Frequency dependence of core loss in rapidly quenched Fe-6.5 wt. %Si

Abstract

The frequency, field, and temperature dependencies of core loss in rapidly quenched Fe-6.5 wt. %Si ribbons are reported. The annealed material exhibits (001)〈uv0〉 fiber texture, resulting in isotropic properties in plane; equivalent losses and B-H loops are seen in tape-wound toroids and in annuli punched from ribbon. Hysteresis losses predominate in the present Fe-6.5%Si up to about 1 kHz, as the thin gauge and high resistivity reduce eddy current losses from those of conventional nonoriented steels. The 2-kHz/1.0-T core losses are a factor of 6–8 higher in conventional M-15 than in Fe-6.5%Si. The core losses of Fe-6.5%Si are about 40% higher at 77 than at 373 K. The loss data are not in agreement with the predictions of Bertotti’s theory.