US2436189A - Arc extinguishing device - Google Patents

Description

Feb. 17, w BOEHNE ARC EXTINGUISHING DEVICE Filed Sept. 17, 1945 His Attorney.

Patented Feb. 17, 1948 ARC EXTINGUISHING DEVICE Eugene W. Boehne. Drexel Hill, I'a., assl nor to General Electric Company,

New York a corporation of Application September 17, 1945, Serial No. 816,905

My invention relates to improvements in arc extinguishing devices and more particularly to arcextinguishing devices for circuit breakers and especially circuit breakers for interrupting unidirectional currents having a high rate 01 rise.

Since unidirectional currents do not periodically pass through zero values as do alternating currents. the problem of circuit interruption is more diillcult and especially so with so-called anode circuit breakers used in controlling arc rectiflers because of the high rate of rise of current when'an arc-back occurs. Arc extinguishin: devices for such circuit breakers are therefore subject to severe duty. Since vaporized metal in the are stream tends to maintain and stabilize the are, it is necessary vapor in the are at a minimum. The metallic content of the arc stream is dependent principally upon metal derived from the arc runners. It is therefore important that the ends of the arc in contact .with the arc runners be kept moving continuously in order to avoid heat concentration and the consequent high vaporizing action and also that are runners be made of metal having a high melting temperature. Since the metallic contentof the arc is built up in the end portions .of the are where it is attached to the arc runners, it is important to pocket these metal-laden end portions apart from the central or body portion of the are in order to keep the metallic contamination of the central portion of the arc to a minimum. If the arc portions are thus pocketed, then it is necessary to exhaust the metal-laden vapors of the end portions of the arc in sucha way that they cannot mingle with the exhaust of the central portion of the arc. Otherwise a conducting path may be created over the top 01' the arc extinguishing device with consequent failure to interrupt. In addition to the technical factors involved. there are also the important economic factors of cost, simplicity and flexibility of application.

An object of my invention is to provide for circuit breakers an improved are extinguishing device wherein the formation of metallic vapor from the arc runners is minimized. Another object of my invention is to provide an improved arc extinguishing device wherein the end portions of the arc are pocketed in compartments apart from a compartment for the central or body portion of the arc in order to reduce the metallic vapor content thereof. Still another ob- Ject of my'invention is to prevent any reforma- Claims. (Cl. 200-147) to keep the metal 'ing device in consequence of a mingling of the exhaust portions of the ends of the arc and the central portion thereof. A further object of my invention is to provide a relatively simple and economical arc extinguishing device which is especially adaptable for air circuit breakers and which is readily removable from the circuit breaker structure for replacement. inspection and repairs. These and other objects of my invention will appear in more detail hereinafter.

In accordance with my invention, I provide an improved arc extinguishing device comprising insulating means forming an arcing compartment wherein .an arc runner mounted near the lower edge thereof and extending generally upwardly is provided with an end which is curved through an angle such as to keep the end of the arc moving continuously until interruption occurs. Also in accordance with my invention, I provide an 50 improved arc extinguishing device comprising intion of the are at the top of the arc extinguishb5 sulating means forming three compartments. two of which are provided with are runners of electric current conducting material with their base portions extending into the third compartment.

Further in accordance with my invention. I provide the insulating means with an elongated opening between each of the compartments in which the runners are mounted and the third compartment whereby an are attached to the runners can be continuous from the arc runner in one of the two compartments into the third compartment and onto the arc runner in the other of the two compartments in order to minimize the metallic vapor content oi the central portion of the are.

My invention will be better understood from the following description when considered in connection with the accompanying sheet of drawings. and its scope will be pointed out in the appended claims.

In the accompanying drawing. Fig. 1 is a side elevation of an arc extinguishing device embodying my invention with parts broken away for clearness; Fig. 2 is a perspective view of the embodiment of my invention shown in Fig. 1 with parts broken away for clearness; and Fig. 3 is a sectional view on the line 3-3 of Fig. 1.

In Fig. 1, I have illustrated an embodiment of my invention as applied to a circuit breaker such as that disclosed in Letters Patent 01' the United States 2,329,003, issued September 7, 1943. Since the circuit breaker itself forms no part of my invention, only such parts of the circuit breaker are shown as are pertinent to an understanding of the application of my invention. Thus, in

v ing material and a filler .8 prevent sidewise movement of this filler Fig. 1 the circuit breaker is shown as including an upper terminal stud assembly I on which is movably supported a plurality of relatively movable main stationary contacts 2 and a stationary arcing contact 3. Cooperating with the main stationary contacts 2 is a movable main contact 3 and with the stationary arcing contact 3 is a movable arcing contact 5. Both the movable main contact 4 and the arcing contact 5 are connected to the lower terminal stud, not shown, of the circuit breaker by a suitable flex ble lead 6.

In accordance with my invention, I provide an improved arc extinguishing device which compri es insulating means forming three compartments. As shown, the insulating means comprises ihree spaced p ates 1, 8 and 9 of suitable insulating material forming two compartments which are open at the top and front edges but are closed at the rear edge by insulating spacers l and I l. Near the base of the compartment between the intermediate insulating plate 8 and the outside insulating plate 9, I mount two spaced divergent arc runners 2 and i3 of suitable electric current conducting material so shaped that their bases l4 and I respectively extend into the compartment between the intermediate insulating pla e 8 and the outside insulating plate 1. In order to transfer to the arc runners I2 and I3 an arc drawn between the cooperating arcing contacts 3 and 5 upon separation thereof. the stationary arcing contact 3 may be positioned directly on the arc runner l2 or in suitable conductive relation therewith, and the base |5 of-the arc runner I3 is so positioned as to receive the arc from the movable arcing contact 5 upon movement thereof away from the contact 3. The are runner I2 is mounted directly on the terminal studiassembly and the'space between the arc runner and the insulating spacers l0 and H is occupied by fillers I6 and H of suitable insulatl8 which slides behind the arc runner from the side. The plates I arliad With this arrangement, the parts l6, l1 and 8 remain on the upper stud assembly I when the arc chute .is removed. Bolts l9 passing through insulating bushings 20 serve to hold the plates 1, 8-and 9 and the spacers Ill and H in the assembled relation,

The are runner I3 is supported adjacent the lower front edge of the arc chute on a spacer 22 of suitable insulating material between the plates 1 and 8 and, a spacer 2| of suitable insulating material between the plates 8 and 3 with intervening baflle plates 23 of suitable insulating material between the spacer and the outside plates. Bolts 24 passing through insulating bushings 25 serve to maintain the assembly of the spacers 2| and 22, the baffle plates 23 and the insulating plates I, 8 and 9. The lower end 26 of the arc runner l3 extends downward over the spacers 2| and 22 and is provided with a terminal portion 21 from Whch a conductor 21' leads to the lower terminal stud. not shown, of the circuit breaker.

In accordance with my invention, to avoid heat concentration and consequent burning of the arc runner l3 at the upper end 28 thereof, I so curve this end as to keep the root of the are attached thereto continuously moving. As shown, the angle of curvature is approximately 180 since this amount also helps to lock the runner in place on its supporting spacer 2|. However, for the purpose of keeping the root of the arc continuously moving, if the runner curves sufiiciently to extend somewhat beyond the line of tangency to a vertical plane, the desired action will be obtained. In general, a curvature of approximately will serve the purpose. In order to obtain arc movement without the use of blowout coils, the arc runners l2 and I3 are preferably made oi electromagnetic electric current conducting mater al such as steel which hasa melting point sufficiently high to minimize the metallic vapor contamination of the arc compartments whereby to expedite arc extinction.

Further in accordance with my invention, in order to minimize the contamination of the central or body portion of the are by the metallic vapor formed at the end portions of the are, I provide means for isolating the end portions of the are from the central or body portion thereof. Thus, in accordance with my invention, I provide means for dividing the compartment between the plates 8 and 9 into two compartment divisions or parts whereby to maintain the ends of the arc in the compartment between theplates 8 and 9 and the central or body portion of the arc in the compartment between the plates I and 8 as indicated by the dash-dot line 29 in Fig. 2. As sh wn, this means comprises a barrier 3 0 of suitable insulating material extending upwardly from the bases l4 and i5 of the arc runners in the compartment between the intermediate plate 8 and the outside plate 9. In order tohave the body portionof the arc in the compartment .between the outside plate 1 and the intermediate plate 8, I provide intercommunicating means between this compartment and'the two parts of the compartment between the intermediate plate 8 and the outside plate 9. As shown, this intercompartment communicating means is provided in the intermediate plate 8 as two elongated divergent openings 3| and 32 extending from the ba e 33 of the barrier 30 and respectively above the arc runners |2 and I3 and approximately parallel thereto. By the phrase respectively above the arc runners l2 and i3, I mean that relatively to the faces of the arc runners, the openings 3| and 32 are toward the discharge openings of the arc chute. In orderto provide easy flow lines for the gases and to permit their being exhausted in opposite directions, the edges 34 of the barrier 30 and its base portion 33 are suitably curved and I the edges of the openings 3| and 32 are suitably beveled. Also in order to present a smooth flow surface, the base 33 of the barrier 30 is recessed at 35 to receive the edge of the intermediate plate 8 between the openings 3| and 32 therein. The barrier 3|] is held in place by suitable bolts 35 passing through insulating bushings 31. The intermediate plate 8 is made enough larger than the outside plates 1 and 9 to prevent reformation of the are at the top and front edges of the arc chute.

Assuming the circuit breaker arcing contacts 3 and 5 are closed, as shown in Fig. 1, and that the circuit breaker is opened in response to an overload condition, then an arc will be drawn between the contacts 3 and 5 and this arc will be transferred from the arcing contact 5 to the base l5 of the arc runner |3 as indicated by the dash-dot line 38 in Fig. 2. Because of the interaction between the flux of the current in the arc stream and the fluxes induced in the magnetic arc runners i2 and I3, the ends of the arc will quickly be driven into the two parts of the compartment between the outside plate 3 and the intermediate plate 8, but the body portion of the are will remain in the compartment between the intermediate plate 8 and the outside plate I.

As the ends of the are are forced upward along the arc runners l2 and ii. the arc takes successive positions, one of which is indicated by the dash-dot line II, with the are passing through the openings 3i and 32. Eventually, as the 'ends of the arc reach the ends of the arc runners, the

' arc is extinguished. When the end oi the are attached to the arc runner l3 res ches the curved portion 28 thereof, it travels down over this curved portion and continues to move up and down on the curved portion without producing any concentrated heating thereby reducing the metallic vapor content and the pitting or damage to the arc runner. maintained in separate compartments which are effectively isolated from the compartment which contains the body portion of the arc, the metallic content of the central portion of the arc in the compartment between the outside plate 1 and the intermediate plate 8 is held at a minimum which reduces the stability of the ar in consequence of the increased resistance 01' this portion of the arc and therefore expedites the arc interruption.

While I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangements shown, but seek to cover in the ap ended claims all those modifications that fall within the true spirit and. scope of my invention.

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

1. In an arc extinguishing device for a circuit breaker having relatively movable cooperating arcing contacts, three spaced plates of insulating material forming two compartments, insulating means dividing one of said compartments into two parts, an arc runner of electric current conducting material in each 01' said two parts. said device being adapted to be mounted with the bases 01' said arc runners adjacent the circuit breaker contacts for receiving an arc formed between the contacts upon separation thereof, the

intermediate one of said plates being provided with an elongated opening above each of said are runners whereby an are formed upon separation of the circuit breaker contacts can extend from the arc runner in one part of said one compartment into and through the other compartment and onto the arc runner in the other part or said one compartment.

.2. In an arc extinguishing device for a circuit breaker having relatively movable cooperating arcing contacts, three spaced plates oi insulating material forming two compartments, two spaced divergent arc runners of electric current conducting material mounted in one of said compartments, said device being adapted to be mounted with the bases of said arc runners adjacent the circuit breaker contacts for receiving an are formed between the contacts upon separation thereof, and means for maintaining the end por-,

tions of the arc in said one compartment and the body of the arc in the other of said compartments comprising an insulating barrier extending upward in said one compartment from the bases of said arc runners and intercommunicating means- Since the ends of the are are two parts. an arc runner oi electric current conducting magnetic material in each or said two parts having its base portion extending into the other or said compartments, said are runners diverging irom their base portions, said device being adapted to be mounted with the bases of said are runners adjacent the circuit breaker contacts for receiving an are formed between the contacts upon separation thereof, the intermediate one of said plates being provided with two deep divergent notches respectively positioned above said arc runners and interconnecting near the bases thereof whereby an are formed upon separation of said contacts can extend from the arc runner in one part of said one compartment into and through the other compartment and onto the arc runner in the other part of said one compartment with its extremities traveling outwardly on the arc runners under the cooperating magnetic eiiects of the arc and the magnetic arc runners.

4. In an arc extinguishing device for a circuit breaker having relatively movable cooperating arcing contacts, three spaced plates 01' insulating material forming two compartments, two spaced divergent arc runners of electric current conducting material mounted in one of said compartments having their bases extending into the other or said compartments, said device being adapted to be mounted with the bases of said are runners adjacent the circuit breaker contacts for receiving an are formed between the contacts upon separation thereof, and means for maintaining the end portions of the arc in said one compartment and the body of the arc in the other of said compartments comprising an insulating barrier extending upwardly in said one compartment from the bases of said are runners and interments provided in the intermediate one of said plates as two divergent elongated openings extending from the bottom of said barrier and respectively above said are runners and said intermediate plate extending upwardly above the top edges of the adjacent plates sufficiently to prevent the body of the are from moving into said one compartment before the arc is extinguished.

5. In an arc extinguishing device for a circuit breaker having relatively movable cooperating arcing contacts, three spaced plates of insulating material forming two compartments, means for dividing one of said compartments into two parts comprising an insulating barrier extending downwardly from the top of one of the outside plates and between said one outside plate and the intermediate plate, an arc runner oi! electric current conducting magnetic material in each of said two parts having its base portion extending into the other of said compartments, said device being adapted to be mounted with the bases of said arc runners adjacent the circuit breaker contacts for receiving an are formed between the contacts upon separation thereof, said intermediate plate being provided with divergent elongated notches extending outwardly from the bottom of said insulating spacer and above the respective are runners whereby an are formed upon separation of the circuit breaker contacts can extend from the arc runner in one part of said one compartment into and through the other compartment and onto the arc runner in the other part of said one compartment with its extremities traveling outwardly from the arc runners under the cooperating magnetic repelling action of the arc and the magnetic arc runners.

6. In an arc extinguishing device for a circuit breaker having relatively movable cooperating arcing contacts, three spaced plates of insulating material forming two compartments, insulating means dividing one or said compartments into two parts, an arc runner of electric current conducting magnetic material in each of said two parts having its base portion extending into the other of said compartments, said are runners diverging irom their base portions, said device being adapted tobe mounted with the bases of said are runners adjacent the circuit breaker contacts or receiving an arc formed between the contacts upon separation thereof, the intermediate one of said plates being provided with an elongated opening above each of said are runners whereby an are formed upon separation of the circuit breaker contacts can extend from the arc runner in one part of said one compartment into and through the other compartment and onto the arc runner in the other part 01 said one compartment with its extremities traveling outwardly on the arc runners under the cooperating magnetic effects of the arc and the magnetic arc runners.

i. In an arc extinguishing device tor a circuit breaker having relatively movable cooperating arcing contacts, insulating means forming three compartments, an arc runner of electric current conducting material in each of two of said compartments, said device 1 being adapted to be mounted with the bases oi! said are runners adlacent the circuit breaker contacts tor receiving an are formed between the contacts upon sepabreaker in a circuit,

said runner adjacent ration thereof, said insulating means being provided above the respective arc runners with an elongated opening between each of said two compartments and the third compartment and said openings communicating with each other near the bases 0! said are runners whereby an arc formed upon separation of the circuit breaker contacts can extend from the arc runner in one of said two compartments into and through the third compartment and onto the arc runner in the other of said two compartments.

8. In an arc extinguishing device for a circuit breaker having relatively movable cooperating arcing contacts, insulating means forming three compartments, an arc runner of electric current conducting magnetic material in each of two of said compartments having its base portion extending into the third compartment,.said arc runners diverging from their base portions, said device being adapted to be mounted with the bases or said are runners adjacent the circuit breaker contacts for receiving an are formed between said contacts upon separation thereof, said insulating means being provided above the respective arc runners with an elongated openlag between each of said two compartments and the third compartment, said openings-communicating with each other near the bases of said extremities traveling outwardly on the are runners under the cooperating magnetic eflects oi the arc and the magnetic arc runners.

9. In an arc extinguishing device for a circuit breaker having relatively movable cooperating arcing contacts respectively in conductive relation with terminals for connecting the circuit insulating means forming two substantially parallel arc compartments, an electric current conducting arc runner in one of said compartments adapted to be connected to one or the circuit breaker terminals. said device being adapted to be mounted with the base of the circuit breaker contacts for receiving an are formed between the contacts upon separation thereof and said insulating means being provided above said runner with an elongated intercompartment communicating openin approximately parallel to the arc runner whereby an arc struck to said are runner upon separation of the circuit. breaker arcing contacts will extend from the arc runner in said one compartment through said opening intothe other compartment and to the other of the circuit breaker terminals.

10. In an arc extinguishing device for a circuit breaker having relatively movable cooperating arcing contacts respectively in conductive rela= tion with terminals for connecting the circuit breaker in a circuit, insulating means forming two substantially parallel arc compartments, an insulating barrier approximately vertically dtviding one of said compartments into two w v two electric current conducting arc runners re=- Y runners upon separation of the circuit breer arcing contacts extends from the arc runner in one or said compartment divisions through one or said openings into and through the other com pa-rtment and through the other or said openings into the other compartment division to the other are runner.

EUGENE W. B0

earnestness orrrsn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 682,217 Merrick Sept. 10, 190i 1,713,229 Hewlett May 14, 1929 1,836,994 Slepian Dec. 15, 1931 1,934,518 Anderson Nov. "8. 1933 1,963,643 Brainard et al June 19, 1934 2,337,949 Walle Dec. 28, 19%3 connected respectively formed between the contacts

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