Danfoss VLT Series Design Manual page 156

8. Troubleshooting
WARNING/ALARM 7
DC over voltage:
If the intermediate circuit voltage exceeds the
limit, the frequency converter trips after a
time.
Possible corrections:
Selecting OVC function will extend the ramp
times.
Alarm/warning limits:
VLT HVAC
Undervoltage
Voltage
8
low
Voltage
high (w/o brake -
w/brake)
Overvoltage
The voltages stated are the intermediate circuit
voltage of the VLT HVAC with a tolerance of ±
5 %. The corresponding mains voltage is the
intermediate circuit voltage (DC-link) divided
by 1.35
WARNING/ALARM 8
DC under voltage:
If the intermediate circuit voltage (DC) drops
below the "voltage warning low" limit (see ta-
ble above), the frequency converter checks if
24 V backup supply is connected.
If no 24 V backup supply is connected, the
frequency converter trips after a given time
depending on the unit.
To check whether the supply voltage matches
the frequency converter, see
Specifications
WARNING/ALARM 9
Inverter overloaded:
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 gives a warning at 98%
and trips at 100%, while giving an alarm. You
cannot reset the frequency converter until the
counter is below 90%.
156
Select Over Voltage Control function
in par. 2-17
Connect a brake resistor
Extend the ramp time
Activate functions in par. 2-10
Increase par. 14-26
3 x 200-240 3 x 380-500
V AC V AC
[VDC] [VDC]
185 373
warning 205 410
warning 390/405 810/840
410 855
3.2 General
.
MG.11.B2.02 - VLT
The fault is that the frequency converter is
overloaded by more than nominal current for
too long.
WARNING/ALARM 10
Motor ETR over temperature:
According to the electronic thermal protection
(ETR), the motor is too hot. You can choose if
you want the frequency converter to give a
warning or an alarm when the counter rea-
ches 100% in par. 1-90. The fault is that the
motor is overloaded by more than nominal
current for too long. Check that the motor par.
1-24 is set correctly.
WARNING/ALARM 11
Motor thermistor over temp:
The thermistor or the thermistor connection is
disconnected. You can choose if you want the
frequency converter to give a warning or an
alarm in par. 1-90. Check that the thermistor
is connected correctly between terminal 53 or
54 (analog voltage input) and terminal 50 (+
10 Volts supply), or between terminal 18 or 19
(digital input PNP only) and terminal 50. If a
KTY sensor is used, check for correct connec-
tion between terminal 54 and 55.
WARNING/ALARM 12
Torque limit:
The torque is higher than the value in par.
4-16 (in motor operation) or the torque is
higher than the value in par. 4-17 (in regen-
erative operation).
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 sec., then the frequency
converter trips and issues an alarm. Turn off
the frequency converter and check if the mo-
tor shaft can be turned and if the motor size
matches the frequency converter.
ALARM 14
Earth fault:
There is a discharge from the output phases
to earth, either in the cable between the fre-
quency converter and the motor or in the
motor itself.
Turn off the frequency converter and remove
the earth fault.
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VLT HVAC Drive Design Guide