Mitsubishi Electric 800 Series, Instruction Manual, Page: 670 / 727

Measurement of main circuit voltages, currents and powers
PRECAUTIONS FOR MAINTENANCE AND INSPECTION
669
7
7.2.6
Measurement of inverter output frequency
In the initial setting, a pulse train proportional to the output frequency is output across the pulse train output terminals FM and
SD of the inverter. This pulse train output can be counted by a frequency counter, or a meter can be used to read the mean
value of the pulse train output voltage. When a meter is used to measure the output frequency, approximately 5 VDC is
indicated at the maximum frequency.
For detailed specifications of the pulse train output terminal FM, refer to
page 362 .
7.2.7
Insulation resistance test using megger
• For the inverter, conduct the insulation resistance test on the main circuit only as shown below and do not perform the test
on the control circuit. (Use a 500 VDC megger.)
NOTE
• Before performing the insulation resistance test on the external circuit, disconnect the cables from all terminals of the inverter
so that the test voltage is not applied to the inverter.
• For the continuity test of the control circuit, use a tester (high resistance range) and do not use the megger or buzzer.
7.2.8
Pressure test
Do not conduct a pressure test. Deterioration may occur.
U
V
W
Inverter
500 VDC
megger
Power
supply
IM
Motor
R/L1
S/L2
T/L3