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A cord pattern, where magnetic flux density distribution is separated into strong and weak parts like the magnetic domain, appears in magnetic anisotropic numerical calculation results. It is obtained in the strong magnetic anisotropic material. The same cord patterns are also found in the measured magnetic domain structure. Fractal structure of the cord patterns is also observed through the partial enlargement of the calculated cord patterns. The similar cord pattern resembled to the magnetically numerical calculation is also obtained in the structural numerical analysis of the metal crystal level. The fractal cord patterns emerge as a fundamental characteristic of anisotropy in numerical calculation and in physical observations. [ABSTRACT FROM PUBLISHER]

The 3-D magnetic field numerical analysis of a full-scale magnetic shielding room is advantageously performed by using the equivalent B--H method. In the proposed numerical method, the magnetic anisotropy and the nonlinearity due to material magnetic saturation are taken into account, by directly introducing the magnetization characteristics of the considered materials. An equivalent element, which substitutes the plural finite elements having different material properties for a homogeneous one, is introduced to reduce the number of unknowns. When the equivalent B--H method is applied to a full-scale magnetic shielding room (length 5.8 m, width 3.3 m, height 3.3 m), the measured leakage magnetic flux density distribution is found to be in good agreement with the calculated one, proving the reliability of the proposed approach, which can be adopted in many large-scale electromagnetic field problems. [ABSTRACT FROM AUTHOR]

The magnetic field analysis results on grain-oriented silicon steel sheet and nongrain-oriented silicon steel sheet by the isotropic method, the two-axis isotropic method, the two-axis anisotropic method, the ç anisotropic method, and the θHB anisotropic method, which are 2-D magnetic analysis methods, are compared. In analyzing the magnetic field in the isotropic material, the isotropic method is more appropriate than the two-axis isotropic method. For the anisotropic material in which the magnetic flux density is much less than saturation magnetic flux density, the two-axis anisotropic method is more preferable than the ç anisotropic method, because the result of the two-axis anisotropic method is similar to that of the θHB anisotropic method. However, for the analysis in high magnetic flux density near the saturation magnetic flux density, the ç anisotropic method is more suitable than the two-axis anisotropic method. [ABSTRACT FROM AUTHOR]

A linear induction motor to be able to achieve induction heating and tension in thin steel sheet treatment process is researched. The major problems in the application of the linear induction motor are meandering of thin steel sheet by the electromagnetic force in the normal direction, the heating characteristic, and the evaluation of the thrust force as a tension. As a result of the investigation of the frequency characteristic by means of electromagnetic FEM calculation, it is confirmed that the electromagnetic force in the normal direction which consists of repelling force caused by the magnetization and repulsive force caused by Lorentz force becomes almost zero at the crossover frequency. In this frequency, the temperature of the steel sheet at the front and back have almost the same distribution. Since the tension value converted from the thrust force is about 10% of experiment equipment, the linear induction motor is also useful for the auxiliary function of the tension roll. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 168(2): 38–47, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20845 [ABSTRACT FROM AUTHOR]

The 3-D polycrystal magnetic field analysis method by means of coordinate transformation is proposed. The local coordinates are fixed in each crystal grain and the global coordinates are defined in the polycrystal steel. Though it is assumed that each crystal grain has the same magnetized characteristics as those of a single crystal grain, the crystal grain shape and its orientations of α, β, and γ angles are taken into account. When the proposed model is applied to the real grain oriented (GO) steel with 56 crystal grains in 80-mm x 80-mm, and with 0.35-mm thickness, the calculation results are compared with the grain orientations measured by X-ray diffraction. The GO steel has a higher degree of (110)1001] texture with about 3% silicon. The calculated results of higher magnetic flux density part and lower magnetic flux density part in the real GO steel are explained by the α angle distribution. The calculated inclination angle distribution and the measured α angle distribution seem to be in good agreement. The calculated normal component of the magnetic flux density reflects the β angle distribution of the real GO steel. It is concluded that the proposed 3-D polycrystal magnetic field analysis is appropriate. [ABSTRACT FROM AUTHOR]

Basic characteristic of electromagnetic force in induction heating application of single-sided linear induction motor (SLIM) which uses electromagnetic AC field is investigated by means of 2-D and 3-D numerical electromagnetic FEM calculation. The electromagnetic force in the normal direction consists of the attractive force caused by magnetization and the repelling force caused by Lorentz force. Although the normal force is canceled by them and becomes zero at crossover frequency, the value is different, which is 2 kHz in 2-D model and is 5 kHz in 3-D one respectively. Since 2-D model expresses only center section of 3-D model and can not express the complex behavior of the eddy current in the whole model, the repelling force caused by Lorentz force is considered to be overestimated when the electromagnetic force value of 2-D model is converted into 3-D one. As a result, the crossover frequency of 3-D model becomes large in comparison with 2-D one. This means that an evaluation by using 3-D model is demanded in order to correctly evaluate the crossover frequency. On the other hand, at low frequency in which the attractive force caused by magnetization becomes dominant, the normal forces of the 2-D and 3-D model are in good agreement. This means that the evaluation by using 2-D model is effective at low frequency. [ABSTRACT FROM AUTHOR]

We describe a method to analyze the effects of shrink fitting and stamping on the mechanical stress distribution and iron loss in motor cores. Shrink fitting and stamping are important processes in manufacture of motor cores from electrical steel. The mechanical stress distribution is evaluated by a structural finite-element method, and the iron loss is evaluated by combined analysis of the electromagnetic field (by a finite-element method) and mechanical stress. The method clearly shows that the iron loss becomes larger as the width of the shrink fit increases, an effect borne out by experiment. In regard to the effect of stamping, calculation results again agree well with experimental data. [ABSTRACT FROM AUTHOR]

A high-response inductive electromagnetic sensor can be made by arranging a conductive and/or magnetic material between the primary coil and the secondary coil. Compared with the conventional inductive electromagnetic sensor, the new sensor has a larger responsivity index (used here to evaluate its characteristics), though it also has a smaller induced voltage at the secondary coil. [ABSTRACT FROM AUTHOR]

We evaluate the verification of combined system ac and dc electromagnetic field using magneto hydrodynamic calculation. For the effect of level magnetic flow (LMF) that gives the molten steel the breaking force in proportion to the velocity using dc magnetic field, we confirm that the velocity at meniscus becomes stabilized in the time domain and the space domain, though the conventional dual electromagnetic stirring is difficult to realize the stabilization of the meniscus flow dynamics. In the proposed process, it is also confirmed that the velocity at the inner mold is constant in spite of dc magnetic field. [ABSTRACT FROM AUTHOR]