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Different parts of the cylindrical coils are exposed to electromagnetic forces due to electric current flowing through it. These forces can deform the coil in axial and radial directions in abnormal operating conditions. So, in design process of cylindrical coils in many magnetic devices, mechanical stresses exerted on different parts of these kinds of coils should be determined. In this paper, analytical expressions for the forces in axial direction are derived in order to calculate the forces exerted on different parts of the cylindrical coils. In order to evaluate the precision of the method, the finite element method (FEM) is used and the results obtained by FEM are compared with the results of the analytical equations. Results obtained by finite element analysis confirm the analytical method. Due to inherent difficulties in calculation of the forces in radial direction, distribution of the latter on the coil body is calculated by FEM. The results show that the outer turns of the coil in two axial ends are exposed to the largest axial tension, while radial stresses are largest in the middle parts of the coil. In this paper, the calculations focus on the cylindrical coils; however, the method can be used for the calculation of the magnetic force distribu-tion on different parts of spiral coils, disc coils and any type of air-cored coils with different sizes. [ABSTRACT FROM AUTHOR]

Single-sided linear induction motors (SLIMs) have been widely used in industry, especially in high-speed transportation systems. The performance of the SLIMs is considerably affected by the characteristics of its secondary back-iron. The conductivity of the iron used as well as its magnetic permeability influence the performance of the machine, while the magnetic permeability itself is affected by the input frequency of the SLIM. In this paper, using Dancan equivalent circuit model and considering all phenomena involved in the single-sided linear induction motor, the outputs of the motor such as efficiency, power factor, normal force and output thrust are analytically derived. Then, the effects of the input frequency on depth of the field penetr-ation and saturation level of the secondary back-iron as well as the SLIM outputs are analyzed. To confirm the analytical results, 2D time-stepping finite element method is employed. The results are in good agreement with each other confirming the analytical analysis. [ABSTRACT FROM AUTHOR]