GB725223A - Improvements in or relating to magnetic amplifiers - Google Patents

Abstract

725,223. Magnetic amplifiers. WESTING- HOUSE ELECTRIC INTERNATIONAL CO. June 1, 1953, No. 15159/53. Class 40 (4). In a push-pull magnetic amplifier with autoexcitation, a variable control voltage and a constant biasing voltage are both applied to the control windings. As shown in Fig. 1, the amplifier may comprise separate cores for each load winding 20, 22, 24, 26 and control winding 56, 58, 60, 62. Auto-excitation of each core is established by rectifiers 28, 30, 32, 34, while further rectifiers 36, 38 and 46, 48 provide D.C. outputs to the coils 40, 43 of a differential relay. The control voltage is applied at terminals 68, 69 to impedances 66, 67 and to the series-connected control windings which are so arranged that the windings 56, 58 and 60, 62 respectively augment and oppose the auto-excitation fluxes in the corresponding cores. A bias voltage connected across terminals 70, 72 effects a constant augmentation of all the core fluxes, and the amplifier outputs are balanced only for a particular value of control current. In a modification, Fig. 2, the load windings are energized from a centre-tapped transformer 110 so that rectifiers 100, 102, 104, 106 only are required to provide both auto-excitation and D.C. outputs. Use may also be made of two threelimbed cores, Fig. 3 (not shown), in place of the separate cores shown in Fig. 1.