YOKOGAWA WT500 User Manual page 136

5.3 Setting the Equation for Efficiency
Explanation
5-10
You can create an efficiency equation can by combining measurement function symbols.
The WT500 can determine the energy conversion efficiency of the device using the
numeric values of the measurement functions.
Setting the Equation
Two efficiency equations (η1 and η2) can be defined by assigning the power of an
element or the power of an Σ function as an operand. You can combine up to 4 terms
in Udef1 and Udef2 to set the sum of multiple measurement function symbols as an
operand of an equation.
Equation Examples
• Efficiency of a Single-Phase, Two-Wire Input/Single-Phase, Two-Wire Output
Device
Input: Power of element 1 (P1)
Output: Power of element 2 (P2)
Efficiency equation: P2/P1
Input power: P1
• Efficiency of a Single-Phase, Two-Wire Input/Three-Phase, Three-Wire Output
Device
Input: Power of element 1 (P1)
Output: Σ power of elements 2 and 3 (PΣ)
Efficiency equation: PΣ/P1
• Efficiency of a Three-Phase, Three-Wire Input/Single-Phase, Two-Wire Output
Device
Input: Σ power of elements 1 and 2 (PΣ)
Output: Power of element 3 (P3)
Efficiency equation: P3/PΣ
Note
To correctly compute the efficiency, set the power factors of all elements so that all power
units used in the computation are the same. For example, the efficiency cannot be computed
correctly if elements or wiring units used in the computation have different power units, such as
W (watt) and J (joule).
Output power: P2
Converter
(Inverter, etc.)
IM 760201-01E