GB820625A - Power transformers for mechanical current converters - Google Patents

Abstract

820,625. Converting. LICENTIA PATENTVERWALTUNGS-G.m.b.H. Dec. 2, 1955 [Dec. 2, 1954], No. 34541/55. Class 38 (2). A power transformer capable of carrying more than 1000 amps. for supplying mechanical contact converters in six phase bridge connection having switching chokes, has secondary windings comprising at least three open zig-zag windings each consisting of at least two portions developing voltages equal in value and phase displaced by 120 degrees. There may be two groups of such windings fed from delta and star connected primary windings reapectively, Figs. 1a, 1b, to give 30 degrees phase change between output voltages. Tappings on the primary windings can then give voltage variation without phase change (Figs. 2a, 2b, not shown). When each secondary winding comprises two parts from each of two phases, a series, Fig. 3a, to parallel, Fig. 3b, change in connections is possible to halve the output voltage. A corresponding reconnection from the arrangement of Fig. 1a to a known arrangement (Fig. 4b, not shown) gives a 1: #3 voltage change. Alternatively, the secondary windings may be reconnected into the known arrangement of three open diametrical windings and a delta connected tertiary winding (Fig. 5b, not shown).