Abstract: Apparatus for supplying direct current from a three-phase alternating-current source, comprising a three-phase A.C. transformer; one end of each transformer phase leg being connected via separate yokes to corresponding ends of the other two phase legs, while the respective other ends are interconnected via a common yoke. Individual leg coils are provided on the legs of the thus formed core, while pairs of yoke coils are arranged on the separate yokes. Respective ends of all the yoke coils are interconnected in pairs, and their other ends are connected to input terminals of a six-pulse, three-phase half-wave rectifier unit.