POWER LOSSES IN THICK STEEL LAMINATIONS WITH HYSTERESIS

Magnetic power losses have been experimentally investigated and theore tically predicted over a range of frequencies (direct current-1.5 kHz) and peak inductions (0.5-1.5 T) in 1-mm-thick FeSi 2 wt. % lamination s. The direct current hysteresis properties of the system are describe d by the Preisach model, with the Preisach distribution function recon structed from the measurement of the recoil magnetization curve (B-p=1 .7 T). On this basis, the time behavior of the magnetic induction vs f requency at different lamination depths is calculated by a finite elem ent method numerical solution of Maxwell equations, which takes explic itly into account the Preisach model hysteretic B(H) relationship. The computed loop shapes are, in general, in good agreement with the meas ured ones. The power loss dependence on frequency is predicted and exp erimentally found to change from a similar to f(3/2) to a similar to f (2) law with increasing peak induction. (C) 1996 American Institute of Physics.