Vacon NXS/NXP
88 fault codes documented
Overcurrent
The frequency converter has detected a current exceeding 4 times the nominal current (4*IH) in the motor cable. This can be caused by a sudden heavy load increase, a short circuit in the motor cables, or an unsuitable motor. Ignoring this can lead to drive shutdown and potential damage to motor or drive components.
Overvoltage
The DC-link voltage has exceeded its defined limits. This typically occurs due to an excessively short deceleration time, where regenerative energy from the motor causes the DC bus to rise, or high overvoltage spikes in the supply voltage. Persistent overvoltage can damage the frequency converter's internal components.
Earth fault
The drive's current measurement system has detected that the sum of the motor phase currents is not zero, indicating a leakage current to earth. This is typically a result of insulation malfunction within the motor windings or the motor cables. An unresolved earth fault poses a significant electrical safety hazard and can cause severe damage to both the motor and the drive.
Charging switch
The charging switch is detected as open when a START command is given to the drive. This indicates either faulty operation of the switch or a component failure within the charging circuit. The drive cannot start safely without the charging circuit functioning correctly, potentially leaving the DC bus uncharged or in an unsafe state.
Emergency stop
A stop signal has been received from an option board, indicating an emergency stop condition. This is usually triggered by an external safety circuit for immediate shutdown. The drive will not operate until the emergency stop condition is cleared, ensuring personnel and equipment safety.
Saturation trip
This fault indicates a severe internal component defect, potentially related to a short-circuited or overloaded brake resistor. It's a critical fault that prevents normal drive operation and requires immediate, specialized attention. Attempting to restart the drive or reconnect power without addressing the root cause risks further catastrophic damage to the unit.
System fault
This is a general system fault, indicating either an internal operational malfunction or a defective component within the drive. If the fault persists after a reset, it points to a more fundamental hardware or software issue requiring expert diagnosis. The drive cannot operate normally while this fault is active.
Undervoltage
The DC-link voltage has fallen below its acceptable operating limits. This can be caused by a low incoming supply voltage, a defective input fuse, an external charge switch failing to close, or an internal AC drive fault. Prolonged undervoltage can cause erratic drive behavior, prevent proper starting, and potentially stress internal components.
Input line supervision
The drive has detected a missing phase in the incoming AC supply voltage. This typically indicates a power supply issue, such as a blown input fuse, a tripped circuit breaker, or a disconnected supply cable. Operating the drive with a missing input phase can lead to internal damage, particularly to the input rectifier bridge.
Output phase supervision
The current measurement system has detected that there is no current flowing in one of the motor phases. This typically indicates an open circuit condition in the motor cables or within the motor windings, which can lead to motor damage or uncontrolled operation.
Brake chopper supervision
This fault indicates a problem with the braking system, specifically that no brake resistor is installed, the installed brake resistor is broken (open circuit), or there is an internal failure within the brake chopper itself. The drive cannot dissipate regenerative energy during deceleration without a functioning brake resistor and chopper.
Frequency converter undertemperature
The heatsink temperature of the frequency converter has fallen below –10 °C. Operating the drive outside its specified temperature range can impact component performance and lifespan.
Frequency converter overtemperature
The drive's heatsink temperature has exceeded its maximum safe operating limit (e.g., 90 °C or 77 °C for specific models). This is commonly caused by inadequate cooling airflow, accumulation of dust on heatsinks, high ambient temperatures, or an excessive switching frequency relative to the motor load. Sustained overtemperature will severely degrade and damage the drive's power components.
Motor stalled
The motor has stalled, meaning it is not rotating despite receiving a run command. This is typically due to an excessive mechanical load or an obstruction preventing rotation. A stalled motor will draw very high current, leading to rapid overheating of the motor windings and potentially the drive's output stage.
Motor overtemperature
The drive's internal motor temperature model or an external sensor indicates that the motor is operating at an excessively high temperature, primarily due to an overly heavy load. Prolonged motor overtemperature will degrade the motor winding insulation, leading to premature motor failure and increased energy consumption.
Motor underload
The motor underload protection has tripped, meaning the motor is drawing significantly less current than expected for its commanded speed and assumed load. This could indicate a loss of load, a broken mechanical coupling, or an issue with the process being driven. While not immediately damaging, it suggests an operational issue that needs attention.
Unbalance
An unbalance has been detected between power modules within paralleled power units. This signifies a discrepancy in current sharing or performance among the modules, which can lead to uneven wear and a reduced lifespan of the power components. If persistent, this fault indicates an internal issue within the paralleled power system.
EEPROM checksum fault
A parameter save fault has occurred, indicating an issue with storing or verifying data in the drive's EEPROM (Electrically Erasable Programmable Read-Only Memory). This can be caused by faulty operation or a component failure within the control unit. Incorrect parameters can lead to unpredictable drive behavior or failure to operate correctly.
Counter fault
The values displayed on the internal counters are incorrect. This suggests a corruption of data related to internal drive counters, potentially impacting operational logging or maintenance schedules. While often not critical for immediate operation, it indicates an underlying data integrity issue.
Microprocessor watchdog fault
The drive's internal microprocessor watchdog has triggered, indicating that the control software or hardware has become unresponsive or entered an unexpected state. This can be due to an operational malfunction or a defective internal component. A persistent watchdog fault prevents proper drive control and operation.
Start-up prevented
The drive's start-up sequence has been inhibited, typically because a run request signal was active while a new application program was being downloaded or after a configuration change. This is a safety feature designed to prevent unintended motor starts. The drive will not initiate operation until this preventative condition is safely resolved.
Thermistor fault
The thermistor input on an option board has detected an increase in motor temperature beyond safe limits, or the input itself is not properly terminated if unused. This indicates potential motor overload or inadequate motor cooling. Overheating can severely damage the motor windings, reduce motor lifespan, and lead to efficiency losses.
Safe disable
The Safe Disable input on the OPTAF board has opened, indicating that a safety interlock or command has been activated. This crucial safety function prevents the drive from operating until the condition is addressed. Failure to resolve the underlying safety issue could lead to hazardous machinery operation.
IGBT temperature (hardware)
The hardware-level overtemperature protection for the IGBT inverter bridge has activated, indicating an excessively high short-term overload current. This can be caused by heavy motor loading or an incorrectly sized motor. Persistent high temperatures can permanently damage the IGBTs, leading to catastrophic drive failure.
Fan cooling
The cooling fan of the AC drive failed to start when a run command was issued. This indicates a potential fan motor failure, wiring issue, or a problem with the drive's internal fan control circuit. Without proper cooling, the drive will quickly overheat and trip, potentially leading to damage to internal power components.
CAN bus communication
A message sent over the CAN bus was not acknowledged by another device on the network. This indicates a problem with the CAN bus communication, which could stem from incorrect configuration, wiring issues, or a faulty device on the bus. Loss of communication means the drive cannot be reliably controlled or monitored.
Application
A problem has been detected within the drive's application software. This could be due to a programming error, corrupted application file, or an unexpected runtime condition. An application fault will prevent the drive from executing its programmed functions correctly or at all, disrupting machine operation.
Control unit
There is an incompatibility or communication failure between the NXS Control Unit and the NXP Power Unit (or vice versa). This prevents the control unit from properly commanding the power unit, effectively rendering the drive inoperable. This is often caused by mismatched hardware components or internal communication bus issues.
Device changed (same type)
An option board or control unit has been replaced with another of the exact same type or power rating. While the hardware is compatible, the system registers a component change. A reset is typically required to recognize the new component and ensure existing parameter settings are correctly applied.
Device added (same type)
An option board of the same type, which was previously used in the same slot, has been added to the drive. The drive recognizes the board and has its parameters available. This is primarily an informational alarm, indicating the drive is ready to use the previously stored settings for this specific board.
Device removed
An option board has been removed from its slot, making the device unavailable to the drive. This indicates a configuration change where a previously installed board is no longer present. The drive needs to acknowledge this change to clear the fault status.
Device unknown
The frequency converter has detected an unknown or incompatible option board or drive, or there's a specific mismatch between power unit types (e.g., Power1 not same type as Power2, indicated by subcode S2). This signifies an incorrect or unrecognized hardware component has been installed. Using incompatible hardware can lead to malfunction or damage.
IGBT temperature
The IGBT Inverter Bridge's overtemperature protection has detected an excessively high short-term overload current, causing the IGBTs to heat up rapidly. This fault indicates severe thermal stress on the power stage, which can lead to component failure and ultimately, drive damage if not addressed promptly.
Brake resistor overtemperature
The brake resistor overtemperature protection has activated, indicating that the brake resistor is dissipating too much energy, likely due to overly heavy or frequent braking cycles. This condition can lead to premature resistor failure or a fire hazard if not addressed.
Encoder fault
A problem has been detected in the encoder signals, which are crucial for accurate speed and position feedback. This can be caused by missing or faulty channels (A or B), a reversed encoder, or a missing encoder board. Inaccurate feedback can lead to unstable motor control or drive shutdown.
Device changed (different type)
An option board or power unit has been replaced with a device of a different type or power rating. The drive detects this incompatibility and requires a complete reconfiguration. If parameters are not correctly reset and adjusted, the drive may operate incorrectly, become unstable, or fail to start.
Device added (different type)
A new option board of a different type has been added to the drive. The drive recognizes the new hardware but requires specific configuration to integrate it properly. Without correct parameter setup, the newly added option board may not function, or it could cause system instability.
Division by zero in application
A division by zero error has occurred within the custom application program running on the drive. This indicates a mathematical error in the program logic, which can cause the drive to halt or behave unpredictably. If left unaddressed, the drive cannot execute the affected part of the application, disrupting operations.
Analogue input I in < 4mA
The analogue input configured for a 4-20 mA current loop is receiving a current signal below 4mA. This typically indicates a break or loose connection in the control cable, or a failure of the signal source device. Loss of the analogue signal means the drive cannot receive its intended reference or feedback, leading to incorrect control.
External fault
A digital input configured as an external fault has been triggered, indicating a fault condition in an external device connected to the drive. This causes the drive to trip, preventing further operation until the external fault is cleared. The specific external device must be identified and resolved.
Keypad communication fault
The communication link between the control keypad (or NCDrive software) and the frequency converter has been broken. This prevents local control and monitoring of the drive. It can be caused by a loose connection or a damaged keypad cable.
Fieldbus fault
The data connection between the fieldbus master and the drive's fieldbus option board is defective, leading to a loss of communication. This prevents the drive from being controlled or monitored via the fieldbus network, disrupting integrated system operations. An incorrect installation or a faulty fieldbus master are common causes.
Slot fault
A defective option board or slot has been detected. This indicates a hardware failure within the drive's expansion slots or a faulty option board itself. A slot fault can prevent functionality associated with the board or cause instability in the drive.
Over Temp.
An internal temperature sensor has registered a temperature exceeding its predefined limit, or the sensor itself is disconnected or short-circuited. This indicates inadequate cooling, excessive load, or a sensor malfunction. Overheating can lead to premature component failure and severe damage to the drive.
Identification
The motor identification run has failed. This can happen if the run command was removed before the identification process completed, if the motor is not properly connected to the frequency converter, or if there is a load on the motor shaft during the identification process. A successful identification run is crucial for optimal motor control.
Brake
The actual status feedback from the mechanical brake (e.g., open/closed) does not match the drive's control signal for the brake. This indicates a malfunction in the brake mechanism, its feedback sensor, or the associated wiring. A malfunctioning brake poses a safety risk and can prevent proper machine operation or holding.
Follower communication
The SystemBus communication link between the Master and Follower drives in a multi-drive system is broken. This typically occurs in synchronized applications where communication is critical for coordinated operation. Loss of this link can lead to desynchronization and operational halts.
Cooling
The coolant circulation system for a liquid-cooled drive has failed. This means the drive is not receiving adequate cooling, which will rapidly lead to overtemperature conditions and potential severe damage to internal components. This requires immediate attention to the external cooling system.
Speed error
The motor's actual speed deviates significantly from its commanded speed reference. This can be caused by a faulty encoder connection (if an encoder is used), or for Permanent Magnet Synchronous (PMS) motors, exceeding the pull-out torque. An uncorrected speed error leads to inaccurate motor control, poor process performance, and potential instability.
Run disable
The 'Run Enable' signal, which is required for the drive to operate, is currently low or inactive. This is a safety interlock designed to prevent the drive from starting. The drive will remain disabled until the run enable condition is met and the corresponding signal is active.
Emergency stop
An emergency stop command has been received from a digital input or via the fieldbus. This triggers an immediate drive stop for safety reasons. The drive will not accept a new run command until the fault is reset and the emergency stop condition is cleared.
Input switch open
The main input power switch for the drive is detected as open, preventing power from reaching the drive and making it inoperable. This could refer to a physical disconnect switch, a tripped circuit breaker, or an internal contactor. The drive cannot function without incoming power.
PT100 board 2 temp fault
Temperature limit values set for a second PT100 board (or set of inputs) have been exceeded. This can also occur if more PT100 inputs are selected in parameters than are physically connected, or if a PT100 cable is broken. This fault indicates an overtemperature condition or an issue with the sensor wiring.
Follower fault
In a Master-Follower configuration, this fault code is generated when one or more of the follower drives trip into a fault state. This indicates an underlying issue with a specific follower drive, which then propagates to the master. The master cannot resume normal operation until the root fault on the follower drive(s) is identified and resolved.
Over current fault
The drive has detected an abnormally high current in one of the output phases, exceeding a hardware trip limit of 4 times the nominal current (Ih). This indicates an immediate and severe electrical overload condition. If left unresolved, it can lead to component damage or system instability.
Overvoltage fault
The DC-link voltage has surpassed the drive's protective limits (e.g., above 911 Vdc for a 500 Vac unit or 1200 Vdc for a 690 Vac unit). This can be a hardware trip or sustained overvoltage due to control supervision. Persistent overvoltage can damage power components and reduce drive lifespan.
Earth fault
The earth fault protection ensures that the sum of the output phase currents is not zero, indicating a current leakage to ground. This protection works in conjunction with overcurrent protection for high current earth faults. An unaddressed earth fault poses a significant safety hazard and can cause severe damage to the drive or motor.
Undervoltage fault
The DC-link voltage has dropped below acceptable limits, potentially triggering an undervoltage control supervision (S3). This could be caused by a low supply voltage, an internal frequency converter fault, a broken input fuse, or an open external charge switch. Prolonged undervoltage can cause erratic drive behavior and component stress.
Line Synchronization Fault
The drive has detected a missing input line phase, as indicated by phase supervision for both diode supply (S1) and active front end (S2). This means one or more incoming power phases are not present or severely degraded. Running with a missing phase can cause damage to the drive and connected equipment.
Line phase supervision
The current measurement system has detected an imbalance where one phase current is either missing or significantly different from the other phases. This indicates an issue with the power delivery to the motor. Operating with unbalanced phases can lead to motor overheating and drive component stress.
Drive under temperature fault
The heatsink temperature of the drive has fallen below an acceptable operating limit, specifically under –10°C. Operating at excessively low temperatures can affect the performance and lifespan of electronic components.
Drive over temperature fault
The heatsink temperature of the drive has exceeded its acceptable operating limits, triggering a fault. An overtemperature warning typically precedes the actual trip limit. Sustained high temperatures significantly reduce the lifespan of power semiconductors and other internal components.
EEPROM checksum fault
An error has occurred with the EEPROM checksum, indicating a parameter save fault, faulty operation during data storage, or a component failure within the EEPROM memory. This can lead to incorrect drive configuration.
Counter fault
The values displayed on the internal counters of the drive are incorrect or corrupted. This affects the accuracy of operational data logging.
Microprosessor watchdog fault
The drive's internal watchdog timer has detected an issue preventing normal microprocessor operation or startup. This can occur if the drive startup is prevented or a run request is active while a new application is being loaded. This fault indicates a critical internal control issue.
Start-Up prevention
The drive's startup sequence has been prevented, possibly because a run request was active while a new application was being loaded. This is a safety measure to prevent unintended operation during critical configuration changes.
Thermistor fault
The thermistor input on the option board has detected an excessively high motor temperature. This fault can be caused by motor overheating or a broken thermistor cable. Continued operation with an overheated motor can lead to winding damage.
IGBT temperature
The IGBT Inverter Bridge over-temperature protection has activated due to an excessively high short-term overload current. This indicates the power semiconductors are being stressed beyond their safe operating limits. Repeated trips can degrade the IGBTs.
Device added (default param.)
An option board of a different type has been added to the drive, causing the drive to load default parameters. This indicates a change in hardware configuration that requires re-parameterization.
4mA supervision
The current at an analog input has dropped below the 4mA supervision limit. This typically indicates a failure in the signal source, a broken control cable, or a loose connection within the current loop circuitry. This means the drive is not receiving expected sensor feedback.
External fault
A digital input configured for external fault monitoring has been activated, signaling a fault condition from an external device or system. This is a generic fault triggered by an external safety or monitoring circuit.
Keypad communication
The communication link between the control keypad (or NCDrive software) and the AC drive has been interrupted or broken. This prevents control and monitoring via the keypad interface.
Fieldbus communication Slot D
The data connection between the fieldbus Master and the fieldbus option board installed in Slot D has been broken. This results in a loss of communication with the control system.
Slot fault
This fault indicates a problem with an option board or the slot it is installed in, suggesting either a defective board or an issue with the slot's electrical connection.
Temperature sensor board 1 fault
The temperature protection function for sensor board 1 has detected an issue, which could be an exceeded temperature limit, an unwired or non-functional sensor, or a short circuit in the sensor wiring (A1-A3 conditions). This compromises temperature monitoring.
Cooling
For liquid-cooled units, this protection detects a failure in the cooling liquid circulation, typically via an external sensor connected to the Cooling Monitor digital input. It generates a warning when the drive is stopped and a fault (with a coast stop) when running. Continued operation without proper cooling will lead to severe overheating.
MCB State Fault
The Main Circuit Breaker (MCB) state is inconsistent with the drive's command. This includes scenarios where the MCB opens when commanded to close, closes when commanded to open, opens externally while the AFE unit is running, or is in a tripped state as reported by a digital input. This is a critical safety and operational fault.
Temperature sensor board 2 fault
The temperature protection function for sensor board 2 has detected an issue, which could be an exceeded temperature limit, an unwired or non-functional sensor, or a short circuit in the sensor wiring (A1-A3 conditions). This compromises temperature monitoring.
Fieldbus communication Slot E
The data connection between the fieldbus Master and the fieldbus option board installed in Slot E has been broken. This results in a loss of communication with the control system.
LCL Temperature
The LCL (Line Commutated Inductor) temperature has reached its warning limit, indicating elevated temperatures within the input filter components. While currently a warning, it suggests conditions that could lead to an over-temperature fault if unaddressed.
Charging Fault
The drive failed to reach the required DC voltage within the set charging time for the Main Circuit Breaker (MCB). This can be due to a non-operational charging circuit, a high load on the DC link during charging, or an insufficient supply voltage for the charging circuit. This prevents the drive from starting up properly.
Main Fuse
This fault is triggered by a digital input fault, indicating a problem related to the main fuse. It's an external input signaling a main fuse issue. This could mean the main fuse has blown or its monitoring circuit has an error.
Aux Voltage
This fault is triggered by a digital input fault, signaling an issue with the auxiliary voltage supply. This suggests a problem with the external auxiliary power source or its monitoring.
Safe Stop
This fault is triggered by a digital input, indicating that a safe stop command or condition has been activated from an external device. This is a critical safety interlock.
Insulation
This fault is triggered by a digital input fault, indicating an insulation problem detected by an external monitoring device. This points to a potential electrical leakage somewhere in the system.
Earth Switch fault
This fault is triggered by a digital input fault, indicating an issue with the earth switch. This suggests the earth switch may be in an incorrect state or its monitoring circuit has an error.
High Amb Temperature
This fault is triggered by a digital input fault, signaling an excessively high ambient temperature detected by an external sensor. This indicates the operating environment is too hot for the drive.
Leakage fault
This fault is triggered by a digital input fault, indicating an electrical leakage detected by an external monitoring device. This is a general leakage indication from an external system.