Hitachi NES1-002LB, Quick Reference Manual

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Chapter 11 Maintenance and Inspection
11 - 3
11.3 Ground Resistance Test with a Megger
When testing an external circuit with a megger, disconnect all the external circuit cables from the inverter
to prevent it from being exposed to the test voltage.
Use a tester (in high-resistance range mode) for a conduction test on the control circuit. Do not use a
megger or buzzer for that purpose.
Apply the ground resistance test using a megger only to the main circuit of the inverter. Do not carry out
the test using a megger for its control circuit.
Use a 500 VDC megger for the ground resistance test.
Before the main circuit test with a megger, and then connect terminals R/L1, S/L2, T/L3, U/T1, V/T2, W/T3,
P/+ and PD/+1 by wires as shown in the figure below. Subsequently, carry out the test.
After the test using the megger, remove the wires from terminals R/L1, S/L2, T/L3, U/T1, V/T2, W/T3, P/+
and PD/+1.(Single phase input model is R/L1, S/L2, T/L3, U/T1, V/T2, W/T3, P/+ and PD/+1)
11.4 Withstand Voltage Test
Do not carry out a withstand voltage test for the inverter. The test may damage its internal parts or cause
them to deteriorate.
Motor
R/L1 S/L2 T/L3 U/T1 V/T2 W/T3
PD/+1 P/+
G
IM
Power supply
Do not connect
power supply
cables to the
inverter.
500 VDC megger
Be sure to remove the
jumper for switching the
internal filter function.
Do not connect the inverter
cables to the motor.
DC500V Megger