Mitsubishi D700 Inverter

This is a panel display code (specifically for FR-PU04/FR-PU07) that indicates a CPU fault (E.CPU) is active. The underlying issue is a communication fault of the built-in CPU, leading to inverter output stoppage. It signals a critical internal processing error that prevents normal operation.

This fault appears when there is a mismatch between the type of signal (voltage or current) being input to terminal 4 and the inverter's configuration settings. Specifically, it occurs if voltage (current) is applied while Pr. 267 (Terminal 4 input selection) and the physical voltage/current input switch are set differently. This can lead to incorrect speed commands or erratic operation.

This fault indicates that the brake transistor has detected an alarm condition, typically due to excessive regenerative energy from the motor. This usually happens during rapid deceleration or when driving high-inertia loads, leading to overheating of the braking components. Continuous overheating can damage the inverter's internal brake circuit and external brake resistor.

This fault activates when the inverter's output current surpasses the level defined by Pr. 150 (Output current detection level). It serves as a protective measure, indicating that the motor or load is drawing more current than configured, possibly due to an overload or incorrect parameter settings. Exceeding this limit can lead to inverter or motor damage.

This fault indicates an internal communication fault within the inverter's built-in CPU. This is a critical internal error that causes the inverter output to stop, suggesting a potential hardware malfunction or severe internal interference. Such a fault can lead to complete loss of control and operation.

This fault occurs when an earth (ground) fault is detected on the inverter's output side, typically in the motor or its connecting cables, specifically during startup. This protective function, active when Pr. 249 is set to '1,' immediately trips the inverter to prevent damage. An unresolved ground fault poses an electrical shock hazard and can severely damage the inverter or motor.

This fault signifies a loss of one or more phases (R/L1, S/L2, T/L3) on the inverter's input power supply. This protection, which can be enabled by Pr. 872, stops the inverter to prevent damage to its internal converter section and DC bus capacitors. Continuous operation with an input phase loss can drastically shorten the inverter's lifespan. It may also trip due to large unbalanced phase voltages or if the load on the inverter is very light.

This fault occurs when the resistor within the inverter's inrush current limit circuit overheats. This typically happens due to frequent power ON/OFF cycles to the inverter, stressing the charging components, or an internal component failure. Prolonged overheating can damage the inverter's power supply section and lead to critical failures.

This fault indicates a loss of one or more phases (U, V, W) on the inverter's output side, typically between the inverter and the motor. This protective function, which can be enabled by Pr. 251, stops the inverter output to prevent motor damage from unbalanced current flow. Operating a three-phase motor with a phase loss can severely overheat and damage the motor windings.

This fault occurs when the inverter's output current reaches or exceeds approximately 200% of the rated current during the acceleration phase. This indicates an excessive load, a short circuit, or incorrect parameter settings, causing the protective circuit to trip. Repeated overcurrent events can lead to overheating and potential damage to the inverter's power components or the connected motor.

This fault indicates that the inverter's output current has reached or exceeded approximately 200% of its rated value while operating at a constant speed. This is typically caused by sudden increases in mechanical load, a short circuit, or a ground fault in the motor or its cabling. Persistent overcurrent can lead to overheating and premature failure of inverter components.

This fault signifies that an external thermal relay (for motor overheat protection) or an internal motor temperature relay has tripped, causing its contacts to open. The inverter has stopped its output to protect the motor from overheating. This function is active only when the 'OH' signal (value 7) is set in any of Pr. 178 to Pr. 182 (input terminal function selection). Prolonged motor overheating can lead to winding insulation breakdown and motor failure.

This fault occurs when the inverter's output frequency drops to 1Hz due to stall prevention operation and remains at that level for 3 seconds, ultimately leading to an inverter trip. The display shows "OL" during active stall prevention. This indicates that the motor is experiencing a continuous overload condition that the stall prevention function cannot overcome. Sustained overload can lead to motor and inverter damage.

This fault indicates an error with the inverter's internal parameter storage device (EEPROM) on the control circuit board. This can be caused by a corrupted memory block or by an excessive number of parameter write cycles, which can wear out the EEPROM. A corrupted EEPROM can lead to incorrect operation, loss of critical configuration data, or complete inverter malfunction.

This fault indicates that the resistance of the PTC thermistor, connected between inverter terminals 2 and 10, has exceeded the threshold set in Pr. 561 (PTC thermistor protection level), causing the inverter to trip. This typically signals motor overheating due to overload. This protective function is active only when Pr. 561 is set to a value other than '9999'. Continued overload and overheating can severely damage the motor.

This fault indicates a loss of communication between the inverter and the Parameter Unit (PU) or another device via RS-485. This can be due to a disconnected cable, incorrect communication settings (Pr. 75, Pr. 121, Pr. 122), or excessive consecutive communication errors. Loss of communication will stop inverter output, potentially halting the connected process.

This fault signifies that the inverter has attempted to automatically resume operation a specified number of times (configured in Pr. 67) after a previous fault, but has failed to clear the underlying problem. The inverter will now trip to prevent further damage. This code indicates a persistent issue that needs direct investigation and manual intervention.

This fault indicates a malfunction in the inverter's safety circuit or an open circuit in the lines between S1 and SC, or S2 and SC. This is a critical safety system fault, preventing the inverter from operating until the safety circuit integrity is restored. It ensures the machine cannot start under unsafe conditions.

This alarm indicates a problem with the inverter's cooling fan. It appears on the operation panel when the cooling fan stops due to an alarm condition or operates differently from the settings configured in Pr. 244 (Cooling fan operation selection). Insufficient cooling can lead to inverter overheating and potential damage to internal components.

This alarm indicates that the inverter's safety stop function has been activated, resulting in the output being shut off. This typically occurs when an external safety circuit triggers or if the safety stop inputs (S1, S2) are not properly shorted to SC when the function is not intentionally in use. Failure to address an unintended safety stop will prevent the inverter from operating.