Stray Load Loss Calculation of Induction Motors Using Electromagnetic Field Analysis

In this paper, we investigate the main factors of stray load loss of cage induction motors from both results of measurement and electromagnetic field analysis. The losses generated at the rotor cage, stator and rotor cores are calculated by the combined 3-D-2-D finite element analysis considering the magnetic saturation and harmonics, which vary due to the load condition. On the other hand, the total and stray load losses of the motor are measured due to IEEE standard 112. The relationship between the measured losses and the practical losses generated at each part of the motor are investigated from these results. It is clarified that the main part of the stray load loss in case of the analyzed motor is the increase of the harmonic losses due to load, which are the harmonic rotor cage losses and harmonic core losses including the inter-bar current losses.