YOKOGAWA wt3000, Руководство пользователя, Страница: 31 / 384

2-5
IM 760301-01E
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App
Index
Faunctional Description
Measurement Functions
The physical values such as rms voltage, average current, power, and phase difference
that the WT3000 measures and displays are called measurement functions. Each
measurement function is displayed using a symbol corresponding to the respective
physical value. For example, “Urms” represents the true rms value of the voltage.
Elements
Element refers to a set of input terminals that can input a single phase of voltage and
current to be measured. The WT3000 can contain up to four elements, which are
numbered from 1 to 4. An element number is appended to the measurement function
symbol for the measured data that the WT3000 displays, so that the correspondence
between the numeric data and the element can be seen. For example, “Urms1”
represents the true rms value of the voltage of element 1.
Wiring System
You can specify five wiring systems--single-phase, two-wire; single-phase, three-wire;
three-phase, three-wire; three-phase, four-wire; and three-phase, three-wire (three-
voltage, three current)--on the WT3000 to measure the power of various single-phase
and three-phase power transmission systems. For details, see section 2.3.
Wiring Unit
A wiring unit refers to a set of two or three input elements of the same wiring system that
are grouped to measure three-phase power. Depending on the wiring system pattern
(see section 2.3), up to two wiring units can be constructed, which are represented by
symbols Σ A and Σ B. The measurement function of a wiring unit is called a Σ function.
For example, “Urms Σ A” represents the true rms value of the average of the voltage of
the input elements that are assigned to wiring unit
Σ
A.
• Configuration example of wiring systems and wiring units
Voltage
input
Current
input
Three-phase, three-wire
Σ
A
Element 1 Element 2 Element 3 Element 4
Three-phase, three-wire
Σ
B
Wiring system
Wiring unit
2.2 Measurement Modes and Measurement Functions