Measurement Of Main Circuit Voltage, Current, And Power - Mitsubishi Electric FATEC FR-A800 Manual

4
PREVENTIVE MAINTENANCE
4.2.3

Measurement of main circuit voltage, current, and power

● How to measure the voltage and current of each part
Since the voltages and currents on the inverter power supply and output sides include harmonics,
measurement data depends on the circuits measured.
When instruments for commercial frequency are used for measurement, measure the following
circuits with the instruments given on the next page.
● When installing meters etc. on the inverter output side
When the inverter-to-motor wiring length is large, especially in the 400 V class, small-capacity
models, the meters and CTs may generate heat due to line-to-line leakage current. Therefore,
choose the equipment which has enough allowance for the current rating.
When measuring and indicating the output voltage and output current of the inverter, it is
recommended to utilize the terminals AM and FM output function of the inverter.
Ar
Vr
Three-phase
As
power supply
Vs
At
Vt
Instrument types
Input voltage
Input current
Inverter
W
R U Au
11
W
S V Av
12
W
T W Aw
13
P N
V
+ -
Examples of measuring points and instruments
4.2 Maintenance and inspection
W
21
Vu
To the motor
Vv
W
22
Vw
Output voltage
Output current
: Moving-iron type
: Electrodynamometer type
: Moving-coil type
:
Rectifier type
49
1
2
3
4
5
6
7
8