YOKOGAWA WT332E User Manual page 123

7.4 Features
7.4.2 Frequency Measurement
Item
Measured item
Method
Frequency measuring range Varies depending on the data update interval (see description given later) as follows:
Measurement range
Frequency filter
Accuracy
7.4.3 Computation
Item
Computing equation of apparent power (S), reactive power (Q), power factor (λ), and phase angle (Φ)
i : Input element number
UΣ[V]
IΣ[A]
PΣ[W]
SΣ[VA] Si=Ui×Ii
QΣ[var]
Qi= S −
2
i
λΣ λi = Pi/Si
Φ[°]
Φi = cos
7-10
Specifications
Voltage and current frequencies applied to the selected input element can be measured.
WT332E (two element model)
Select voltage (U1)/current (I1) of input element 1 or voltage (U3)/current (I3) of input element 3.
WT333E (three element model)
Select voltage (U1)/current (I1) of input element 1, voltage (U2)/current (I2) of input element 2 or
voltage (U3)/current (I3) of input element 3.
Reciprocal method
Data Update Interval
0.1 s
0.25 s
0.5 s
1 s
2 s
5 s
10 s
20 s
Auto*
* Limit of the measurement lower limit frequency by the Timeout setting
Timeout : lower limit frequency
1 s 2.0 Hz
5 s 0.5 Hz
10 s 0.2 Hz
20 s 0.1 Hz
Only for the direct current input of the WT310EH, the maximum measurement range is 20 kHz.
Auto switching among six types: 1 Hz, 10 Hz, 100 Hz, 1 kHz, 10 kHz, and 100 kHz
Select OFF or ON (cutoff frequency at 500 Hz).
Requirements
• When the input signal level is 30% or more of the measurement range if the crest factor is set
to 3 (60% or more if the crest factor is set to 6 or 6A)
• Frequency filter is ON when measuring voltage or current of 200 Hz or less.
Accuracy: ±(0.06% of reading)
Specifications
Single-Phase, Three-
Wire (1P3W)
(U1+U3)/2
(I1+I3)/2
P1+P3
S1+S3
Q1+Q3
P
2
i
PΣ
S Σ
P PΣ
− 1
i 1 −
( ) ( )
cos
S
S Σ
i
Measurement Range
20 Hz ≤ f ≤ 100 kHz
10 Hz ≤ f ≤ 100 kHz
5 Hz ≤ f ≤ 100 kHz
2.0 Hz ≤ f ≤ 100 kHz
1.0 Hz ≤ f ≤ 100 kHz
0.5 Hz ≤ f ≤ 100 kHz
0.2 Hz ≤ f ≤ 100 kHz
0.1 Hz ≤ f ≤ 100 kHz
0.1 Hz ≤ f ≤ 100 kHz
Three-Phase, Three- Three-Phase, Three-
Wire (3P3W) Wire (3V3A)
(U1+U2+U3)/3
(I1+I2+I3)/3
3 3
( S + 1 S 3 )
2
3
Three-Phase, Four-
Wire (3P4W)
P1+P2+P3
S1+S2+S3
( S 1 + S 2 + S 3 )
Q1+Q2+Q3
IM WT310E-02EN