The effect of third harmonic flux distortion on the core losses in thin magnetic steel laminations

A simple and practical method of estimating the effect of 3rd harmonic flux distortion on the total core loss in a thin lamination is described. The necessary eddy current correction factor is derived using simple methods. For distortion levels of less than 30%, it is shown that the hysteresis loss remains unchanged from its sinusoidal value, to a good approximation. Experimentally measured losses in 0.014" and 0.025" laminations, at distorted flux levels ranging from 0.8 to 1.9 T, are used to verify the results of the analysis.