Measurement Of Main Circuit Voltages, Currents And Powers - Mitsubishi Electric FR-V500 Series Instruction Manual

7.4 Measurement of main circuit voltages, currents and powers

7.4.1 Insulation resistance test using megger
1) 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.
2) For the continuity test of the control circuit, use a tester (high resistance range) and do not use the megger or buzzer.
3) 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 500VDC megger.)
7.4.2 Pressure test
Do not conduct a pressure test. Deterioration may occur.
Measurement of voltages and currents
Since the voltages and currents on the inverter power supply and output sides include harmonics, measurement
data depends on the instruments used and circuits measured.
When instruments for commercial frequency are used for measurement, measure the following circuits with the
instruments given on the next page.
Three-phase
power supply
Instrument
types
CAUTION
Use an FFT to measure the output voltage accurately.
A tester or general measuring instrument cannot measure accurately.
R
Power
S
supply
T
500VDC
megger
Earth (Ground) terminal
Earth (ground) terminal
Input voltage
Input current
Inverter
Ar
U
W11 R
Vr
As V
W12 S
Vs
At
W13 W
T
Vt
P N
V
+ -
Examples of Measuring Points and Instruments
Measurement of main circuit
voltages, currents and powers
Motor
U
Inverter
IM
V
W
Au
W21
Vu
Av
Vv
Aw
W22
Vw
: Moving-iron type
: Electrodynamometer type
: Moving-coil type
: Rectifier type
101
Output voltage
Output current
To motor
7