GB290753A - Improvements in lightning arresters - Google Patents

Abstract

290,753. Nobuhara, K. Feb. 22, 1927. No Patent granted (Sealing fee not paid). Protective arrangements.-A lightning arrester for the protection of distribution lines &c. comprises an air gap 6, Fig. 1, a low resistance 5, and an automatic circuit-breaker 4, adapted to give an indication when the circuit is broken. The parts are duplicated, a connection being made to each distribution line 1, while the earth connection 3 is common to both sets. The circuitbreaker may comprise a fuse wire a, Fig. 4, soldered to resilient copper wires b supporting a weight c having arms c<1> in engagement with the walls of the fuse box. The weight is attached to the box by a chain or cable d and, when the wire a is fused, the weight will hang down so that it can be observed from a distance. Fig. 2 shows an arrangement in which carbon resistances 5 are mounted on a fire-proof insulating plate 7 fixed to the bottom of a casing 8. Lead wires 15 from circuit-breakers enter the casing through insulated tubes 9. The air gaps are electrically connected to the casing from which a line 11 extends to an earth plate. The casing is mounted on the arm of a pillar 13 by means of holders 14. The enclosed parts may be situated in the casing of a pole transformer and connected in parallel with the primary coils of the transformer, the automatic breakers being common to the arrester and transformer. The earth plate may comprise a hollow pile e with perforations f so that salt water may be supplied to impregnate, and thus increase the conductivity of, the surrounding ground.