Patent GB-484760-A (GB)
Title: Improvements in or relating to electric circuit interrupters having arc-extinguishing devices
IPC: H01H33/18
Filed: 1937-05-27
Abstract: 484,760. Liquid-blast switches. WESTINGHOUSE ELECTRIC & MANUFACTURING CO. May 27, 1937, No. 14721. Convention date, May 29, 1936. [Class 38 (v)] A circuit-interrupter comprises a pair of separable contact-members for establishing an arc, a pair of spaced arc-terminals for receiving the arc, a coil in series with the contact-member for producing a radial magnetic field to move the arc on to said arc-terminals, each of said arc-terminals having a curved path thereon between which said arc is adapted to play in one long section, and a second coil in series with said arc-terminals for producing a radial magnetic field between said arc-terminals to move the arc laterally along said arc-terminals. Fig. 1 (not shown) illustrates a tank or enclosure with two insulating bushings, as 12, for lead-in conductors, as 13, each of which supports an assemblage of five arc-quenching units 23, of the character shown in Fig. 2, and the lowermost units of the assemblages being electrically joined by a bridging-bar engageable with contacts 19, Fig. 3. Each unit 23 comprises a stack of circular insulating plates, some 27 of which are relatively thin and slotted at 29, whereas the alternate plates 25 are thicker and recessed at 31 for retaining arc-quenching fluid within the passage defined by slots 29. The end plates 33 carry arcuate arc-horns 35 extending into slot 29, and next each end plate is a preferably magnetic plate 37, the upper of which in each unit contains a coil 65 on which is mounted the fixed contact 43 of the unit. The associated movable contact 45 extends through a guide 47 in the lower plates 33, 37 and is connected by parallel-motion linkage 49 to a central, spring-controlled, operating rod 51 carrying the contact 19 and producing, when lowered, a simultaneous separation of all the contacts 45. The foot 41 of conductor 13 is strapped at 73 to a plate 71 to which a screw 69 connects the end of upper coil 65 remote from contact 43. Contact 45 is connected at 79 to a bracket 81 which is connected by studs 83 to lower plate 37, which in turn is connected by members 85, 87, 89 to the coil 65 of the next lower unit 23. In this way, each coil 65 is in series with its associated contacts 43, 45 and the latter are also connected in series to produce, on separation, five serially-connected ares, which are acted on by the radial fields due to coils 65 to transfer their upper ends from contacts 43 to the upper arc-horns 35. Each plate 37 is additionally provided with an edge-wound coil 75 of a considerably larger number of turns than coil 65, the upper coil having one end connected by lead 78 to plate 71 and the other end connected to the upper arc-horn 35. When, therefore, the arc is transferred by coil 65 to the horn 35, upper coil 75 is energized by the arc-current and its radial field moves the arc along the upper horn. The lower horn 35 is connected by a screw 91 to end plate 37 and also with one end of the lower coil 75, the other end of which is connected by a lead 95 to the lead 97 of the upper coil 75 of the next lower unit 23, which coil is connected in turn to the upper arc-horn 35 of that unit. By means of this connection of the shunt coils 75 of adjacent units, movement of the arc by the coil 65 of the lower unit on to the upper horn 35 of the lower unit, in addition to energizing the upper coil 75 of the lower unit, energizes the lower coil 75 of the upper unit, so producing movement of the arc from contact 45 on to the lower horn 35. Such action, however, is not possible in the case of the lowermost unit 23 and accordingly transfer of the arc from contact 45 to the lower archorn 35 of that unit must be effected by a coil 103 similar to the coil 65 in the upper plate 37 of that unit. The coil 103, Fig. 3, is connected by a screw 107 to a bracket 105 which is mounted on, and connected to, plate 37 and also connected to contact 45 by a lead 79. The other coil-end is connected by screws 109 to a bracket 111 insulatingly carried by plate 37. Bracket 111 is connected in turn by a lead 115 to the associated contact 19. The coil 75 is connected at one end to the lower horn 35 and at the other end by screw 107 to plate 37. Excess pressures due to interrupting large currents may be relieved by means of passages 120, 121 which permit escape of gas and quenching-liquid from the passages 29. Specification 454,186 is referred to.