A comparison of theoretical and experimental values of power loss of grain-oriented 3% silicon–iron

Abstract

The localised power loss and domain wall movement under sinusoidal flux conditions has been measured for individual grains in polycrystalline Goss textured 3% silicon–iron. The power losses obtained from six models of wall motion were compared with the experimental losses. The rigid domain wall models (Pry and Bean, bra-ket array and skew walls) predicted losses higher than the measured values. The flexible domain wall models (Lee, isotropic bowing, and anisotropic bowing) predict losses closer to those measured. The best fit was obtained with a model which takes into account the variation of wall energy with wall orientation and includes the ruckling process, which confirms the published observations that ruckling is the major method of flux reversal. For peak sinusoidal flux densities Bm up to 1.6 T the power loss is proportional to (Bm)1.82. For stable and repetitive wall motion the power loss depends upon the average normalised wall velocity v as (v)1.88. The changes in domain wall spacing with frequency are also reported.