GB403814A - Improvements in and relating to the conversion of current - Google Patents

Abstract

403,814. Discharge devices. AKT.- GES. BROWN, BOVERI, ET CIE, Baden, Switzerland. Jan. 13, 1933, No. 1178. Gonvention date, Jan. 22, 1932. [Class 39 (i).] Gaseous discharge tubes in which all the main electrodes are made emissive and are continuously indirectly heated so as to be capable of functioning either as anodes or cathodes, are employed in a rectifier or inverter system in order that power may be transmitted in either direction without necessitating a change over of connections on the D.C. side. Fig. 2, shows a single phase arrangement in which a pair of solid emissive electrodes A, B are associated with a supply transformer T L which has an additional winding T G for energizing a grid G. By means of a change-over switch the grid may be given a potential in phase with the potential of either of the two main electrodes at will, thus determining which electrode shall operate as anode. The grid potential may be supplied through resistances, inductances or condensers c. Fig. 3 shows the corresponding polyphase arrangement with the grid potentials supplied through a phase-shifting transformer T G for regulation. The control voltage may be applied to the grids through a glow discharge tube which becomes conductive at a predetermined voltage. As an alternative to grid control, ignition impulses may be applied between the main electrodes as described in Specification 400,772, [Group XXXV]. The Specification as open to inspection under Sect. 91 comprises also a further polyphase arrangement Fig. 4 (Cancelled) in which a mercury electrode B is used in conjunction with three solid emissive electrodes A. This subject-matter does not appear in the Specification as accepted.