Analysis of a Nonintrusive Efficiency Estimation Technique for Induction Machines Compared to the IEEE 112B and IEC 34-2-1 Standards

International efficiency testing standards, such as the IEEE 112-B and IEC 34-2-1, can determine the efficiency of an induction machine (IM) accurately at the cost of hindering the machine´s productivity. Alternatively, various methods used to determine a machine´s efficiency in situ do so at the cost of accuracy. This paper proposes a method that determines an IM´s efficiency over a range of load conditions from tests conducted and centered around one thermally stable load point in the least intrusive manner possible. The results are then compared to those of the IEEE 112-B and IEC 34-2-1 motor testing standards using segregated loss analysis. It was found that despite the proposed algorithm being unable to accurately determine core losses, the efficiency of a machine can be estimated to within 0.5%-2.1% and 1.1%-1.7% error, when compared to the IEEE 112-B and IEC 34-2-1 standards, respectively over a 25%-150% machine load profile (dependent upon the proposed method´s implementations).