Symptom
Possible Cause
Test
Solution
Motor not running
Service switch open or missing
motor connection
Check if the motor is connected
and the connection is not
interrupted (by a service switch or
other device).
Connect the motor and check the
service switch.
No line power with 24V DC option
card
If the display is functioning but no
output, check that line power is
applied to the Adjustable
frequency drive.
Apply line power to run the unit.
LCP Stop
Check if [Off] has been pressed.
Press [Auto On] or [Hand On]
(depending on your operation
mode) to run the motor.
Missing start signal (Standby)
Check
5-10 Start
for correct setting
for terminal 18 (use default
setting).
Apply a valid start signal to start
the motor.
Motor coast signal active
(Coasting)
Check
5-12 Coast inv
. for correct
setting for terminal 27 (use default
setting).
Apply 24V on terminal 27 or
program this terminal to No
operation.
Wrong reference signal source
Check reference signal: Local,
remote or bus reference? Preset
reference active? Terminal
connection correct? Scaling of
terminals correct? Reference signal
available?
Program correct settings Check
3-13 Reference site.
Set preset
reference active in parameter
group
3-1* References
. Check for
correct wiring. Check scaling of
terminals. Check reference signal.
Motor running in wrong
direction
Motor rotation limit
Check that
4-10 Motor speed
direction
is programmed correctly.
Program correct settings.
Active reversing signal
Check if a reversing command is
programmed for the terminal in
parameter group
5-1* Digital inputs.
Deactivate reversing signal.
Wrong motor phase connection
See
in this
manual.
Motor is not reaching
maximum speed
Frequency limits set wrong
Check output limits in
4-13 Motor
speed high limit [RPM], 4-14 Motor
speed high limit [Hz],
and
4-19 Max
output frequency.
Program correct limits.
Reference input signal not scaled
correctly
Check reference input signal
scaling in
6-* Analog I/O mode
and
parameter group
3-1* References.
Program correct settings.
Motor speed unstable
Possible incorrect parameter
settings
Check the settings of all motor
parameters, including all motor
compensation settings. For closed-
loop operation, check PID settings.
Check settings in parameter
group
1-6* Analog I/O mode
. For
closed-loop operation, check
settings in parameter group
20-0*
Feedback.
Motor runs rough
Possible overmagnetization
Check for incorrect motor settings
in all motor parameters.
Check motor settings in parameter
groups
1-2* Motor data, 1-3* Adv
motor data
, and
1-5* Load indep.
setting.
Motor will not brake
Possible incorrect settings in the
brake parameters. Possible too
short ramp-down times.
Check brake parameters. Check
ramp time settings.
Check parameter group
2-0* DC
brake
and
3-0* Reference limits
.
Basic Troubleshooting
VLT
®
AutomationDrive Instruction
Manual
9-2
MG.33.AI.22 - VLT
®
is a registered Danfoss trademark
9
9
