GB365845A - Improvements in or relating to the derivation of uni-directional electric currents from an alternating source - Google Patents

Abstract

365,845. Rectifying alternating current ; charging batteries. DEAN, F. L. W., 21, Bartlett's Buildings, Holborn Circus, London. Feb. 25, 1931, No. 5962. [Classes 38 (ii) and 38 (iv).] In an arrangement for supplying wireless sets &c. from mains in which a column of static contact rectifiers of the metallic oxide type is used for high tension supply, provision is made whereby one or a small group of the rectifier elements may be used for supplying low tension current for battery charging for example. Fig. 2 shows one arrangement in which switching provision is made whereby with one setting the transformer secondary 25 supplies high tension current through the whole column of rectifying elements 21 whilst a battery 33 supplies low tension current. In the alternative setting, the high tension supply is interrupted, and the battery is charged from the transformer secondary 26 through the end pair of rectifying elements 22, 23. In a modification (Fig. 3 not shown), two separate transformers are used and the two rectifying elements at opposite ends of the column are brought into parallel relation when battery charging connections are established. In a further arrangement, Fig. 5, a pair of condensers 83, 84 are used in conjunction with a midpoint tapping on the rectifier column to provide a voltage doubling circuit fed by the whole of the transformer secondary 86, 87 when the high tension supply connections are established by raising switches 92, 93, 94 to the upper positions. With the switches in the lower positions, the part 87 of the transformer secondary feeds the battery charging circuit through the end rectifying elements of the upper half of the column. In a further arrangement, Fig. 6 (not shown), a separate transformer is provided for high tension supply, and the connections are modified to bring the rectifying elements at opposite ends of the column into use for battery-charging. In another arrangement, Fig. 4 (not shown) in which the voltage doubling circuit is employed, the arrangement is such that either of the two rectifying elements at the centre of the column may be used at will for low tension supply.