Danfoss VLT HVAC Basic FC 101

According to the electronic thermal protection (ETR), the motor is excessively hot due to prolonged operation above 100% load. This indicates a severe mechanical overload on the motor. Ignoring this alarm can lead to permanent motor damage or reduced lifespan. The frequency converter can be configured to issue a warning or alarm based on the counter reaching 100% in parameter 1-90.

The motor's thermistor temperature sensor or its connection is faulty or disconnected. This means the drive cannot accurately monitor the motor's temperature, risking undetected overheating. An unresolved thermistor fault could lead to severe motor damage due to thermal stress if the motor is indeed overheating.

The inverter's peak current limit has been exceeded, causing the frequency converter to trip into an alarm state after approximately 1.5 seconds of warning. This typically indicates a sudden increase in motor load, such as shock loading, a jam, or excessively fast acceleration of high-inertia loads. Persistent overcurrents can severely stress and damage the frequency converter's power components and the motor.

A discharge of current from one or more output phases to ground has been detected, indicating an insulation breakdown. This fault can occur either in the motor cables connecting the drive to the motor or within the motor windings themselves. This is a critical safety fault posing an electrical shock hazard and potentially leading to severe damage to the frequency converter and motor if not promptly addressed.

A direct short circuit condition has been detected either within the motor's windings or across its terminal connections. This is a highly critical fault that triggers a trip-lock, requiring a power cycle to reset after the cause is rectified. Operating with a short circuit can cause immediate and irreparable damage to the frequency converter's IGBTs or other power components.

The frequency converter has stopped receiving valid control word commands via its serial communication interface, leading to a timeout. This alarm is active when parameter 8-04 Control Timeout Function is not set to [0] Off. If configured to Stop and Trip, the drive will safely ramp down and then trip, indicating a loss of communication. Unresolved communication loss prevents external control of the drive.

The frequency converter's internal cooling fan is either not running, seized, or improperly mounted, specifically affecting 400 V, 30–90 kW units. This protection function ensures adequate heat dissipation from the drive's components. Continued operation without a functioning fan will inevitably lead to critical overheating and premature failure of the frequency converter.

This alarm indicates that a major power-related component, specifically the power section or switch mode power supply, within the frequency converter has been replaced. It serves as a service notification rather than an operational fault, confirming a hardware change. The drive should function normally after this alarm, assuming proper installation of the new part.

The frequency converter has detected a change in its internal type code, typically occurring after a control card replacement or a full drive swap. This alarm acts as an informational message signaling a significant change in the drive's identity or configuration. While not an immediate operational fault, it indicates a need to verify parameter settings for the new hardware.

A high back EMF voltage has been detected, indicating that the Permanent Magnet (PM) motor is rotating while the drive is attempting to control or start it. This can interfere with the drive's control algorithms and prevent a successful start.

The motor phase U connection between the frequency converter and the motor is missing or interrupted. This prevents proper motor operation and can lead to damage if ignored.

The motor phase V connection between the frequency converter and the motor is missing or interrupted. This prevents proper motor operation and can lead to damage if ignored.

The motor phase W connection between the frequency converter and the motor is missing or interrupted. This prevents proper motor operation and can lead to damage if ignored.

An unspecified internal fault has occurred within the frequency converter. This indicates a potential hardware or firmware issue requiring specialized attention, and continued operation may cause further damage.

There is an electrical discharge from one of the output phases to ground, either in the cable between the frequency converter and the motor or within the motor itself. This poses a significant safety risk and can cause severe equipment damage.

The supply voltage on the power card, which generates 24 V, 5 V, and ±18 V, is out of range. This indicates a problem with the switch mode power supply (SMPS) on the power card, affecting the drive's ability to control the motor's power transistors.

The detected 24 V DC voltage on terminal 12 of the control card has dropped below 18 V. This can impact the reliability of the control card and any external devices powered by this supply, potentially leading to incorrect operation or shutdowns.

The settings for motor voltage, motor current, or motor power are presumably incorrect. This prevents the Automatic Motor Adaptation (AMA) function from accurately identifying motor parameters, leading to suboptimal or incorrect motor control.

The motor current detected during the Automatic Motor Adaptation (AMA) process is too low. This usually indicates an incorrect motor current setting in the parameters or an issue with the motor connection itself, hindering proper parameter identification.

The motor connected is too large for the Automatic Motor Adaptation (AMA) function to be successfully performed by this frequency converter. The drive may not be adequately sized for the motor, which can lead to inaccurate parameter identification or drive overload.

The motor connected is too small for the Automatic Motor Adaptation (AMA) function to be successfully performed. This can lead to inaccurate motor parameter identification, potentially causing suboptimal motor control or unexpected behavior.

The parameter values found from the motor during the Automatic Motor Adaptation (AMA) process are outside the acceptable range for the frequency converter. This indicates an incompatibility between the motor and drive or severely incorrect initial motor data settings.

The Automatic Motor Adaptation (AMA) process was interrupted by the user. This is not an error but an indication that the parameter identification sequence was not completed, meaning the drive may not be optimally tuned for the motor.

The Automatic Motor Adaptation (AMA) process failed to complete within the expected time frame. This can occur due to various reasons, including excessive motor heating from repeated attempts, which can affect resistance measurements and prolong the process.

An internal fault occurred within the frequency converter during the Automatic Motor Adaptation (AMA) process. This suggests a problem with the drive's internal diagnostics or control logic, preventing accurate motor parameter identification.

An external interlock signal has been activated, causing the frequency converter to trip. This typically originates from a safety device or process control, indicating a condition that requires intervention before normal operation can resume to prevent injury or damage.

The temperature on the frequency converter's power card is outside its acceptable operating range (either too high or too low). Extreme temperatures can lead to premature component failure or immediate drive shutdown to prevent damage.

The control card and power card installed in the frequency converter are incompatible with each other. This prevents the drive from starting or operating correctly, requiring compatible hardware components for functionality.

The frequency converter's parameter settings have been reset to their factory default values, typically following a manual reset operation. This means all previous application-specific configurations are lost, and the drive will operate with generic settings.

This warning, specific to PM motors, indicates that the back electromotive force (EMF) voltage has exceeded 90% of the inverter's maximum voltage threshold (U invmax) and has remained high for over 5 seconds. This condition suggests that the motor is generating excessive voltage, potentially due to overspeeding or regenerative braking issues, which could lead to overvoltage trips.

The frequency converter has been activated into 'Fire Mode'. This mode forces the drive to continue operation even under fault conditions to maintain critical systems (e.g., smoke extraction fans) during an emergency. Be aware that this overrides normal safety shutdowns.

While in Fire Mode, one or more warranty-voiding alarms have been suppressed, indicating that the drive is operating under extreme conditions beyond its normal limits. This significantly increases the risk of equipment damage and voids the product warranty.

The motor current has exceeded the value set in parameter 4-18 (Current Limit). The drive is actively limiting the current to protect itself and the motor, but prolonged operation at this limit indicates an overloaded condition that can cause wear or damage.

The signal on one of the analog inputs is less than 50% of the minimum value programmed for that input. This condition is typically caused by broken wiring, a loose connection, or a faulty signal-sending device connected to the frequency converter's analog input.

No motor is detected as connected to the output of the frequency converter. This condition prevents the drive from operating and indicates a potential wiring issue or a missing motor connection.

A phase is missing on the supply side of the frequency converter, or the mains voltage imbalance is excessively high. This message can also appear due to a fault in the input rectifier within the frequency converter, potentially leading to drive malfunction or damage.

The DC-link voltage inside the frequency converter has exceeded its predefined limit. This often occurs during deceleration of high inertia loads, where regenerative energy is fed back into the DC link, and can lead to component damage or drive trips if not controlled.

The DC-link voltage has dropped below the undervoltage limit. This typically indicates an insufficient or fluctuating supply voltage to the frequency converter, leading to a drive trip after a fixed time delay, which varies by unit size. Continued operation with low voltage can cause instability.

The frequency converter is experiencing an overload, with the internal thermal counter indicating that current levels are exceeding 100% for an extended duration. This activates electronic thermal protection, issuing a warning at 90% and an alarm trip at 100% to prevent damage. The drive cannot be reset until the counter falls below 90%.

The torque measured by the motor is below the threshold set for no-load conditions, strongly indicating a broken or severely slipping belt in the mechanical system. This results in a loss of power transmission to the driven equipment.