GB840743A - Improvements relating to air-break electric circuit interrupters - Google Patents

Abstract

840,743. Air-break switches; arc rupturing in switches. METROPOLITAN - VICKERS ELECTRICAL CO. Ltd. Jan. 17, 1958 [Jan. 23, 1957], No. 2487/57. Class 38 (5). The body of an arc-chute is moulded from a thermosetting synthetic resin, e.g. an epoxy resin, and includes an arc quenching device which is provided therein either during the moulding process or by subsequent insertion into recesses formed during the moulding. Thus arc plates may be integrally moulded with the arcchute or preformed metal or insulating plates may be embedded in the body during moulding or fitted into recesses formed in the body during moulding. In this latter case, the edges 5<SP>1</SP> (Fig. 2d) of the plates 4 are slid into complementary recesses 5 in the body and the recesses are protected from the arc by flared portions 6 on the plates. The plates may extend only partly across the arc-chute body with alternate plates extending from alternate sides of the body. Arc-splitter pins may be used instead of arc plates. Fig. 1 shows an arc-chute 1a, 1b moulded integrally with a housing 1e for a circuit-breaker having a fixed contact 15 and a moving contact 19. A magnetic blow-out coil may be connected between the conductor 14 and the fixed contact 15 or between the conductor 14 and an arcing contact and embedded in the housing 1e during its moulding. An airpuffer cylinder may also be integrally moulded in the wall of the housing. Alternatively, as shown in Figs. 7 and 7a, the housing may be formed with a channel 34 in which the moving contact 19 swings, the channel constituting the air-puffer cylinder and the moving contact, the piston. An aperture 35 leading to a nozzle 36 directed towards the arc path is provided in the moving contact. A number of arc-chutes may be integrally moulded for a multi-pole or multiple-break switch. According to the Provisional Specification prestressed reinforcement may be provided in the moulded body.