Non-saturating ac/dc power supply

Claim 1

An AC/DC power supply comprising: a. a polyphase AC power source including a main transformer having primary and secondary windings, the secondary windings being star connected and having a common neutral terminal; b. a polyphase autotransformer including star connected singlephase autotransformers, each single-phase autotransformer having one terminal connected to each secondary winding of said polyphase AC Power source and a common neutral terminal connected to the common neutral terminal of said secondary windings of said polyphase AC power source; c. simultaneously movable tap connections located one on each single-phase autotransformer, said tap connections dividing each single-phase autotransformer into two sections of varying ratio for providing a variable AC power supply; and d. similarly polarized diodes connected at one terminal to each tap connection and at the other terminal to a common output terminal for providing a variable DC power supply between said output terminal and said common neutral terminal, each singlephase autotransformer being connected to each secondary winding of said polyphase source through a line connection having a certain resistance, and wherein the sum of said line resistance and the internal resistance of the secondary winding of said polyphase source for each phase is appreciable as compared to the resistance of each single-phase autotransformer, and further comprising a compensating resistor connected in series with one of the sections of each single-phase autotransformer for causing the DC current flowing through each diode to divide itself proportionally between each section of each single-phase autotransformer at each tap connection thus causing the ampereturns of the two sections to oppose each other without creating any appreciable DC saturatioN in the polyphase autotransformer.