Measurement of main circuit voltages, currents and powers
PRECAUTIONS FOR MAINTENANCE AND INSPECTION
105
5
5.2
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 wiring length between the inverter and the motor is large, the meters and CTs may generate heat due to line-to-line
leakage current. Therefore, choose equipment which has enough capacity for the current rating.
To measure and display the output voltage and output current of the inverter, it is recommended that the terminal AM and FM/
CA output functions of the inverter are used.
+
-
Ar
As
At
Vr
Vs
Vt
Au
Av
Aw
Vu
Vv
Vw
W21
V
U
V
W
Inverter with
converter unit
Three-phase
power supply
To the motor
Input voltage
Input current
Output voltage
Output current
R/L1
S/L2
T/L3
P/+
N/-
W11
W12
W13
W22
Summary of Contents for FR-A842-07700
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