US2445190A

US2445190A - Electric circuit breaker

Info

Publication number: US2445190A
Application number: US568983A
Authority: US
Inventors: Benjamin E Spiro; Ralph J Baskerville
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1944-12-20
Filing date: 1944-12-20
Publication date: 1948-07-13
Anticipated expiration: 1965-07-13
Also published as: GB605124A

Description

July 13', 1948' B. E. sPlRo ETAL 2,445,190

ELECTRIC CIRCUIT BREAKER Filed Dec. 20,. 1944 2 sheets-sheet 1 m, l f l llllllllllllllllml Y "I, f/

A? f5 F'g f6 by @M4 T hen Attorney.

July 13, 1948. B, E, SPIR() AL 2,445,190

ELECTRIC CIRCUIT BREAKER Filed Deo. 20, 1944 2 Sheets-Sheet 2 Inventor-s: Benjamin lpir-og Faiph J.Basker-ville Then Attorneg.

Patented July 13, 1294s ELECTRIC CIRCUIT BREAKEB.

Benjamin E. Spiro, Philadelphia, and Ralph J. Baskerville, Merwood Park, Pa., assignors to General Electric New York Company, a corporation of Application December 20, 1944, Serial No. 568,983

Our invention relates to electric circuit breakers and more particularly to electric air circuit breakers of the type disclosed and claimed in Linde Patent 2,293,513, granted -August 18, 1942, and assigned to the same assignee as the present application. Specically, our invention is an immovement on a circuit breaker of the type disclosed in Linde Patent 2,335,088, granted November 23, 1943, and also assigned to the same assignee as the present application.

Air circuit breakers of the type disclosed in the above-mentioned Linde patents have been used very extensively within the past several years.. These circuit breakers. employ an arc chute of inorganic material, which arc chute is closely adjacent the contacts of the circuit breaker between which the arc is drawn. Our inventionis particularly concerned with the construction of the arc chute and supporting means therefor which are simple and compact and which permit ready accessibility to the contacts of the circuit breaker.

It is an ,object of our invention to provide an arc chute for an electric circuit breaker which is simple, compact, emcient in operation, and which is readily removable to permit inspection of the contacts of the associated circuit breaker.

It is anotherl object of our invention to provide a new and improved arc chute including supporting means therefor for an electric circuit breaker.

Further objects and advantages of our inventionl will become apparent as the following description proceeds 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.

For a better understanding of our invention, reference may be had to the accompanying drawings in which Fig. 1 is an elevational view of an electric circuit breaker embodying our invention with 'certain portions broken away; Fig. 2 is a sectional view of the arc chute only, taken on line 2`2 of Fig. l; Fig. 3 is an exploded view of the arc chute of Fig. 1 to illustrate the construction of the arc chute, and Fig. '4 is a sectional view taken online 4-4 of Fig. 3 assuming an assembled arc chute in Fig. 3.

Referring now to the drawings, there is illustrated an electric circuit breaker in some respects quite similar to the electricl circuit breaker dis- 3 Claims. (Cl. 20D-JM) tacts 2 and arcing contacts I and cooperating movable current carrying contact 4 and movable arcing contact 5. Movable contacts l and l are supported on an arm B which is pivotally mounted at I to one end of a circuit breaker conductor vstud 48. The relatively stationary contacts 2 and 9 serve as plug type disconnect contacts for the circuit breaker unit and when they are connected to a live power circuit relative separation of the contacts will cause an arc to be drawn.

For the purpose of interrupting a power arc drawn between the contacts, an arc extinguishing structure or arc chute, generally indicated at I2 is provided to receive the arc. Generally such a circuit breaker comprises a plurality of arc chutes, one for each phase conductor of the power circuit to be controlled. It will be understood that our invention is equally applicable to a single phase or polyphase circuit breaker. As is illustrated in the drawings, the arc chute I2 is of the so-called down draft type such as is disclosed in Linde Patent 2,335,068, referred to above. By down draft type is meant that the arc gases from the arc chute are discharged downwardly. It should be understood, however, that our invention is also applicable to circuit breakers which are not of the down draft type,

closed in the above-mentioned4 Linden Patent 2,335,068. The electric circuit breaker illustrated comprises a main supporting frame or unit I for the relatively movablecontact structure which comprises relatively iixed current carrying consuch, for example, as circuit breakers, wherein the gases from the arc chutes are discharged laterally as in Linde Patent 2,293,513.

The arc chute I2 of our circuit breaker is preferably constructed in accordance with the arc shield disclosed and claimed in Boehne Patent 2,270,723, granted January 20, 1942, and assigned to the same assignee as the present application. Preferably, the arc extinguishing structure or-arc chute I2 comprises spaced side walls I3 and Il composed of arc resisting material such as an asbestos cement compound, each side wall having on the side facing the other wall a plurality of parallel fins, ridges or barriers I5, as best shown by Figs. 2 and 4. The ilns I5 are prei- Ierably integral with the side walls I3 and Il, which side walls are preferably clamped together as by means of bolts IB with the ridged or ilnned sides thereof adjacent to each other. The length and spacing or the fins or ridges I5 are such that when the sidewalls I3 and Il are clamped together the ilns are spaced and interleaved with respect to each other, that is, in staggered relation so as to form a. s'inuous or zigzag passage i1 into which the arc is driven from the entrance portion i8 of arc chute I2 which is best shown in Fi 4.

eferring more particularly to Fig. 4, there is illustrated a transverse section of the zigzag arc passage I1 defined by interleaving fins or ridges I8. 'I'he fins or ridges i5 are shown as tapering towards the entrance I8 of the arc chute I2. It will be observed that this tapered portion of the uns causes thearc passage I1 to be more and more restricted as the arc approaches the exhaust portion of the chute.

Preferably th'e chute sides I8 and I8 are molded with the ridges or fins I8 integrally formed therewith and -any recesses, raised portions or the like are formed during the molding process. To save the expense of two separate molds, our chute sides I8 and I8 may be molded as identical pieces from a single mold. Fig. 3 shows how the chute sides I8 and I8 may be molded as identical pieces, the dotted portions I8 and 28 being initially included in the molded chute sides I8 and i8, respectively. I'he dotted portion i8 of chute side I8 is cut away and correspondingly the dotted portion 28 of ch'ute side I8 is cut away so that the chute sides are defined by the solid lines of Fig. 3. The fins of the chutes are arranged so as to be unsymmetrical about a central arc dividing member 2i associated with each chute side whereupon interleaving of the ribs or fins I8 will result upon assembly of the chute sides initially molded identical in shape.

As initially molded and clearly evident from Figi. 3. each chute side I8 and I8 is provided with L-shaped recesses 22 and 28, with the base of the L-shaped recesses 22 and 28 pointing towards each other. Each chute side I8 and I8 is also provided with a pair of curved arcing horn recesses 28 and 25 which are of similar shape. recess 28 being inverted relative to recess 28. By cutting away portion I8 of chute side I8, indicated in dotted lines in Fig. 3, a portion of each of the recesses 22 and 28 is cut away. Byfcutting away portion 28 of chute side I8, indicated in dotted lines in Fig. 3, a portion of each of the recesses 28 and 28 is cut away. y

The lower end of -arc chute I2 is the exhaust end of the arc chute. In order to cool the arc gases properly before being exhausted from the chute a pluralityvof parallel arranged cooling plates 28 are provided. These cooling plates 28 are very similar to the cooling plates provided in the above-mentioned Linde patentsl for cooling the arc gases and are preferably formed of copper or other good thermal conducting material. These cooling plates are inserted in notches 21 preferably molded in the ch'ute sides I8 and I8.

The construction of the contacts of the circuit breaker form no part'of our invention. Preferably, however, movable arcing contact l supported on pivotally mounted arm 8 moves through the entrance portion I8 of arc chute I2. As illustrated. movable arcing contact 8 moves closely adjacent to an arcing horn 28 supported in recesses 28 and 28 of chute sides I8 and I8, respectively, the edges of arcing horn 29 being disposed In the cooperating recesses 28 and 28. Arcing horn 28 is provided with an extension 88 which includes `the opening 8l so that arcing horn 28 may be electrically connected, as by a bolt passing through opening 8i to one side of the associated electric circuit. An arcing horn 82 adapted to be 4 electric circuit is positioned in cooperating recesses 2l and 28 of chute sides I8 and i8, respectively. -Arcing horn 82 is electrically connected to a blowout coil 88 mounted on a core 88 and separated from the coil by an insulating cylinder 88. The core 88 of the blowout coil 88 is adapted to extend through drilled openings such as 88 in the chute sides I8 and I8 so as to abut magnetic plates 81, one associated with each' chute side I8 and I8. A suitable bolt 88 passing through the chute sides, plates 81 and an opening in core 88 holds the core 88 and magnetic plates 81 together so as to produce a strong magnetic field for mov- Raised portion 88 cooperates with a notched-out portion 88 in the magnetic plates 81.

One end of magnetic blowout coil 88 is connected to arcing horn 82. as is indicated at 8|.

` The other end of magnetic blowout coil 88, as is indicated at 82, is connected to a conducting supporting member 88 which is a bar-like piece bent across its width into a generally U-shaped conguration the lower portion oi' which matches the cooperating recesses 28 and 22 formed in chute sides I8 and I8, respectively. When the chute sides I8 and i8 are bolted together, as indicated in Figs. 2 and 8, the lower portion which includes leg 88 of the U-shaped member 88 is held with its edges effectively keyed into the L-shaped recesses 28 and 22 in chute sides I8 and I8, respectively. Accordingly the arc chute I8 may be supported firmly and reliably from the upper leg of the U-shaped member 88 for it will vbe apparent that the support 88 cannot be displaced from its keyed position in the assembled are chute until the 'two sides are unbolted and separated from one another.

It will be discerned that the are chute supporting member 88 derives'its tenacity with respect to the are chute from the fact that the main body portion of the member is provided with an effective anchorage aiforded by'the projecting or offset portionV 88 and the corresponding grooves or recesses provided in the chute sides for snugly receiving therein the edges of the main body and oil'set portions of the supporting member.

Preferably, conducting supporting member 88 is fastened by means of a single cap screw 8l to an extension 88 of the stationary contact strueture which is electrically connected to the bottomof conductorstud 8.

In orderto support the other side of the arc chute I2, we provide a fabricated supporting member 81 comprising two vertically extending pieces 88 identical in configuration. Joined together at the top by a U-shaped crossover member 88. The lower ends of the vertical members 88 making up fabricated supporting member 81 are provided with an open ended disengaging slot 88. A single cap screw 8i passing through the bight of U-shaped member 88 of supporting member 81 holds the fabricated support 81 to the contact block supported from conductor stud 8. The open ended disengaging slots 88 are adapted to cooperate with a bolt 82 passing through are chute I2 and through the opening 8| in arcing h'orn 28. It will be obvious that with the above construction theare chute I2 can readily be removed merely by removing the cap screw 88 and loosening the boit 82 after which the arc associated with the other side of said 'I8 chute I2 may be slid to the left, as viewed in Fig. 1, whereby bolt l2 becomes freed from the disensaglng slots Il. v

From the above discussion, it will be obvious that the cooperating recesses 23 and 22 of chute sides I3 and Il, respectively, provide a very simple means for securely ailixing the arc chute supporting member I3 into the ch'ute structure without the requirement of any additional fastening means whatsoever and furthermore with this construction a very easily removable arc chute is obtained. Moreover, it will be observed that during the interrupting operation, that is, after the movable contacts 4 and 5 have separated from the coacting stationarycontacts 2 and 3 respectively, the upper portion of supporting member 43 further cooperates in that it serves as a shunt path around the fixed contacts through which current flows for energizing the blowout coil coincidental with the transfer of the arc root from the fixed arcing contact 3 to the arc runner 32.

While we have shown and described a particular embodiment of our invention, it will be obvious to those skilled 'in lthe art that various changes and modiilcations may be made without departing from our invention in its broader aspects and we, therefore, aim in the appended cla-ims to cover all such changes and modifications as fall within the true spirit and scope of our invention.

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

1. In an electric circuit breaker, supporting structure, an arc chute constructed of complement-ary parts, grooves in adjacent surfaces ot said complementary parts, said grooves having one portion thereof angularly disposed with respect to another portion thereof, a supporting member having-a portion thereof adapted to project outwardly from said arc chute and another portion thereof having an oil'set portion and being adapted to flt within the grooves in the complementary parts of said arc chute. whereby said supporting member is secured in position with re- -spect to said arc chute, and means cooperating with the portion oi' said supporting member which projects outwardly from said arc chute for securing said supporting member to said supporting structure.

2. In an electric circuit breaker, supporting structure, an arc chute constructed of complementary parts, grooves in adjacent surfaces of said complementary parts, said grooves having one portion thereof angularly disposed with respect to another portion thereof, a supporting member having a portion thereof adapted to prolect outwardly from said arc chute and another portion thereof having an offset portion and being adapted to fit within the grooves in the complementary parts of said arc chute, whereby said sup- Porting member is secured in position with respect to said arc chute, means cooperating with the portion of said supporting member which projects outwardly from said arc chute 'for securing said supporting member to said supporting structure, a supporting arm secured to said supporting structure, and means for securing said arc chute to said supporting arm.

3. In an electric circuit breaker, supporting structure, an arc chute, a supporting member secured to said arc chute and having an outwardly projecting portion, means for removably securing the outwardly projecting portion of said supporting member to said supporting structure,- a supporting arm secured at one end thereof to said supporting structure, a slot in the other end of said arm, and means on said arc chute for removably connecting said arc chute to said supporting arm byv a sliding engagement with said slot.

BENJAMIN E. SPIRO. RALPH J. BASKERVILLE.

REFERENCES CITED The following references are oi"record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 40 `1,398,981 Tritle Dec. 6, 1921 1,804,729 Wilms et al. May 12, 1931 1,914,129 Jennings June 13, 1933 1,955,961 Jackson Apr. 24, 1934 2,020,935 -Ellis et al Nov. 12, 1935 45 2,098,578 Hammerly Nov, 9, 1937 2,270,723 -Boehne Jan. 20, 1942 2,335,068 Linde Nov. 23, 1943 2,349,881 Slepian May 23, 1944