Every machine downtime results in measurable financial losses. Danfoss VLT drives communicate issues directly via warning and alarm codes. The list below will help you quickly identify the fault and take appropriate action.
Danfoss VLT Drive Error Codes
Danfoss VLT series frequency converters are versatile devices used in many demanding industrial applications. They feature an advanced self-diagnostic system that helps maintenance teams locate faults. Below, we discuss in detail the warning and alarm messages for these drives, along with their technical causes.
Error 1 - Voltage too low 10 V
Possible cause of the Danfoss VLT inverter error
The supply voltage from terminal 50 on the control board has dropped below 10 V. This indicates an overload on this circuit. Disconnect some of the control equipment from this terminal. The maximum allowable load on the circuit is 15 mA.
If the problem persists, contact a professional service provider: inverter repair.
Error 2 - Current zero error
Possible cause of the Danfoss VLT inverter error
The signal at terminal 53 or 54 has dropped below 50 percent of the value configured in the minimum voltage or minimum current parameters. This situation indicates a wiring problem, a faulty connected sensor, or an open current loop.
If the problem persists, contact a professional service provider: inverter repair.
Error 3 – No motor
Possible cause of the Danfoss VLT inverter error
The inverter does not detect a connected motor at its power output. You must check the cable connections and any contactors located between the inverter and the machine’s stator terminals.
If the problem persists, contact a professional service provider: inverter repair.
Error 4 - Power phase loss
Possible cause of the Danfoss VLT inverter error
The device has detected a missing phase on the mains side or excessive asymmetry in the supply voltages. This message also appears in the event of a physical failure of the internal input rectifier. It is essential to check the power supply and input currents.
If the problem persists, contact a professional service provider: inverter repair.
Error 5 - High DC circuit voltage
Possible cause of the Danfoss VLT inverter error
The voltage in the DC intermediate circuit has exceeded the control system’s overvoltage limit. The inverter remains active in this state but indicates very unfavorable system operating conditions.
If the problem persists, contact a professional service provider: inverter repair.
Error 6 - Low DC circuit voltage
Possible cause of the Danfoss VLT inverter error
The DC link voltage has dropped below the lower limit permitted by the control system. The device continues to operate, warning of significant drops in power supply efficiency.
If the problem persists, contact a professional service provider: inverter repair.
Error 7 – DC circuit overvoltage
Possible cause of the Danfoss VLT inverter error
The voltage in the intermediate circuit has exceeded the hardware hard limit. After a certain period of time, the inverter will shut down in an emergency to protect the power transistors and capacitors. This phenomenon most often occurs during sudden braking of large inertial loads.
If the problem persists, contact a professional service provider: inverter repair.
Error 8 - DC circuit voltage too low
Possible cause of the Danfoss VLT inverter error.
When the DC circuit voltage drops drastically, the system checks for the presence of an external 24 V backup power supply. If it is absent, the inverter shuts down in an emergency. It is necessary to verify that the power grid parameters comply with the device specifications.
If the problem persists, contact a professional service provider: inverter repair.
Error 9 - Inverter overload
Possible cause of Danfoss VLT inverter error
The drive warns of an emergency shutdown due to prolonged operation at excessive current. The electronic thermal protection issues a warning at 98 percent and stops the drive at 100 percent. The system can only be reset after the electronics have cooled down and the error value has dropped below 90 percent.
If the problem persists, contact a professional service provider: inverter repair.
Error 10 - ETR Motor Overheating
Possible cause of the Danfoss VLT drive error
According to the built-in electronic protection, the motor has reached a critical temperature. There has been a prolonged current overload of the drive above the rated value. Make sure that the motor’s nameplate current values have been correctly entered into the configuration.
If the problem persists, contact a professional service provider: inverter repair.
Error 11 - Motor thermistor overheating
Possible cause of the Danfoss VLT inverter error
The thermistor circuit has been disconnected, or the sensor itself is indicating a critical winding temperature. Check the correctness of the wire connections between the inverter’s control inputs and the reference power supply.
If the problem persists, contact a professional service provider: inverter repair.
Error 12 - Torque limit
Possible cause of the Danfoss VLT inverter error
The torque required for operation has exceeded the limits set in the protection parameters. This applies to both power consumption mode and power injection to the grid during generator operation.
If the problem persists, contact a professional service provider: inverter repair.
Error 13 - Overcurrent
Possible cause of the Danfoss VLT inverter error
The peak current of the power system has been exceeded. The warning is displayed on the panel for approximately 10 seconds, after which the device cuts off power to the motor. Verify that the mechanical components can rotate freely and ensure that the inverter’s power rating is suitable for the driven machine.
If the problem persists, contact a professional service provider: inverter repair.
Error 17 - Control word timeout
Possible cause of the Danfoss VLT inverter error
The system has lost stable control communication with the master device. If the appropriate fault response has been selected in the parameters, the drive will safely reduce speed and generate an alarm. A common solution is to optimize the hardware response time settings.
If the problem persists, contact a professional service provider: inverter repair.
Error 23 - Internal fan error
Possible cause of the Danfoss VLT inverter error
The external cooling fans have suffered a mechanical failure or are not connected to the power supply at all. Lack of effective cooling will quickly lead to thermal failure of the entire drive.
If the problem persists, contact a professional service provider: inverter repair.
Error 24 - External fan error
Possible cause of the Danfoss VLT drive error
The system’s fan speed monitoring function has been triggered. The system has detected irregularities in the operation of the forced-air cooling system. This protection can be disabled in the parameters, but this increases the risk of thermal damage.
If the problem persists, contact a professional service provider: inverter repair.
Error 25 - Braking resistor short circuit
Possible cause of the Danfoss VLT inverter error
The external braking resistor has short-circuited, and this condition has been detected by the sensors. The drive can continue to operate, but the software deactivates the energy dissipation logic to prevent damage to the equipment. The braking resistor must be replaced.
If the problem persists, contact a professional service provider: inverter repair.
Error 26 - Braking resistor power limit
Possible cause of the Danfoss VLT inverter error
The calculated power dissipated by the resistor has exceeded the safe percentage threshold. The system notifies the operator when the component reaches 90 percent load. Exceeding the 100 percent threshold results in a hard shutdown of the drive.
If the problem persists, contact a professional service provider: inverter repair.
Error 27 - Brake chopper fault
Possible cause of the Danfoss VLT inverter error
A short circuit in the internal braking transistor has been detected. This causes continuous and uncontrolled current flow to the external resistor. The software ignores the braking circuit, but the hardware fault generates actual heat loss. You must physically disconnect the power supply and remove the resistor wires.
If the problem persists, contact a professional service provider: inverter repair.
Error 28 - Brake test error
Possible cause of Danfoss VLT inverter error
The system has diagnosed a circuit continuity issue. The resistor is not properly connected to the appropriate inverter terminals, or there is an internal break within the heat sink module itself.
If the problem persists, contact a professional service provider: inverter repair.
Error 29 - Drive Overheating
Possible cause of the Danfoss VLT inverter error
The power module’s heat sink has heated up beyond safe operating limits. An emergency shutdown occurs at 90 degrees for lightweight enclosures and at 80 degrees for enclosures with a high protection rating. This situation suggests an urgent review of the environmental conditions around the device.
If the problem persists, contact a professional service provider: inverter repair.
Error 34 - Fieldbus Communication Error
Possible cause of the Danfoss VLT drive error
The expansion card responsible for the industrial network has stopped functioning properly. The drive cannot exchange the necessary configuration and control data with the process unit.
If the problem persists, contact a professional service provider: inverter repair.
Error 35 - Option error
Possible cause of the Danfoss VLT inverter error
The main control system has detected abnormal behavior or a physical failure of an internal option card attached to the motherboard. Depending on the extent of the damage, service intervention is required.
If the problem persists, contact a professional service provider: inverter repair.
Error 36 - Mains power failure
Possible cause of the Danfoss VLT inverter error
The appearance of this message indicates a sudden loss of supply voltage while the mains monitoring option is active. Checking the main circuit breakers, power fuses, and power supply contactors usually resolves this hardware issue outside the machine.
If the problem persists, contact a professional service provider: inverter repair.
Error 37 - Phase Asymmetry
Possible cause of the Danfoss VLT inverter error
A significant asymmetry in current flow has been detected between the power modules in multi-module inverters. This situation suggests degradation of the internal semiconductor components in the system.
If the problem persists, contact a professional service provider: inverter repair.
Error 40 - Digital output overload, terminal 27
Possible cause of the Danfoss VLT inverter error
The external device connected to digital output 27 is drawing too much current or a short circuit has occurred. Maintenance personnel must check the target relay coils and system settings.
If the problem persists, contact a professional service provider: inverter repair.
Error 41 - Digital output overload, terminal 29
Possible cause of the Danfoss VLT drive error
The software has detected a physical short circuit or excessive current draw on terminal block 29. A thorough inspection of the external circuit outside the drive enclosure is recommended.
If the problem persists, contact a professional service provider: inverter repair.
Error 42 - Digital output overload on the expansion module
Possible cause of the Danfoss VLT inverter error
A hardware overload or a hard short circuit has occurred in the circuit connected to output terminals X30/6 or X30/7. The response to this error must be to disconnect the circuits and measure the insulation of the external line.
If the problem persists, contact a professional service provider: inverter repair.
Error 47 - 24 V supply voltage too low
Possible cause of the Danfoss VLT inverter error
The internal backup power distribution system is insufficient in terms of current capacity. The external power supply is overloaded by auxiliary circuits connected directly to the equipment’s power logic.
If the problem persists, contact a professional service provider: inverter repair.
Error 58 - Internal AMA error
Possible cause of the Danfoss VLT inverter error
A calculation or measurement failure occurred during the automated motor adaptation (AMA) procedure. The inverter is unable to perform a static machine test.
If the problem persists, contact a professional service provider: inverter repair.
Error 59 - Current Limit
Possible cause of the Danfoss VLT drive error
The current generated on the shaft significantly exceeds the limit set by the software. The system blocks the increase in power.
If the problem persists, contact a professional service provider: inverter repair.
Error 60 - External Lockout
Possible cause of the Danfoss VLT drive error
The master machine has sent a stop signal. The drive will return to normal operation only after the 24 V control voltage is restored to the appropriate terminal and the alarms are reset.
If the problem persists, contact a professional service provider: inverter repair.
Error 62 - Output frequency at maximum limit
Possible cause of the Danfoss VLT inverter error
The output circuits will not increase the speed because the drive has encountered a hard limit set directly in the machine’s configuration block.
If the problem persists, contact a professional service provider: inverter repair.
Error 65 - Control board overheating
Possible cause of the Danfoss VLT inverter error
The logic module on the motherboard has reached a dangerous temperature threshold of 80 degrees Celsius. The system cuts off power to protect the integrated circuits from permanent charring of the damaged thermal insulation and silicon structure.
If the problem persists, contact a professional service provider: inverter repair.
Error 66 - Temperature too low
Possible cause of the Danfoss VLT drive error
The thermistor built into the heat sink reports an anomaly in the form of a temperature close to zero. This is generally due to a failure in the measurement system. In response, the ventilation system begins to operate at full capacity as a precautionary measure due to the risk of actual overheating of the power section.
If the problem persists, contact a professional service provider: inverter repair.
Error 76 - Power unit configuration error
Possible cause of the Danfoss VLT inverter error
The device’s environmental scan reports incompatibility. The number of power modules declared by the software differs from the components physically installed in the cabinet.
If the problem persists, contact a professional service provider: inverter repair.
Error 243 - Braking transistor short circuit
Possible cause of the Danfoss VLT inverter error
The inverter confirms severe damage to the IGBT circuit controlling the external modules. Ignoring this message carries a risk of fire. For safety reasons, disconnect the entire machine from the power supply.
If the problem persists, contact a professional service provider: inverter repair.
Error 244 - Heat Sink Temperature
Possible cause of the Danfoss VLT inverter error
Significant heat loss and the load on individual modules indicate a critical condition in the system responsible for dissipating heat from the inverter. Reporting tools allow you to precisely identify the location of the faulty ventilation unit.
If the problem persists, contact a professional service provider: inverter repair.
