Qualitative Analysis of and Components of Rotational Power Loss

Four types of electrical steel are analyzed: nonoriented, conventional grain-oriented, double grain-oriented, and high-permeability grain-oriented. The results of field-metric measurement under rotational magnetization were recorded as B_x-H_x and B_y-H_y loops under controlled circular flux density B and circular magnetic field strength H. All the measurements were carried out at 50 Hz. A qualitative analysis of the rotational power loss is carried out by splitting the total power loss into P_x and P_y components and plotting as P_y = f (P_x) curves. These curves can take one of two distinctive forms, depending on the type of magnetization (controlled circular B or controlled circular H) and on the anisotropy of the material. The shapes of the two types of P_y = f (P_x) curves mostly follow piecewise straight lines. In the slanted I type, the curve exhibits two, and in the looped O type, there are four linear regions. The sharp changes in the P_y = f(P_x) curves are strongly linked with the shapes of B-H loops, and this technique is another tool for qualitative analysis of rotational power loss in electrical steels.