Danfoss VLT AutomationDrive FC 301 Instruction Manual page 43

Diagnostics and Troubleshoo...
WARNING 5, DC link voltage high
The intermediate circuit voltage (DC) is higher than the
high-voltage warning limit. The limit is dependent on the
frequency converter voltage rating. The unit is still active.
WARNING 6, DC link voltage low
The intermediate circuit voltage (DC) is lower than the low-
voltage warning limit. The limit is dependent on the
frequency converter voltage rating. The unit is still active.
WARNING/ALARM 7, DC overvoltage
If the intermediate circuit voltage exceeds the limit, the
adjustable frequency drive trips after a time.
Troubleshooting
Connect a brake resistor
Extend the ramp time
Change the ramp type
Activate the functions in 2-10 Brake Function
Increase 14-26 Trip Delay at Inverter Fault
If the alarm/warning occurs during a power sag,
use kinetic backup (14-10 Line Failure)
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 back-up supply is connected. If no 24 V DC back-
up 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
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.
MG33AN22
Instruction Manual
WARNING/ALARM 10, Motor overload temperature
According to the electronic thermal protection (ETR), the
motor is too hot. Select whether the adjustable frequency
drive issues a warning or an alarm when the counter
reaches 100% in 1-90 Motor Thermal Protection. The fault
occurs when the motor runs with more than 100%
overload for too long.
Troubleshooting
WARNING/ALARM 11, Motor thermistor over temp
Check whether the thermistor is disconnected. Select
whether the adjustable frequency drive issues a warning or
an alarm in 1-90 Motor Thermal Protection.
Troubleshooting
Danfoss A/S © Rev. 2014-02-10 All rights reserved.
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.
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 to
1-25 are set correctly.
If an external fan is in use, check in 1-91 Motor
External Fan that it is selected.
Running AMA in 1-29 Automatic Motor Adaptation
(AMA) tunes the adjustable frequency drive to the
motor more accurately and reduces thermal
loading.
Check for motor overheating.
Check if the motor is mechanically overloaded.
When using terminal 53 or 54, check that the
thermistor is connected correctly between either
terminal 53 or 54 (analog voltage input) and
terminal 50 (+10 V supply). Also check that the
terminal switch for 53 or 54 is set for voltage.
Check 1-93 Thermistor Source selects terminal 53
or 54.
When using digital inputs 18 or 19, check that
the thermistor is connected correctly between
either terminal 18 or 19 (digital input PNP only)
and terminal 50. Check 1-93 Thermistor Source
selects terminal 18 or 19.
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