GB677820A - Improvements in and relating to apparatus for the control of poly-phase rectifiers - Google Patents

Abstract

677,820. Rectifying. GENERAL ELECTRIC CO., Ltd., and FRIEDLANDER, E. S. Nov. 29, 1950 [Nov. 29, 1949], No. 30600/49. Class 38 (ii). A polyphase rectifier system comprises a rectifier transformer having the phases divided into two groups with a saturable interphase transformer interconnecting the two groups, wherein means are provided to control the direct current supplied to the saturating winding in a sense tending to balance the currents in the two groups of phases. Each group of phases is further sub-divided and connected through additional interphase transformers 11, 12 respectively, the centre taps 13, 14 of which are connected to an end of the main winding 15 of the saturable interphase transformer through similar circuits comprising a control winding 16 or 17 of a saturable reactor 18 and an operating winding 19 or 20 of a reversing switch 21. Any disparity between the current in the two groups of phases alters the impedance of the winding 26 of the saturable reactor 18 and so allows the A.C. voltage supplied to the rectifier bridge 23 to vary thereby varying the direct current supplied to the saturating winding 22, the reversing switch 21 being operated such that the sense of the direct current applied to the winding 22 tends to reduce the disparity between the currents flowing in the two halves of the main winding 15. Alternatively the reversing switch may be replaced by a differential or a polarized relay and further the bridge 23 may be replaced by a D.C. generator.