3-9
IM 760301-01E
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App
Index
Before Starting Measurements
Note
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After wiring, the wiring system must be selected. See section 4.1, “Selecting the Wiring System.”
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When measuring large currents, voltages or currents that contain high frequency
components, take special care in dealing with mutual interference and noise when wiring.
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Keep the measurement cables as short as possible to minimize the loss between the circuit
under measurement and the instrument.
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The thick lines on the wiring diagrams shown in sections 3.9 to 3.11 are the sections where
the current flows. Use appropriate wires that are suitable for the current.
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In order to make accurate measurements of the voltage of the circuit under measurement,
connect the cable to the circuit as closely as possible.
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In order to make correct measurements, separate the measurement cables as far away from
the earth ground wires and the instrument’s case as possible to minimize the static
capacitance to earth ground.
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To measure the apparent power and power factor more accurately on an unbalanced three-
phase circuit, it is recommended that a three-voltage, three-current system using three-
phase, three-wire 3P3W (3V3A) be used to make the measurement.
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If you supply current exceeding approximately 2.8 Arms to the 2-A input element, the
protection circuit activates and bypasses the measurement circuit of the WT3000. This
prevents damage to the measurement circuit. Because current does not flow through the
measurement circuit of the WT3000, the measured value may become 0 A, but the input peak
over-range indicator at the top section of the screen illuminates in red. If this happens, the
measured value is approximately 0 A, but current is actually flowing through the circuit under
measurement. Therefore, do not disconnect the wires to the measurement terminals.
3.5 Wiring Precautions