7-11
IM WT310E-02EN
Specifications
1
2
3
4
5
6
7
App
Index
• On this instrument, S, Q, λ, and Φ are derived through the computation of the measured values of voltage, current, and active
power. Therefore, for distorted signal input, the value obtained on this instrument may differ from that obtained on other
instruments that use a different method.
• If the voltage or current is less than 0.5% (less than or equal to 1% if the crest factor is set to 6 or 6A) of the rated range, zero
is displayed for S or Q, and error is displayed for λ and Φ.
• For Q[var], when the current leads the voltage, the Q value is displayed as a negative value; when the current lags the voltage,
the Q value is displayed as a positive value. The value of QΣ may be negative, because it is calculated from the Q of each
element with the signs included.
Lead and lag detection
(Phase angle Φ’s D (lead)
and G (lag))
The lead and lag of the voltage and current inputs can be detected correctly for the following:
• Sine waves
• When the measured value is 50% or more (100% or more when the crest factor is 6 or 6A) of the
measurement range
• Frequency: 20 Hz to 2 kHz(WT310EH: to 1 kHz)
• Phase difference: ±(5° to 175°)
Scaling
Set the current sensor transformation ratio, VT ratio, CT ratio, and power factor when applying the
external current sensor, VT, or CT output to the instrument.
• Significant digits: Selected automatically according to significant digits in the voltage and current
ranges.
• Selectable range: 0.001 to 9999
Averaging
Select the method from the following two types.
• Exponential averaging method
• Moving average method
Select the attenuation constant for exponential averaging; select the sample number from 8, 16,
32,and 64 for moving average.
Efficiency
Computation of efficiency is possible on the WT332E/WT333E.
Crest factor
Computes the crest factor (peak value/RMS value) of voltage and current.
Four arithmetic operation
Six types of four arithmetic operations possible
(A+B, A–B, A*B, A/B, A
2
/B, and A/B
2
)
Average active power during
integration
Computes the average active power within the integrated period.
7.4.4 Integration
Item
Specifications
Mode
Select manual integration mode, standard integration mode, or repetitive integration mode.
In the case of Auto Update Rate cannot use the Integration function.
Timer
Automatically stop integration by setting a timer.
Selectable range: 0 hours 00 minutes 00 seconds to 10000 hours 00 minutes 00 seconds
(Set automatically to manual integration mode for 0 hours 00 minutes 00 seconds)
Count overflow
Holds the elapsed integration time and integration value and stops integration when the elapsed
time of integration reaches the maximum integration time of 10000 hours or when the integrated
value reaches the maximum or minimum displayable integration value (999999M or –99999M).
1
1 WP: 999999 MWh/-99999 MWh, q: 999999 MAh/-99999 MAh
Accuracy
±(Power accuracy (or current accuracy) + 0.1% of reading) (fixed range)
* In the case of auto range, the measurement is not carried out during a range change.
The first measurement data after the range change is added for the period which measurement
was not carried out.
Range setting
Auto range or fixed range for Integration is available.
For details on range switching, see section 7.4.1, “Voltage, Current, and Active Power
Measurements.”
Valid Frequency Ranges for
Integration
Active power
DC to 45 kHz
Current
When the measurement mode is RMS:
DC, lower limit frequency determined by the data update interval to 45 kHz
When the measurement mode is VOLTAGE MEAN:
DC, lower limit frequency determined by the data update interval to 45 kHz
When the measurement mode is DC:
DC to 45 kHz
Timer accuracy
±0.02%
Remote control
Start, stop, and reset operations are available using an external remote signal.
(applies to products with the /DA4 or /DA12 option)
7.4 Features
