US2761938A - High voltage circuit breakers - Google Patents

Description

Sept. 4, 1956 Original Filed Jan. 11, 1947 J. D. WOOD ETAL 2,761,938

HIGH VOLTAGE CIRCUIT BREAKERS 5 Sheets-Sheet l g 52 M 6 g 45 Q 0 34 o 0 1Q o INVENTORS 1 EPAfi M F18- BY den/w? jam/51 mmmx @M lrram avs 3 Sheets-Sheet 2 p 1956 J D WOOD ETAL HIGH VOLTAGE CIRCUIT BREAKERS Original Filed Jan. 11, 1947 oaM aM United States Patent HIGH VOLTAGE CIRCUIT Joseph D. Wood, Stralford Village, .and Arthur Stephen.

Caswell, Philadelphia, Pa, ass'ignnrs to il-T E Circuit Breaker Company, Philadelphia,-Pa.

Gar present invention which is.a division-f United States Patent No. 2,613,299, issued'October 7, 1952, and

United States Patent No. 2,646,481, issued =luly 2 1; 19.53, relates to high voltage high capacity circuit breakers, andrmore particularly to circuit breakers having an inter rupting rating of 50,000 kva.:and better in:anyvoltage range between 2360 andSOOOWoltsand at'current ratings of 660 and 1200 amperes.

Essentially our inventionis directed to the production of high voltage high capacity ah- :break switchgear 'in such .a manner .as to provide the increased interrupting capacity required by means of the simplest :elements which are manufactured and assembled bymass :productionrmethods in themost economical way.

.In order to achieve this result, =it.- has been necessary to design-our novel circuitbreakcr so: that the various elements thereof may be manufactured :in individual relatively inexpensive single unitary circuit breaker :bya 1 struction utilizing castings and welded parts and shave usually been custom-builtfor a particular-job rather-than made in aparticular grouping .ortlinerfol' particular-interrupting capacities. I

.Our novelconstruction fabricated entirelysfrom shut or bar stock into many sub-assemblies :and using no castings lends itself .to massproduction manufacturing methods which .together- .with simplicity in .design .reduce the .cost .of the high voltage high capacity breaker to a point where its cost compares favorably audat times is even less than many low voltage relatively low capacity mounted on and "removed 'from the circuit *breakers.

Both the upper and 'lower "back connection members have secured thereto the back disconnect contacts which are part of the same assembly,

The mechanism assembly which includes all of 'the operating members constitutes a single sub assembly which may readily be mounted on the circuit breaker-panel'a'nd disconnected therefrom-and which may be connected =to'themovable contact arm by passing as'ing'lepinthroug'h the'connecting link. r

Accordingly anobject of our-invention is the-construction of a high capacityhigh noltage circuit :breaker,

capable zof-zzinterrupting arcs of eithQQOdc-va. capacity or 2,761,938 Patented Sept. 4,1956

2 even better, and economical in design. and .construcfi-Qn, capable .of .unit subfassembly =manufacturing operation, The foregoingand manyother .objects of our invention will become apparent from -.the..following description of the drawingsin which V Figure .1 is a side viewinperspective, partlybroken away showing our novel circuitbreaker -.assembledand mounted on a truck.

Figure 2 is .a side, back view, iuperspective, showing our novel circuit .breakenmounted .on a truck with .the interphase barrier in position.

Figure 3 is anvenlarge d side front view .in perspective partially broken away showing the lower terminalase sembly, upper terminal assembly, the blow-out .coil assembly and the movablecontact-bridge assembly.

Figure4is a detail "of 'thecoristruction of the front end of lower terminal of our novel circuit Ibreakerlf Referring ,now toFiguresf 1, 2 and 3, our novel circuit breaker is shown preferably mounted on a movable truck. The movable truck comprisesa back main supporting structure --which includes the vertical support members 10 and .11 connected together 'andfinterbraced at thelower end by the masonite panel 12 and at the central and upper portion by the cross-bars 13,14 and 15 which are connected v as shown, "in any. appropriate manner, was for in.-

stance by .boltsandnuts toTthe-vertical members It and Also, .thec ontro l switch contacts indicated generally .at

'70 of Figures 1 and 2 and'the. grounding contacts .71, [72 of Figures 1 and 2 maybe standard units. The essential elements .as above pointed out with respect to these units is the unit assembly arrangement which is possible with the-construction'herein shown.

The rear endof the operating mechanism assembly 46 is supported on the cross bar 74 which is held .by-the ibolts 75,75 across the top of thelower panel '12. vCross. 'bar 74 also provides means for supporting additional assemblies. The specific novel assemblies or sub-as sembliesshown in Figures :1 and 2 and forming an essential.

part ofthe novel circuit breaker here shown-are the op.- erating mechanismshown'in Figure 1, the lower terminal assembly shown inFigure 4, the upper terminal assembly .o'fPigure 3, the movable contact arm or'br'idge assembly of Figure '3, the blow out assembly of Figures, and an arc chute assembly. The specific operation ,of these individual assemblies renders possible the entire high speed high capacity circuit breaker which our novel -unit embodies. .eration are specifically described in connection with Fig- Additional assemblies which facilitatethe .op-

ures'S and9 which show the interphase barrier assembly.

The various assemblies above mentioned will be de scribedin order, going from the bottom toward the .top of :the circuit breaker without specific emphasis on any one of "the assemblies over the other.

"It must be emphasized, however, that an important feature vof-the circuit breaker is in the novel are chute construction in conjunction with the novel blow out ,con-

struction.

The operating mechanism utilizes .as .closely :as possible the simple'principle-of the lever operated switch :with only enough addition thereto to provide automatic 4 response to toyercurrent conditions :in order to :trip %the circuit breaker and also to provideasolenoidaclosingrmeans. The sundescribed. I

Thus, while the arc chute assemblyand the blowout assembly make possible'the high capacity operation and high speed operation which are essential to theoperation of the circuit breaker asa whole, the simplicity of the other assemblies makes possible the economical and eflicient construction,

The individual unit assemblies facilitate storage of parts preparatory to final assembly and thus make it possible to fill orders quickly.

' Thus the first sub-assembly which consists of the back panel and the back wheels 20 and 21 is essentially a simple flat member which may readily be stored and does plification of this operating mechanisrnmakes possible i the production of the inexpensive circuit breaker'herein not take up any substantial amount of space (see Figures l and 2). V v

"Heretofore, the difficulty. encountered in pre-manufacture of sub-assemblies in anticipation of future orders resided in the fact that the main frame of the circuit breaker or other switchgear usually was as big as the circuit breaker itself, so that the manufacture and especially the storage of the main frame presented the same 23 is secured at the rear endto the lower end of the vertical members 10 and 11 above the bearings 17 and 18 for'the rear wheel. The bottom platform 23 in connection with the back panel form the vertical supporting mem' bers 10 and 11 andtheir interbracing structure and taken together with the rear wheels 20 and 21 and the front swivel wheel 24 comprises the truck or mounting'for. the

circuit breaker and constitutes a single sub-assembly which i may readily be stored without requiring any additional space and which may readily be attached by two screws to the lower end of the vertical members 10 and 11.

This type of unitary sub-assembly construction which may readily be interconnected with other elements in order to make a complete truck, facilitates modification and of variation of sub-assemblies in order to meet the specific orders. I

Thus in the event various control elements must be multiplied to a substantial extent in the final circuit breaker thus requiring perhaps a custom built lower platform 23,.

this lower platform 23 may be built tothe unique specifications of the customer and may then be combined with the standard back panel construction which is kept in stock. However, the entire truck construction including the first and second subassemblies above described are built in full anticipation of all requirements to which the particular circuit breaker may be put, so that partic-.

ular custom made back or bottom portions of a track will be required only in exceptional cases. The upper terminal assembly 30, and the lower terminal assembly 31 for each of the three poles is formed from a single bar of copper of rectangular cross section appropriately insulated by phenolic insulation as described more specifically hereinafter in connection with Figure 3. The terminal assembly elements 30, 31 are carried by the vertical supports 10 and 11, as well as the central vertical support 32 which is carried between the lower masonite plate 12, and the upper cross bar 14, as shown in Figure 2.

Each of the vertical members 10, 11 and 32 is recessed at 33, 33 to receive theterminal members and accurately position the same. Each of the terminals is provided with a side plate or flange 35 hereinafter more specifically I described inconnection with Figure 2.

4 1 Each of the vertical reinforcements 10, 11 and 32 is a rectangular steel member, so that While the recesses 33, 33 are cut out in the vertical reinforcement they are incised only in the portion of the rectangular steel member I which is normal to the back panel 56. The legs of each of the rectangular members 10, 11 and 32 carry the bolts 36, 36 whichengage the flange members 35 of the terminal element. Thusit will-be seen that two bolts or screws 36 are all that are necessary to secure each of the terminal elements in place, these bolts being locked in secured position by the nut 37 as shown'in Figure 2.

Each of the upper and lower terminal assembly members 30 and 31 also carry the spring biased disconnect contact elements 38, 38 also hereinafter more specifically described in connection with Figures 1 and 2, but shown also in Patent Number 2,029,028. The intermediate cross bar 13, which is secured to the vertical members 10, 11 and 32 by the bolts 40, also carries at its outer end the wheels 42 on an appropriate shaft extension thereof, the said wheels 42 cooperating with appropriate" tracks in the compartment to guide the truck into and out of the compartment properly. V The racking and indicator assembly shown generally at 43 of Figures 1 and 2 also carries the front wheels 5 44, 44 to ride on the guide tracks of the compartmnet in which the circuit breaker is housed.

The movable contact assembly shown generally at 50 of Figures 1 and 3 is connected at its lower end to the lower terminal assembly 31 in the manner hereinafter described, and is provided with a link 51 which is connected to the contact operating arms 52 projecting up from the operating mechanism assembly 46. The movable contact bridge assembly which of course has as many poles as there are upper and lower terminal assemblies, three in the particular instance shown, is provided with contact elements hereinafter more particularly described v in connection with Figure 3.' The blowout coil assembly 53 which includes. thecoil 54 of Figure 3 and the laminated blow out iron legs 55, is mounted on the upper insulating back panel 56 also across the bars 15 and 14 and the upper portion of vertical supporting members 10 and 11 and is supported thereby. 1 1 I It is spaced from the bars-10, 11, 32, 14, 15 by the upper insulating back panel 56 which panel is secured across the bars 10, 11 and 32 as shown in Figures 2 and 3.' Appropriate openings 59, 59 are provided in the panel 56 to permit the terminal members 30 and 31 to project therethrough in a manner shown-in Figures 1 and 3.

The operating mechanism shown in the perspective front view of Figure 3 in the parent application Serial Number 721,648 filed January 11, 1947, comprises essentially a simple switchoperating mechanism with the' addition of the necessary .tip unit trip-free operation and solenoid closing mechanism necessary for automatic circuit breaker operation.

Lower terminal assembly The lower terminal 31 has the side flanges 156, 156

secured thereto in any suitable manner, to cooperate with the movable contact arm as shown in Figure 3. usual procedure for insulating a terminal bar such as that shown in Figures 1, 2 and 3, phenolic insulation material is wrapped around the bar and tightly pressed thereon. This is a complicated process which must be performed on special machinery and by those having special skills in the field.

In the present construction, instead of wrapping phe- In the *3 nolic insulation tightly around the "bar 11.50, the flat tube 151 is used, said tubebeing provided-with a conductive lining'162. This tube is placed over the bar 150 and then pressed into tight :engagement with the bar 150 to provide theinsulation cover'there'for.

The principal reason'for Wrapping the insulation in the prior art ,was that no minute air pockets could be permitted since at high voltages these would result'in corona discharge, causing. progressive dielectric deterioration and thereby resulting inbreakdown of the insulation. Consequently great care was required in'the wrapping of the insulation. I

Wehave discovered 'thatby using asle'eve of insulating material and making fthe' inner surface fthe -sleeve conductive,'the sleeve may "simply be presseddown around the tube toconform with-the'contour of the bar and provicle a completely engaging surface to surface contact thus avoiding anydeleterious effects resulting from any minute air pockets that 'may remain. Thus where the prior cost of wrappingsu'ch bars was-in the neighborhood of $12.00 per bar "and it was necessary "to send-the bar out to be wrapped by-special machinery, our invention makes possible the insulation .of the bar at the circuit breakerp'lant at' -a cost-of'about" $l:50.

Upper terminal assembly .The upper terminal assembly '30 shown in Figures 1, 2 and 3 also comprises abar'160 of copper ,having an insulating sleeve1'61 mounted thereover in the same manner as previously described in connection with the lower terminal assembly of Figure 3.

The rear end of the bar 160 has the conformation 164 to receive and hold the main disconnect contacts 38 shown in Figures 1 and 2. The front end of bar 160 has secured thereto the stationary main contact 167 and the stationary arcing contact 166 (Figure 3). The upper end of the front portion of bar 160 has secured thereto the insulating blocks 165 and 16S (Figures 1 and 3),

which have secured thereto the insulating plate 170 having the upper slotted extension 170a. Connector 171 is secured in any suitable manner to the insulating blocks 165 and 168 but is insulated from the contact bar 160 and the arcing contact 166 and stationary contact 167.

Connector 171 has a slotted or cut away portion 179 at its front end between which, and spaced from either edge, the forward end 208 of the movable contact arm 204 comes to rest when the contacts are in engagement as will be described hereafter.

Movable contact assembly In Figure 3, we have shown one of the contact arms 80. The contact arm 80 comprises a pair of copper bars 180, 181 between which is secured, at the upper end by pin 205, the arcing contact arm 204. The movable arcing contact arm 204 is held in proper spaced relation by the spacer washers 184'184, all of which are forced into proper current carrying relation by the spring washers 233-233. The upper inside edge of the copper bars 180-131 carry special arc resisting silver alloy contact blocks 185 which comprise the main movable contacts.

The lower ends of the bars 180 and 181 are provided with the registering openings to receive the pin 187 (Figures l and 3) which pin passes through the openings and through the slotted openings 188 (Figure 4) of the front end 152 of the lower terminal 31 which is received between the arms 180181.

The pin 187 is provided on each side with a lug 190 (Figures 1, 3 and 4) carrying the bar 191 which passes through openings 193a (Figures 3 and 4) of the side flanges 156. Compression springs 193 on each side are captured between flanges 156 on each side and the lug 190 of pin 187 on each side thus forcing the lower end or pivot of the contact arm out toward the right with respect to Figures 1 and 3 at the pivot point 186.

The contact arm effectively pivots about pin 200 (Figuresl and 3) which is connected'betweent'arms181 and "and'which carries the end "of link 51 "connected to contact operating arm 52. Thus, 'compressionsprings 193 force the contact arm' 80 to rotate counterclockwise about the pin 200 within the limit of the lengthof slot 188 on the lower terminal and thus forces the movable contact into close wiping-engagement with the-stationar-y contact member 167 "(Figures 1 and '3').

in any position'of-the'arm 80 otber'than the closed position of the arm 80, compression springs 193 push The forward end 152 of the lower =termina1 'of Figure 4 is provided with silver alloy inserts 202, 202 "tobear against the inner surfaces of arms 180, 181 of contact arm 18%. Thus it will be seen-that no pig'tails are used, but appropriateelernents are used on pin 187 to squeeze the lower ends of arms 181, .180 against the insert 'contacts 202 on thelower terminal.

fltecontact springs I193 areilocated close'tothe pivoted stud #187 .which is 'a distinct -advantage:because they are welliaway fromarcing-zone. The tconnectionof link 51 to the contact arms is at a point 200, as above pointed out, well above the center point of the arms 80, so as to make these contacts blow-on contacts as explained in the following description.

In response to a rise in currents, magnetic forces developed in these contacts tend to increase contact pressure at all contact points. The arcing contact arm 204 is pivotally mounted on the pin 205 between the contact arms 180, 181 and the spacer washers 184, and is provided with an arcing contact element 206 and the horn 207. The lower end of arcing contact arm 204 is connected by the floating pin 210 to the link 211 which in turn at this lower end bears against the milled surface 212 of the milled pin 213 carried between the arms 180, 181.

Tension spring 215 connected between lug 216 and spring eye 217 is arranged to rotate link 211 clockwise around the bearing furnished by the milled portion 212 of pin 213. The lug 216 is adjustably mounted on screw 220 which in turn is received in the tapped opening 221 of pin 222 carried between the arms 180, 181. Rotation of screw 220 results in moving lug 216 to change the tension of spring 215 and thus increase the bias thereof.

Spring 215 thus acts on links 211 to cause the toggle 211210204 to collapse in a direction to force the arcing contact 206 to the left. The full collapse of this toggle is prevented by the adjustment of screw 220 which bears against the end 225 of arcing contact arm 204. Tension spring 215, however, thus drives the arcing contact element 206 out to the left with respect to Figure 3 where it will make contact with the stationary arcing contact 166 before the main contacts engageand where it will maintain contact with the stationary arcing contact until after the main contacts have separated.

Since the center 205 of arcing contact arm 204 is well above the mid-point thereof, a blow-on action of the arcing contact occurs, also thus ensuring that the arcing contacts will remain firmly in engagement until the main contacts have separated.

The position of the arcing tips 206 above the main contacts 167 forms an upward loop in the circuit which tends to initiate a blow out action to start the arc upward when drawn.

In order to protect the lower terminal structure against any possible defect in the arc chute or blow-out mech anism which would tend to drive an are down, an insucontact: separates.

lower terminal bar 150.

Spring 215 ensures that the movable arcing contact will 7 move into engagement with the stationary arcing contact as the contact arm begins to open and before the main The arcing contacts will then stay in engagement for a substantial portion of the opening movement depending on the setting of screw 220 I '(Figure3).

Since many variations and modifications of our invention should now be obvious to those skilled in the art, We prefer to be bound not by the specific disclosure herein contained, but only by the appended claim.

We claim:

In a multi-pole automatic circuit interrupter comprising a first terminal sub-assembly, a second terminal subassembly, operating mechanism and an insulation back panel; said first terminal sub-assembly comprising an electrical conducting bar having disconnect contacts secured to one end and stationary contacts at the other end; said second terminal sub-assembly comprised of an electrical conducting bar, a movable con-tact arm and a link; said last mentioned bar having disconnect contacts secured to oneend and one end of said movable contact arm pivoted at the other end; a secondend of said movable contact arm having movable contacts secured thereto; said link connected at one end to-said movable contact arm and at the other end to said operating mechanism; said stationary contacts and said movable contact moved to engaged and disengaged position with respect to each other by said operating mechanism through said'link and said movable contact arm; said back panel mounted on three vertical support bars; each of said vertical support bars associated with one pole of said multi-pole circuit interassembly; said first andsecond terminal assembly 'being individually and independently mounted'on and removable from said support bars and said back panel; each of said vertical support bars having individual clamping means to position and maintain said first and second terminal assembly associated therewith.

References Cited in the file of this patent UNITED STATES PATENTS 1,828,281 Crabb's Oct. 20, 1931 2,259,005 Scott Oct. 14, 1941 2,378,124 Bolsterli June 12, 1945

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