Efficiency optimization requires improved characterization of polyphase induction motor losses

Industry standards, including IEEE 112, have for many years characterized the component losses of three-phase induction motors as primary and secondary I
²
R, core, friction and windage, and stray load loss. The definitions of each of the losses, as epitomized in IEEE 112, guarantee that a significant part of the losses will be characterized as stray load loss. It also guarantees that the secondary I
²
R loss will be underestimated and that the core loss associated with field distortions due to load current are not properly identified. This paper will discusses issues with existing test standard loss models and describe model methods that better characterization motor losses, providing the opportunity to further optimize motor efficiency.