Danfoss VLT HVAC Drive FC100 Service Manual page 70

Troubleshooting
Troubleshooting:
Check connections on the serial communication
cable.
Increase 8-03 Control Word Timeout Time
Check the operation of the communication
equipment.
Verify a proper installation based on EMC
requirements.
ALARM 18, Start failed
The speed has not been able to exceed AP-70 Compressor
Start Max Speed [RPM] during start within the allowed time.
(set in AP-72 Compressor Start Max Time to Trip). This may
be caused by a blocked motor.
Warning/ Alarm 19, Discharge Temperature High
Warning:
The discharge temperature exceeds the level programmed
in par. 28-24. If so programmed in par. 28-25 the drive
lowers the speed of the compressor in an attempt to lower
the discharge temperature.
Alarm:
The discharge temperature exceeds the level programmed
in par. 28-26.
WARNING 22, Hoist mechanical brake
The report value will show what kind it is.
0 = The torque reference was not reached before time-out.
1 = There was no brake feedback before the time-out.
WARNING 23, Internal fan fault
The fan warning function is an extra protective function
that checks if the fan is running/mounted. The fan warning
can be disabled in 14-53 Fan Monitor ([0] Disabled).
For the D, E, and F Frame filters, the regulated voltage to
the fans is monitored.
Troubleshooting
Check for proper fan operation.
Cycle power to the frequency converter and
check that the fan operates briefly at start up.
Check the sensors on the heatsink and control
card.
WARNING 24, External fan fault
The fan warning function is an extra protective function
that checks if the fan is running/mounted. The fan warning
can be disabled in 14-53 Fan Monitor ([0] Disabled).
Troubleshooting
Check for proper fan operation.
Cycle power to the frequency converter and
check that the fan operates briefly at start up.
Check the sensors on the heatsink and control
card.
High Power Service Manual for Modular F Frame Drives
WARNING 25, Brake resistor short circuit
The brake resistor is monitored during operation. If a short
circuit occurs, the brake function is disabled and the
warning appears. The frequency converter is still
operational but without the brake function. Remove power
to the frequency converter and replace the brake resistor
(see 2-15 Brake Check).
WARNING/ALARM 26, Brake resistor power limit
The power transmitted to the brake resistor is calculated as
a mean value over the last 120 seconds of run time. The
calculation is based on the intermediate circuit voltage and
the brake resistance value set in 2-16 AC brake Max.
Current. The warning is active when the dissipated braking
is higher than 90% of the brake resistance power. If Trip [2]
is selected in 2-13 Brake Power Monitoring, the frequency
converter will trip when the dissipated braking power
reaches 100%.
WARNING/ALARM 27, Brake chopper fault
The brake transistor is monitored during operation and if a
short circuit occurs, the brake function is disabled and a
warning is issued. The frequency converter is still
operational but, since the brake transistor has short-
circuited, substantial power is transmitted to the brake
resistor, even if it is inactive.
Remove power to the frequency converter and remove the
brake resistor.
There is a risk of substantial power being transmitted to
the brake resistor if the brake transistor is short-circuited.
WARNING/ALARM 28, Brake check failed
The brake resistor is not connected or not working.
Check 2-15 Brake Check.
ALARM 29, Heatsink temp
The maximum temperature of the heatsink has been
exceeded. The temperature fault will not reset until the
temperature falls below a defined heatsink temperature.
The trip and reset points are different based on the
frequency converter power size.
Troubleshooting
Check for the following conditions.
For the D, E, and F Frame frequency converters, this alarm
is based on the temperature measured by the heatsink
sensor mounted inside the IGBT modules. For the F Frame
®
MG90K202 - VLT is a registered Danfoss trademark
WARNING
Ambient temperature too high.
Motor cable too long.
Incorrect airflow clearance above and below the
frequency converter
Blocked airflow around the frequency converter.
Damaged heatsink fan.
Dirty heatsink.
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