Power factor (PF)
KEW 2062/2062BT
- 45 -
KEW 2062/2062BT
Power factor (PF)
Effective input range
Same as the active power
Display range
-1.000 to 0.000 to 1.000
Accuracy
±1dgt to the result determined by each measured value
* ±2dgt when measuring balance 3P3W, ±3dgt when measuring balance
3P4W
Polarity sign
Phase delay: no sign, Phase advance: -
Formula
PF=
�
P
S
� �
; however, PF = cos (θ) only when balance 3P3W
*
In case of Three-phase circuit, determined by sum value.
* Nothing is displayed where S=0.
* Polarity sign appears based on the voltage-current phase difference (
θ
).
0° to -90° to180° : No sign
(+) Phase delay
0° to +90° to 180°: Negative (-) Phase advance
* Average value is determined by averaging the amount of advance and
delay, based on PF=1 as reference.
[
Example
]
Where measured value is PF=0.99, -0.92, and +0.96:
difference between 0.99 and 1= -0.01 (advance),
difference between -0.92 and 1= +0.08 (delay), and
difference between 0.96 and 1= -0.04(advance).
The total difference will be -0.01+0.08+(-0.04)=0.03 (delay).
Then divide the value by 3 (number of measurement): 0.03÷3=0.01
(delay). The average PF is 0.01 behind to1 (PF average value);
therefore, -0.99 (advance) will be the average PF.
Voltage current phase difference (
θ
) [deg]
(at Single-phase 2-wire measurement only)
Display range
-180.0 to .00 to 179.9
The LCD shows “---” when readings are out of the display range of
active power.
Polarity sign
Phase delay: no sign, Phase advance: -
Measurement
method
Compare current waveform against voltage waveform with zero-cross
position.
* When S=0, nothig is displayed.
* Polarity sign indicates current phase angle with the voltage phase as
reference (0°).
No sign (+) Phase advance
Negative (-) Phase delay
KEW 2062/2062BT
Harmonics function
KEW 2062/2062BT
- 46 -
Harmonics function
Measurement
method
Frequency fixed sampling
Perform sampling 256 times per input cycle (50/ 60 Hz) and do FFT
calculation. Sampling frequency changes depending on the preset
nominal frequency.
50Hz…12.8ksps(every
78μs)
, 60Hz…15.4ksps(every
65μs)
Connect to
L
＝
V
1
, N=V
3
, L/ R/ S/ T (clamp onto power wires) = A
Effective frequency
50/ 60 Hz
Analysis order 1st to 30th order
Window width 1
cycle
Window type
Rectangular
Number of
analysis data
256 points
Analysis rate
Once/ 1 sec.
Harmonics RMS voltage
(Vk: 1
st
fundamental wave to 30
th
harmonics) [Vrms]
Range, Display digit, effective input range
Same as the RMS voltage
Display range
Same as the RMS voltage
*Content rate 0.0% to 100.0% against fundamental wave
Accuracy
RMS:
1 to 10
th
: ±5.0%rdg±10dgt
11 to 20
th
: ±10%rdg±10dgt
21 to 30
th
: ±20%rdg±10dgt
Content range:
±1 against the calculated results of each order.
Formula
To connect L
＝
V
1
, N
＝
V
3
:
Vk=
��
(
Vkr
)
2
+ (
Vki
)
2
1
n=-1
k :
Harmonics order
Vr : Real number after voltage
FFT conversion
Vi : Imaginary number after voltage
FFT conversion
* Content rate
=
𝑉𝑉𝑉𝑉𝑉𝑉𝑉𝑉
×
100
𝑉𝑉𝑉𝑉1
(
𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹
𝑤𝑤𝑤𝑤𝐹𝐹𝐹𝐹𝑤𝑤𝑤𝑤𝐹𝐹𝐹𝐹
)
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.com
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