Investigation of the importance of the anisotropy of cold-rolled electrical steel sheet

Abstract

The importance of the anisotropy of nonoriented cold-rolled electrical steel laminations employed for stators of synchronous machines has been investigated by a suitable method of calculating the field quantities and the iron loss. There are two particular directions in such laminations, the rolling and cross-rolling direction. The nonlinear magnetic induction vs. magnetic field and power loss vs. magnetic induction relationships measured in those two directions under sinusoidal flux density conditions represent the given material data of the calculation method. The corresponding properties in all other directions have been obtained by interpolation. The finite difference method for two-dimensional geometries was used to calculate the distribution of the magnetic field quantities. A method of estimating the rotational power loss from the distribution of the flux density is described. The results of the calculations for two salient pole machine models under no-load conditions for two different degrees of anisotropy and two different orientations of the rolling direction are reported and compared with the results for isotropic laminations.