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This study mainly investigates the key secondary parameter effecting on transverse force and the changing trend of its components, which include the repulsive and restoring components. Firstly, considering the transverse displacements, skin effect and end effects, the full 3D finite element models of the single‐sided linear induction motor (SLIM) are built. Secondly, when the width of the secondary varies, the transverse force and its two components are presented and analysed. At the same time, the air‐gap flux densities and the eddy currents along the transverse directions are calculated. Then when the topological transform of aluminium plate (e.g. Al‐cap type) and back‐iron plate (e.g. laminated type) are applied, the transverse force and its components are given. Finally, the transverse force, thrust and efficiencies are compared in the SLIMs with different secondaries as well as some experiments are given. It is shown that the width of the secondary is the main factor influencing the transverse force. [ABSTRACT FROM AUTHOR]

Due to the influence of the switch and rail equipment, the secondary cannot be laid continuously in the linear metro. An equivalent circuit of the single‐sided linear induction motor (SLIM) is presented to consider the discontinuity of the secondary plate, and the electromagnetic characteristics of the motor with the discontinuous secondary are obtained. First, the analysis model of the SLIM considering the missing part of the secondary plate is proposed. Second, the variation of the length of the coupled region between the primary and secondary are considered by the method of approximate linearisation to correct the parameters including the primary leakage inductance, magnetising inductance, secondary resistance and secondary leakage inductance. Third, three typical cases of the relative position between the primary and discontinuous secondary are analysed, and the equivalent circuit in each case is deduced according to the distribution of the secondary magnetic motive force and air gap flux density. Then, two coefficients considering the longitudinal end effect, on the basis of the corrected secondary time constant, are proposed to correct the magnetising inductance and secondary resistance. Finally, the analytical results are verified by the results measured on the test rig of an SLIM. [ABSTRACT FROM AUTHOR]

The secondary is an important design factor of single‐sided linear induction motors (SLIMs), as well as has influence on the cost and performance of SLIMs. In this study, the cap‐lamination secondary is designed and relations of the secondary parameter and performance of SLIMs are calculated. First, the aluminium (Al) cap and lamination back iron of the cap‐lamination secondary are designed and discussed. Then, improvements in performance caused by two potentially significant effects of the cap‐lamination secondary, i.e. the thick cap edge and lamination, are identified. Second, a flat‐solid secondary is applied and two SLIMs, which are the same primary and two different secondaries, are calculated by three‐dimensional finite‐element method. Eddy current densities in the Al and back iron plate, which are two parts of the secondary, are analysed. Owing to different transverse edge effects, variations of the air‐gap flux density are calculated with different secondaries. Finally, the numerical results of the thrust, power factor, and efficiency are experimentally validated by measurements on test rig of SLIMs. It shows that the SLIM with cap‐lamination secondary, which has higher performance, is affected greatly by the conductor structure of the secondary and the lamination of the iron back plate. [ABSTRACT FROM AUTHOR]

Electromagnetic variations of the single‐sided linear induction motor (SLIM) are calculated by three‐dimensional (3D) finite‐element method (FEM) when the primary is displaced sideways from a symmetrical position. For geometrical and electrical asymmetry, a full 3D model, which considering the longitudinal and transverse end effects, overhangs of the primary windings and secondary, as well as lateral displacement, is developed. Apart from the thrust and vertical force, lateral force is produced when the transverse asymmetry occurred. Hence, the calculation equation of thrust, vertical and lateral forces in each element of the 3D FEM model and boundary conditions are presented. Air‐gap flux densities along the longitudinal and transverse directions with different lateral displacements are obtained, as well as the distortion coefficients of the air‐gap flux density is proposed. Corresponding induced currents in the secondary are predicted. Finally, the variations of the thrust, vertical and lateral forces are experimentally validated by measurements on reciprocal power‐fed test rig. It shows that the flux in between overhangs of the primary winding and secondary has great effect on the lateral force, the thrust and vertical force decrease with the increase of the lateral displacement. [ABSTRACT FROM AUTHOR]