GB1235300A - Magnetic arc blow-out device - Google Patents

Abstract

1,235,300. Arc extinguishing in switches. E. MAGGI. 9 Sept., 1968 [9 Sept., 1967], No. 42756/68. Heading H1N. In an arc extinguishing arrangement an arc 141 driven away from separating contacts 121, 130 by permanent magnets 123, 133 is made to run across the surface of a resistor stack 112 thus inserting progressively more resistance in series with the arc. As shown in Fig. 7 a main movable contact 124 is withdrawn in the direction of the arrow (this may be an arcuate path, Fig. 6, not shown). The auxiliary contact 130 initially follows under springs 137 causing a first arc 141 to be struck; this is driven by a first pair of magnets 120 on to the resistor 112 where it is then acted on first by magnets 118, then by magnets 123 moving the other end of the arc on to a second resistor 153. The contact 124 separates from the auxiliary contact 130 to strike a second arc 144 which is driven (in the other direction) along resistor 153 and a runner 115 by pairs of magnets 133, 128. The pairs of magnets 123, 133 have insulated pole pieces 127, 139 which are interleaved so as to provide a labyrinthine path to extend the arc. If the arcs are not cleared in the first half cycle they restrike at the contacts and move in the opposite directions into the unused sections of the chute during the next half cycle. A number of simpler forms of the invention are described: in Figs. 1-3 (not shown) intended for D.C. use only the upper half of the arc-chute is required; the auxiliary contact 130 and the resistor 153 are omitted. In a modification of this (Fig. 4, not shown) the arc runner 115 is replaced by a second resistor (32<SP>1</SP>). In a double chute for A.C. the auxiliary contact 130 and resistors 153 may also be omitted (Fig. 5, not shown) or it is possible to omit the resistors 112 allowing both arcs to run on resistors 153 only (Fig. 9, not shown). The arc-chute may be in open air or immersed in an arc extinguishing gas or liquid in a tank (207) (Fig. 6, not shown). The resistors which may be subdivided by metal plates 113 into sections of different resistivity may be made of high resistivity manganese alloys or of coils of resistance wire or of finely divided carbon or metal in a ceramic base. Non linear resistors may be made of silicon carbide crystals bonded by ceramic.