Wiring For Accurate Measurements - YOKOGAWA WT1800 User Manual

2.7

Wiring for Accurate Measurements

When you are wiring a single-phase device, there are the four patterns of terminal wiring positions
shown in the following figures for wiring the voltage input and current input terminals. Depending on
the terminal wiring positions, the effects of stray capacitance and the effects of the measured voltage
and current amplitudes may become large. To make accurate measurements, refer to the items below
when wiring the voltage input and current input terminals.
Effects of Stray Capacitance
When measuring a single-phase device, the effects of stray capacitance on measurement accuracy
can be minimized by connecting the instrument's current input terminal to the side that is closest to the
earth potential of the power supply (SOURCE).
• Easily affected
SOURCE
SOURCE
Effects of the Measured Voltage and Current Amplitudes
• When the measured current is relatively large
Connect the voltage measurement terminal
between the current measurement
terminal and the load.
SOURCE
SOURCE
Explanation
For details on the effects of stray capacitance and the effects of the measured voltage and current
amplitudes, see appendix 3, "How to Make Accurate Measurements."
IM WT1801-03EN
±
I
I
U
U LOAD
±
±
I
I
U
U LOAD
±
±
I
I
U
U LOAD
±
U
U LOAD
±
± I
I
• Not easily affected
U
SOURCE
± I
I
U
U
SOURCE
±
±
I
• When the measured current is relatively small
Connect the current measurement terminal
between the voltage measurement terminal and
the load.
I
I
U
U
SOURCE
±
U
U
SOURCE
±
±
I
U
LOAD
±
LOAD
I
±
LOAD
LOAD
I
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App
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