Procedures for the additional losses assessment and analysis in high-efficiency induction machines

The minimum efficiency levels introduced by the most recent standards EU MEPS (European Union Minimum Energy Performance Standards) for industrial low voltage induction motors up to 375 kW (2, 4 and 6 poles) call for a general redesign of the induction motors. The reduction of the additional losses by design innovations and use of new materials with enhanced electromagnetic characteristics can represent a key factor to improve efficiency. To verify the redesign effectiveness, a more accurate evaluation of the stray load losses (SLLs) is however required, according to the latest EN IEC standards 60034-30 and 60034-2-1. In the paper, the application of the “torque procedure” for the evaluation of the additional load losses to a test motor is presented; the corresponding results will be compared with the ones related to FEM analyses to identify possible critical issues.