US1965440A - Oil circuit breaker - Google Patents

Description

y 3, 1934- H. TRENCHAM ET AL 1,965,440

OIL CIRCUIT BREAKER Filed April 13, 1952 I I)lIIIIIIIIIII'IIIIIIIIDIII lllllllllllllll'lllll EIIIIIIIIIII 1/ I "1111 n "11, "111, 1 "11," k I! lhventcrs: Hen ry Trench am,

Herbert; C. Heath,

Their Attorney.

Patented July 3, 1934 OIL CIRCUIT BREAKER Henry Trencham, Ruislip, and Herbert Christopher Heath, Wembley, England, assignors to grenfiral Electric Company, a corporation of New Application April 13, 1932, Serial No. 605,098 In Great Britain April 13, 1931 7 Claims. (Cl. 200150) suitable metal. The cap 6 is adapted to enclose one end of the insulating tube '7 forming an explosion chamber which is thus capable of swinging about the contact 2.

For the purpose of directing the oil blast in accordance with the circuit opening movement, the tube 7 is connected to the operating link or lift rod 8, as at '7', and forms part of the movable element of the circuit breaker. Within this tube is pivotally mounted at '7' the bridge or contact bar 9 arranged longitudinally of the tube, one end being adapted to engage the contact finger 10 which is in electrical contact with the fixed contact 2 and which extends through cap 6 within the tube, and the other end adjacent or projecting from the open. end of the tube and adapted to engage the other stationary contact 1.

The pivotally mounted contact bar is resiliently biased, for example by means of a flat spring 11, so that it is, in the open position of the circuit breaker, out of engagement with the contact finger 10. The end of the pivotally mounted contact bar projecting from the open end of the tube is thus maintained in such a position that when the tube 7 is swung clockwise by the operating link of the circuit breaker from the open circuit position (as shown in dotted lines), the end of the contact bar 9 is first brought into engagement with the stationary contact 1 and on continued movement of the operating link is swung round about its pivot and brought into engagement with the finger 10 within the tube.

On opening movement of the common actuating means including the operating link the spring bias on the contact bar maintains the projecting end thereof in engagement with the contact finger l. The other end of the conductor is separated under the action of the spring bias so that contact at the inner end of the tube is initially broken, forming an arc which produces within the tube a pressure driving the oil within it towards the oil blast contacts. On further movement of the insulating tube, these latter contacts separate and the oil blast extinguishes the are between them. The oil blast, therefore, is directed continuously into and through the are at the outer open end of the insulating tube during the entire switch opening movement.

The arrangement wherein the insulating tube, which forms an explosion chamber, is moved bodily by the switch actuating means permits a comparatively small explosion chamber structure and a short pressure generating are for a given opening stroke of the switch.

It should be understood that our invention is The present invention relates to oil circuit breakers of the type wherein a blast of oil is produced between separable contacts so that rapid extinction of the arc formed therebetween is effected.

In circuit breakers of the oil blast type the operation has been proposed wherein pressure is produced in the oil in which the contacts are immersed by the arc formed between separable contacts, and this pressure is utilized to drive a blast of oil across other separable contacts in series with the first-named, or pressure-producing contacts, so that the arc formed between the second, or oil-blast pair of contacts is rapidly suppressed.

The object of the present invention is toprovide an improved oil circuit breaker of the above type which is eflicient in operation, of simple construction, and is made up of a relatively small number of parts.

In carrying the invention into effect, the explosion chamber in which the pressure is generated for effecting the oil blast is moved in accordance with the circuit opening operation. To this end the conducting crossbar or bridging member of the circuit breaker carrying the movable contact adapted to bridge the stationary contacts is preferably enclosed within an insulating casing and movable with respect thereto, the insulating casing being arranged to be moved by means connected to the actuating mechanism of the circuit breaker. The crossbar itself is so biased within the casing that it tends to be maintained out of engagement with one of the stationary contacts, that conact and the co-operating contact surface on the crossbar constituting the pressure-generating contacts. By this means it is ensured that separation at the pressure-generating contacts takes place before the separation of the oil blast contacts.

Our invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize our invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

The single figure of the drawing is an elevational View, partly in section, of a circuit breaker constructed in accordance with the present invention.

In the drawing, 1 and 2 indicate two stationary contacts supported by bushing insulators 3 extending through the cover 4 of a tank 5 containing an insulating liquid 5' as oil in which the contacts are immersed. Pivotally mounted on contact 2, as at 2, is a conducting cap member 6 of not limited to specific details of construction and arrangements thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of our invention.

What we claim as new and desire to secure by Letters Patent of the United States, is:

l. A circuit breaker of the oil-blast type comprising relatively movable contact structure immersed in an insulating liquid, said contact structure arranged to form a pressure generating arc and another are in series therewith upon opening of the circuit, a casing forming an explosion chamber in which said pressure generating arc is formed for directing a blast of insulating liquid from said chamber through the other arc, and means operatively connected to said contact structure and explosion chamber casing for moving the same so that the blast directed from said chamber is moved through said are in a continually changing direction in accordance with the circuit opening operation.

2. A circuit breaker of the oil-blast type comprising an insulating liquid, relatively movable contact structure immersed in said liquid forming a pressure generating arc and another are in series upon opening of the circuit, an insulating casing forming an explosion chamber within which said pressure generating arc is formed, and means for efiecting angular movement of said insulating casing in accordance with the circuit opening operation for directing through an angle a blast of insulating liquid from said chamber across the other arc.

3. A circuit breaker of the oil-blast type comprising an insulating liquid, relatively movable contact structure immersed in said liquid, an insulating casing pivotally mounted forming an explosion chamber open only at one end thereof, said contact structure arranged to form an are wi hin said explosion chamber and another are transversely of and adjacent the opening of said chamber upon opening the circuit, actuating means for opening said contact structure and moving said explosion chamber about its pivotal mounting arranged so that pressure generated by the are within said chamber directs a blast of insulating liquid from the open end of said chamber through said other are throughout the movement of said explosion chamber, and means limiting the movement of said explosion chamber so that the pressure generating arc is short as compared with said other arc.

4. A circuit breaker of the oil-blast type com prising an insulating liquid, contact structure including a pair of stationary contacts and a bridging member immersed in said liquid, an insulat ing casing forming an explosion chamber pivotal- 1y connected with respect to one of said stationary contacts and enclosing said bridging member so that a pressure generating arc is formed in said chamber upon opening of the circuit, and actuating means for rotating said insulating casing directing a blast of insulating liquid through another arc during the circuit opening operation.

5. A circuit breaker of the oil-blast type comprising contact structure including a pair of stationary contacts and a. bridging member immersed in an insulating liquid, an insulating casing forming an explosion chamber open at one end pivotally connected at its other end with respect to one of said stationary contacts, said bridging member being disposed within said casing and resiliently biased into engagement with one of said stationary contacts, and an operating rod pivotally connected to said bridging member and to said insulating casing arranged so that an initial pressure generating arc is formed within said chamber for directing a blast of insulating liquid through the other are adjacent the open end of said chamber concurrent with pivotal movement of said casing.

6. A circuit breaker of the oil-blast type comprising an insulating liquid, coacting contact structure including a pair of stationary contacts and a movable bridging member forming two breaks in series immersed in said liquid, an insulating casing enclosing one of said stationary contacts and a part of said bridging member, said casing being closed at one end thereof, and contact actuating means arranged so that a pressure generating arc is formed between said bridging member and a fixed contact within said casing adjacent the closed end thereof and another are is formed between the other fixed contact and bridging member exteriorly of said casing and transversely of the open end thereof, the pressure generated within said casing by said firstnamed are causing a blast of insulating liquid from said casing through said second-named arc.

'7. A circuit breaker of the oil-blast type comprising an insulating liquid, coacting contact structure including a pair of fixed contacts and a movable bridging member immersed in said liquid, an insulating casing forming an explosion chamber open only at one end thereof, one of said fixed contacts being located within said casing at a point remote from the open end thereof, the other fixed contact being located exteriorly of said casing and adjacent the open end there of, said casing enclosing a part of said bridging member, and actuating means for said bridging member arranged so that the arc formed between said bridging member and an enclosed fixed contact causes a blast of insulating liquid from said chamber through the arc formed between the other fixed contact and bridging member exteriorly of said casing.

HENRY TRENCHAM.

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