GB369671A - Improvements in or relating to devices for indicating when a flash-over has occurred across an insulator or chain of insulators - Google Patents

Abstract

369,671. Indicating faults. BULLERS, Ltd. and DAGNALL, H. C. R., 6, Laurence Pountney Hill, London. Dec. 31, 1930, No. 39334. [Class 37.] In combination with an insulator or chain of insulators for use in an overhead power line and having arcing-horns between which a discharge may occur away from and along the length of the insulators, there is arranged in the path of the discharge an indicator which is displaced, fractured, or destroyed when a discharge occurs. A chain of insulators 1, Fig. 1, is provided with arcing-horns 5 and an arcing-ring 6 between which a discharge takes place on the occurrence of a surge of lightning. Arranged in the path of this discharge are balls 13 of fusible metal, such as " Wood's metal," carried at the ends of arms 10 which are secured to the metal cap of an insulator near the centre of the chain. On the occurrence of a discharge, the balls 10 are fused and indicate, by their disappearance, that a discharge has taken place. The fusible elements may be of different shapes and may be attached to the ends of the horns 5 instead of to intermediate arms 10. They may be arranged so that, in consequence of their fusion, the length of the gap between the horns 5 and ring 8 is increased, thus extinguishing the arc. Instead of fusible metal, a readily ignitable material, such as celluloid, or a material which would be broken by the discharge may be employed. For example, a strip of celluloid or of fusible metal may be threaded through a hole in the end of each arcing horn 5. A star-shaped disc of fusible metal or combustible material may be secured to the arcing horn by a pin. An indicating arm hinged to the end of the horn 5 may be held up by a fusible metal cap and dropped into indicating position by destruction of the cap. Fig. 8 shows an insulator 27 carried by a. pin 28 on a cross-bar 29 and provided with an arcing horn 5. Secured to the cross-bar 29 by a bolt 30 is a fusible or ignitable indicating-member consisting of a socket 20 and laterally extending arms 21 arranged to project beyond the breadth of the cross-bar so as to be visible from below.