Theories of linear induction motors with completely filled and half filled endslots

New theories for linear induction motors (l.i.m.s) with completely filled and half-filled primary endslots are presented. End effects due both to the discrete nature of the windings and the finite iron length are taken into account by formulating the boundary-value problem on the basis of the m.m.f. distribution and representing the m.m.f. wave packets of the stator windings by Fourier integrals. The paper reveals that the stationary pulsating m.m.f. wave, which appears in the air gap of an l.i.m. with completely filled slots owing to the finite length of the stator iron core, has a very adverse influence on the motor performance, a phenomenon which has not been previously discussed. A new theory of compensation is proposed to improve the performance of this type of motor. The paper also shows that idealised theories of the l.i.m. are very special cases of those given here. A simplified formulation of the boundary-value problem of the l.i.m., taking into account the end effects due both to the discrete nature of the windings and the finite stator iron length, is also given. The results are compared with published experimental data, and with those obtained from an idealised l.i.m. excited by a sinusoidally distributed current sheet of the same magnitude.