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VLT
®
HVAC Drive Instruction Manual
WARNING 24, External fan fault
The fan warning function is an extra protection function that checks if the
fan is running / mounted. The fan warning can be disabled in
Fan Monitor
par. 14-53
([0] Disabled).
For the D, E, and F Frame drives, the regulated voltage to the fans is
monitored.
Troubleshooting:
Check fan resistance.
Check soft charge fuses.
WARNING 25, Brake resistor short circuit
The brake resistor is monitored during operation. If it short circuits, the
brake function is disconnected and the warning appears. The adjustable
frequency drive still works, but without the brake function. Turn off the
adjustable frequency drive and replace the brake resistor (see
Brake Check
par. 2-15
).
WARNING/ALARM 26, Brake resistor power limit
The power transmitted to the brake resistor is calculated as follows: as a
percentage, as a mean value over the last 120 seconds, on the basis of
the resistance value of the brake resistor, and the intermediate circuit
voltage. The warning is active when the dissipated braking energy is
Trip
higher than 90%. If
[2] has been selected in par. 2-13
Monitoring
, the adjustable frequency drive cuts out and issues this alarm,
when the dissipated braking energy is higher than 100%.
WARNING/ALARM 27, Brake chopper fault
The brake transistor is monitored during operation and if it short-circuits,
the brake function disconnects and issues a warning. The adjustable fre-
quency drive is still able to run, but since the brake transistor has short-
circuited, substantial power is transmitted to the brake resistor, even if it
is inactive.
Turn off the adjustable frequency drive and remove the brake resistor.
This alarm/ warning could also occur should the brake resistor overheat.
Terminal 104 to 106 are available as brake resistor. Klixon inputs, see
section Brake Resistor Temperature Switch.
WARNING/ALARM 28, Brake check failed
Brake resistor fault: the brake resistor is not connected or not working.
Brake Check
Check par. 2-15
.
ALARM 29, Heatsink temp
The maximum temperature of the heatsink has been exceeded. The tem-
perature fault will not be reset until the temperature falls below a defined
heatsink temperature. The trip and reset point are different based on the
drive power size.
Troubleshooting:
Ambient temperature too high.
Too long motor cable.
Incorrect clearance above and below the drive.
Dirty heatsink.
Blocked air flow around the drive.
Damaged heatsink fan.
For the D, E, and F Frame drives, this alarm is based on the temperature
measured by the heatsink sensor mounted inside the IGBT modules. For
the F Frame drives, this alarm can also be caused by the thermal sensor
in the rectifier module.
Troubleshooting:
ALARM 30, Motor phase U missing
Motor phase U between the adjustable frequency drive and the motor is
missing.
Turn off the adjustable frequency drive and check motor phase U.
ALARM 31, Motor phase V missing
Motor phase V between the adjustable frequency drive and the motor is
missing.
Turn off the adjustable frequency drive and check motor phase V.
ALARM 32, Motor phase W missing
Motor phase W between the adjustable frequency drive and the motor is
missing.
Turn off the adjustable frequency drive and check motor phase W.
ALARM 33, Inrush fault
Too many power-ups have occurred within a short time period. Let unit
Brake Power
cool to operating temperature.
WARNING/ALARM 34, Fieldbus communication fault
The serial communication bus on the communication option card is not
working.
WARNING/ALARM 35, Out of frequency ranges:
This warning is active if the output frequency has reached the high limit
(set in par. 4-53) or low limit (set in par. 4-52). In
loop
(. 1-00) this warning is displayed.
WARNING/ALARM 36, Mains failure
This warning/alarm is only active if the supply voltage to the adjustable
frequency drive is lost and par. 14-10
Check the fuses to the adjustable frequency drive
MG.11.AB.22 - VLT
®
is a registered Danfoss trademark
Check fan resistance.
Check soft charge fuses.
IGBT thermal sensor.
Line Failure
8 Troubleshooting
8
Process Control, Closed-
is NOT set to OFF.
8-7
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