GB315284A - Improvements relating to apparatus for rectifying alternating currents - Google Patents

Abstract

315,284. Stevens, S. A., and Westing- house Brake &. Saxby Signal Co., Ltd. April 4, 1928. S t a t i c contact rectifiers, arrangements of. - An arrangement for supplying two or more load circuits with direct current at different voltages from an alternating current supply source comprises two or more bridge circuits each comprising a pair of opposed rectifying elements, these elements conducting current in a direction towards their common point of connection in the case of one pair 2, 3, and away from their common point of connection in the case of the other pair 4, 5, the common points of connection together with the neutral point of the supply source, for example the mid-point 11 of secondary of the supply transformer, being connected to the load circuit terminals 8, 9, 10. In the arrangement according to Fig. 2, a voltage corresponding to the full voltage of the secondary of the transformer is available at terminals 8, 9 for supplying current to the plate circuit of a valve 17 of a wireless receiver, whilst a voltage corresponding to half the voltage of the transformer secondary is available at terminals 8, 9 for supplying current to the plate circuit of the valve 15. In the modification shown in Fig. 3, the two bridge circuits are connected across different proportions of the transformer secondary so that different voltages are available between the terminals 8, 10, and 9, 10 respectively, the neutral lead 12 being in this case common to the two load circuits. Arrangements involving combinations of those shown in Figs. 2 and 3 and additional bridge circuits fed by an additional secondary winding on the transformer in order that a wider range of anode voltages as well as grid-biasing voltages may be available are also described. Fig. 6 shows an arrangement adapted for use on polyphase supply systems, the rectifiers in this case being arranged in two groups 47, 48 oppositely connected with respect to their common points of connection 49, 50 and connected to a threephase transformer secondary 43. The neutral point 51 and the points 49, 50 are connected to the output terminals 52, 53, 54 so that voltages corresponding to that of each phase winding are available between the terminal 54 and either of the terminals 52, 53, whilst a voltage corresponding to that between phases is available between terminals 52, 53.