Apparatus for supplying direct current from a three-phase alternating-current source

Claim 1

Apparatus for supplying from a three-phase A.C. source direct current with a V-I characteristic that has an approximately flat curve, to achieve higher D.C. output voltages even at lower D.C. output currents, comprising: a three-phase A.C. transformer (3); a six-pulse, three-phase half-wave rectifier unit (4) including rectifying elements, as well as input (27 to 32) and output (1, 2) terminals, the latter for feeding a D.C. load; said transformer including a strictly symmetrical iron core constituted by a plurality of yokes (8 to 10) about phase legs (5 to 7) which latter are so arranged that one end of each leg is connected by means of separate ones of said yokes to respective other ends each of two other legs, while the respective other ends of said legs are all interconnected; individual primary coils (11.., 12.., 13..) provided each about at least one of said phase legs and having respective input terminals (14 to 16) for connection to the three-phase A.C. source; and secondary yoke coils (21 to 26) arranged in pairs (21/22, 23/24, 25/26) about said yokes, wherein respective one ends of said yoke coils are joined and the joints all lead to one (1) of said rectifier output terminals, while the other ends of said yoke coils are individually connected to said rectifier input terminals.