Measurement Of Main Circuit Voltages, Currents, And Powers - Mitsubishi Electric FR-A820-00046 (0.4K) Instruction Manual

7.2
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.
NOTE
• When installing meters etc. on the inverter output side
When the inverter-to-motor wiring length is long, 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.
To measure and display the output voltage and output current of the inverter, it is recommended to use the terminal AM and
FM/CA output functions of the inverter.
 Examples of measuring points and instruments
784
7. PRECAUTIONS FOR MAINTENANCE AND INSPECTION

7.2 Measurement of main circuit voltages, currents, and powers

Input voltage
Input current
Ar
W11
Vr
Three-phase
As W12
power supply
Vs
At
W13
Vt
Instrument
types
Inverter
Au
R/L1 U W21
Vu
Av
S/L2 V
Vv
Aw
W
T/L3 W22
Vw
P/+ N/-
V
+ -
Output voltage
Output current
To the motor
: Moving-iron type
: Electrodynamometer type
: Moving-coil type
: Rectifier type