YOKOGAWA WT200 User Manual page 45

Explanation
IM 253421-01E
4.5 Setting the Scaling Constant when External PT/CT is Used
About the Scaling Function
This function is useful when measuring parameters such as voltage, current, and
power by using an external transformer such as a potential transformer (PT) or a
current transformer (CT). In this case, the output from the secondary side of the
transformer is applied to the input terminals of the instrument. You can specify the PT
ratio, CT ratio, or power coefficient as the scaling constant on this instrument.
Measured/computed value Scaled result
Voltage V
Current A
Active power W
Reactive power var
Apparent power VA
Setting the Scaling Constant
The scaling constants are set in the following order. The setting ranges from 0.001 to
9999. The initial value is 1.000.
• P: Sets the PT ratio on display A
• C: Sets the CT ratio on display B
• F: Sets the power coefficient on display C
Turning Scaling ON/OFF
Select the scaling menu once again after having set the scaling constants. The initial
value is oFF.
• on: When this setting is selected, pressing the ENTER key will start scaling and the
SCALING indicator will light.
• oFF: When this setting is selected, pressing the ENTER key will stop scaling and
SCALING indicator will extinguish.
Note
When the scaling constant × measurement range exceeds 9999M(10
display will appear (see section 2.3).
P × V
P: Voltage scaling constant (PT ratio)
C × A
C: Current scaling constant (CT ratio)
F × P × C × W
F: Power scaling constant
F × P × C × var
F × P × C × VA
6
), the computation over
4-9
4