GB635675A - Improvements in lightning arresters - Google Patents

Abstract

635,675. Protective arrangements. FORGES ET ATELIERS DE CONSTRUCTIONS ELECTRIQUES DE JEUMONT, and TEZNER, S. March 24, 1948, No. 8613. Convention date, March 26, 1947. [Class 38 (iv)] Lightning arresters for medium and high voltages comprising seriesconnected spark - gaps located alternately on opposite sides of the axis and voltage dependent resistances, have elements arranged in parallel connection with each of the spark-gaps which constitute both capacitances, whereby the voltage distribution over the gaps is maintained during normal lowfrequency conditions, and resistances, which in association with the capacitances to earth determine the distribution during highfrequency or steep wavefront conditions. These elements are constituted by sectors 18, 19 secured to metal plates carrying the gap electrodes 13, the sectors being of semi-conductive material having relatively, high resistances, such as a synthetic resin in which conductive material is dispersed. The metal plates are separated by insulating spacers 10 and the spark-gap electrodes, of which one of each pair is adjustable, have horn-like extensions and are each embraced by pole-piece loops 16 of magnetic material to produce a blow-out effect upon the arcs. Blocks of voltage-dependent resistance material 7, arranged below the gapseries, are centred by insulating blocks 8 and supported on a metal plate 4 closing the insulating container 1 and connected to a terminal member 5. A cover 2 carries the high-tension terminal. To determine the capacitances to earth of the gap elements, part of the container may be metallized.