J. Sievert

Rotational power losses have been measured on nonoriented grain-oriented silicon steel sheets under different rotational flux conditions. Several methods have been proposed for this purpose. Among these, a method based on the measurement of the field quantities B/sub x/, B/sub y/, H/sub x/, and H/sub y/ seems to be the most convenient as far as the preparation of the test specimen is concerned. In this method, the rotational power loss P/sub r/ is measured as the torque loss generated from the angle of lag between the H-vector and the B-vector caused by the rotating field. The effect of the axis ratio of the rotational flux components and of the inclination angle of field strength relative to the rolling direction of a sample sheet on the rotational power loss was investigated with the method. This loss was compared with the conventional loss, which was shown as the sum of loss P/sub t/ in the x and y directions. Although in the nonoriented steel sheet P/sub t/ (conventional rotational loss) is larger than P/sub r/, in the grain-oriented steel sheet P/sub t/ is smaller than P/sub r/. When the field strength was applied in the nonoriented sheet at a 45 degrees angle from the rolling direction of the sheet, the rotational power loss reached minimum values.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

In a magnetic material, even under an alternating or a two-dimensional rotating magnetic excitation, the magnetic flux is three dimensional (3-D) due to the rotation of magnetic domains. For measurement of 3-D magnetic properties of materials, a novel tester has been developed. The test principle, construction, and calibration of the 3-D magnetic property tester will be presented. Experimental results of B and H loci and core losses with 3-D magnetic fluxes are included and discussed. The system is working and the results are validated.

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.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>