GB560901A - Improvements in and relating to electric valve circuits for interchanging power between alternating current and direct current circuits - Google Patents

Abstract

560,901. Converting. BRITISH THOMSON-HOUSTON CO., Ltd. July 21, 1942, No. 10147. Convention date, July 22, 1941. [Class 38 (ii)] In an arrangement for interchanging power between d.c. and a.c. circuits 2, 1 and comprising a plurality of sequentiallyconducting electric discharge devices 8, 9 with controlled ignition, the ignition current to each discharge device is interrupted in response to cessation of current in the anode circuit of the preceding discharge device. In the arrangement of Fig. 1, phase - controlled ignition current is supplied to immersion-igniter electrodes 12 from the two secondaries of a transformer 13, but the ignition circuit of each valve is completed only through the anodecathode path of the other valve. A modification including transfer electrodes is described with reference to Fig. 2 (not shown). In the arrangement of Fig. 3, the ignition impulses are supplied through grid - controlled auxiliary valves 32, 34, and commutating condensers 40, 41 are connected between the anodes of each auxiliary valve and the opposite main valve whereby each auxiliary valve is rendered non- conductive immediately the main valve other than that whose ignition it controls ceases to conduct. A three-phase version of this arrangement is described with reference to Fig. 5 (not shown).