OPERATION INSTRUCTIONS DANFOSS ENG

Symptom Possible cause Test Solution
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 6-0*
Analog I/O Mode and parameter group 3-1*
References. Reference limits in parameter
group 3-0* Reference Limits.
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*
Load Depen.Setting. 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* Addl. 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.
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 short circuits detected.
Motor overload Motor is overloaded for the application. Perform start-up test and verify motor
current is within specifications. If motor
current is exceeding nameplate full load
current, motor may run only with reduced
load. Review the specifications 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 Mains 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.
Adjustable
frequency
drive
acceleration
problems
Motor data are entered
incorrectly
If warnings or alarms occur, see
chapter 7.4 List of Warnings and Alarms
Check that motor data are entered correctly
Increase the ramp-up time in 3-41 Ramp 1
Ramp-up Time. Increase current limit in
4-18 Current Limit. Increase torque limit in
4-16 Torque Limit Motor Mode.
Adjustable
frequency
drive
deceleration
problems
Motor data are entered
incorrectly
If warnings or alarms occur, see
chapter 7.4 List of Warnings and Alarms
Check that motor data are entered correctly
Increase the ramp-down time in 3-42 Ramp
1 Ramp-down Time. Enable overvoltage
control in 2-17 Over-voltage Control.
Diagnostics and Troubleshoo... Instruction Manual
46 Danfoss A/S © Rev. 11/06/2014 All rights reserved. MG11AK22
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