Danfoss VLT FC 103 User Manual

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Troubleshooting
Check for proper fan operation.
Cycle power to the drive and check that the fan operates briey at start-up.
Check the sensors on the heat sink.
9.3.23 WARNING 25, Brake Resistor Short Circuit
Cause
The brake resistor is monitored during operation. If a short circuit occurs, the brake function is disabled and the warning appears.
The drive is still operational, but without the brake function.
Troubleshooting
Remove the power to the drive and replace the brake resistor (refer to parameter 2-15 Brake Check).
9.3.24 WARNING/ALARM 26, Brake Resistor Power Limit
Cause
The power transmitted to the brake resistor is calculated as a mean value over the last 120 s of run time. The calculation is based on
the DC-link voltage and the brake resistor value set in parameter 2-16 AC Brake Max. Current. The warning is active when the dissipa-
ted braking power is higher than 90% of the brake resistor power. If option [2] Trip is selected in parameter 2-13 Brake Power Monitor-
ing, the drive trips when the dissipated braking power reaches 100%.
9.3.25 WARNING/ALARM 27, Brake Chopper Fault
Cause
The brake transistor is monitored during operation, and if a short circuit occurs, the brake function is disabled, and a warning is
issued. The drive is still operational, but since the brake transistor has short-circuited, substantial power is transmitted to the brake
resistor, even if it is inactive.
Troubleshooting
Remove the power to the drive and remove the brake resistor.
9.3.26 WARNING/ALARM 28, Brake Check Failed
Cause
The brake resistor is not connected or not working.
Troubleshooting
Check parameter 2-15 Brake Check.
9.3.27 ALARM 29, Heat Sink Temp
Cause
The maximum temperature of the heat sink is exceeded. The temperature fault is not reset until the temperature drops below a
dened heat sink temperature. The trip and reset points are dierent based on the drive power size.
Troubleshooting
Check for the following conditions:
The ambient temperature is too high.
The motor cables are too long.
Incorrect airow clearance above and below the drive.
Blocked airow around the drive.
Damaged heat sink fan.
Dirty heat sink.
9.3.28 ALARM 30, Motor Phase U Missing
Cause
Motor phase U between the drive and the motor is missing.
AQ357954340588en-000201 / 130R0881 | 127Danfoss A/S © 2020.09
Maintenance, Diagnostics, and
Troubleshooting
VLT® Refrigeration Drive FC 103
Operating Guide

Danfoss VLT FC 103 Specifications

General

Brand	Danfoss
Model	VLT FC 103
Category	DC Drives
Language	English