17-5
IM CW240E
CW 240 Specifications
17
Measurement
Item
Wiring
3 Phase 3 Wire
3 Current
3 Phase 4 Wire
Average Voltage
Uave
(U
1
U2
U3) / 2
*2
I
Iave
( I 1
I 2
I 3 ) / 3
*3
∑
P
P
1
P2
P3
*5
∑
Q
Q1
Q2
Q3
*5
Average Current
Active Power
Reactive Power 2
*4
Apparent Power
S
U
I
∑
S
Power Factor
Reactive power
method not used
*6
∑
PF
Reactive power
method used
∑
PF
Phase Angle
*6
∑
PA
∑
PF
=
S
1
S2
S3
*5
∑
S
∑
P
Q
=
S
2
P
2
∑
P
2
∑
Q
2
∑
PF
=
∑
PA
= cos
–1
∑
PF
∑
P
*1: In the case of distorted wave input, there may be a difference with other measuring devices
that use a different measurement principle.
*2: Line voltage for 3 phase 3 wire, and phase voltage for 3 phase 4 wire.
*3: I2 for 3 phase 3 wire (2 power-meter method) is the result calculated through vector operation.
*4: When not using the reactive power method. Even in this case, the operation is performed by
multiplying the polarity of Q of each phase calculated with the reactive power method.
*5: For 3 phase 3 wire, the voltage used when obtaining the electric power of each phase is the
phase voltage from the virtual neutral point.
*6: The operation is performed by multiplying the polarity of Q of each phase calculated with the
reactive power method.
*7: In the case of unbalanced input with 3 phase 3 wire (2 power-meter method), there may be
a difference with other connections or measuring devices that use a different measurement
principle.
P1, P3, Q1, Q3, S1, S3, PF1, and PF3 have not physical meaning as values in the operation
process of the 2 power-meter method.
Equations
Symbol
_
_
_
_
TIP
The active power, reactive power, apparent power, power factor, and phase angle
measure the value of each phase.
17.1 CW 240 Specifications