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IM 760301-01E
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App
Index
Before Starting Measurements
3.8
Guide for Selecting the Method Used to
Measure the Power
Select the measurement method according to the amplitude of the measured voltage or
current from the table below. For details on the wiring methods, see the respective
sections.
• Measurement Method of Voltage
When the voltage is less
than or equal to 1000 V
When the voltage
exceeds 1000 V
See section 3.9
Voltage
wiring
Direct input is not possible
See section 3.11
Direct input
VT (voltage transformer)
• Measurement Method of Current
Shunt-type current sensor
When the voltage is less
than or equal to 1000 V
When the current is less
than or equal to 30 A
When the current
exceeds 30 A
When the current is less
than or equal to 2 A
When the current
exceeds 2 A
When the voltage
exceeds 1000 V
See section 3.9*
Current
wiring
Input
element
Direct input is not possible
Shunt-type current
sensors cannot be used
See section 3.10**
See section 3.10
See section 3.11
See section 3.11
30 A
2 A
Direct input
Clamp-type current sensor
(voltage output type)
Clamp-type current sensor
(current output type)
CT (current transformer)
*
Voltage: 1000 V or less (maximum allowable voltage that can be measured)
600 V or less (rating voltage of EN61010-2-030)
Do not touch the inside of the external current sensor input BNC connector.
** The voltage is less than or equal to 600 V.
• Notes when Replacing Other Power Meters with the WT3000
In three-phase, three-wire systems (3P3W) and three-phase, three-wire systems
[(3P3W) 3V3A] (three-voltage, three-current systems), the wiring system may be
different between the WT3000 and another product (another digital power meter) due
to the differences in whether the reference voltage used to measure the line voltage
(see appendix 4) is of S phase or T phase. To make correct measurements, see the
referenced sections in the selection guide above and check the wiring method of the
three-phase, three-wire system.
The wiring system of three-phase,
three-wire system differs
WT3000
WT1600
PZ4000
WT2000
WT1000
WT230
WT130
2533
2532
etc.
For example, if you replace the WT2000 (used in a three-phase, three-wire system)
with the WT3000 and leave the wiring unchanged, the measured power of each
element is different between the WT2000 and the WT3000. Refer to this manual and
wire the system correctly.