Recent advances in the one- and two-dimensional magnetic measurement technique for electrical sheet steel

Abstract

The problems connected with measuring the magnetic properties of electrical sheet steel under the condition of one-dimensional (alternating) and two-dimensional excitation (circular, elliptic, and alternating with rotation of the direction) are surveyed. Regarding the classical case of one-dimensional excitation, the relationships between the SST (single-sheet tester) and Epstein results, and different types of SSTs and their peculiarities are considered. The main arguments in favor of the SST that determines the field strength from the magnetizing current (MC method) in comparison with that using the H procedure are greater simplicity and, therefore, greater reproducibility to be expected in practice. It is also shown that single-yoke construction is inadequate for accurate loss measurements on an electrical steel sheet. Various methods for the determination of rotational power loss are in use. The thermometric methods appear to be less effective than the more convenient and versatile field-sensing methods, which yield more information. Digital procedures are particularly useful for this kind of measurement. New magnetic circuits are under test. Standardization was deemed desirable, but a method for this purpose has not been agreed upon.