US2095441A - Circuit breaker - Google Patents

Description

Oct. l2, 1937.

R. R. HowE CIRCUIT BREAKER 3 Sheets-Sheet l Filed April 25, 1934 Oct. 12, 1.937. R, R, HQWE 2,095,441

CIRCUIT BREAKER Filed April 25," 1934 3 Sheets-Sheet 2 1 '/ll VIII/[IL III/1111111. v

Oct. l2, 1937.

R. R. HOWE CIRCUIT BREAKER 3 Sheets-Sheet 3 Filed April 25, 1934 Patented Oct. 12, 1937 UNITED STATES PATENT OFFICE CIRCUIT BREAKER ration ot Delaware Application April 25, 1934, Serial No. 722,305

11 Claims.

This invention relates in general to circuit breakers and more particularly to circuit breakers of the fluid break type which are used to intern rupt circuits carrying a large amount of energy and in which the arc formed during interruption of the circuit is extinguished in oil or some sim-- ilar insulating and arc extinguishing fluid.

In circuit interrupters yof the above type many attempts have been made to utilize the insulating properties of clean, cool, unionized oil in extinguishing the arc, but great difficulty has been experienced in the introduction of such oil into the gap between the separating contacts at the proper time due to the blast action of the gases generated by the arc. The prior developments attempting to solve this problem have resorted to enclosure of the separating contacts, to the utilization of inefficient and cumbersome pump means, the pump elements of which attempted to push a body of oil in the general direction of the separating contacts, and to pump means 1n which the pump elements are under tension during the entire normal (circuit closing) condition of the interrupter.

It is, therefore, an object of this invention to overcome these difliculties and to provide an improved method of and means for introducing insulating and arc extinguishing fluid between the separating contacts of a circuit interrupter to efllciently interrupt the circuit. v

Another object of this invention is to providean improved circuit breaker in which the introduction of insulating liquid between the separating contacts may be regulated as to the direction, time of starting and acceleration of the moving liquid so that the insulating liquid available for extinguishing the arc and interrupting the circuit is used in a very efficient manner.

It is also an object of this invention to obtain the above advantages without resorting to enclosure of the separating contacts, thus allowing the generated gases to freely expand and to be easily directed away and removed from the hot arc region, and further to provide a symmetrical, well balanced structure which will divide the generated gas pressure throughout the tank and which structure is so constructed that no additional current paths are formed when the oontacts are separated.

It is a further object of this invention to obtain the above advantages by means of a simple. compact interrupter in which the Contact and pump means are of unitary construction, easily removable for inspection, adjustment or repair.

These and other objects and advantages are obtained by this invention, the various novel features of which will be apparent from the drawings and description herein and will be more particularly pointed out in the claims.

Various illustrated examples of the application of this invention are shown in the accompanying drawings, in which:

Fig. 1 is an end view, partly in section and with the tank partly cut away, of a circuit breaker embodying the present invention;

Fig. 2 is a fragmentary view showing a modification of the contact arrangement of the circuit breaker of Fig. 1;

Fig. 3 is an enlarged view of the pistons used in the circuit breakers of Figs. 1 and 2;

Fig. 4 is an end view, partly in section, of another circuit breaker embodying the present lnvention;

Fig. 5 is a top view of the cam and roller mechanism taken along the line V-V of Fig. 4;

Fig. 6 is a section view of the contact structure taken along the line VI-VI of Fig. 4;

Fig. '7 is a fragmentary view of another embodiment of this invention utilizing a contact structure such as shown in Fig. l and an oil impulse means as shown in Fig. 4;

Fig. 8 is a fragmentary end View, partly in section, of another circuit breaker embodying the invention;

Fig. 9 is a top view of the baffle plates taken along the line IX-IX of Fig. 8; and

Fig. 10 is an end view of another piston arrangement which may be used with circuit breakers of this invention.

The circuit breaker shown in Fig. 1 has a tank I containing a body of insulating liquid such as oil. A supporting member 3 is removably mounted in the tank in any suitable manner. As shown in this figure, it may be brazed or welded in the removable cover 2. The bushing members 4 are inserted in apertures. in the member 3 and are held therein by means of the clamps 5. Contact rods 6 extend through the bushing members and have attached thereto current carrying members I0 having lower portions 1 which are the stationary contacts. Cooperating with the stationary contacts 1 are movable contact members 8 having portions 9 forming arcing tips. The movable Contact members 8 are formed on the upper end of cylinders I I which are carried by a bridging member I2 which in turn is carried by an operating rod I3. The operating rod I3 is connected to Contact operatingr mechanism not shown. A tubular member I4 of insulating material is rigidly fixed to the supporting member 3 as by threaded engagement with a member l5 which is attached to the member 3 as'by means of bolts I6. The member I4 carries at its lower end a cross member 2| carrying pistons 22 which cooperate with the cylinders I I to force fresh cool oil between the separating contacts as more fully described hereinafter. The member I4 has a guide member 23 for the contact operating rod I3 and is slotted at its lower end to allow for movement of the bridging member I2.

The pistons 22 are slidably connected to the.

cross member 2I being biased upwardly by springs 24. By selection of a biasing spring of the proper strength, a predetermined pressure is exerted on the oil or other insulating liquid in the cylinders I I previously to its introduction between the separating contacts. Further, the slidable connection of the pistons22 tothe cross member 2| insures opening of the contacts upon movement of the operating rod I3, regardless of whether or not the piston becomes jammed in the cylinder, the oil outlet at the top of the cylinder becomes clogged, or any such disabling of the pump means which would otherwise prevent opening of the contacts. Bleeder holes 25 are f cut in the lower part of the cylinders II to allow refilling of the cylinder II upon contact closing movement thereof. Concurrently mounted on the members I are frustro-conical plates 26 which direct the arc gases and hot oil upwardly away from the contactsand which extract heat therefrom. Vents such as 21 allow the gases to escape. Pistons 22 have apertures 21 and valve members 28, which, as shown in Fig. 3, allow oil to flow into the cylinders I I uponupward movement thereof to the contact closing position.

Upon contact opening movement of the operating rod I3, the bridging member I2 and cylinders II are moved downwardly. When the contacts 8 have moved past the tips of v.the contacts 1, arcs are drawn which transfer to the arcing tips 9. Upon first movement of the cylinders springs 24 are compressed, storing up energy so that when the arcs are drawn the `oil in the cylinders II is forced with a high velocity out of the cylinders and through the arcs. The hot cil and arc gases in the region of the separating contacts are forced through the cooling plates 26, thus drawing cool oil from the bottom of the tank toward the region of the separating contacts. It is thus seen that a body of clean fresh cool oil is forced between the separating contacts as soon as the arc is drawn which at the time of zero current will extinguish the arc and interrupt the circuit.

Due to the symmetrical arrangement of the cylinders II and piston members 22, unequal stresses on the contact operating mechanism are avoided and the generated pressures are more evenly divided through the tank. Upon reclosing of the contacts, the cylinders Il are filled `with fresh oil through the apertures 21 and 25 and are thus ready for the next operation. Av

dash pot mechanism 29 operates in conjunction with the lower end of the rod I3 to avoid a heavy shock upon opening of the circuit.

An important feature `of the invention is the unitary construction of the contacts and pump means so that by merely removing the'supporting member 3, which is done in the interrupter of Fig. 1 by removing the cover, or by dropping the tank therefrom, the entire unit is available for inspection, repair or adjustment.

The circuit breaker shown in Fig. 2 hasl a piston 22 and a cylinder II operating in much the same manner as shown in Fig. 1. The bridging member I2 has a slot 3| which directs a stream of oil from the cylinder II against and past a contact 32 which is carried by the bridging member I2. Bushing member 4 carries a conducting member 30, connected to the contact rod 6, which carries an arcing contact 33 and a current carrying contact 34. The contact 33 is biased downwardly by a spring 35 and its movement is limited by a stop member 36. Directing and cooling plates 31 direct the movement of the oil and arc gases upwardly away from the contact region and absorb heat therefrom.

Upon downward movement of the bridging member I2 contact between the bridging mem- `ber I2 and the contact 34 is rst broken, the

contact 33 remaining in contact with contact 32 until the stop member 36 engages member 30. Upon further movement of the bridging member I2 contacts 32 and 33 separate and an arc is drawn. The first downward movement of the bridging member I2 and cylinder I I compresses a spring 24 and starts movement of the oil in the cylinder II through the slot 3l across the contacts 32, 33 into the cooling plates 31. Thus the movement of the oil has started before actual breaking of the contacts 32 and 33 so thatv upon the drawing of the arc, cool oil is forced at a high velocity across the moving contact 32 and vthe arc is extinguished at the time of Zero current. The slot 3I is placed in the bridging member I2 so that the stream of oil not only envelopes the moving contact 32 but is in such angular direction that the arc gases and hot oil are blown upwardly away from the moving contact,

and sumcient cool unionized oil is introduced be- A tween the separating contacts to insulatethem at a time of zero current thus extinguishing the arc. In the embodiment of the invention as shown in Figs. 4, 5 and 6 the supporting member 3 has an enlarged portion 42 which adjustably carries a rod 4i threaded at its upper portion. The rod 4I is held in position by the adjusting nuts 43. Depending from the rod 4I is a cam 40 connected thereto in any suitable manner such as shown by a nut and bolt. The contact bridging member comprises a cylindrical tube 44 carried by arms 46 in some suitable manner so aslto be movable therewith as by means of clamps 45. The arms 46 are connected to the operating rods 48 slidably mounted in the enlarged portion 42 of the supporting member. The cylinder 44 has a slot 41 therein through which the cam member extends, so that it may cooperate with rollers 52 of pistons 50. The pistons have bifurcated ends 5I carrying the rollers 52 by means of pins 53, the rollers being flanged as shown at 54 riding over the edges of the cam member 40 so that downward movement of the cylinder 44 imparts longitudinal movement to the pistons. The pistons 50 are biased toward the cam by means of springs 55 held by a stop member such as 56. The contact rods 6 have connected thereto current carrying members 3U which carry the cur- 9,095,441 be started simultaneously with or at a time before the breaking of the cont cts 33 and I2. By suitably shaping the face of the cam member 40 the desired acceleration of the piston may be attained. vAlso due to the shape of thecam face the tendency for the breaker to reclosedue to the blast action of the arc on the piston is minimized.

As shown inv Fig. 7 a cam and piston arrangement shownin Fig. 4 may be applied to contact mechanisms such as shown in Fig. 1. Inthis iigureanozzle member 6B is vthreaded into the cylinder u providing a stop for the spring member l5. Upon opening o f the contactsan arc is drawn between the arcing tip 9 and the xed contact 1 which isimmediately extinguished bythe action' of the oil forced out of the nozzle at a high velocity across the arc. f y

Fig. 7 further illustrates how the embodiment of the invention as illustrated in Fig. 4 may be modified to includev the safety feature of the invention. 'I'he piston 5l has an acxiliary piston (I slidably held on the rod 59 and biased away from the piston by means of a spring .49. A predetermined pressure is therefore applied to the oil in the houle y65 at the time of separation of the contacts. The opening of the contacts, upon movement of the contact operating rods 48, is insured regardless of a possible disabling of the piston. 4l or clogging of the oil flow. In the. interrupters as shown in Figs. 4 and 7, the cam member I0 may be ilxed to the bottom of the tank rather than to the supporting member l as shown.

In the embodimentof the'invention as shown in Figs. 8 and 9, the bridging member 'in is connected to the operating rod 1|, carrying a cross member 12 connected thereto as by a pin 13. Depending from the cross member 12 are rods 'I4 carrying pistons 1.5 slidable thereon which cooperate with cylinders 11 to produce an impulse of oil upon contact opening movement of the rod 1I. Current carrying contacts 61 connect the bridging member 10 with the member Iii, when the breaker isin closed position. Extending lfrom thecylinder I1 to the fixed contact 1l is a4 pipe Il held by a clamp 82, the pipe and clamp being of insulation if-necessary to prevent the arc from `iumping across between the pipe or clamp and the bridging member 10. Directing .and cooling plates I3 are connected with the tank side wall but insulated therefrom and are held-in spaced relation by spacer members Il which direct the oil away from the arcing region as shown'by the arrows in Fig. 9. Upon movement of the operating rod'il, the piston l5 first compresses the spring I6 and is then forced downwardly into the cylinder '|1. Cool oil is thus forced at a high velocity out of the pipe li across the fixed contact Il and the hot oil and arc gases are directed away from the arcing region by the plates 83. Thus the arc drawn is blown oil' the fixed contact 18 and the circuit is interrupted. The methods as shown in Figs. 2 and 4 wherein4 the stream of oil is directed against the moving contact and the method shown in Fig. 8 wherein the stream of oil is directed against the fixed contact may be combined to obtain a more emclent tion.

In the embodiment shown in Fig. 10 a single cylinder and piston are used to supply the impulse for introducing the jets of oil for both sets of breaking contacts (not shown). The piston is biased upwardly by a spring Il and is slidably carried on a rod I1 suitably fixed to a member circuit interrup- VI! carried by a tubular member 0I of insulating material. This tubular member is flanged at its upper end and fastened to the cover member as by studs 93. 'I'he operating mechanism rods 94 are connected by an upper cross member 95 which carries a cylinder 96. Pipes O0 which'lead the oil tothe contacts are connected to the upper end of the cylinder and are clamped to the rods Il by means kofclamps Il." A lower cross member lll .carries the bridging member lli which can'ies the moving contact members. Valve member In is supplied for the piston so that the cylinder may rell with oil when it moves upwardly.

It is to be understood that changes may be made in the embodiments of the present invention described and illustrated by those skilled in the `ait'without departing from the spirit of the invention or from the scope of the following claims. K

It is claimed and desired to secure by Letters Patent: f

1. In a circuit interrupter, the vcombination of a tank containing arc extinguishing liquid, a supporting member removably mounted in said tank, a plurality of bushings carried by said supporting member, a plurality of contact members carried by said bushings, a bridging member, contacts carried by said bridging member and cooperating with said contact members to make and break a circuit, bridging member operating means extending through said supporting member, a stationary member rigidly depending from said supporting member, and means including a piston and cylinder forming pump elements providing for the ow of a jet of 'arc extinguishing liquid between said contact members and said contacts upon separation thereof, one of said pump elements being carried by said stationary member and the other of said pump elements being carried by said bridging member.

2. A circuit breaker of the impulse type comprising a casing containing arc extinguishing liquid, a supporting member removably mounted in said casing. bushings carried by said supporting member, contact members carried by said bushings, a bridging member having contacts oooperating with said contact members to form two breaks in series, a caxn member depending from said supporting member. means whereby*I `said cam member cooperates with said bridging member previously to `and during the separation said-contacts and contact members for forcin said arc extinguishing liquid under pressure across the arcing surfaces of said contacts.

3. In a circuit interrupter of the impulse type in whichthe circuit is made and interrupted by a plurality of pairs of serially connected contacts immersed in a tank of insulating liquid, thecombination of a tubular bridgingmember carrying one of each of said pairs of contacts,` a plurality of pistons in said bridging member, means 'including a cam whereby said pistons cause movement of said insulating liquid within said bridging member upon contact openingv movement thereof and nozzle means for regulating the direction and velocity of said moving insulating liquid so that it will be forced across the arcing surfaces of said contacts and extinguish the arcs.

4. In a circuit breaker, the combination of tank containing insulating and `arc extinguishing liquid, a plurality of pairs of contacts immersed in said liquid, a tubular bridging member carrying one each of-said pairs of contacts and connecting the same in series, a plurality of pistons operable rwithin said bridging member,

cam means/for oper vting said pistons at a pr e` determined velocity and acceleration upon con' tact opening movement of said bridging member to cause movementof said liquid,`and rrneansfor regulating the direction and velocity of said movement of said liquid so that upon' separation AofI said pairs of contacts and .the 'drawing' of ran arcY therebetween said liquid is forcibly introduced vbetween .the separating contacts thereby displacing the hot liquid and arc gases andre-v u therefrom, a piston carried vby and movablerelative to ysaid stationary member, a cylinder movable-with saidlbridging member and cooperating with said piston and means including an aperture in saidl cylinder whereby saidliquid is forcibly introduced across the arcing surfaces ofy said contacts, .i i.

6. In a circuitbreaker the combination of a tankcontaining insulating liquid, a plurality of terial depending l member, and means tons associated with said stationary member'and pairs of coactingV contacts immersedA in said liquid,a supporting member removably mountedin said.tank,.a lstationary member of insulating mafromv said supporting member, slots in` said.stationary member,v a conducting bridging memberl extendingfthrough said slots and serially connectingl said pairs of contacts, a. plurality of cylinders carried by said bridging including a plurality of-piscooperating 4with saidY cylindersy to drive said liquidV between said contacts upon separation thereof. v

V'7. In a circuit interrupter ofthe impulse type in which the circuitis made and'in'terrupted by aplurality of pairs of serially connected coacting contacts immersed in a tank of arc extinguishing liquid, the combination of means for supporting one of each of said pairs'of contacts, means for actuating the other'of each of said pairs of contacts, means including a piston and cylinder imvmersed, in' said liquid for lforcing a jet of said liquid betweenmsaid contacts upon separation ,thereof and means whereby saidl contact 'supporting means, said contact actuating means and said piston andicylinder means are removably supported in said tank as ay single unit.

8. A' circuit breaker comprising a tank. containing arc extinguishing liquid, a plurality of pairs of coacting contacts immersed in said liquid, va bridging member serially connecting said contacts, a supporting vmember mounted in said `member removably pump means for forcibly introducing said liquid f across the arcing surface of one of said contacts,

tank, a stationaryinsulating member depending therefrom, a piston carried'by said stationary member, a cylinder movable with said bridging member and cooperating with said piston, means including: said piston and said cylinder whereby said liquid isforcibly introduced across the' arcing surfaces of said contacts, and means operable upon failure of operation of said liquid introducingnmeans for causing said piston .tomove relative tosaid stationary member.

' 9. In a circuit interruptor of the impulse type in which the circuit is made and interrupted by a plurality of pairs of serially connected contacts immersed in a tank of insulating liquid, the combination of a tubular bridgingfmember having an opening at each end thereof and carryingone of each of ysaid pairs of contacts at each said opening, a plurality of pistons in said bridging member, and means including a camfoperable` upon the contact opening movement ofl said bridging member for actuatingsaid' pistonsto cause movement of a portion of said liquid.

through said openings.

10. A circuit interrupter-comprisingl a-casing containing arc extinguishing liquid, a plurality of pairs of xed and movable contacts cooperating `to draw an are y' in said liquid, `afmovable bridging member supporting and electrically connecting said movable contacts, a stationary memberl removably supported in said casing, pump means for forcibly introducing said liquidacross the arcing surface of one Yof said contacts, said means including relatively movable elements,

oneof said elements being carred'bysaid stationary member and another of said elements being carried by said movable bridging member,

and means operative under abnormal conditions for operatively disabling said pump means so as to permit separation of said contacts. Y

11. A circuit interrupter comprising acasing containing Yarc extinguishing liquid, a plurality -of pairs of xed and movable contacts cooperating to draw an arc in said liquid,` a movable bridging member supporting and electrically connecting said movable contacts, a stationary supported in said casing,

sa'id-v means including relatively movable elem-ents, one of said elements beingl carried by said stationary member and another of said elements being carried .by said .movable bridging member, and means for resiliently connecting vone of said elements to its supporting member whereby said element is biased in the direction of movement thereof relative to the other ofsaid elements. CHARLESv S. HEGEL,

AAd'mim'sfrator of the Estate of Ramon R. Howe,

Deceased.

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