Protective and Diagnostic Functions7- 3Main Circuit UndervoltageThe main circuit DC voltage is belowthe Undervoltage Detection Level(L2-05).200 V Class: Approx. 190 V400 V Class: Approx. 380 VMain Circuit MC Operation FailureThe MC stopped responding duringInverter operation.Applicable Inverter Capacities200 V Class: 37 to 110 kW400 V Class: 75 to 300 kW• An open-phase occurred with theinput power supply.• A momentary power loss occurred.• The wiring terminals for the inputpower supply are loose.• The voltage fluctuations in the inputpower supply are too large.• A fault occurred in the surge pre-vention circuit.Reset the fault after correcting itscause.Control Power FaultThe control power supply voltagedropped.The wiring of the control power cir-cuit is incorrect.• Fix the wiring.• Try turning the power supplyoff and on.• Replace the Inverter if the faultcontinues to occur.Inrush Prevention Circuit FaultMalfunction in the inrush preventioncircuit.The MC did not respond for 10 s eventhough the MC ON signal has beenoutput.Applicable Inverter Capacities200 V Class: 37 to 110 kW400 V Class: 75 to 300 kW• The MC in the main circuit failed.• The MC excitation coil is burnedout.• Try turning the power supplyoff and on.• Replace the Inverter if the faultcontinues to occur.Main Circuit Voltage FaultThe main circuit DC voltage oscillatesunusually (not when regenerating).This fault is detected when L8-05 isset to "Enabled."• An open-phase occurred in the inputpower supply.• A momentary power loss occurred.• The wiring terminals for the inputpower supply are loose.• The voltage fluctuations in the inputpower supply are too large.• The voltage balance between phasesis bad.Reset the fault after correcting itscause.Output Open-phaseAn open-phase occurred at theInverter output.This fault is detected when L8-07 isset to "Enabled."• There is a broken wire in the outputcable.• There is a broken wire in the motor-winding.• The output terminals are loose.Reset the fault after correcting itscause.The motor being used has a capacityless than 5% of the Inverter rated out-put current.Check the motor and Invertercapacity.( )Cooling Fin OverheatingThe temperature of the Inverter's cool-ing fins exceeded the setting in L8-02or the overheat protection level.OH: The temperature exceeded thesetting in L8-02 (Stopping method canbe changed by L8-03.).OH1: The temperature exceeded100°C (Stopping method: Coast tostop).The ambient temperature is too high. Install a cooling unit.There is a heat source nearby. Remove the heat source.The Inverter's cooling fan has stopped.Replace the cooling fan. (Contactour sales representative.)Inverter's Internal Cooling FanStopped(11 kW or more)The Inverter's internal cooling fan hasstopped.(11 kW or more)Table 7.1 Fault Displays and Processing (Continued)Display Meaning Probable Causes Corrective Actions
