Induction motor efficiency measurements in accordance to IEEE 112-B, IEC 34-2 and JEC 37 international standards

The IEEE 112-B, IEC 34-2 and the JEC 37 international standards represent the most important references for the three-phase induction motor efficiency measurements. These standards recommend different measurement procedures, in particular for the stray losses determination and the temperature corrections of the copper losses. In this paper, these international standards are used to evaluate the efficiency of four standard three-phase induction motors of the same series (rated 4, 7.5, 11 and 15 kW, 380 V, 4 poles). The main differences in the measurement procedures are highlighted and some critics at the prescribed methodologies are reported.