Three-phase induction-motor control using static-frequency doublers

A simply constructed device, combining the benefits of static switching and static power modulation, which may be employed to control a standard 3-phase induction motor is described. Inherent reduced voltage starting and reversal without switching of the main supply lines are features of the device. Methods of performance prediction sufficiently accurate for system design requirements are given. Such divergencies as exist between predicted and realized performance for an experimental system consisting of device and standard motor are explained.