Danfoss VLT 3000 Drive Fault Codes List

Access the complete reference guide for the obsolete Danfoss VLT 3000 drive. Learn to diagnose Trip Lock errors, reform aging capacitors, and plan retrofits to FC 302.

Danfoss VLT 3000 Fault Codes Reference Table

Danfoss VLT Faults and Alarms

Fault Code and Meaning	Cause 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.

 

How to Read VLT 3000 Faults (Manual Diagnostics)

The VLT 3000 does not support modern MCT 10 software via USB. Troubleshooting in 2026 involves physical inspection and interpreting the front panel:

• LED Indicators: The front panel has specific LEDs.
  • Yellow (Warning): A limit is reached (e.g., Current Limit), but the drive is still running.
  • Red (Alarm): The drive has tripped. If the Red LED is flashing, it is a standard trip. If it is solid or accompanied by a “Locked” message, it is a Trip Lock.
• Display Messages: The small LCD (on equipped models) displays text codes like “OVT” (Over Voltage), “OC” (Over Current), or “EARTH FAULT”. Unlike modern drives, these messages are often abbreviated.
• Capacitor Reforming (Critical): If you have a spare VLT 3000 that has been sitting on a shelf for more than 2 years, do not power it up immediately. The DC bus electrolytic capacitors have likely dried out. You must apply voltage gradually using a Variac over several hours, or the capacitors will explode.

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Frequently Asked Questions (FAQ)

Q: What is the difference between “Trip” and “Trip Locked”?

A:

• Trip: The drive stops, but you can reset it immediately by pressing the Reset button (e.g., for Overload).
• Trip Locked: A severe hardware fault (e.g., Short Circuit or Earth Fault). You must cycle the main power (turn off, wait for display to discharge, turn on) to reset the logic.

Q: How do I reset a Danfoss VLT 3000?

A:

1. Press the RESET button on the keypad.
2. Toggle the Digital Input (usually Terminal 16 or 17, depending on programming).
3. If the drive is “Trip Locked,” you must cycle the mains power.

Q: What is the modern replacement for the VLT 3000?

A: The direct successor is the Danfoss VLT AutomationDrive FC 302.

• The mounting footprints are different, so you will likely need a retrofit backplate.
• The parameter structures differ significantly, so you cannot simply “copy/paste” the settings; a manual conversion of motor data and I/O logic is required.

Q: Why does the drive trip on “OVT” (Over Voltage) at stop?

A: This is common in aging VLT 3000 units.

• The internal braking circuit may have failed.
• The DC bus capacitors may have lost capacity due to age, reducing their ability to absorb regenerative energy during deceleration.
• Fix: Increase the ramp-down time or replace the drive.