US2545334A - Electric circuit interrupter - Google Patents

Description

March 13, 1951 c. J. BALENTINE ELECTRIC CIRCUIT INTERRUPTER 2 Sheets-Sheet 1 Filed June 25, 1950 His Attorney.

Inverwbor. Gonradd. B alenbine,

March 13, 1951 c. J. BALENTINE 4 ELCECTRIC CIRCUIT INTERRUPTER Filed June 23, 1950 2 Sheets-Sheet 2 Fig.4. 4

Inventor: Conrad J. Ba\enbine,

His Attorney.

Patented Mar. 13, 1951 2,545,334 ELECTRIC CIRCUIT INTERRUPTER,

Conrad J. Balcntine, Philadelphia, Pa., assignor to General Electric Company, a corporation of New York Application June 23, 1950, Serial No. 169,981

My invention relates to electric circuit interrupters for high voltage circuits, and particularly to high speed circuit breakers of the liquid blast type for opening high voltage alternating current power circuits within a few half cycles.

More specifically, my invention is a further development and an improvement upon the series-break type of interrupter disclosed in U. S. Patent 1,548,799 granted on an application filed by J. D. Hilliard, which is assigned to the same assignee as the present application.

Nowadays the principle upon which this type of interrupter operates is known as oil blast action, this being the process whereby an are that is drawn past an expulsion port within an oil confining structure is extinguished by displacement of the oil caused by a pressure established therein in the region adjacent the arc.

In theabove-mentioned Hilliard patent, the

pressure for blasting the arc to be interruptedis generated by means of a series so-called pressure-generating arc, although it is well understood that other means may be employed for establishin blast action such, for example, as an impulse piston. An example of a fluid blast breaker wherein the oil blast action is produced by means of an impulse piston is discl sed in U. S. Patent 2,147,497 to Prince et al.,which is,

assigned to the same assignee as the present application.

Conventional forms that fluid blast action may assume are well known and may be defined as radial blast, axial blast, and cross blast. These three different forms are shown clearly in Figs. 1, 2 and 3 respectively of the above-mentioned Hilliard patent. Frequently, these several blast 2 Claims. (01. 200-450) actions are combined. For example, it will be apparent that the oilblast produced in the case'; of Fig. 1 of the above Hilliard patent is an in-} ward radial blast between the spaced superposed bafiles, which blast continues as an axial blast down the bore of the throatinsulator as the .7

contact rod pulls downward from the interrupter into the tank. In other cases an axial blast is directed through, say, a hollow contact and then is caused to diverge radially outward as, for -example, inU. S. Patent 2,434,506 to Buchwald et al., which is assigned tothe same assignee as the present application.

While known interrupters of the type referred to above, generally provide for injecting at high 50v mg blade contact, such as 1s shown In Fig. 1 of T velocity one or more blasts. or jetsof fluid, toward the are at predetermined relatively small I.

localized points along the. arc length, I have found that improved interruptionis accomplished if a relatively large volume of oil is quickly moved laterally into the arc path so that a large portion of. the length of the arc is simultaneously sub-. jected to the influence of the displaced fluid and also ifa plurality of exhaust passages are dis-:

posed at a small angle with respect to each other on the side of the interrupting unit which is; opposite from the side of the unit from which the fresh fluid under pressure is directed into thearcing passage.

:prior arrangements and which, in addition, is

simple and compact in construction.

Another object of the invention is to provide a circuit interrupter of the fiuid blast type wherein a mass of fiuid is moved under pressure into the are from one side thereof so as to encounter, and displace substantially the entire length of the arc from between the separating contacts and. to vent the interrupting chamber in a manner-.-

which is adequate to scavenge the ionized gaseous products of arcing out into the enclosing tank but which at the same time does not allow the arc itself to be forced through the venting structure into the containing tank.

Further objects and advantages of my invention willbecome apparent as the following de scription proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to. aiid forming a part of this specification.

In the drawings, Fig. 1 represents a sectional view of a circuit interrupting unit embodying my; invention takenalong the lme 22 of Fig. 3;" Fig.2 is a perspective View partly in section of albafile structure embodying my invention, which T structure is disposed within the lower portion. of the unit shown in'Fig. 1; Fig. 3 is a cross sectional view along the line 3-3 of the interrupter shown in Fig. 1; and Fig. 4 is a view of the various baifie plates utilized in the assembly. of the structure shown in Fig. 2.

The interrupting unit shown in Fig. 1 of the drawingsis adapted to be mounted along with another similar unit inside a relatively large oil; filled enclosingmetallic tank. These two inter- I rupting units would cooperate with a reciprocat-Q the above-mentioned Hilliard Patent 1,548,799.

'With reference to Fig. 1, the interrupting unit is shown secured to the electric bushing I constru'cted of insulating material through the bore,

tallic nut 3 which secures the metallic flange-'4' compressively with respect to the bushing; Adapter unit in turn is secured to the flange 4 by means of bolts 6. confining casin 1 for the interrupter unit is threaded onto the lower portion of the adapter unit at 8. For the purpose of tightening of the casing 7, wrench holes 9 may be provided'anda conventional set screw may be utilized for lock- The enclosing pressure 4 numeral 28. These two chambers are separated by a common wall 36 having a communicating aperture therein as shown. The arc confining baiiles 29 in the pressure-generating chamber and the thick wall membe 33 are secured within the casing by means of suitable insulating spacer sleeves or rings 3|, 32, 33 and 34, which are all maintained compressively in placeby means of the threaded ring nut shown at the upper end of the casing.

The intermediate contact i5 is biased in the downward direction by means of springs, such as 35 and 35, which engage a ring 37 of insulating the tightened casing 1 with respect to the adapter unit 5, as shown. The lower portion of the enclosing casing 1 is partially enclosed bya throat member l0 constructed of insulating material, whichthroat is se'curedintol the casing bypmeans of. dowel pins or screws H; Throat member 10; is provided with :a conical. opening, l2tthrough which the movable contact. I3tverti-i cally travels into or:out of theinterrupten dur; ing theopeningor closing operation.respectively of: the circuit breaker.

The contact structure disposedwith-in the en closing casing? comprisesa relatively fixed butt contact I4 and an intermediate fiOating'COlltact; [5.7 The relatively fixed contact 54 is mountedfor liinited resilient movement about a fixed rguiderod-I6 whichis screwed into the flanged-cylindrical spring retainer member H; It-will be observed that the'butt: contact l4-. and its associated -par-ts which are mounted about the guiderodlb, together-with the-guide rod--l6 andits springretainerll, constitutea completesub-assembly which is screwed into the adapter 5. This easily renewable contact unit isprevented-from-"slacking back by--any con-- vehtionalmeans; such as the-locking plate l9;' whichmay engage a suitable flat surface on the side 0f--the spring retainer t1 and-whichisheldfixedly-by thescrew 2-0;"

- Electricalcontact is maintained-between "the butt contact M and the adapter-thy means of" conventional flexible connecting braids; suchas is'indicated at 2 I:

The limited resilient vertical movement 'or' wipe 'of the. fixed contact i l providesior slight variations in the closed'position of the movable contact l3'and; also for'subsequent erosion of the arcing contact faces. Nested springs 22and' 23i-of" suitable strength for adequate contact pressure; bias the fixed-contact I4 toward its. lower extreme position as determined by/the,

head 24"of. the guide rod it which abuts) the lower rim of the threaded sleeve member 25'." This" sleeve 25 is screwed fixedly into-contact, l4"an'd' may beequipped with'ani anti-friction bushing 26';

As' pointed out above, pressure could'be es tablished for causing the oilj'to blastan'd [ex-3' tinguish the interrupting arc"'in any suitable manner. I have chosen toillustrate my inven:

tion in conjunction with an interrupter wherein", pressure is established by a pair of series cone" tacts, such as M: and I5, which draw apressure generatingarc just before, the interrupting are between the contacts isi'and'lti-is drawn Thus,

the enclosing casing T isshown as including a" pressures-generating chamber generally indicated by the numeral 2'! and" any interrupting chamber j of'which the upper portionisindicated by'the' ing-material which is secured to the lower portion 15" of -the contact, If: by means or" a pin 38.

When the interrupter contacts are in the open position, as shown in Fig. l, the intermediate contact i5 assumes its fully open position by engagingthe lower baiile structure, generally designated by the numeral 39, which is held compressively' iii-position between1-;the ;lower:v throat member. it andv the insulating spacer sleeve 34:. i To close the interrupten contactszfrom-the open,' position shown, the-contact I3, firstis elevated; through the arcing chamber. pas-sage generally j designated by the numeral. tuwhichxpassage-is constituted by thegenerally, hollow bailieistruce; ture -39. After. the-contact ISLcIoseStheiintere: rupting arcgap by engagingatheglowerl end otxthe; intermediate contact i5, both 'ofwthese contacts." rise in unison.-v Contact. l5 'nowr is elevated Slidr; ingly in the-wall 38 against the bias of; its springs 35aand 36' sothat it eventuallyicloses; the epressure generating arcgap; by engaging the lower; surface-of therelatively fixed contactcmember. l4; Movingcontact l3iis ifinally arrested byits: operatinginechanism- (not shown) .iwhen the. fixedcontact Mhas-beenmoved upwarda short f suitable --wipe distanceby the intermediate contact t5:-

When the circuit breaker is trippedopen; the a movable contact l3 moves-downwardly at high. speed with the intermediate contact l 5 infollowup engagement due'toits springs- 35 and -36;as

3 will be-understood irom F-ig. 1, until'thecontact.

Ht isarrested-by engagementof its: ring 37 with-ti the baiile--structure=- Duringthisinitial: downe wardinovement, the-gap producedbetween cone tacts Hi and 1-5 establishes an initial are I which": generates pressure within the upper chamberfl; P This} pressure will urge oil tomove downwardly through the opening in both the baffle plates :2 9e

and the wall 36* into the interrupting-- chamber 285 Assoon as" the moving contact I 3 leavesthe intermediate contact 55, a second or series" are is established within the arcing passage 40;. Since thebafiie structure is vented to-the-1ow-' pressure region irr'the' enclosing tank- (not shown) through suitable expulsion openings such as 41" provided in th'e" walls of'casi-ng 1, and-be -v cause of the high pressure generated in the up perrchamberil, the--oil-in the lower chamber 28" consequentlyis pressurized and caused -to movethrough the 'bafile structure 39 whereby the seriesinterrupting arc drawnin the-passage lfi may-be displaced'lateral-lytherefrom and-is extinguished by the flow andpressureot'the oil through-the interrupting Chamber'ZB.

In accordance, with myinvention,the-baffle structure '39, is so constructed, as will bemore clearly' pointed 1 out hereinafter, that arc extin -y guishingf fluid under, pressure is directed -side- 1 wise into'the arcing passage lfl'sorasto engage the arc along substantially: its entire length" 76"- while this fluid and the associated are products exhaust from the passage 49 through restricted branch arcing passages within the baille structure 39 which radiate outwardly therefrom. As will be more fully explained hereinafter, these exhaust passageways are arranged so that the extinguishing fluid proceeds laterally through the arcing passage 99 into the branch passages without substantial movement axially along the arc itself as it is drawn by the downwardly moving contact l3 in arcing passage 49 durin the interrupting operation.

The baflle members shown in Fig. 4 and designated by the letters A, B, C and D are assembled to form the bolted, stacked, bafile structure shown in Fig. 2. Obviously, baffle B is simply bafile A laid on its reverse face.

An arcing passage 40 is somewhat generally defined centrally Within the baffle structure 39 by reason of the vertical alignment of the enlarged portion of each of the appropriately configured apertures in the several kinds of bafiies which constitute the complete stack. Defined on one side of this central passage 40 is a vertical channel 42 down through which extinguishing fluid must flow in passing from the oilcontaining reservoir chamber 28 toward the arcing passage 49. From vertical channel 42 the fluid is forcibly displaced laterally into the interrupting arc as it is drawn within the central passage 40.

For the purpose of discharging the ionized products of arcing from the interrupter structure while holding the arc itself entrapped therein for blasting by are extinguishing fluid directed into the arcing passage, the bafiies A, B and C are respectively provided with an open end slot 43a, 43b, and 430 and a closed slot 44a, 44b, and 440 associated in V relationship. With the bafiies of Fig. 4 arranged as shown in Fig. 2 it will be obvious that the V-slots of the bafiies form a pair of supplementary arc-confining passages 45 and 46 which diverge from each other and lead out from the arcing passage 40. Thus it will be clear that the closed ends of the slots 44a, 44b, and 440 constitute arc retain- I ing barriers which however are not effective to prevent the flow of arc gases from within the arcing passage 40 so that the latter may be immediately filled with fresh dielectric liquid after the arcs extinguishment at a current zero. erably the combined widths of the restricted arcing passages 45 and 46 are substantially less than the width 41 of the channel 42 or of the arcing passage 40. The purpose of the barrier portion 48 of the C baffie is to insure that the arc will not wander or loop back into the channel 42. Thus, irrespective of whether the arc is squeezed into one or other (or both) of the divergent passages, ionized arc products may vent through the open ends of the V-slots so that flow of fresh dielectric liquid may proceed under pressure into the passage 40 throughout the interrupting operation.

While I have shown and described a particular embodiment of my invention, it will be obvious Prefto those skilled in the art that various changes and modifications may be made without departing from my invention in its broader aspects and I, therefore, intend in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

I claim:

1. An interrupting unit for an electric circuit breaker of the fluid blast type comprising baffle structure including a plurality of stacked plates of insulating material provided with a substantially centrally disposed openin therein, the central openings in said plates defining a main arcing passage, the openings in some of said plates being elongated to one side to form a fluid channel in communication with said main arcing passage and being slotted in two divergent directions on the other side to form a pair of supplementary arcing passages, one slot in each slotted plate extending to the outer edge of the plate and one slot in each plate being closed at its outer end, said slotted plates being stacked so that the slots in alternate plates are coincidental, and means for establishing pressure within said unit.

2. An interrupting unit for an electric circuit breaker of the fluid blast type comprising bafiie structure including a plurality of stacked plates of insulating material provided with a substantially centrally disposed opening therein, the central openings in said plates defining a main arcing passage, the openings in some of said plates being elongated to one side to form a fluid channel in communication with said main arcing passage and being slotted in two divergent directions on the other side to form a pair of supplementary arcing passages, one slot in each slotted plate extending to the outer edge of the plate and one slot in each plate being closed at its outer end, said slotted plates being stacked so that the slots in alternate plates are coincidental, the central opening in at least one of said plates being closed on the side thereof adjacent said fluid chamber to form an arc barrier, an opening in said one of said plates in registry with the elongated openings in the other of said plates for defining a portion of the walls of said fluid channel, and means for establishing pressure within each unit.

CONRAD J. BALENTINE.

REFERENCES CiTED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,902,507 Juhlin Mar. 21, 1933 1,955,532 Coates Apr. 17, 1934 2,372,589 Leeds et al Mar. 27, 1945 FOREIGN PATENTS Number Country Date 460,219 Great Britain Jan. 25, 1937 797,657 France May 1, 1936

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