US2666117A - Circuit interrupter - Google Patents

Description

Jan. 12, 1954 w, M, LEEDS 2,666,117

I CIRCUIT INTERRUP'I'ER Filed Ma 18. 1950 s Sheets-Sheet 2 5 Fig.2.

Winthrop M;Leeds.

zw f v I Patented Jan, 12, 1954 UNITED STATES PATENT OFFICE 2,666,117 cmcorr mrnaaur'rnn Winthrop M. Leeds, Pittsburgh, Pa., asslgnor to Westinghouse Electric Corporation, East Pittsburgh, Pat, a corporation of Pennsylvania Application May 18, 1950, Serial No. 162,655

23 Claims.

' This invention relates to circuit interrupters in general, and more particularly to arc-extinguishing structures therefor. 1

The general object of my invention is to provide an improved high-speed type of circuit interrupter or simple construction in which the electrical circuit passing therethrough may be more eiiectively interrupted than heretofore.

Another object is to provide an improved circuit interrupter in which the arc-extinguishing assemblage may be bodily moved near the end or the opemng operation to thereby establish a pair break is established adjacent one end or the movable arc-extinguishing assemblage and an interrupting break is established adjacent the other end or the arc-extinguishing assemblage.

Still a further object is to provide an improved circuit interrupter of the type described in the immediately preceding paragraph in which improved low4current piston means are incorporated into the structure and in which more effective fluid flow is achieved to more quickly and rapidly bring about extinction of the interrupting arc.

of disconnect gaps in the circuit between the line terminal members and arc-extinguishers.

Still another object is to provide a more eiiective arc-extinguishing structureior the moderate voltage ranges, for instance kv. to 69 kv., in which only a single pressure-generating break and a single interrupting break are required to efiectively interrupt the circuit.

The main. advantage of my construction over prior art structures is the high speed of operation possible by initially moving only the light-high speed contacts, while the relatively heavy are extinguishing assemblage remains stationary. Prior art structures utilizinga grid assemblage bridging the terminals have the grid assemblage rigidly connected to the lift rod; consequently, the

arrangement cannot be high speed in operation. with my construction, however, high speed is possible because'only the light contacts are moved during the arcing period, while the heavy grid is moved only as adisconnecting function.

Another object is to provide an improved high ,speed type of circuit interrupter of the liquidbreak type in which a pair of terminal bushings extend into an enclosure wherein a movable arcextinguishing assemblage bridges the terminal bushings in the closed circuit position of the device, and in which the arc-extinguishing assemblage bodily moves as a unit'near the end of the opening operation to insert a pair of disconnect gaps into the circuit after the high speed contacts have cleared the circuit.

A further object is to provide a circuit interrupter of the type specified in the immediately preceding paragraph in which the operating rod effects opening of the contact structure and following a predetermined time delay operates to eilect movement of the arc-extinguishing assem blage to its open disconnect position.

-Another object is to provide an improved liquidbreak circuit interrupter in which a movable arcestinguishing assemblage bridges a pair" or tel? minal bushings wherein a pressure-generating Further objects and advantages willbecome apparent upon reading the following specification taken in conjunction with the drawings in which:

Figure 1 is aside elevational view, partially in Fig. 5 is a sectional view taken along the line VV of Fig. 2;.

Fig. 6 is a sectional view taken along the line VI-VI of Fig. 2;

Fig. '1 is a side elevational view, partially in' vertical section of a modified type of circuit interrupter embodying principles of my invention and shown in the closed circuit position;

Fig. 8 is a sectional view taken along the line VIII-VIII of Fig. '7;

Fig. 9 is a view similar to that 01 Fig. '7, but showing the contact structure in the partially open circuit position;

Fig. 10 is a fragmentary sectional view taken along the line X-X of Fig. '1;

Fig. 11 is a fragmentary sectional view taken along the line XI-XI of Fig. 7; and

Fig. 12 shows a modified type of interrupting unit in the open circuit position.

Referring to the drawings, and; more particularly to Fig. 1 thereof, the reference character I designates a suitable enclosure such as a tank filled to the level 2 with a suitable arc-extinguishing fluid 3, in this instance circuit breaker oil. Depending from the cover 4 of the tank 1 are a pair of terminal bushings 5, 0. Secured to the lower ends of the terminal bushings I, 3 are stationary disconnect contact assemblages I, 8.

Bridging the space between the stationary disconnect contact assemblages I, 8 is a movable arcextinguishing assemblage or fluid flow transmitting means generally designated by the reference numeral I0, and the internal structure of which is more clearly shown in Figs. 2-8. Associated with the movable arc-extinguishing assemblage ID are a pair of rod-shaped movable arcing contacts II,' I! secured to the outer extremitie of a conducting cross-bar l3, the latter being reciprocally movable in a vertical direction by an insulating lift rod i 4.

The insulating rod I4 is actuated by suitable mechanism, not shown, responsive to manual operation or to the existence of'overload conditions existing in the circuit controlled by the interrupter.

Referring more particularly to Fig. 2, it will be noticed that secured to the top of the arcextinguishing assemblage ID are a pair of movable disconnect contacts |5, |5 which enter contact housings II, II, the latter being threadedly secured and clamped to the lower ends of terminal studs I9, 20 passing interiorly through the terminal bushings 5, 5.

Disposed interiorly within the contact housings l1, iii are contact segments 3| biased radially inwardly by flexible leaf springs 22 and serving to electrically interconnect the stationary disconnect contacts 23 with the movable disconnect contacts l5, l5.

As shown more clearly in Fig. 2, the movable disconnect contacts l5, II are integrally formed with cap structures 24, 35' secured by bolts 26 -to the top insulating plate 21 of the movable arcextinguishing assemblage Ill. Preferably I provide arcing rings 28, 23 into which I threadedly secure the lower extremities of the bolts 25.

Disposed interiorly within the cap structures 24, 25 are a plurality of contact segments 30 biased radially inwardly by flexible leaf springs 3| to bridge the movable disconnect contacts 5, i6 with the rod-shaped movable arcing contacts II, II. Preferably, apertures 32 are provided at the top of the cap structures 24, 25 controlled by a washer-shaped movable valve 33. In the closed position of the interrupter, as shown in Fig. 2, the valve 33 rests upon the top of the contact segments 30 permitting the apertures 32 to be open and allow gas to escape as the assemblage l0 fills with fluid. However, during high-pressure conditions within the movable arc-extinguishing assemblage III, the valve 33 is forced by the pressure upwardly away from the contact segments 30 to close the apertures 32 and thereby eflectively close the pressure-generating arc passage 34 at its upper end and also close the interrupt-- ing arc passage 35 at its upper end.

Associated with the top insulating plate 37 of the movable arc-extinguishing assemblage I0 is a combination dashpot and low current piston means generally designated by the referenc numeral 36. The piston means 38 includes an insulating cylinder 3'! having its lower end 38 threadedly secured to the top plate 21 of the assemblage Hi. The upper end of the cylinder 31 is provided with an inwardly extending flange portion 39 which serves as the upper seat for an insulating washer 43. The washer 4|! in turn provides the upper seat for a compression spring 4|, the lower end of which seats within an annular recess 42 provided in an insulating plate 43, the latter being disposed immediately adjacent to the top insulating plate 31. An enlarged portion 44 of the operating rod l4 strikes the plate 43 near the end of the opening operation 3 to forceably drive the movable arc-extinguishing assemblage |3 to its disconnect position as shown by the full lines inFlg. 1.

The interrupting structure for the arc-extinguishing assemblage III will now be described. As noticed in Figs. 2 and 3, the arc-extinguishing assemblage l3 includes a plurality of suitably formed insulating plates disposed in contiguous relation by a plurality of insulating tie rods 45 (Fig. 4) Immediately below the insulating plate 43 is an insulating plate 46, the configuration of which is more clearly shown in Fig. 4. With reference to Fig. 4', it will be observed that the insulating plate 48 is provided withan elongated cutout portion 41. Disposed within the cutout portion 41 is an insulatingplate 43, which, in conjunction with the plate 46, forms two fluid flow passages 49 which interconnect the pressure-generating arc passage or pressure-generating chamber 34 with the interrupting arc passage or interrupting chamber 35. It will be observed that the insulating plate 48 has an enlarged aperture 50 provided therethrough through which passes the operating rod |4.

Disposed immediately below the insulating plate 43 is an insulating plate 5|, the configuration of which is more clearly shown in Fig. 6. With reference to Fig. 6, it will be noticed that the insulating plate 5| has apertures 52, 53 provided therethrough, through which pass the movable contacts II, II. Also, the plate 5| has provided therein the aperture 50, which also was the case in Fig. 4, accommodating travel of the operating rod l4. Apertures 54 are provided in the several plates to accommodate the insulating tie rods 45, the latterserving the purpose of rigidly holding the plates together in contiguous relationship.

Immediately below the insulating plate 5| is an insulating plate 55, the configuration of which is more clearlyshown in Fig. 5. Asnoticed in this figure, the insulating plate 55 is composite, being formed by the cooperation oi Y :3. insulating plates 53, 51. Each of these plates 58, 51 is'provided with the apertures 54 to accommodate the insulating tie rods 45. The insulating plate 55 is provided with a cutout portion 53 as shown. It will be observed that the plates 53, 51 are spaced apart to provide two outwardly extending discharge passages 59, 60 leading in diametrically opposed directions out of the assemblage Ill. The function of the discharge passages 59, 60 will become more apparent hereinafter.

Immediately below the insulating vent plate 55, is a second orifice insulating plate 5|, then follows an inlet insulating plate 46, and another orifice insulating plate 5|, a vent plate 55, and another orifice insulating plate 5|.

Immediately below the lower orifice plate 5| is an insulating plate 6| having a configuration similar to that of the orifice insulating plate 5| with the exception that the apertures 52, 53 are considerably enlarged as shown at 52, 53. In addition, the insulating plate 5| is provided with a centrally disposed annular aperture 54 which accommodates an accelerating compression spring 55.

The lowest plate of the movable arc-extirguishing assemblage I0 is designated by the ref erence character 65. It is similar in construction to that of the insulating plate 8| but in s place of the enlarged apertures 62, I3 is provided with only small apertures :61.- 33, through which pass the rod-shaped arcing contacts II, it with only slight clearance.

The operation of my improved circuit interrupter will now be explained. In the closed circuit position of the interrupter, as shownin Fig. 2, the electrical circuit therethrough includes terminal stud i3, stationary disconnect contact-23. contact segmentsll, movable disconnect contact li. contact segments 33, movable arcing contact If, conducting cross-bar l3, movable arcing contact I I, contact segments 33, movable disconnect contact I6, contact segments II associated with the right-hand stationary disconnect contact assemblage I. stationary disconnect contact 23 associated with the righthand stationary disconnect contact assemblage I, to the right-hand terminal stud II of the interrupter.

when it is desired to effect opening of the interrupter. or in response to overload condi-- tions existing in the electrical circuit controlled by the interrupter, suitable mechanism, not shown. is actuated to cause rapid downward motionof the insulating lift rod l4. The'downward movement of the insulating lift rod i4 is accelerated by the accelerating springs associated with the pole unit mechanism, not shown,

. blage It at the time of initial downward movement of the arcing contacts M, ii. These two forces are: (1) Upward force exerted by compression spring 65 upon the assemblage l0, and

(2) Internal gas pressure within the assemblage times the area of the moving arcing contact tips II, II. J

The downward movement of the contacts II, I! causes a pressure-generating are 69 to be established between the upper tip of the movable contact II and the arcing ring 23 within the pressure-generating arc passage 34, as shown more clearly in Fig. 3. Simultaneously an interrupting are 13 is established between the upper tip of the movable contact I! and the arcing ring 23 within the interrupting arc passage 35. Thisdrawing of the two arcs 63, 13 occurs before the enlargedv portion 44 associated with the operating rod i4=enters the dashpot 36.

During relatively high current conditions, the pressure generated by the pressure-generating are 63 withinzithe pressure-generating arc passage 34 closes the valve 33 against the apertures 32 and drives arc-extinguishing fluid, in this instance circuit breaker oil disposed within the assemblage it, toward the right, as indicated by the arrows H in Fig. 4, through the inlet passages 43 and into the interrupting arc passage 35. The, oil, forced through the passages 43, strikes the interrupting are 13 and comes into intimate contact therewith by being compelled to pass through the apertures or orifices 53, before the oil is permitted to exhaust out of the assemblage l3 throughthe diametrically opposed exhaust passages 63, 63 as provided by the composite vent plate II. The direction of the outward flow of oil is indicated by the arrows II of "Fig. 5.

It will be-observed that there are two inlet plates 46 which provide oil to passinto the interrupting passage 36 at a plurality of levels. It will also be noted that the discharge passages 63 63 associated with each vent plate 66 are disposed at two or a plurality of: intermediate levels. Obviously, for a higher voltage application there could be provided more of the inlet plates 46 and more of the intermediately disposed vent plates 55.

During the interruption of relatively low amperage currents, where the gas generated by the low current pressure-generating arc is inadequate to establish suificient pressure within the pressuregenerating arc passage 34, reliance may be had upon the piston means or dashpot 36. In other words, following predetermined downward travel of the operating rod I4, the enlarged portion 44 thereof enters the dashpot 36 and forces'the piston 43 downwardly against the pressure of spring 4| to move fluid, in this instance oil, .out of the piston chamber 13, as formed by the cylinder 31, downwardly through the apertures 50 provided in the several plates, and toward the left, as indicated by the arrows 14 of Fig. 3, into the pressure-generating arc passage 34. This oil, forced into the pressure-generating arc passage 34 by the actuation of the piston means 36, strikes the pressure-generating are 69 to effectively bring interrupting action to bear thereupon. Furthermore, this oil forced from the piston chamber I3 passes through the apertures 52 associated with the pressure-generating arc passage 34 and is sent onwardly through the inlet passages 49, provided by the inlet plates 46, to strike the interrupting are 10 and to become exhausted from the unit It in the manner heretofore described.

From the foregoing, it will be apparent that during the interruption of high currents the circuit will be interrupted by the time the enlarged portion 44 of the operating rod l4 enters the dashpot 36 to forcibly drive the movable arcextinguishing assemblage l0 downwardly to its open circuit disconnect position, as shown in Fig. 1. In the case of interrupting high currents, the actuation of the piston means 36 merely serves to flush contaminated oil out of the unit In, interruption of the arcs already having taken place. During the interruption of low currents, where sufflcient pressure is not generated within the pressure-generating arc passage 34, reliance may be had upon the piston means 36 for the sending of the requisite quantity of oil toward the pressure-generating are 63 and then onwardly toward the interrupting arc Hi. It will be noticed that during such low current interruption, effective interrupting conditions are brought to bear upon both arcs 63, 10 by the actuation of the piston means 36, the oil from the piston chamber 13 'being sent sequentially through the pressure are 63 and then onwardly toward the interrupting are 70, to thereafter become exhausted from the unit III through the discharge passages 53, 60.

As in the case of high current interruption, at the end of the actuation of the piston means 36. the movable arc-extinguishing assemblage i0 is forceably moved downwardly to its open circuit disconnect position wherein two insulating disconnect gaps are inserted into thecircuit, in addition to the gaps already provided between the contacts H, H and the arcing rings 28, 29.

.the closing operation. the-lift rod ll moves upwardly. v Because of the presence of the accelerating compression spring OI, the movable arc-extinguishing assemblage il causes re-engagement between-thecontacts II. II and I, It prior to closing of the arcing contacts. Thus, the disconnect, contacts are re-engaged before engagement of the arcing contacts.

The foregoing description indicates how i. have provided an improved circuit interrupter of the type particularly adaptable for moderate voltcable thereto. For instance, it will be readily apparent to one skilled in the art that repetition of the plate structure may be' provided to adapt the structure for higher voltage application, that is providing three or more inlet plates It, and three or more vent plates II to suit the particular voltage application. However. the structure is simple and may be readily adaptable to moderate voltage applications where a single pressure-generating arc and a single interrupting are associated with eachpole of the interrupter are sufiicient to eflect circuit interruption.

Referring to Figs. 7 through 11. it will be observed that I have provided a somewhat simpler and cheaper embodiment of my invention. Referring to Fig. 7, it will be'noticed that the arcing contacts ii, I! in this instance pass upwardly entirely through the modified movable arc-extinguishing assemblage 18. As noticed in Figs. 7 and 8, the upper ends of the arcing contacts II, II engage finger contacts 19, so associated with the contact housings II, III of the interrupter. These contact housings O I, 82 are threadedly secured and clamped tothe lower ends of the terminal studs l9, II.

In this particular embodiment of my invention, a pair of cooperable lift rods 83, 84 are provided, being secured together at their lower ends by a pair of brackets ll, Ila afiixed to opposite sides of the conducting crossbar i8. A support It is secured by bolts II to the lower end of the movable assemblage l8. interposed between the support 86 and the brackets It, 85a are a pair of compression springs 88 which serve the same function as the accelerating compression spring previously described in connection with the first embodiment of my invention.

The movable arc-extinguishing assemblage I8 is simplified in this construction of my invention by being made out of a section of an insulating cylinder Cl. An insulating disc 00 is threadedly secured to the left-hand end of the assemblage II as shown in Fig. 7. The interrupting arc passage 35 is in this particular embodiment of my invention formed by a sub-assemblage 9! of suitably formed insulating plates, the construction of which is more readily apparent upon examination of Figs. 10 and 11.

The sub-assemblage 0| of insulating plates includes a top insulating plate 82 having a configuration more clearly shown in Fig. 10. The plate II has a U-shaped cutout portion 93 removed therefrom. Below the insulating plate I is an insulating orifice'plate having a configuration more clearly shown in Fig. 10 and being designated by the reference character 04. The plate 84 has an aperture or orifice 95 formed therein.

Below the orifice plate 04 is an insulating composite vent plate generally designated by the reference character 90 and more clearly shown in Fig. 11. The vent plate 06 includes two plates .1, ll spaced apart and cemented in position a withrespecttotheotherplatesoftbesub-assemblage ll so as to form diametricallyopposed vent passages ll, Ill leading outof the! assemblag'e ll. Suitable apertures III are provided through the tube ll to register with thevent passages ".10.. as more clearly shown in Figs. Below the vent plate 00 is a second orifice N which is followed by a second inlet plate 02. Then follows anorifiee plate .a vent plate It and another orifice plate It. An inlet plate I! constitutes the lowest plate of the sub-assembl'ageli.

The several plates of the sub-assemblage ll are cemented together in a preliminary process step and the sub-assemblage Ii is then machined to havea cylindrical contour, as indicated in Fig. 8. When this isdone. the sub-assemblage .li may be inserted into the right-hand end of the tube II and so positioned that thevent passages II, I register with the apertures ill providedthrough the tube II. If desired. the subassemblage I may be cemented into the proper position relative to the insulating tube It or inserted therein by a press fit. when this is done, a second disc ill, similar to the disc I. may be threadedly secured at III to the righthand end of the tube II to securely hold the sub-assemblage I in place.

The operation of the modified type of interrupter will now be explained. In the closed circuit position, the electrical circuit extending through the interrupter includes terminal stud l0, stationary contact fingers 1!, movable contact Ii, conducting cross-bar ll. movable contact l2, stationary finger contacts 80 to the terminal stud 20. During the opening operation, the lift rods l8, ll are moved downwardly together in the same manner as the lift rod 14 of Fig. i. This initially effects expansion of the accelerating compression springs II to thereby cause the assemblage II to remain stationary and to cause rapid downward separating motion of the rod-shaped contacts II. I! away from the finger contacts II, II to draw a pressure-generating are and an interrupting are I. as shown in Fig. 9. The pressure-generating are 00 reacts upon the oil disposed within the tube II to generate pressure within the pressuregenerating chamber A at the left-hand end of the assemblage II. The pressure generated within the pressure-generating chamber A forces oil to move in the direction of the arrows "M of Fig. 9 and Fig. 10. This oil fiows upwardly and downwardly through the apertures or orifices 98 provided by the orifice plates 04 to thereby come into intimate contact with the interrupting arc ll.

, assemblage ll through the oppositely disposed vent passages l9. plates 86.

In this embodiment of myinvention, it will be noticed that I have not provided any piston means, reliance being had entirely upon lengthening of the pressure-generating and interrupting arcs 89, 10 to eflect circuit interruption during low current conditions.v Duringjhigh current conditions, the pressure generated at the pressure-generating arc is within the pressuregenerating chamber ll will be adequate to effect the requisite flow of oil into the interrupting about extinction of the in- It then passes out of the IN provided by the vent ably drive the same downwardly to the fully open circuit position or the interrupter, not shown. In this position naturally the assemblage I8 will be spaced away from the contact housings 8|, 8! in a manner similar to that shown in Fig. 1.

It will be observed that during the closing operation, the accelerating springs 88 will cause the assemblage 18 to strike the contact housings ll, 82 prior to contact engagement. Thereafter, the contacts II, I! will engage the stationary finger contacts 19, 80 to complete the electrical circuit passing through the interrupter.

It will be noted that this embodiment of my invention is simple in construction and high speed in operation. Further, few parts are involved, and maintenance is easily achieved by the ready accessibility of the several parts.

Fig. 12 shows a further embodiment of my invention identical in all respects to the embodiment of Figs. 7-11 except the accelerating compression springs 88 are omitted. Theoperation is the same asheretofore described in connection with Figs. 7-11, but inertia is relied upon to keep the tube 88 up during the interruption period. When the tube 88 does move down, either by being struck by band I05, or by gravity after a delay, then it will be notced that a larger disconnect gap X is obtained than was possible in Figs. 7-11 using the springs 88. This is so because the springs 88 held the tube 89 up against the band I05 in the fully open position of the interrupter.

Further, it will be noticed that in the embodiment of Fig. 12 reclosing during the closing opsets of finger contacts are required. Also, it will be noted that the arcing contacts are fiat blades entering a pair of stationary fingers instead of round rods and finger clusters as in Fig. 1. The compression springs 88 may be omitted, as in Fig. 12, and inertia relied upon to keep the tube 89 up during the arcing period.

It is to be noticed that the extreme high speed of operation is possible because initially only the relatively light moving contacts are moved, the relatively heavy extinguishing assemblage remaining stationary during the arcing period.

Although I have shown and described specific structures, it is to be clearly understood that the same were for the purpose of illustration and changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. A circuit interrupter including an enclosure, a pair of terminal bushings extending within the enclosure and having stationary contacts associated therewith, a pair of movable rodshaped contacts, a conducting cross-bar mechanically and. electrically interconnecting the pair of movable contacts, an operating rod for' actuating the cross-bar, a movable arc-extinguishing assemblage, the movable contacts being movable with the operating rod and actuated thereby, said movable contacts being movable substantially through the assemblage inthe closed circuit position or the interrupter, the arc-extinguishing assemblage having a lost-motion connection with respect to the cross-bar and operating rod, and the arc-extinguishing assemblage remaining. stationary adjacent the two stationary contacts during the initial portion of the opening operation while the two movable contacts move away from the stationary contacts to draw arcs within the then stationary arc-extinguishing assemblage.

2. A circuit interrupter including an enclosure, a pair of terminal bushings extending within the enclosure and having stationary contacts associated therewith, a pair of movable rodshaped contacts, a conducting cross-bar mechanically and electrically interconnecting the pair of movable contacts, an operating rod for actuating the cross-bar, a movable arc-extinguishing assemblage, the movable contacts being movable with the operating rod and actuated thereby, said movable contacts being movable substantially through the assemblage in the closed circuit position of the interrupter, the arc-i extinguishing assemblage having a lost-motion connection with respect to the cross-bar and operating rod, biasing means biasing the arc-extinguishing assemblage in the directionrof the stationary contacts during the opening operation, and the arc-extinguishing assemblage re- I maining stationary adjacent the two stationary contacts during the initial portion of the opening operation while the two movable contacts move away from the stationary contacts to draw arcs within the then stationary arc-extinguishing assemblage.

3. A circuit interrupter including an enclosure, a pair of terminal bushings extending within the enclosure and having stationary contacts associated therewith, a pair of movable rodshaped contacts, a conducting cross-bar mechanically and electrically interconnecting the pair of movable contacts, an operating rod for actuating the cross-bar, a movable arc-extinguishing assemblage having motion relative to the movable contacts, the movable contacts being movable'with theoperating rod and actuated thereby, and said movable contacts being movable entirely through the arc-extinguishing assemblage in the closed circuit position of the interrupter to engage the stationary contacts.

4. A circuit interrupter including an enclosure, a pair of terminal bushings extending within the enclosure and having stationary contacts associated therewith, a pair of movable rod-shaped contacts, a conducting cross-bar mechanically and electrically interconnecting the pair of movable contacts, an operating rod for actuating the cross-bar, a movable arc-extinguishing assemblage, the movable contacts being movable with the operating rod and actuated thereby, said movable contacts being movable substantially through the assemblage in the closed circuit position of the interrupter, the arc-extinguishing assemblage having a lost-motion connection with respect to the cross-bar and operating rod, a pressure-generating are being established adjacent one stationary contact, an interrupting are being established adjacent the other stationary contact, the arc-extinguishing assemblage serving as fluid flow com- .municating means interconnecting the two arcs initial portion oi the opening operation while the two movable contacts move away from the stationary contacts to draw arcs within the then stationary arc-extinguishing assemblage.

5. A circuit interrupter including an enclosure, a pair of terminal bushings extending within the enclosure and having stationary contacts associated therewith, a pair of movable rod-shaped contacts, a conducting cross-bar mechanically and electrically interconnecting the pair 01' movable contacts, an operating rod for actuating the cross-bar, an arc-extinguishing assemblage having movement relative to the cross-bar, the movable contacts being movable with the operating rod, said movable contacts being movable through the arc-extinguishing assemblage in the closed circuit position of the interrupter to engage the stationary contacts, a pressure-generating are being established adjacent one stationary contact, an interrupting are being established adjacent the other stationary contact, and the arc-extinguishing assemblage serving as fluid flow communicating means interconnecting the two arcs to thereby effect their extinction.

8. A circuit interrupter inc uding an enclosure, a pair of terminal bushings extending within the enclosure and having stationary contacts as'soci-.

ated therewith, a pair of movable rod-shaped contacts, a conducting cross-bar mechanically and electrically interconnecting the pair oi movable contacts, an operating rod for actuating the cross-bar, an arc-extinguishing assemblage, the movable contacts being i'lxedly secured to and movable with the operating rod, said movable contacts being movable substantially through the assemblage in the closed circuit position 01 the interrupter, the arc-extinguishing assemblage having a lost-motion connection with respect to the cross-bar and operating rod, movable disconnect contact means carried by the movable arcextinguishing assemblage externally thereof to engage the stationary contacts, and the movable contacts-engaging the disconnect contact means internally oi the arc-extinguishing assemblage.

7. A circuit interrupter including an enclosure, a pair of terminal'bushings extending within the enclosure and having stationary contacts associated therewith, a pair of movable rod-shaped tacts associated with the terminal studs, a pair of rod-shaped movable contacts, a cross-bar connecting the movable contacts, an operating rod for actuating the cross-bar, a pressure-generating are being established adjacent one stationary contact and an interrupting are being established adjacent the other stationary contact, and fluid flow transmitting means having ,a lost-motion connection with the cross-bar and carried therewith during the closing operation.

9. A circuit interrupter including a pair of 4 spaced terminal studs, a pair of stationary contacts associated with the terminal studs, a pair 01 rod-shaped movable contacts, a cross-bar connecting the movable contacts. an operating rod for actuating the cross-bar, a pressure-generating are being established adjacent one stationary contact and an interrupting are being established adjacent the other stationary contact. and fluid flow transmitting means having a lost-motion connection with the cross-bar and carried therewith during the closing operation. and biasing means biasing the fluid flow transmitting means away from the cross-bar.

, 10. A circuit interrupter including an enclosure, a pair oi terminal bushings extending within the enclosure and having stationary contacts associated therewith, a pair of movable rod-shaped contacts, a conducting cross-bar mechanically and electrically interconnecting the pair oi movable contacts, an operating rod for actuating the cross-bar, an arc-extinguishing assemblage, the movable contacts being iixedly secured to and movable with the operating rod. said movable contacts being movable substantially through the assemblage in the closed circuit position of the interrupter, the arc-extinguishing assemblage having a lost-motion connection with respect to the cross-bar and operating rod, piston means ,associated with the arc-extinguishing assemblage, the operating rod carrying an actuating portion, and the actuating portion actuating the piston means during the opening operation.

11. A circuit interrupter oi the liquid break Type including a pair of spaced stationary contacts, a pair of rod-shaped movable contacts, a cross-bar connecting the pair of movable contacts, and operating rod having an actuating portion for operating the cross-bar, one movable contact establishing a pressure-generating arc, the other movable contact establishing an interrupting arc, fluid flow transmitting means substantially enclosing the two arcs and having a lost-motion connection with the cross-bar, piston means carried by the fluid flow transmitting means, and the actuating portion of the operating rod actuating the piston means and also moving the fluid flow transmitting means to the open circuit position. o

12. A circuit interrupter including a pair 0! spaced terminal studs, a pair of stationary contacts associated with the terminal studs, a pair of rod-shaped movable contacts, a cross-bar connecting the movable contacts, an operating rod for actuating the cross-bar, a pressure-generating arc being established adjacent one stationary contact and an interrupting are being established adjacent the other stationary contact and fluid flow transmitting means only vented adjacent one end thereof having a lost-motion connection with the cross-bar and carried therewith during the closing operation. I

13. A circuit interrupter including a pair of spaced terminal studs, a pair ot stationary contacts associated with the te minal studs, a pair of rod-shaped movable contacts, a cross-bar connecting the movable contacts, an operating rod for actuating the cross-bar, a pressure-generating arc being established adjacent one stationary contact and an interrupting arc being established adjacent the other stationary contact, fluid flow transmitting means having a lost-motion connection with the cross-bar and carried therewith during the closing operation, and piston means carried by the fluid flow transmitting means and operated by the operating rod.

14. A circuit interrupter including a pair 0! 13 spaced terminal studs, a pair of stationary contacts associated with the terminal studs, a,pair oi rod-shaped movable contacts, a cross-bar connecting the movable contacts, an operating rod necting the movable contacts, an operating rod for actuating the cross-bar, a pressure-generating are being established adjacent one stationary contact and an interrupting are being established adjacent the other stationary contact, and fluid flow transmitting means having a lost motion connection with the cross-bar and carried therewith during the closing operation, the two movable contacts being movable completely through the fluid flow transmitting means in the closed circuit position of the interrupter, and biasing means biasing the fluid flow transmitting means away from the cross-bar.

16. A circuit interrupter including a pairof spaced terminal studs, a pair of stationary contacts associated with the terminal studs, a pair of rod-shaped movable contacts, a cross-bar connecting the movable contacts, an operating rod for actuating the cross-bar, a pressure-generating are being established adjacent one stationary contact and an interrupting are being established adjacent the other stationary contact, fluid flow transmitting means having a lostmotion connection with the cross-bar and carried therewith during the closing operation, and the fluid flow transmitting means coming to rest in the open position of the interrupter immediate- 1y adjacent to the cross-bar.

17. In a circuit interrupter of the liquid break type, a tank containing an arc extinguishing liquid, two terminal bushings extending into the tank, relatively stationary contact means disposed at the interior end of each terminal bushing, a movable arc extinguishing assemblage including a pressure-generating unit and an interrupting unit hydraulically interconnected by a conduit means, movable contact means including a movable pressure-generating contactand a movable interrupting contact, a movable conducting cross-bar electrically and mechanically connecting the two movable contacts, an operating rod fixed to the cross-bar to cause the actuation of the same, and a lost-motion connection between the movable contact means and the movable arc extinguishing assemblage so that during the initial portion of the opening operation only the movable contact means first moves and subsequently, after an appreciable delay, the arcextinguishing assemblage moves therewith.

18. In a circuit interrupter of the liquid'break type, a tank containing an arc extinguishing liquid, two terminal bushings extending into the tank, relatively stationary contact means disposed at the interior end of each terminal bush ing, a movable arc extinguishing assemblage includingapressure-generating unit and an interrupting unit hydraulically interconnected by 1 4 a conduit means, movable contact means including a movable pressure-generating contact and .a movable interrupting contact, a conducting cross-bar electrically and mechanically connecting the two movable contacts, an operating rod fixed to the cross-bar to cause the actuation of the same, a lost-motion connection between the movable contact means and the movable arc extinguishing assemblage, means biasing the movable arc extinguishing assemblage to the closed circuit position, and the operating rod having an actuating portion to iorceably drive the extinguishing assemblage therewith during the final portion of the opening operation.

19. In a circuit interrupter of the liquid break type, a tank containing an arc extinguishing liquid, two terminal bushings extending into the tank, relatively stationary contact meansdisposed at the interior end of each terminal bushing, a movable arc extinguishing assemblage including a pressure-generating unit and an interrupting unit hydraulically interconnected by a conduit means, movable contact means including a movable pressure-generating contact and.

a movable interrupting contact, a conducting cross-bar electrically and mechanically connecting the two movable contacts, an operating rod fixed to the cross-bar to cause the actuation of the same, a lost-motion connection between the movable contact means and the movable arc extinguishing assemblage so that during the initial portion of the opening operation only the movable contact means first moves and subsequently, after an appreciable delay, the arc-extinguishing assemblage moves therewith, and the movable contacts being movable through the units to engage the stationary contact means in the closed circuit position 01' the interrupter.

20. In a circuit interrupter oi the liquid break type, a tank containing an arc extinguishing liquid, two terminal bushings extending into the tank, relatively stationary contact means disposed at the interior end of each terminal bushing, a movable arc extinguishing assemblage including a pressure-generating unit and an interrupting unit hydraulically interconnected by a conduit means, movable contact means having a lost-motion connection with the assemblage including a movable pressure-generating contact and a movable interrupting contact, an insulating operating rod for actuating the assemblage and the movable contact means, and the assemblage remaining momentarily stationary during the initial portion of the opening operation while the movable contacts move relative thereto establishing arcing within the pressure-generating and interrupting units.

21. In a circuit interrupter of the liquid break type, a tank containing an arc extinguishing liquid, two terminal bushings extending into the tank, relatively stationary contact means disposed at the interior end of each terminal bushing, a movable-arc extinguishing assemblage including a pressure-generating unit and an interrupting unit hydraulically interconnected by a conduit means, movable contact means including a movable pressure-generating contact and a movable interrupting contact, a conducting cross-bar electrically and mechanically connecting the two movable contacts, an operating rod fixed to the cross-bar to cause the actuation of the same, and a lost-motion connection be tween the movable contact means and the movable arc extinguishing assemblage, movable disconnect means associated with the end of each unit and contacting the stationary contact means connect means interlorly of the units during the opening operation.

22. In a circuit interrupter oi the liquid break type, a tank containing an arc extinguishing liquid, two terminal bushings extending into the tank, relatively stationary contact means disposed at the interior end or each terminal bushing, a'movable arc extinguishing assemblage including a pressure-generating unit and an interrupting unit hydraulically interconnected by a conduit means, movable contact means including a movable pressure-generating contact and a movable interrupting contact, a conducting cross-bar electrically and mechanically connecting the two movable contacts, an operating rod fixed to the cross-bar to cause the actuation of the same, a lost-motion connection between the movable contact means and the movable are extinguishing assemblage, movable disconnect means associated with the end of each unit and contacting the stationary contact means in the closed V circuit position, the movable contacts pulling away from the movable disconnect means interiorly or the units during the opening operaing, a movable arc extinguishing assemblage including a pressure-generating unit and an interrupting unit hydraulically interconnected by .a conduit means, movable contact means including a movable pressure-generating contact and a movable interrupting contact, a conducting cross-bar electrically and mechanicallwconnecting the two movable contacts, an operating rod iixed to the cross-bar to cause the actuation of the same, a lost-motion connection between the movable contact means and the movable are extinguishing assemblage, movable disconnect means assoeiated'with the end of each unit and contacting the stationary contact means in the closed circuit position, the movable contacts pulling away from the movable disconnect means interiorly or the units during the opening oporation, the movable disconnect means enclostion, and the movable disconnect means enclosing said ends of the units to increase the pres sure formed therein during the opening operation.

23. Ina circuit interrupter of the liquldbreaktype, a tank containing an arc extinguishing liquid, two terminal bushings extending into the,

tank, relatively stationary contact means disposed at the interior end of each terminal bushing said ends oi the units to increase the pressure formed therein during the opening operation, and valve means associated with the movable disconnect means to vent the units at the end of the opening operation.

. WIN'I'HROP M. LEEDS.

References Cited in the ills of this patent UNITED s'rA'ms PATENTS Number Name Date 1,530,444 Trencham -1--- Mai-:17, 1925 2,156,450 Cole May 2, 1939 2,419,106 Baker et a1 Apr. 15, 1947 FOREIGN PATENTS Number Country Date 661,181 Germany Mar. 9,1932 413,751 Great Britain July 26, 1934

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