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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 [alpha], [beta] and [gamma] 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)[001] 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 a angle distribution. The calculated inclination angle distribution and the measured [alpha] angle distribution seem to be in good agreement. The calculated normal component of the magnetic flux density reflects the [beta] angle distribution of the real GO steel. It is concluded that the proposed 3-D polycrystal magnetic field analysis is appropriate. Index Terms--Crystal grain shape, finite-element method, GO material, grain orientation, magnetic field analysis, polycrystal.

The authors investigate the effects of double-axis electromagnetic stirring (DAEMS) in continuous casting process, which is composed of a rotational electromagnetic stirrer and a vertical electromagnetic stirrer, using unsteady 3-D hydrodynamic calculation of the molten gallium model. To evaluate the free-surface stability, averaged standard deviation of the free surface is calculated. From the calculation results, it is found that there is an optimum intensity balance between a vertical magnetic stirrer and a rotational magnetic in order to stabilize the free surface. Index Terms--Continuous casting, electromagnetic stirring, free surface, 3-D magnetohydrodynamic calculation.

We propose a new type of magnetic shield structure, in which some closed magnetic paths surround a defined space. Because there are some openings between paths, the freedom in designing and the ease of constructing a shield room are attained. This structure shows better magnetic shield performance than conventional shield structures when openings between magnetic paths, widths of magnetic paths, and weight distribution of magnetic materials are designed appropriately. Index Terms--Electrical steels, magnetic noise, permeability, saturation magnetization, shield coefficient, shield efficiency, soft magnetic materials.

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 31D model are in good agreement. This means that the evaluation by using 2-D model is effective at low frequency. Index Terms--Crossover frequency, electromagnetic force, finite element method (FEM), induction heating, linear induction motor, thin steel plate.

The numerical model following the equivalent magnetic domain method is proposed to calculate the anisotropy of the magnetic properties of electrical steel. The angle difference between magnetic flux density vector and magnetic field vector, which is observed in the measurement data, is clearly expressed by the proposed model. The angles characteristics of stepwise or lamped shape are shown to be consequences of the strong magnetic anisotropic property. Index Terms--Angle difference, anisotropic steel, finite-element method, magnetic field vector, magnetic flux density vector, rotational magnetic field.

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 dearly 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. Index Terms--Finite-element method, iron loss, mechanical stress, motor core, shrink fit, stamping effect.

We present a finite-element method for numerical calculation of electromagnetic fields in silicon steel that takes into account the effect of mechanical stress on the steel's mechanical properties. The effect of the mechanical stress is considered in terms of the magnetic permeability in each element. To evaluate the usefulness of the calculation method, we have applied it to an electric motor under uniform and nonuniform mechanical stress distribution. In case of uniform stress distribution, the iron loss distribution is uniform too. The area of increased iron loss corresponds to the area where the mechanical compressive stress is applied. In case of nonuniform mechanical stress distribution, the magnetic flux flows so as to avoid the mechanical compression stress area. The iron loss has a tendency to increase further under mechanical compressive stress because of the increase of the magnetic flux density in the zone of no mechanical stress and the poorer characteristics of the iron loss as a function of magnetic flux density under mechanical compressive stress. Index Terms--Electrical motor, electromagnetic field calculation, finite-element method, magnetic characteristics, mechanical stress, silicon steel.

The free surface velocity strongly influences steel quality in the casting process, so an accurate calculation method is required. The velocity at the free surface is imparted through the wall of the continuous casting mold in an electromagnetic stirring operation. The wall friction in the solidification calculation model is modeled by the Darcy flow coefficient, which was found to be 0.7 from the operation data, according to the oscillation mark made by the free surface deformation. The calculated velocity is in good agreement with the operational velocity. Index Terms--Continuous casting, Darcy flow, electromagnetic stirring, magnetohydrodynamics, solidification, steel making.

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. Index Terms--Electromagnetic sensor, high responsiveness, level sensor, linkage magnetic flux, magnetic flux density.

It is made clear why the pulse electromagnetic casting (EMC) makes the surface steel quality good from the point of view of fluid dynamics by means of magnetohydrodynamic calculation with shadow method. In order to obtain good surface quality, the free surface profile should follow the pulse electromagnetic force and fluid dynamics are stable and uniform for the rectangular axis. By means of the pulse mode in EMC operation, the fluid dynamics make stable and uniform the unstable flow in continuous EMC operation and the free surface profile is maintained as convex. Index Terms--Continuous casting, electromagnetic application, free surface, magnetohydrodynamic, magnetohydrodynamic calculation, pulse electromagnetic casting (EMC), shadow method, stability.