a
power problem. Check the mains sup-
ply.
If the imbalanced leg stays on same in-
put terminal, it is a problem with the AC
drive. Contact the supplier.
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