Power-factor improvement in linear induction motors

Linear induction motors have long been known to have low power factor, not merely on account of the usually large airgaps that they require, but also because a considerable proportion of the reactive VA arises as the result of the transient phenomena associated with the front and back edges of the primary. It is possible to reverse the effect of these transients by a novel arrangement of stator windings, so that leading reactive VAs are generated which offset the effects of magnetisng current and leakage reactance. Test results for a traction-type motor for a speed of 22 m/s (80 km/h) are given which show a power factor of 0.8 at the peak efficiency point of 75%