Control device for a direct current semiconductor regulator

An inductive load 1, more specifically a direct current motor, is fed by a direct current source through a semiconductor regulator which contains two parallel switching controllable semiconductor rectifier elements with identical conduction direction which in turn are in series with a respective one-half of center tapped output autotransformer. Parallel to the semiconductor regulator is an additional and identical semiconductor regulator. The center tap points of both semiconductor regulator autotransformers are connected with the terminals of a third output autotransformer which is similarly center tapped, whereby the center tap point of the third output autotransformer is connected to a terminal (+) of the inductive load. The control assembly is made in such a manner that it produces clock frequency signals with identical control levels for both semiconductor rectifier elements; however, these signals for the two parallel switching arrangements are, electrically offset by 90 degrees. In this way, it is possible to operate the motor in RPM ranges where a minimum of ripple current is obtainable.