GB630517A - Improvements in and relating to electric converter systems - Google Patents

Abstract

630,517. Rectifying. BRITISH THOMSONHOUSTON CO., Ltd., and BOAG, J. W. May 6, 1947, No. 12256. [Class 38 (ii)] In a mercury arc converter system, an auxiliary rectifier operates in parallel with and on the same number of phases as the main rectifier and is supplied from windings on the main and the interphase transformer of similar connection but of such different voltages that the waveforms obtained approximate to those of a rectifier having three times the number of phases. In a six-phase rectifier giving 18 phase waveforms, the star points of two threephase groups of main transformer secondary windings 1, supplying main anodes at 2, are connected to an interphase transformer 3 which has further windings 4 connected to the star points of two three-phase groups of auxiliary windings on the main transformer, supplying auxiliary anodes at 6. The transformer winding ratios are shown. In a modification, the main secondary and auxiliary windings are of the triple bi-phase type, and the interphase transformer and its further windings are of the three-phase zig-zag connected type, Fig. 2 (not shown). Also described are twelve phase rectifiers giving 36 phase waveforms, having four groups of three star-connected main secondary and auxiliary windings, and a fourphase interphase transformer, Fig. 3 (not shown), or three single-phase interphase transformers, Fig. 4 (not shown). Specification 524,933 is referred to.