The inverter output is shut off if the communication fault of the built-in CPU occurs.
Check for devices producing excess electrical noises around the inverter.
• Take measures against noises if there are devices producing excess electrical noises around the inverter.
• Contact your sales representative.
Operation panel power supply short circuit/RS-485 terminals power supply short circuit
• When the power supply for the operation panel (PU connector) is shorted, the power output is shutoff and the
inverter output is shut off. The use of the operation panel (parameter unit) and the RS-485 communication via
the PU connector are disabled.
To reset, enter the RES signal from the terminal, reset through communication via the RS-485 terminals, or
switch power OFF then ON again.
• When the power supply for the RS-485 terminals are short circuited, this function shuts off the power output.
At this time, communication from the RS-485 terminals cannot be made.
To reset, use
• Check that the PU connector cable is not shorted.
• Check that the RS-485 terminals are connected correctly.
• Check PU and the cable.
• Check the connection of the RS-485 terminals.
24 VDC power fault
• When the 24 VDC power output from the PC terminal is shorted, this function shuts off the power output.
At this time, all external contact inputs switch OFF. The inverter cannot be reset by entering the RES signal.
To reset it, use the operation panel, or switch power OFF, then ON again.
• Check for a short circuit in the PC terminal output.
• Check that the 24 V external power supply voltage is correct.
• Repair the short-circuited portion.
• Supply the power at 24 V. (If the power with insufficient voltage is supplied to the 24 V input circuit for a long
time, the inverter internal circuit may heats up. Although it will not damage the inverter, supply power at the
correct voltage .)
Abnormal output current detection
The inverter output is shut off if the output current exceeds the Pr.150 Output current detection level setting.
This functions is available when "1" is set in Pr.167 Output current detection operation selection. When the
initial value (Pr.167 = "0") is set, this protective function is not available.
Check the settings of Pr.150, Pr.151 Output current detection signal delay time, Pr.166 Output current
detection signal retention time, and Pr.167. (Refer to
Inrush current limit circuit fault (Standard models and IP55 compatible models only)
The inverter output is shut off when the resistor of the inrush current limit circuit is overheated. The inrush current
limit circuit is faulty.
• Check that frequent power ON/OFF is not repeated.
• Check if the input side fuse (5A) in the power supply circuit of the inrush current limit circuit contactor (FR-F840-
03250(132K) or higher) is blown.
• Check that the power supply circuit of inrush current limit circuit contactor is not damaged.
Configure a circuit where frequent power ON/OFF is not repeated.
If the problem still persists after taking the above measure, contact your sales representative.
on the operation panel, enter the RES signal, or switch power OFF then ON again.
FR-LU08 indication Circuit fault
FR-LU08 indication 24 VDC power fault
FR-LU08 indication OC detect level
FR-LU08 indication Inrush overheat
6. PROTECTIVE FUNCTIONS
6.5 Causes and corrective actions