6-1 Inspection and Maintenance Megger test •For a megger test of the external circuit, be sure to disconnect all the terminals of the Inverter so as not to apply the test voltage to the Inverter. •Use a high resistance tester for a power distribution test of the control circuit. Do not use a megger or buzzer. •Conduct an Inverter megger test only to the main circuit, not to the control circuit. •Use a 500 V DC megger for a megger test.
•For a megger test of the Inverter main circuit, remove the short-circuit bar used for switching the Inverter built-in filter function and then short-circuit terminals R/L1, S/L2, T/L3, U/T1, V/T2, W/T3, P/+2, +1, N/-, RB, Ro, and To with the wires, as shown below. After the megger test, remove the short-circuit wires from terminals R/L1, S/L2, T/L3, U/T1, V/T2, W/T3, P/+2, +1, N/-, RB, Ro, and To, and reconnect the short-circuit bar for switching the Inverter built-in filter function. Note that the RB terminal is provided only for the Inverters with 22 kW or lower capacity.
P/+2 +1 N/- RB U/T1 Motor 6 Power supply R/L1 S/L2 V/T2 IM T/L3 W/T3 Inspection and Maintenance Do not connect the power wire. Ro To Ground terminal Ground terminal Do not connect to the motor. 500 V DC megger Be sure to remove the short-circuit bar for switching the built-in filter function. Withstand Voltage Test Do not conduct a withstand voltage test on any part of the Inverter. Doing the test is dangerous and may cause damage or deterioration to the parts inside the Inverter. Checking the Inverter and Converter •The quality of the Inverter and converter can be checked using a tester.
(Preparation) Disconnect the externally connected power supply wires (R/L1, S/L2, T/L3), the motor connection wires (U/T1, V/T2, W/T3), and the regenerative braking resistance (P/+2, RB). Prepare a tester. (Usable range is 1 Ω measurement resistance.) (Checking method) •The quality can be judged by measuring the conduction state of Inverter main circuit terminal blocks R/L1, S/L2, T/L3, U/T1, V/T2, W/T3, RB, P/+2, and N/- while alternating the tester polarity. Note 1: Before checking, measure the voltage between P/+2 and N/- at DC voltage range in advance, and confirm that the smoothing capacitor is sufficiently discharged. 6-7