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This paper proposes the identification of the B-H curve of anisotropic magnetic laminations in the direction normal to the sheet surface. An automated procedure for linking an identification algorithm implemented in a Matlab environment with a commercial finite-element code Opera for 3-D magnetic field analysis has been used. In particular, an optimization procedure is proposed, where the computation time is reduced by adjusting the refinement of the FEM mesh. The use of a multiprocessor computer allowed to perform parallel computations and to realize the calculation in a reasonable time. The finite element mesh density is changed during operation of the procedure depending on the level of magnetic flux density difference between calculation and measurements.

This paper proposes a mixed experimental/numerical technique to characterize magnetic laminations in the direction normal to their surface. The principle, which uses static excitation to avoid errors caused by eddy currents, is explained and a specific test bench is proposed. Measurements of the magnetic flux density are made using a sensor being moved in and out of the air gap and are supplemented by 3-D numerical modeling where the final characteristic is obtained through iterations until the computed and measured values agree within assumed tolerance. Comparisons with previously published approach based on an analytical model are made and specific properties of the characteristic of anisotropic laminations are discussed.

The paper develops an efficient computational method for establishing equivalent characteristics of magnetic joints of transformer cores, with special emphasis on step-lap design. By introducing an equivalent material, the method allows the real three-dimensional structure of the laminated thin sheets to be treated computationally as a two-dimensional problem and enables comparative analysis of designs. The characteristics of the equivalent material are established by minimizing the magnetic energy of the system. To verify the proposed approach, a series of experiments have been conducted. First, the anisotropic characteristics of the step-lap were established, and then space components of the flux density at specified positions measured. This enabled detailed analysis of the flux distribution in the step-lap region, in particular the way in which the flux travels between the laminations close to the air-gap steps. Encouraging correlation between the homogenized 2-D model and experiment has been observed.

This paper presents results of force and torque calculations using Finite Difference Method in integral form as well as Finite Element Method with Hermitian Elements. Forces and torques have been calculated by the Maxwell stress tensor and the virtual work principle. Calculation results for reversible electromechanical converters and stepping motors have been considered giving some practical conclusions about advantages of the different methods. >