Finite-element analysis of linear induction machines

The paper presents a 2-dimensional finite-element analysis applicable to all practical forms of the plate-rotor, flat, linear induction motor. The analysis accounts for longitudinal end effects, finite plate thickness, slotting and discrete winding distribution; it yields detailed space profiles of the flux density and other distributions. The finite-element formulation is presented for the actual slotted model as well as the stator current-sheet representation. The problem of induction in moving media is treated by the extension of previous finite-element machine applications. The formulation results in a set of linear equations which are solved by a modified version of Liebmann's extrapolated process; the solution algorithm employs power mismatch in the machine to indicate accuracy, and nonlinear extrapolation to speed up convergence. The theory is supported by experimental findings.