Overcurrent (OC)

- Description: The Inverter output current instantaneously exceeded the overcurrent detection level.
+ Cause and Action: The output side of the Inverter is shorted or grounded due to motor coil burnout, poor motor coil insulation, or cable damage. The load is excessive, or the acceleration and deceleration time settings are too short. A special motor or a motor with a capacity exceeding the maximum output capacity of the Inverter is used. The magnetic contactor on the output side of the Inverter was opened and closed. Determine the cause of the error, take the necessary action, and reset the system.

Ground Fault (GF)

- Description: A ground fault current exceeding 50% of the rated Inverter output current flowed from the output side of the Inverter.
+ Cause and Action: The output side of the Inverter is grounded due to motor coil burnout, poor motor coil insulation, or cable damage. Determine the cause of the error, take the necessary action, and reset the system.

Fuse Pre-arcing (PUF)

- Description: The fuse of the main circuit blew out.
+ Cause and Action: The output transistor is broken, in which case replace the Inverter. The output transistor will break if the B1 or negative terminal is shorted with the T1 (U), T2 (V), or T3 (W) terminal. The output side of the Inverter is shorted or grounded. Determine the cause of the error, take the necessary action, and reset the system.

Load Short-circuit (SC)

- Description: The Inverter output or load is shorted.
+ Cause and Action: The output side of the Inverter is shorted or grounded due to motor coil burnout, poor motor coil insulation, or cable damage. Determine the cause of the error, take the necessary action, and reset the system.

Main Circuit Overvoltage (OV)

- Description: The DC voltage of the main circuit exceeded the overvoltage detection level.
+ Cause and Action: The deceleration time setting is too short, and regenerative energy from the motor is excessive. Increase the deceleration time or connect the Braking Resistor Unit. A surge is imposed when the phase advance capacitor is switched. Insert an AC reactor into the power input side of the Inverter. The voltage of the power supply to the Inverter is too high. Lower the voltage within the rated power supply voltage.

Main Circuit Undervoltage (UV1)

- Description: The DC voltage of the main circuit dropped to or below the undervoltage detection level.
+ Cause and Action: Power supply to the Inverter has phase loss. An instantaneous power interruption occurred. Power input terminal screws are loose. The voltage fluctuation of power supply to the Inverter is excessive. Determine the cause of the error, take the necessary action, and reset the system.

Control Power Supply Fault (UV2)

- Description: A voltage fault occurred in control output power supply.
+ Cause and Action: Turn the power supply to the Inverter OFF and ON. If this problem persists, replace the Inverter.

Inrush Current Preventive Circuit Fault (UV3)

- Description: The inrush current preventive circuit is malfunctioning.
+ Cause and Action: Turn the power supply to the Inverter OFF and ON. If this problem persists, replace the Inverter.

Short-phase Input (SPI)

- Description: The DC voltage of the main circuit fluctuates excessively while the Inverter is not affected by regenerative energy.
+ Cause and Action: Power supply to the Inverter has phase loss. An instantaneous power interruption occurred. Power input terminal screws are loose. The voltage fluctuation of power supply to the Inverter is excessive. The voltages of the phases of power supply to the Inverter are uneven. Determine the cause of the error, take the necessary action, and reset the system.

Short-phase Output (SPO)

- Description: The Inverter output has phase loss.
+ Cause and Action: The output cable is broken. A motor coil is broken. Motor output terminal screws are loose. Determine the cause of the error, take the necessary action, and reset the system.

Heat Sink Overheat (OH1 and OH2)

- Description: The temperature of the heat sink exceeded approximately 90°C (OH1) or 100°C (OH2).
+ Cause and Action: The ambient temperature is too high. Install a cooling fan or air conditioner. A heat-generating object exists near the Inverter. Remove the object. The cooling fan of the Inverter is not operating. Replace the cooling fan. High carrier frequency (400V-class models). Decrease the set value of n050.

Braking Resistor Overheat (RH)

- Description: The braking resistor protection function worked.
+ Cause and Action: Regenerative energy from the motor is excessive. Increase the deceleration time, connect a small load, or connect the Braking Resistor Unit to the Inverter. The voltage of the power supply to the Inverter is too high. Lower the voltage within the rated power supply voltage.

Control Transistor Overheat (RR)

- Description: The control transistor protection function worked.
+ Cause and Action: Regenerative energy from the motor is excessive. Increase the deceleration time, connect a small load, or replace the Inverter with a model that has a capacity one rank or two ranks higher. The voltage of the power supply to the Inverter is too high. Lower the voltage within the rated power supply voltage.