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Chapter 2 Measurement Procedure
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1
N
2
3
Red
Yellow
Black
Red
Yellow
Black
Yellow
Black
Red
Power supply side
Load
Figure 5. Power and power factor measurement
on Three-Phase Four-Wire Circuit
[Three-Phase Four-Wire Circuit]
The power and power factor of a three-phase four-
wire circuit are measured similar to measurement on
a three-phase three-wire circuit (provided the load is
balanced). No neutral wire is used for this
measurement, however.
In case of unbalanced load, measurement is
conducted similar to measurement on a single-phase
two-wire circuit. Set the instrument in single-phase
measurement mode.
Connect the black cord to the neutral wire as shown
in Figure 5, then switch the red cord and clamp
sensor to the respective wires. In this way, the
power and power factor between the wires can be
measured.
(To use the phase sequence detection function,
connect the voltage cords to the three wires,
excluding the neutral wire, for measurement.)
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