GB409698A - Improvements in and relating to electric converting apparatus - Google Patents

Abstract

409,698. Converting. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Willis, C. H. ; 184, Prospect Avenue, Princeton, New Jersey, U.S.A.) Sept. 30, 1932, No. 27215. Convention date, Oct. 1, 1931. [Class 38 (ii).] Apparatus for transmitting energy in either direction between a D.C. circuit 10 and a singlephase A.C. circuit 11 under any desired power factor conditions comprises a transformer 12 and a pair of electric valves 15, 16 interconnecting the circuits, and a condenser 20 connected between the cathodes of the valves in series relationship with a portion of the load current of the apparatus, the potential drop of the condenser being available for opposing the E.M.F. of the transformer winding for commutating the current between the valves at times when it would otherwise be impossible. The valves are controlled by applying voltages to their grids from a transformer 21 energized from a phase-shifting transformer 23. In the arrangement shown, the condenser 20 is connected across a winding 19, the mid-point of. which is connected to one side of the D.C. circuit. The usual commutating condenser 18 is connected across the anodes of the valves. For a full wave converting apparatus, the upper direct current terminal 10 may be connected to the ends of the transformer winding 14 through an additional pair of valves, with a commutating winding and condenser connected across the cathodes in a similar manner to the winding 19 and condenser 20.