YOKOGAWA WT500, Руководство пользователя

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IM 760201-01E
Before
You Start Measuring
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App
Index
3.11 Wiring the Circuit That You Will Measure with a
VT or CT
This section explains how to wire a measurement cable from an external VT or CT to
a voltage or current input terminal. Also refer to this section when wiring a clamp-type
current sensor that outputs current.
To avoid electric shock and damage to the instrument, follow the precautions given in
section 3.5, “Precautions for Wiring the Circuit That You Will Measure.”
When the maximum voltage of the circuit under measurement exceeds 1000 Vrms, you
can make measurements by connecting an external VT to the voltage input terminal.
If the maximum current value of the circuit under measurement exceeds the maximum
range of the input elements, 40 Arms, you can measure the current by connecting an
external CT, or a clamp-type sensor that outputs current, to a current input terminal.
Connecting to the Input Terminal
Voltage Input Terminal
The terminals are
f
4-mm safety banana jacks (female).
Only insert a safety terminal whose conductive parts are not exposed into a voltage input
terminal.
If you are using the 758931 Safety Terminal Adapter that comes with the package, see
section 3.6.
Current Input Terminal
• When the voltage of the circuit under measurement is being applied to the current
input terminals, do not touch the current sensor input terminals. Doing so is dangerous
because the terminals are electrically connected inside the instrument.
• When connecting a measurement cable from an external current sensor to a current
sensor input connector, remove the cables connected to the current input terminals.
In addition, when the voltage of the circuit under measurement is being applied to
a current sensor input terminal, do not touch the current input terminal. Doing so is
dangerous because the terminals are electrically connected inside the instrument.
• The screws used on the terminal (binding post) are M6 screws. Wind the wire around
the screw, use the separately sold Fork Terminal Adapter (758921), or pass the crimp-
on lugs through the screw axis, then tighten firmly with the terminal knob.
• For the dimensions of the terminal parts, see section 3.9.
Number of Installed Input Elements and Wiring Systems
The selectable wiring systems vary depending on the number of input elements that are
installed in the WT500. For details, see “Number of Installed Input Elements and Wiring
Systems” in section 2.3, “Measurement Conditions.”
General VT and CT Handling Precautions
• Do not short the secondary side of a VT. Doing so may damage it.
• Do not short the secondary side of a CT. Doing so may damage it.
Also, follow the VT or CT handling precautions in the manual that comes with the VT
or CT that you are using.