Danfoss VLT 3000 Drive

Danfoss VLT 3000 Drive Fault Codes:

Fault Code and MeaningCause and Remedy

Inverter fault (INVERTER FAULT)
Fault code 1



A fault in the VLT frequency converter’s power section.

Cause:

Internal failure within the power section of the drive.



Remedy:


  • Contact Danfoss.

Overvoltage (OVER VOLTAGE)
Fault code 2



The intermediate circuit voltage (DC link) is above the inverter’s overvoltage limit.

Cause:

The intermediate circuit voltage is too high. This can happen if:

  • The load drives the motor (generator mode/regenerative energy).

  • The mains supply voltage is too high.

  • Deceleration ramp (ramp-down) is too short for the inertia.





Remedy:


  • Check the supply voltage.

  • Check/adjust deceleration ramps (increase ramp down time).

  • Check if a brake resistor is required.

Undervoltage (UNDER VOLTAGE)
Fault code 3



The intermediate circuit voltage is below the inverter’s undervoltage limit.

Cause:

The intermediate circuit voltage is too low.

  • Mains drop-out or phase loss.

  • Blown fuse.





Remedy:


  • Check the mains supply voltage.

  • Check input fuses.

Overcurrent (OVER CURRENT)
Fault code 4



The inverter’s peak current limit (approx. 250% of rated current) has been exceeded for more than 7-11 seconds.

Cause:


  • Short circuit between output phases.

  • Sudden heavy load change.

  • Motor shaft blocked.





Remedy:


  • Check for short circuits in motor or cables.

  • Check motor load and mechanical coupling.

  • Note: This fault is “Trip locked” (requires mains power cycle to reset).

Earth fault (GROUND FAULT)
Fault code 5



Discharge from the output phases to earth.

Cause:

Leakage current detected either in the cable between the VLT frequency converter and the motor, or within the motor itself.



Remedy:


  • Check motor cables for insulation faults.

  • Check motor for ground faults.

  • Note: This fault is “Trip locked”.

Overtemperature (OVER TEMP.)
Fault code 6



An excess temperature has been measured inside the VLT frequency converter.

Cause:

Internal overheating. This may be due to ambient temperature being too high or fan failure.



Remedy:


  • Allow a cooling off period.

  • Check cooling fans.

  • Check ambient environment temperature.

  • Reset is only possible after the unit has cooled down.

Inverter overloaded (OVER LOAD)
Fault code 7



The electronic thermal inverter protection reports that the drive has cut out due to overload.

Cause:

Excessive current for too long. The protection counter reached 100%.



Remedy:


  • Reduce the load on the motor.

  • Check if the drive is undersized for the application.

Motor overloaded (MOTOR TRIP)
Fault code 8 and 15



According to the electronic thermal motor protection, the motor is too hot.

Cause:

Motor is drawing high current for an extended period, or low speed operation without sufficient cooling.



Remedy:


  • Check motor load.

  • Check parameter 315 settings (Trip vs Warning).

  • Ensure motor cooling (especially at low RPM).

Current limit (CURRENT LIMIT)
Fault code 9



The motor current has exceeded the value in parameter 209 for longer than permitted in parameter 310.

Cause:

Mechanical overload or incorrect current limit settings.



Remedy:


  • Check mechanical load.

  • Verify settings in Parameter 209 and 310.

Auto optimization fault (TUNING. FAULT)
Fault code 13



Failure during the Adaptive Motor Tuning (AMT) process.

Cause:


  • Connected motor is very small or very large relative to the VLT.

  • Motor is loaded more than 50% during tuning.

  • Special motor type (e.g., synchronous).

  • Electrical noise or poor earth connection.





Remedy:


  • Ensure motor is not loaded during tuning.

  • Check earth connections.

  • Verify motor size compatibility (should not be >5-6 sizes different).

Reference faults (REF. FAULT)
Warning



Fault to the analogue input signal (terminal 53 or 60) with “live zero” selected.

Cause:

Signal level is below half of the zero level (e.g., below 2mA on a 4-20mA signal).



Remedy:


  • Check signal cables for breaks.

  • Check the source of the analogue signal.

No motor (NO MOTOR)
Warning



The motor check function (parameter 313) detects that no motor is connected.

Cause:

Missing motor connection on the output phases.



Remedy:


  • Check cable connection between VLT and Motor.

EEPROM fault (EEPROM ERROR)
Warning/Error



EEPROM fault detected.

Cause:

Data changes are not saved when mains voltage is switched off.



Remedy:


  • Contact Danfoss service.

24 V fault (NO 24 VOLT)
Warning



24 V voltage supply from power section to control card is absent.

Cause:

Internal power supply failure.



Remedy:


  • Check internal connections or contact service.

Key Disabled (KEY DISABLED)
Error Message



Keypad interaction attempted but keys are locked.

Cause:

Factory setup is active, or keys disabled via parameters 006-009, or Lock switch is open.



Remedy:


  • Change parameter 001 to setup 1-4.

  • Check switch settings.
Inverter fault
The VLT power section is defective.
Cause:
Defect in the power section.



Remedy:


  • Contact Danfoss Service or supplier.
Overvoltage
The voltage of the VLT frequency converter’s intermediate circuit (DC-voltage) is too high.
Cause:
Line voltage too high, transients on the line voltage, or regenerative motor operation.



Remedy:


  • If the fault indication is given when the speed is reduced, increase the ramp-down time.

  • If ramp-down adjustment is not possible, the application may require a VLT frequency converter with brake.

  • If the fault occurs in other situations, check the mains supply.
Undervoltage
The voltage of the VLT frequency converter’s intermediate circuit (DC-voltage) is too low.
Cause:
Line voltage too low or defect in the VLT frequency converter’s charging circuit/rectifier.



Remedy:


  • Check whether the line voltage is OK.
Overcurrent
The peak current limit of the inverter has been reached.
Cause:
This may be due to a short-circuit in the output of the VLT frequency converter or ground failure.



Remedy:


  • Check the motor and the motor cable for ground failure.
Ground fault
Ground failure on the VLT frequency converter output.
Cause:
Earth leakage or the motor cable is too long.



Remedy:


  • Consult the data sheets for permitted cable length.

  • Check the motor and the motor cable for earth leakage.
Over-temp
The temperature inside the VLT frequency converter is too high.
Cause:
Ambient temperature is too high (max. 40/45 °C), cooling ribs are covered, or the fan is defective.



Remedy:


  • Reduce the ambient temperature by increasing the ventilation.

  • Uncover/clean the cooling ribs.

  • Replace the fan.
Overload
The electronic VLT protection is active. The motor has consumed more than 105% of rated current for too long.
Cause:
Motor has consumed excessive current for an extended period.



Remedy:


  • Reduce the motor load.

  • If reducing load is not possible, the application may require a larger VLT frequency converter.
Motor trip
The electronic motor protection is active. Current consumed at low speed has been too high for too long.
Cause:
The motor has been loaded excessively at low speed.



Remedy:


  • Exchange the motor for a bigger one.

  • Provide extra cooling for the existing motor.

  • The electronic motor protection can be de-activated in parameter 315.