Danfoss VLT HVAC Drive FC 102 Operating Manual page 104

Operating Guide | VLT® HVAC Drive FC 102
8.4.7 WARNING 6, DC Link Voltage Low
Cause
The DC-link voltage (DC) is lower than the low voltage warning limit. The limit depends on the drive voltage rating. The unit is still
active.
8.4.8 WARNING/ALARM 8, DC Undervoltage
Cause
If the DC-link voltage drops below the undervoltage limit, the drive checks for 24 V DC back-up supply. If no 24 V DC back-up supply is
connected, the drive trips after a fixed time delay. The time delay varies with unit size.
Troubleshooting
• Check that the supply voltage matches the drive voltage.
• Perform an input voltage test.
• Perform a soft-charge circuit test.
8.4.9 WARNING/ALARM 9, Inverter Overload
Cause
The drive has run with more than 100% overload for too long and is about to cut out. The counter for electronic thermal inverter
protection issues a warning at 98% and trips at 100% with an alarm. The drive cannot be reset until the counter is below 90%.
Troubleshooting
• Compare the output current shown on the LCP with the drive rated current.
• Compare the output current shown on the LCP with the measured motor current.
• Show the thermal drive load on the LCP and monitor the value. When running above the drive continuous current rating, the
counter increases. When running below the drive continuos current rating, the counter decreases.
8.4.10 WARNING/ALARM 10, Motor Overload Temperature
Cause
According to the electronic thermal protection (ETR), the motor is too hot.
Select 1 of these options:
• The drive issues a warning or an alarm when the counter is >90% if parameter 1-90 Motor Thermal Protection is set to warning
options.
• The drive trips when the counter reaches 100% if parameter 1-90 Motor Thermal Protection is set to trip options.
The fault occurs when the motor runs with more than 100% overload for too long.
102 | Danfoss A/S © 2020.01
Maintenance, Diagnostics, and
Troubleshooting
AQ275556502253en-000101 / 130R0706