Dynamic behavior of linear induction machines in the heave mode

The performance of linear induction motors subject to velocities normal to the track are calculated both by finite element and Fourier analysis techniques. Results yielded by the two methods for the case of a small traction linear machine are compared. The response to a step increase in air gap of a high speed vehicle levitated and driven by a linear induction machine supplied with constant current is then calculated. The resulting vertical oscillations have a period of about 2.1 s. Electromagnetic damping effects are found to be small; the time constant of decay of the oscillation is found to be about 35 s.