GB654210A - Improvements in or relating to electrical transmission systems - Google Patents

Abstract

654,210. Unattended repeaters. WESTERN ELECTRIC CO., Inc. Nov. 2, 1948, No. 28413. Convention date, Nov. 28, 1947. Drawings to Specification. [Class 40 (iv)] [Also in Groups XL (a) and XL (c)] In an electrical transmission system such as a submarine system the cathode energizing circuits of valves each comprise a pair of heating elements connected in parallel and a resistance R 3 , the ohmic value of which is such that the power dissipation of the heaters is maintained constant irrespective of the failure of one of the heating elements and is determined by the formula where Eo and Io are the voltage across and total current through the heating elements respectively for normal operation and Eo<SP>1</SP> and Io<SP>1</SP> are the values of voltage and current necessary to produce the same heating effect with a single element, i.e. when one element is ruptured. The Specification includes a mathematical analysis of circuits supplied from a constant current source including both linear and norilinear resistances in parallel with the heaters and shows by reference to a graph, Fig. 4 (not shown), the requirements of series resistances to give the same result when the circuit is connected to a constant voltage source. Application of the invention to unattended repeaters in a submarine cable system is described with reference to Fig. 7 (not shown). Specifications 426,547 and 563,099 are referred to.