Danfoss VLT Series Design Manual page 170

8. Troubleshooting
WARNING/ALARM 7, DC overvoltage:
If the intermediate circuit voltage exceeds the
limit, the adjustable frequency drive trips after
a given period of time.
Possible corrections:
Selecting OVC function will extend the ramp
times.
Alarm/warning limits:
VLT HVAC
Undervoltage
Voltage
low
8
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 line voltage is the in-
termediate circuit voltage (DC link) divided by
1.35.
WARNING/ALARM 8, DC undervoltage:
If the intermediate circuit voltage (DC) drops
below the "voltage warning low" limit (see ta-
ble above), the adjustable frequency drive
checks if 24 V backup supply is connected.
If no 24 V backup supply is connected, the
adjustable frequency drive trips after a given
period of time, depending on the unit.
To check whether the supply voltage matches
the adjustable frequency drive, see
eral Specifications
WARNING/ALARM 9, Inverter overloa-
ded:
The adjustable frequency drive is about to cut
out because of an overload (too high current
for too long). The counter for electronic, ther-
mal inverter protection gives a warning at
98% and trips at 100%, while giving an alarm.
You cannot reset the adjustable frequency
drive until the counter is below 90%.
170
Select Overvoltage 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 Gen-
.
MG.11.B4.22 - VLT
The fault is that the adjustable frequency
drive has been overloaded by more than nom-
inal 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 adjustable frequency drive to
give a warning or an alarm when the counter
reaches 100% in par. 1-90. The fault is that
the motor has been overloaded by more than
nominal current for too long. Check that the
motor par. 1-24 is set correctly.
WARNING/ALARM 11, Motor thermistor
overtemp:
The thermistor or the thermistor connection is
disconnected. You can choose if you want the
adjustable frequency drive to give a warning
or an alarm in par. 1-90. Make sure the ther-
mistor is connected correctly between termi-
nal 53 or 54 (analog voltage input) and
terminal 50 (+10 V supply), or between ter-
minal 18 or 19 (digital input PNP only) and
terminal 50. If a KTY sensor is used, check for
correct connection 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, Overcurrent:
The inverter peak current limit (approximately
200% of the rated current) is exceeded. The
warning will last approximately 8-12 sec., then
the adjustable frequency drive trips and issues
an alarm. Turn off the adjustable frequency
drive and check if the motor shaft can be
turned and if the motor size matches the ad-
justable frequency drive.
ALARM 14, Ground fault:
There is a discharge from the output phases
to ground, either in the cable between the ad-
justable frequency drive and the motor or in
the motor itself.
Turn off the adjustable frequency drive and
remove the ground fault.
ALARM 15, Incomplete hardware:
A fitted option is not handled by the present
control board (hardware or software).
® is a registered Danfoss trademark.
VLT ® HVAC Drive Design Guide