Danfoss VLT FC 102 Operating Instructions Manual page 39

Diagnostics and Troubleshoo...
WARNING/ALARM 17, Control word timeout
There is no communication to the frequency converter.
The warning is only active when 8-04 Control Word Timeout
Function is NOT set to [0] Off.
If 8-04 Control Word Timeout Function is set to [5] Stop and
Trip, a warning appears and the frequency converter ramps
down until it stops then displays an alarm.
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 1-77 Compressor
Start Max Speed [RPM] during start within the allowed time.
(set in 1-79 Compressor Start Max Time to Trip). This may be
caused by a blocked motor.
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.
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).
®
VLT HVAC Drive Operating Instructions
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
power is higher than 90% of the brake resistance power. If
[2] Trip is selected in 2-13 Brake Power Monitoring, the
frequency converter trips 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.
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.
ALARM 30, Motor phase U missing
Motor phase U between the frequency converter and the
motor is missing.
Remove power from the frequency converter and check
motor phase U.
ALARM 31, Motor phase V missing
Motor phase V between the frequency converter and the
motor is missing.
Remove power from the frequency converter and check
motor phase V.
ALARM 32, Motor phase W missing
Motor phase W between the frequency converter and the
motor is missing.
Remove power from the frequency converter and check
motor phase W.
MG11AJ02 - Rev. 2013-07-31
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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