Danfoss VLT Micro Drive FC 51 Programming Manual page 67

Troubleshooting
VLT
WARNING/ALARM 8, DC under voltage
If the intermediate circuit voltage (DC link) drops below
the under voltage limit, the frequency converter checks if a
24 V DC backup supply is connected. If no 24 V DC backup
supply is connected, the frequency converter trips after a
fixed time delay. The time delay varies with unit size.
Troubleshooting
Check that the supply voltage matches the
frequency converter voltage.
Perform input voltage test.
Perform soft charge circuit test.
WARNING/ALARM 9, Inverter overload
The frequency converter is about to cut out because of an
6 6
overload (too high current for too long). The counter for
electronic, thermal inverter protection issues a warning at
98% and trips at 100%, while giving an alarm. The
frequency converter cannot be reset until the counter is
below 90%.
The fault is that the frequency converter has run with
more than 100% overload for too long.
Troubleshooting
Compare the output current shown on the LCP
with the frequency converter rated current.
Compare the output current shown on the LCP
with measured motor current.
Display the Thermal Drive Load on the LCP and
monitor the value. When running above the
frequency converter continuous current rating,
the counter increases. When running below the
frequency converter continuous current rating,
the counter decreases.
WARNING/ALARM 10, Motor overload temperature
According to the electronic thermal protection (ETR), the
motor is too hot. Select whether the frequency converter
gives a warning or an alarm when the counter reaches
100% in 1-90 Motor Thermal Protection. The fault occurs
when the motor is overloaded by more than 100% for too
long.
Troubleshooting
Check for motor overheating.
Check if the motor is mechanically overloaded
Check that the motor current set in 1-24 Motor
Current is correct.
Ensure that Motor data in parameters 1-20
through 1-25 are set correctly.
Running AMT in 1-29 Automatic Motor Tuning
(AMT). The inverter peak current limit (approx.
200% of the rated current) is exceeded. The
warning will last approx. 8-12 s, then the
frequency converter trips and issues an alarm.
Turn off the frequency converter and check if the
motor shaft can be turned and if the motor size
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Micro Drive FC 51 Programming Guide
matches the frequency converter. If extended
mechanical brake control is selected, trip can be
reset externally. may tune the frequency
converter to the motor more accurately and
reduce thermal loading.
WARNING/ALARM 11, Motor thermistor over temp
The thermistor might be disconnected. Select whether the
frequency converter gives a warning or an alarm in
1-90 Motor Thermal Protection.
Troubleshooting
Check for motor overheating.
Check if the motor is mechanically overloaded.
WARNING/ALARM 13, Over current
The inverter peak current limit (approx. 200% of the rated
current) is exceeded. The warning will last approx. 8-12 s,
then the frequency converter trips and issues an alarm.
Turn off the frequency converter and check if the motor
shaft can be turned and if the motor size matches the
frequency converter. If extended mechanical brake control
is selected, trip can be reset externally.
Troubleshooting:
Remove power and check if the motor shaft can
be turned.
Check that the motor size matches the frequency
converter.
Check parameters 1-20 through 1-25. for correct
motor data.
ALARM 14, Earth (ground) fault
There is current from the output phases to earth, either in
the cable between the frequency converter and the motor
or in the motor itself.
Troubleshooting:
Remove power to the frequency converter and
repair the earth fault.
Check for earth faults in the motor by measuring
the resistance to ground of the motor leads and
the motor with a megohmmeter.
ALARM 16, Short circuit
There is short-circuiting in the motor or motor wiring.
Remove power to the frequency converter and repair the
short circuit.
WARNING/ALARM 17, Control word timeout
There is no communication to the frequency converter.
The warning is only active when 8-04 Control Word Timeout
Function is NOT set to OFF.
If 8-04 Control Word Timeout Function is set to Stop and
Trip, a warning appears and the frequency converter ramps
down until it trips, while giving an alarm. 8-03 Control
Timeout Time could possibly be increased.
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