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■ Q&A relating to installation
Q
Can it be installed without the IEC rail?
No. Use the IEC rail.
A
Q
What diameter of electric wire can be fitted to the current sensor?
The nominal sectional areas of 600 V vinyl-coated conductors having applicable electric wire diameters are shown below (reference values).
• IV electric wire (600 V vinyl-insulated electric wire)
2
60 mm
(EMU-CT50/CT100), 150 mm
× 1 pc., 325 mm
2
500 mm
• CV electric wire (600-V vinyl-insulated electric wire)
A
2
38 mm
(EMU-CT50/CT100), 150 mm
× 1 pc., 325 mm
2
500 mm
The above values are the standard nominal sectional areas. These electric wires may not pass through the sensor owing to the error of the
outer diameters of vinyl insulators finished by manufacturers or deformation (bending) of the wires.
Check the wire on site.
Q
To what should attention be paid when fitting the current sensor?
Models EMU2-CT5 (-4W), EMU-CT50, EMU-CT100, EMU-CT250, EMU-CT400 and EMU-CT600 are split type sensors. If the parting faces
A
are not completely engaged or there is foreign matter between the parting faces, the sensor cannot exhibit sufficient performance. Fit the
sensor carefully.
■ Q&A relating to connection
Q
Do the current sensor and the power measuring unit have polarity?
Yes.
Connect the current sensor secondary terminals (k and l) to the power measuring unit terminals with appropriate symbols.
A
If the terminals are connected to improper poles, the electric power and electric energy cannot be measured correctly although the current can
be measured.
Q
To what should attention be given for correct wiring?
Check the polarity of the primary current of the current sensor.
"K" and "L" are shown on the power supply side and the load side of the circuit, respectively. An arrow mark is shown in the direction from K to
A
L.
In the case of a 3-wire circuit, check that the current sensor is connected to this unit without misconnection on the sides 1 and 3.
Check that the voltage input terminals P1, P2 and P3 are connected correctly.
Q
How can the wiring between the current sensor and this unit be extended?
For the cables for the split current sensors EMU-CT50, EMU-CT100, EMU-CT250, EMU-CT400 and EMU-CT600, trunk cables are available.
The wiring length can be increased to up to 50 m.
A
For Model EMU2-CT5 (-4W), the wiring length can be increased to up to 10.5 m by using the cable supplied with the sensor. To further
increase the length, use the potential current transformer for split type CW-5S (L), and extend the wiring on the secondary side of CW-5S (L).
■ Q&A relating to setting
Q
Is setting necessary?
It is necessary to set at least the phase and wire system, primary current, primary voltage and sensor type. Set these items appropriately to
A
the circuit to be connected.
For setting, one of the optional small display unit (EMU2-D65) or logging display unit (EMU2-D65-M) is necessary.
Q
Is the unit disordered if the primary current setting is different from the rated current of the connected current sensor?
The unit will not be disordered or burnt out. But quite different measurements will be obtained.
A
Q
Why is it necessary to set the date and time?
The time of occurrence of maximum and minimum values, and time of occurrence of upper/lower alarms are measured.
A
To measure these values, time control is necessary. Therefore, the unit has a built-in clock. Set the clock without fail.
2
(EMU-CT250)
× 2 pcs. (EMU-CT400/CT600)
2
2
(EMU-CT250, 100 mm
× 2 pcs. (EMU-CT400/CT600)
2
(24/32)
2
is recommended)
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