15-21
IM 253710-01E
Motor Evaluation Function (Applicable to Motor Modules)
15
15.8 Computing the Motor Efficiency and Total Efficiency
When the Converter Input Is a Single-Phase Two-Wire System (1P2W) and the Motor
Input Is a Three-Phase Three-Wire System (3P3W)
• Wire the motor input to elements 1 and 2 and the converter input to element 3.
• Select [3P3W-1P2W] for the wiring method.
×
100
Motor output
*
(W)
ΣΑ
(W)
Motor efficiency
η
mA(%) =
×
100
Motor output
*
(W)
ΣΒ
(W)
Total efficiency
η
mA(%) =
* Motor output derived in section 15.7.
Converter
Motor
Motor output
Σ
A = P1 + P2
Σ
B = P3
Power consumption
by the motor
Power consumption
by the motor and
converter
Note
With this wiring method, delta computation function (see section 10.2) can be used to carry
out 3P3W>3V3A transformation or Delta>Star transformation.
•
From the 3P3W>3V3A transformation, you can determine one set of line voltage and
common mode current that is not being measured.
•
From the Delta>Star transformation, three common mode voltages can be determined
from three line voltages.
When the Converter Input Is a Three-Phase Three-Wire System (3P3W) and the Motor
Input Is a Single-Phase Two-Wire System (1P2W)
• Wire the converter input to elements 1 and 2 and the motor input to element 3.
• Select [3P3W-1P2W] for the wiring method.
×
100
Motor output
*
(W)
Σ
B(W)
Motor efficiency
η
mB(%) =
×
100
Motor output
*
(W)
Σ
A(W)
Total efficiency
η
mA(%) =
* Motor output derived in section 15.7.
Converter
Motor
Motor output
Σ
B = P3
Σ
A = P1 + P2
Power consumption
by the motor
Power consumption
by the motor and
converter
