2-12
IM WT1801-01EN
Power Range
The measurement ranges (power ranges) of active power (P), apparent power (S), and reactive power (Q) are
as follows:
Wiring System
Power Range
1P2W (single-phase, two-wire system) Current range × voltage range
1P3W (single-phase, three-wire system)
3P3W (three-phase, three-wire system)
3P3W (3V3A; three-voltage, three-
current method)
Voltage range × current range × 2
(when the voltage and current ranges on the
elements in the wiring unit are set to the same range)
3P4W (three-phase, four-wire system) Voltage range × current range × 3
(when the voltage and current ranges on the
elements in the wiring unit are set to the same range)
• When the result of the equation voltage range × current range exceeds 1000 W (VA or var), the displayed unit
changes to kW (kVA or kvar).
• Number of displayed digits (display resolution)
For a detailed list of the available voltage and current range combinations and power ranges when all the
elements have the same voltage or current range, see appendix 4 in the getting started guide, IM WT1801-
03EN.
In auto range mode, because the voltage and current ranges switch independently according to range
increase and decrease conditions, different power ranges may be set for the same power value.
External Current Sensor Range (
EXT SENSOR; option)
The output of current sensors that produce voltage, such as shunts and clamps, can be applied to an element’s
external current sensor input connector (EXT) and measured. Press EXT SENSOR so that it illuminates, and
then set the external current sensor range.
The external current sensor range can be fixed (when auto range is set to off) or determined automatically (when
auto range is set to on).
Fixed Ranges
When the current range is fixed, you can select a range from the available options. The selected current range
does not change even if the amplitude of the input signal changes. Set the range in reference to the rms value of
the input signal.
• When the Crest Factor Is Set to CF3
You can select from 50 mV, 100 mV, 200 mV, 500 mV, 1 V, 2 V, 5 V, and 10 V.
• When the Crest Factor Is Set to CF6
You can select from 25 mV, 50 mV, 100 mV, 250 mV, 500 mV, 1 V, 2.5 V, and 5 V.
Auto Range
This is the same as the auto range feature for voltage.
2 Fundamental Measurement Conditions
