Patent GB-808999-A (GB)
Title: Metal rectifier stack assemblies
Inventor: ROBINSON THOMAS PHILIP
IPC: H01L25/07
Filed: 1957-02-15
Abstract: 808,999. Rectifying. STANDARD TELEPHONES & CABLES Ltd. Feb. 15, 1957, No. 5215/57. Class 38 (2). [Also in Group XXXVI] A rectifier assembly is characterized in that it comprises a plurality of equal stacks of rectifier plates in coordinate array with parallel axes, minor input and minor output busbars which are parallel to the plates and at right angles to one another being interleaved between the plates, and major input and major output bus-bars, at right angles to their respective minor bus-bars connect said minor bus-bars in parallel. As shown, Fig. 1, for the full-wave rectification of a 3-phase A.C. supply, each phase is supplied to one of three similar groups of stacks of selenium rectifier plates by means of two major input bus-bars 8, 9, to each of which are fixed four minor input bus-bars 10-13 drilled to accommodate insulated spindles 26 on which are located the plates and minor output bus-bars 14-19 of negative polarity and 21-24 of positive polarity, which are joined to the major output bus-bars 20, 20A and 25, 25A, respectively. The major output bus-bars of the same polarity may be connected as by conductors 27, 28, Fig. 4, in which the heavy lines indicate the counter-electrode faces of the plates, shows the disposition of the plates between the input and output busbars, adjacent plates and bus-bars of each stack being separated by conductive spacing washers (not shown). If one group of stacks and the input bus-bars thereto are removed, the assembly will give full-wave rectification of a single-phase supply. In the embodiment shown in Fig. 9, for half-wave rectification of a star or interconnected star secondary 3-phase supply, only positive bus-bars are provided and the negative terminal of the D.C. output is connected to the neutral point of the A.C. supply. If the rectifier plates are reversed, the output bus-bars become negative and the neutral point of the supply feeds the positive D.C. terminal. A similar assembly is used for full-wave rectification of a 6-phase diametric supply, or of a 6- phase double-star connected supply with an interphase transformer, one phase supplying each tier of rectifier stacks, and the positive (or negative) of the D.C. output being taken from the neutral point of the supply or the mid-point of the interphase transformer, as the case may be. For full-wave rectification of a single phase supply derived from the centre-tapped secondary of a transformer, the Fig. 9 arrangement (or its converse) has one group of stacks and input bus-bars thereto removed, the outer points of the transformer secondary being connected to the remaining two groups and the negative (or positive) D.C. output being derived from the mid-point of the transformer. Copper, aluminium, &c., may be used for the bus-bars, fixing being accomplished by bolting, sweating, riveting, hard soldering, or a combination thereof, as appropriate. Each plate shown may be replaced by a plurality of plates in series. If plates whose direction of forward conductivity is opposite that of selenium are used, polarities will be reversed throughout.