YOKOGAWA wt3000, Руководство пользователя, Страница: 363 / 384

App-31
IM 760301-01E
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App App
Index
Appendix
Power transformer
DC power U1 and I1
AC power U3 and I3
AC power U2 and I2
U2 (or I2, U3, or I3)
Input element 1
Input element 2
Input element 3
Synchronization source setup example
Power Transformer with Single-Phase AC Input and Three-Phase AC Output
If the device that converts single-phase AC power to three-phase AC power is
connected and measured as shown in the figure below, set the synchronization
source of input elements on the input end to the same signal and do the same for
the input elements on the output end.
In this example, set the synchronization source of input element 1 to U1 (or I1), and
set the synchronization source of input elements 2 and 3 to U2 (or I1, U3, or I3).
In this case, AC signals of different frequencies are measured. If the
synchronization source of all input elements is set to the same signal, the
measurement period of either the input signal or the output signal will not be an
integer multiple of the signal which is undesirable.
• Single-phase AC power: Connect to input element 1.
• Three-phase AC power: Connect to input elements 2 and 3 using three-phase,
three-wire system.
Power transformer
AC power U1 and I1
AC power U3 and I3
AC power U2 and I2
U1 (or I1)
U2 (or I2, U3, or I3)
Input element 1
Input element 2
Input element 3
Synchronization source setup example
To measure the input/output efficiency with high accuracy without being affected by
the synchronization source setting such as in this case or in the power measurement
or efficiency measurement of aforementioned devices, set the data update rate of the
WT3000 to 250 ms, 500 ms, 1 s, or 2 s. Because the measured value is computed
from the Exponential Average for Measuring Period method described on the next
page, the period of the input signal does not need to be detected.
Note
• The measurement period for the numeric data of the maximum value (Peak) for voltage and
current is the entire span within the data update period regardless of the measurement period
specified above. Therefore, the measurement period for the measurement functions U+pk, U-
pk, I+pk, I-pk, CfU, and CfI that are determined from the maximum value of the voltage and
current is also the entire span within the data update period.
• The measurement period of measurement functions of harmonic measurement is from the
beginning of the data update interval to 9000 points at the harmonic sampling frequency
regardless of the measurement period specified above.
Appendix 6 Setting the Measurement Period