Measurement Of Main Circuit Voltages, Currents And Powers - Mitsubishi FR-A740-00023-EC Instruction Manual

Measurement of main circuit voltages,
currents and powers

6.2 Measurement of main circuit voltages, currents and powers

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.
When installing meters etc. on the inverter output side
When the inverter-to-motor wiring length is large, especially in the 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 AM-5 and CA-5 terminal output function of the inverter.
Ar
Three
phase
As
power
supply
At
Instrument
types
420
Input voltage
Input current
Inverter
W11
R/L1 U
Vr
W12 V
S/L2
Vs
W13
W
T/L3
Vt
P/+ N/-
V
+ -
Examples of Measuring Points and Instruments
Au
W21
Vu
Av
To the motor
Vv
Aw
W22
Vw
: Moving-iron type
: Electrodynamometer type
: Moving-coil type
: Rectifier type
Output voltage
Output current