ASSESSING THE ACCURACY OF ANALYTICAL METHODS  FOR CALCULATING THE NO-LOAD LOSS COMPONENTS  IN INDUCTION MOTORS

This article discusses the methods for reducing the idling losses in high-power induction motors as an opportunity for increasing their efficiency to meet the requirements of modern standards and customers. We have performed a comparative analysis of the tested no-load losses of three induction motors with the calculation results separated into stator copper losses, steel losses and stray losses by two different analytical approaches. Steel losses are supposed to consist of main steel losses and stray pulsation steel losses. Stray losses in a copper rotor cage, caused by stator’s slot frequency currents due to the slotted structure of the stator, are examined separately. The existing approaches to calculating no-load loss components have been proved to be insufficiently accurate for making reasonable engineering decisions aimed at decreasing no-load losses.