Patent GB-246909-A (GB)
Title: Improvements in and relating to apparatus for the conversion of alternating current into high tension continuous current
IPC: H02M7/10
Filed: 1924-11-03
Abstract: 246,909. Dessauer, F., Lorenz, E., and Brenzinger, M. Nov. 3, 1924. Vacuum or low-pressure apparatus, arrangements of; condensers.-In apparatus for converting alternating current into high tension direct current in which a number of similar rectifying units comprising transformers, condensers, and valves are connected in series or series-parallel, the units are so constructed as to be transportable and interchangeable bodily, and the several parts of one unit are made interchangeable with those of the other units. Fig. 1 shows an arrangement in which each unit comprises a pair of condensers 4, 4<1> charged through valves 3, 3<1> from transformers T, T<1>, T<2> the primaries of which are supplied from the alternating current source and the several units being connected in series to the direct current output terminals P, P<1>. The mid points of the windings of the transformer T, its core, and the point of connection of the condensers 4, 4<1> are interconnected by a lead 6, and the outer rectifying units B. C, D, E which have a greater potential difference with respect to the supply circuit than the unit A may be supplied through auxiliary transformers V. When the installation comprises three units only, auxiliary transformers may be dispensed with, the necessary additional insulation of the outer units being provided between the windings of the main trans. formers and the units being insulated from earth. In a further arrangement, the units, one of which is earthed, are supplied from a common highly insulated auxiliary transformer. Fig. 4 shows an alternative arrangement of rectifying unit comprising valves V<1> - - V<4> supplied from a transformer 16 and connected to the direct current output terminals through condensers k<1>, k<2>. Fig. 5 shows another form of rectifying unit which may be employed in which the transformer is divided into two sections P, P<1> arranged to supply direct current at the terminals Y through the valves 31 - - 34 and condensers C. Where the cathodes of the valves, are at the same potential as the secondary winding through direct connection therewith, heating of such cathodes may be effected by additional windings such as Z, Fig. 1, and 22, Fig. 4, on the end of the secondary, whilst in the case of valves the cathodes of which differ in potential from the secondary winding, heating is effected by a separate winding such as Z<1>, Fig. 1. In order to avoid inequalities in heating of the cathodes due to the different effect of leakage fields on differently situated heating windings, these windings are given different widths and depths according to their disposition on the core. The transformer cores are constructed to permit ready replacement of damaged windings; the valves are provided with screwed sockets at their lower ends and resilient contacts at their upper ends to facilitate replacement, whilst the condensers are provided with high resistance leaks or with electromagnetically controlled short circuiting switches to effect their discharge when the installation is shut down.