5-1 Protective Functions and Troubleshooting 5 Maintenance Operations *1. The reset command through the RS terminal or STOP/RESET key is not accepted. Turn off the power. *2. The reset operation via the Digital Operator is not accepted. Be sure to reset via the RS terminal. 5-3 Name Description Display on Digital Operator Check point and remedy Reference page CT error Shuts off the output if an error occurs in the CT (current detector) built into the Inverter. Trips if the CT output is approximately 0.6 V or more when the power is turned on. ek1k0. The Inverter has a failure.
(Repair) CPU error *1 Shuts off the output and displays an error if the internal CPU has worked erroneously or abnormally. Note: If an abnormal value is read from EEPROM, it may become a CPU error depending on the case. ek1k1. Is there any large noise source around? (Countermeasures against noise) The Inverter has a failure. (Repair) External trip If an error occurs in the external equipment or devices, the Inverter receives the signal, and the output is shut off. (Available with the external trip function selected) ek1k2. Has any error occurred in the external devices when the external trip function is selected?
(Correct the external device error.) 4-81 USP error Appears when the power is turned on with the RUN signal input into the Inverter. (Available with the USP function selected) ek1k3. When the USP function was selected, did you turn on the power with the RUN signal input into the Inverter? (Cancel the RUN command and turn on the power.) 4-81 Grounding protection *1 Protects the Inverter if a ground fault between the Inverter output unit and the motor is detected when turning on the power. (This function does not work when there is residual voltage in the motor.) ek1k4. Is there any ground fault? (Check the output wires and motor.) Is there any error in the Inverter itself?
(Disconnect the output wires to check.) Is there any error in the main circuit? (Check the main circuit. Refer to Chapter 6.) (Repair) Incoming overvoltage protection Appears if the incoming voltage continues to be higher than the specification value for 100 seconds while the Inverter is stopped. Trips when the main circuit DC voltage reaches approximately 390 V DC for 200-V class, and 780 V DC for 400-V class. ek1k5. Is the incoming voltage high while the Inverter is stopped?
(Lower the incoming voltage, restrain the power supply fluctuation, apply the AC reactor to input.) Momentary power interruption protection Shuts off the output when a momentary power interruption occurs for 15 ms or more. If the shutoff time is long, it is normally recognized as a power shutoff. Note that, when restart is selected, the Inverter restarts at power-on as long as the RUN command remains. ek1k6. Has the power supply voltage dropped? (Power recovery) Is there a contact failure for MCB and/or Mg? (Replace MCB, Mg.) 4-59 ek1k0. ek1k1. ek1k2. ek1k3. ek1k4. ek1k5. ek1k6.