Frequency and peak induction dependence of eddy current losses in AlSiFe magnetic laminations

The authors present loss separation measurements carried out in AlSiFe (1.7 wt.% Al, 1.9 wt.% Si) nonoriented laminations of thickness 0.22 mm and variable grain size s (24 μm⩽s⩽150 μm) in the frequency range 1 Hz⩽f⩽300 Hz and peak induction range 0.7 T⩽B⩽1.5 T. In agreement with theoretical predictions, the excess loss is found to obey the law P^e =8√σGSV₀ (Ff)^3/2 , where σ is the electrical conductivity, S is the lamination cross-section area, and G=0.1356. The magnetic field V₀ turns out to be proportional to s, so that P_e∝√s, a result already found in previous investigations of SiFe steels. The behavior and absolute value of the product SV₀ found in the present experiments with AlSiFe steels are essentially the same as those found in previous studies in SiFe steels. This suggests that the field V₀ plays a fundamental role in the relationship between microstructure and power losses of nonoriented electrical steels