US1872382A - High speed circuit interrupter - Google Patents

Description

Aug. 16, 1932.` c. AALBORG ET AL HIGH SPEED CIRCUIT INTERRUPTER Filed April 15, 1925 3 Sheets-Sheet l ATTORN EY Aug- 16, 1932- c. AALBORG ET AL 1,872,382

HIGH SPEED CIRCUIT INTERRUPTER Filed April 15. 1925 IS'SheetS-Sheet 2 Aug- 16, 1932 c. AALBORG ET AL 1,872,382

HIGH SPEED CIRCUIT INTERRUPTER Filed April 15, 1925 3 Sheets-Sheet 3 lPatented Aug. 16, 1932 UNITED` STATES PATENT OFFICE CHRISTIAN AALBORG, OF PITTSBURGH, AND JOI-IN B. MACNEILL, OF WILKINSBURG, PENNSYLVANIA', ASSIGNORS TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMIPANY, A CORPORATION OF PENNSYLVANIA HIGH SPEED CIRCUIT INTERRUPTER lApplication led April 15, 1925. Serial No. 23,401.

Our invention relates to electrical protective devices'and particularly to high-speed circuit interrupters.

One object of our invention is to provide a high-speed circuit interrupter for alternating-current circuits.

Another object of our invention is to provide a circuit interrupter that shall have mechanical and electrical means for diminishing the duration of electrical arcs generated during its operation. It is a furtherfobject of our invention to provide a circuit interrupter that shall have improved means for securing full-automatic operation.

It is yet another object of our invention to provide an operation indicator that shall depend for its operation upon the movement of a movable contact member in the circuit interrupter rather than upon the movement of some part or parts of the actuating mechanism for the movable contact member.

Vith the increase in the voltages used on transmission systems, by reason of the normal development of power transmission lines, it has been found necessary to change the construction vof oil circuit interrupters to meet the increasing demands made upon them from the ever-increasing voltages employed. One of the problems incidental to the use of oil circuit interrupters in such systems is the necessity of completely interrupting the arcs drawn within a relatively few cycles of the interrupted current. By reason -of the large amount of thermal energy and great volume of gases generated upon the formation of such arms, it has been found that the metallic parts and insulating portions of such circuit interrupters, and particularly the contact members themselves, are aptto be burned out by a long continued arc.

Inaslnuch as alternating current goes through a point of zero potential twice in each cycle, it is advisable to cause the separating contact members to move a maximum distance during the period of each half current cycle in order that arc re-ignition may be avoided. Accordingly, we have provided a circuit interrupter in which both mechanical and electrical means are combined to cause a high speed of separation between the contact members and to cause the nal interruption of the arc therebetween.

In the accompanying drawings,

Figure 1 is a view, partially in elevation 55 and partially in section, of the operating mechanism of our improved circuit interrupter.

Fig. 2 is a fragmentary view, partially in elevation and partially in section, of the operating mechanism of our circuit interrupter when the latter is in its closed position.

Fig. 3 is a similar view thereof as it appears when the circuit interrupter is in its open position.

Fig/4 is an edge view of an indicating switch.

Fig. 5 is a plan View of our circuit interrupter, and

Fig. 6 is a view, partially in elevation and '(0 partially in section, of the contact-carrying element of our circuit interrupter.

In the several figures of the drawings, similar reference numerals indicate like parts.

Referring to Figs. 1 and 2, our invention 7 5 comprises, in general, a tank 10, main and auxiliary stationary contact members 11 and 12, that o o-operate with movable main and auxiliary contact members 13 and 14, respectively. An operating element or rod 15 80 therefor is secured in position by a quickly detachable release mechanism 16, together with a magnetic blow-out coil 17 that is immersed in the insulating oil within the circuit interrupter in such manner as to be effective between the separating groups of contact members 11, 12 and 13, 14, and particularly between the auxiliary contact members 12 and 14. The tank, contact members, operating rod, release mechanism and cooperating structure form a single pole unit such as is used for controlling the flow of current in a single conductor.

The several contact members 11 to 14, inclusive, may be of any preferred type inasmuch as the details thereof form no part of the present invention, except insofar as they are necessary to complete the several combinations hereinafter'dened. The magnetic blow-out coil may likewise be of any suitable 10 type having an energizing solenoid 18 and a core member 19 of U-shape, the opening in which is placed in proximity to the contact members 11 to 14, inclusive, in order that it may be effective to extinguish arcs drawn therebetween in a manner well known in the art. -Preferably the blow-out coil 17 is connected by a conductor 21 in series with the contact members 11 to 14, inclusive. The blow-out coil 17 is supported by an insulating rod 22.

Referring to Figs. 1 and 6, the supporting rod 15 terminates in a threaded stud 23 for the reception of a nut 24 and an enlarged portion 25 between which the movable contact member 13 is clamped. At a distance above the enlarged portion 25 there is a second enlargement 26, the lower surface of which is in the form of a section of a sphere and the upper surface. 27 of which serves as a support for a relatively movable collar 28 that co-operates with a second relatively7 movable collar member 29 for securing a pair of concentric coil springs 31 and 32 in place. The outer coil spring 31 is of larger gauge material and is of greater overall length than the inner coil spring 32. The two springs may be separated by a barrier 33 of a length less than that of the inner coil spring 32.

Accordingly, the coil springs 31 and 32 are capable of compression between the collars 28 and 29 and when the pressure is removed from the collar members 28 and 29 both springs initially tend to accelerate the separation of the collar members, while the outer spring 31 sustains the movement of separation after the period of initial acceleration. However, should one of the collar members 28 or 29 engage a stop, the inertia of the entire rod may cause the other collar member to first compress the spring 31 and then the spring 32, thereby decelerating the movement of the supporting rod 15. The upper end of the rod 15 terminates in a threaded lug 34 to which is secured, by a pivot 35, a latch 36 having a re-entrant notch 37.

Referring particularly to Fig. 1, the collar 28 is adapted to move between guides 38 that are secured to a. frame 39 of the circuit interrupter. ADownward movement of the collar 28 is limited by a cross piece 41 that also constitutes a portion of the frame 39. The upper collar 29 is disposed below a cross piece 42 of the frame 39 and moves in a downwardly projecting cylindrical guide portion 43. The cross pieces 41 and 42 constitute stops for the expansion of the coil springs 31 and 32 under conditions hereinafter defined.

The cross piece 42 is perforated, as at 43, in order to permit the rod 15 to pass therethrough and the lug 34 is disposed above the Cross piece 42 in order that the latch 36 may engage the releasing device 16. The releasing device 16 is pivotally mounted, as at 44, on a yoke member 45 so that it is movable relative to the frame 39. The yoke 45 is, in turn connected by a suitable linkage mechanism 46 to an operating shaft 47 that may be connected to any desired actuating means, such as a handle or a motor (not shown). The other end of the yoke 45 is pivoted at 49 to the frame 39.

Referring particularly to Fig. 5, the releasing mechanism 16 is guided between four upstanding guide elements 51 that constitute parts of the frame 39. The releasing mechanism 16 comprises a member 53 that is provided with an'upwardly extending bell or dome 54 that terminates in an upwardly projecting lug 55. lithin the dome there is disposed a coil spring 5G that bears against a movable cap member 57 which carries the lug 55 and that normally engages the upper surface of the latch 36. The latch 36 extends upwardly through the member 53 at right angles to the major axis thereof. The member 53 is provided with a. longitudinally extending opening 58 through which the latch 36 extends.

lVithin the opening 58 are disposed a number of rollers 59 and spacers 61. The ends of the opening 58 are closed by suitable plugs 62. A cam-shaped lug 63 is disposed within the casting 53 and extends upwardly through a slot 64 exteriorly thereof. A coil spring 65 is disposed within the member 53 in such manner as to normally bias the lug 63 in an upward position, thereby crowding the rollers and spacers 59 and 61 outwardly. When the latch 36 is in its upper position, one of the rollers 59 engages the notched surface 37 and holds the supporting rod 15 in its upper position against the tension of the compressed springs 31 and 32.

An overload release mechanism 71 is mounted on a bracket 72 that is carried on the pivot 49. Coil springs 73, attached to the frame 39, bias the bracket 72 in a counter-clockwise direction. The mechanism 7]. includes overload coils 74 and a plunger 75 for actuating a lever 76 that is pivoted on a shaft 78 to the bracket 72 in such manner that its free end is slightly above the exposed end of the lug 63. If desired, a g3gcoil spring 79 may be wound about the shaft 78 in order to bias the lever 76 in a clockwise direction against the armature 75.

Referring particularly to Figs. 2 and 3, a

shaft 81 extends through the tank 10 and terminates in a lever 82 that is normally in position to be moved into the path of the lever 76 by the manipulation of a handle 83 located outside of the circuit breaker tank. release for the circuit interrupter.

An indicating switch 91 is connected, by a series of links 92, to a rod 93 that is connected to a bell crank 94 mounted on the These elements constitute a manual frame 39. The bell crank 94 is biased in a clockwise direction by a spring 95 that is connected between the rod 93 and a boss 96 on the frame 39. Upon movement of the lug 55 in a downward direction, the bell crank 94 is turned in a clockwise direction bythe action of the spring 95 and the indieating switch is moved into a downward position, opposite to that shown in Fig. 4. f

Inasmuch as movement of the lug 55 follows directlyfupon movement of the latch 36 of the contact supporting rod 15, it follows that the movement of the indicating switch 91 is a direct indication of the movement of the contact member rather than the movement of some intermediate operating mechanism. s It has frequently been found that the operating mechanism may function to release the movable contact member, but

that the latter may stick closed, thereby giving a false operation of an indicator attached to the operating mechanism. n

The yoke is normally latched in its upper position by a latch 101 that is operated against a spring 102 by a lever 103 having a projection 104 that is disposed in the path of the lug 34, when the latter is in its downward position. The lever 103 engages a lip 105 on the latch 101, thereby turning it in a counter-clockwise direction againstthe bias of the spring 102, to release the yoke 45 when the lug 104 is turned in a clockwise direction as the lug 34 moves downwardly.

. Upon the release of the yokev 45 by the latch 101, the latter moves downwardly under the infiuence of the force .of gravity from its position shown in Figs. 1 and 2 into the position shown in Fig. 3.

Suspended on the lower portion of the cross piece 41 are a number of converging plates 109 that center upon the rod 15 and constitute, in eect, a cylinder, with which the curved surface .26 on the rod 15 acts as a piston when insulating fluid is trapped therein, thereby constituting, in effect, a decelerating dash-pot.

Assuming the circuit interrupter to be in its closed postion, as shownin Figs. 1 and 2,

and the lever 76 to be given a counter-clockf wise movement, either by the action of the overload coils 74 or the operation of the handle 83, the upwardly eiitending lug 63 is depressed against the bias of spring 65. Upon the recession of the lug 63, the movement of the cam surface thereof removes the tension under which the rollers 59 and the spacers 61 have been placed and the notch 37 of the latch 36 is held withinsuiicient pressure to withstand the force of the coil springs 31 and 32. As a result, the coil springs 31 and 32 expand and accelerate the movement of the rod 15 downwardly, carrying therewith the contact members 13 and 14. The downward movement of the rod 15 is greatly accelerated so long as both of the coil springs 31 and 32 are expanding.

However, when the smaller spring 32 has expanded to its limit, the outer spring 31 con tinues to expand, thereby sustaining the downward movement of the rod 15 and continuing its acceleration, although not as rapidly until the collar 28 strikes the cross iece 41, whereby the further expansion o the spring 31 is prevented. However, the rod 15 continues to move downwardly by reason of its kinetic energy'until it has reached a position where a suhcient amount of insulating fluid is trapped between the rounded surface 26 and the plates 109 to act as a dash-pot for retarding futher downward movement. The latter condition occurs only when the contact rmembers 1,1 to 14,`inclusive, have separated suiciently far to prevent arc re-ignition.

During the separation of the movable contact members 13 and 14 from the stationary contact members 11 and 12, the magnetic blow-out coil 17 serves to elongate the arc by a well-known magnetic action and thereby tends to prevent arc re-ignition when the potential of the interrupted current passes through zero.

The downward movement of the rod 15 is checked by the co-opera-tion of the curved surface 26 and the plates 109, the coil spring 31 is compressed by the downward movement of the collar 29 and, if the'inertia of the rod 15 is sufficient, the coil spring 32 is also compressed.

During the downward movement of the latch 36, the cap 57 is forced downwardly by the spring 56 and the cap occupies the space between the rollers 59, formerly occupied by the latch, thereby preventing the-rollers from being dislodged. During the downward movement of the cap 57, the lug moves downwardly with the c ap 57 and the bell crank 94 moves in a clockwise direction, thereby operating the indicating switch 91, as has been described.

During the downward movement of the contact-carrying rod 15, lug 34 engages the projection 104 on the lever 103 which causes the yoke 45'to be unlatched, as heretofore eX- plained. The latter turns about its pivot 49 and drops the entire releasing mechanism 16 into the lower position shown in Fig. 3. At the same time, the overload release mechanism 71 is tilted in a counter-clockwise direction by the contraction of the spring 73. The overload release mechanism 71 is not turned through as large an angle as the yoke 45, it being turned only sufficiently to enable the lever 76 to engage the lug 63 before the contact members can again be closed in the event that an overload continues to energize the electromagnet 74, thereby rendering the circuit interrupter fully automatic.

With tlic'yoke 45 in its lower position, the releasing mechanism 16 is drawn downwardly and the latch 36 again enters the member 53, thereby crowding the cap 57 and the lug 55 into their upper position. Movement of the shaft 47 is transmitted through the mechanism 46 and the yoke 45 is moved upwardly, carrying with it the releasing mechanism 16. Upward movement of the releasing mechanism 16, in turn, draws the contact-carrying rod 15 upwardly and as soon as the collar 29 engages the lower surface of the cross piece 42, the larger spring 31, and then the smaller spring 32, are again compressed. As soon as the lug 34 passes from beneath the lug 104, the latch 101 is in position to engage the yoke 45 upon the completion of the travel of the latter.

During the foregoing movement, the overload mechanism 71 turns slowly in a clockwise direction against the bias of the spring 73, but during the latter stage of movement of the yoke 45, the end of the lever 76 is so disposed with relation to the lug 63 that the contact-carrying rod 15 may be released at any time the electromagnet 74 becomes unduly energized. During the upward movement of the releasing device 16, the lug55 engages the bell crank 94, thereby causing the switch 91 to move to its downward position and give the operator such indication of the position of the contact-carrying member 15 as may be desired.

The foregoing cycle of operations may be continued indefinitely by the application of power to the shaft 47 in order to restore the circuit interrupter to its'closed position. It will thus be seen that we have devised a circuit interrupter in which mechanical accelera very small distance in such manner that they exert substantially negligible friction when compared with the amount of'energy stored in the mechanipal accelerating springs.

IVe do not wish to be`restricted to the specific circuit connections or arrangement of parts herein set forth, as various modifications thereof may be effected without departing from the spirit and scope of our invention. IVe desire, therefore, that only such limitations shall be imposed as are indicated in the appended claims.

IVe claim as our invention:

1. In a circuit interrupter, an operating member comprising a rod, contact members retained in engagement thereby, a pair of relatively movable collars mounted on the rod, and a pair of concentric coil springs disposed between the collars and each of said springs when stressed exerting force independently of the other on each of said collars.

2. In a circuit interrupter, an operating member comprising a rod, contact members retained in engagement thereby, 'a pair of relatively-movable collars mounted on the rod, and a pair of dissimilar concentric coil springs disposed between the collars and one of said springs exerting force after the other spring is unstressed.

3. In a circuit interrupter, an operating member comprising a rod, contact members retained in engagement thereby, a pair of relatively-movable collars mounted on the rod, and a pair of concentric coil springs of unequal unstressed lengths disposed between the collars and each of said springs when stressed exerting force independently of the other on each of said collars.

4. In a circuit interrupter, an operating member comprising a rod, contact members retained in engagement thereby, a pair of relatively-movable collars mounted on the rod, and a pair of concentric coil springs of unequal unstressed lengths disposed between the collars, the shorter spring being interior of the longer spring and said longer spring exerting force after said shorter spring has become unstressed.

5. In a circuit interrupter, an operating member comprising a rod, contact members retained in engagement thereby, a pair of relatively-movable collars mounted on the rod, and a pair of concentric coil springs of unequal unstressed lengths disposed between the collars, the shorter spring being interior of the longer spring, whereby it initially assists the longer spring and each of said springs when stressed exerting force independently of the other on each of said collars in accelerating the rod.

6. In a circuit interrupter, an operating member comprising a rod, a pair of relatively-movable collars mounted on the rod, a stop for one of the collars, and a pair of concentric coil springs of unequal length disposed between the collars, whereby both springs initially accelerate movement of the rod, the longer spring sustains the movement of the rod, and one or both of the springs may serve to decelerate movement of the rod upon the engagement of the collar member with the stop.

7. In a circuit interrupter, an operating member comprising a rod, detachable securing means therefor, a pair of relatively-movable collars mounted on the rod, a stop for one of the collars, and a pair of concentric coil springs of unequal length disposed between the collars, whereby, upon the release of the rod by the securing means, both springs initially accelerate the rod, the longer spring sustains the movement of the rod, and one or both of the springs may decelerate the rod upon the engagement of the collar with the stop. e

8. In a circuit interrupter, an operating member comprising a rod, detachable securmg means therefor, a pair of relatively-movable collars mounted on the rod, a stop for one of the collars, and a pair of coil springs disposed between the collars, whereby, upon the release-of the rod by the securing means, both springs initially accelerate the rod and one or both of the springs may decelerate the rod upon the engagement of the collar with the stop.

9. In a circuit interrupter, a contact-supporting member, accelerating means therefor, detachable securing means for vthe contactsupporting member, electroresponsive means for cont-rolling the s-ecuringmeans under predetermined electrical conditions for releasing the contact-supporting means whereby the latter is actuated by the accelerating means, and means for causing the securing means to engage the contact-supporting means before the accelerated members come detachable securing means for the contactsupporting member, electroresponsive means for controlling the securing means under predetermined electrical conditions for releasing the contact-supporting means whereby the latter is actuated by the accelerating means, and means for causing the securing means to follow and retrieve the contact-supporting means to its initial position against the bias of the accelerating means.

11. In a circuit interrupter, a contact-supporting member, accelerating means therefor, detachable securing means for the contactsupporting member, electroresponsive means for controlling the securing means under predetermined electrical conditions for releasing the contact-supporting means whereby the latter is actuated by the accelerating means, and means for lowering the securing means to engage' the contact-supporting means. Y

12. In a circuit interrupter, a contact-supporting member, accelerating means therefor,

detachable securing means for the contactsupporting member, electroresponsive means for controlling the securing means under predetermined electrical conditions or releas-v raceway carried by the said system, a'notchedI element extending into the raceway, a ball'l in the raceway for engaging the notched element and means for blocking thev ball in engaged position.

14. In a circuit interrupter, a pivotal operating lever, a tripping mechanism carried thereby including a raceway, a notched element extending into the raceway, means in the raceway for engaging the notched element, means for positively wedging the engaging means when in engaged position and means for rendering the wedging means ineffective under predetermined electrical conditions.

15. In a circuit interrupter, a tripping mechanism including a raceway, an operating lever carrying said tripping mechanism, a contact-supporting element extending into the raceway when said operating lever is moved to open-circuit position, balls in the raceway for engaging the contact-supporting element, means for maintaining the balls under pressure and means thereafter for rendering the pressure-maintaining means ineffectivev under predetermined electrical conditions at any position of the operating lever.

16. In a circuit interrupter, a pivotal operating lever, a tripping mechanism comprising a raceway carried by said lever, a contactsupporting element extending into the raceway, means in the raceway for engaging the contact-supporting element, means forv positively maintaining theengaging means in engaged position and a relay for rendering the positive meansy ineffective under predeterlng means ineffective., under predetermined electrical conditions whereby the contact-I supporting element may be withdrawn from the raceway and means for occupying the space in the raceway' made vacant by the withdrawal of the contact-supporting element.

18. In "a circuit interrupter, a tripping mechanism comprising a raceway, a contactsupporting element extending into the raceway, means in the raceway for engaging the contact-supporting element, means for maintaining the engaging means under pressure, means for rendering the pressure-maintaining means ineffective under predetermined electrical conditions whereby the 'contactsupporting element may be withdrawn from ythe racewayand means for automatically occupying the space in the raceway made vacant by the withdrawal of the contact-supporting element. l

19. In a circuit interrupter, a pole unit including a stationary Contact member, a movable contact member and an operating rod for actuating said movable contact member, an actuating element extending out of said pole unit for connection to a circuit breaker actuating device, and means Within said pole unit for disconnecting saidmovable contact member from said actuating element to allow movement of said contact member independently of said actuating element.

20. In a circuit interrupter, a pole unit including a stationary contact member, a movable contact member and an operating rod for actuating said movable contact member, a lever system Within said pole unit for actuating said operating rod, an actuating element extending from said lever system out of said pole unit for connection to a circuit breaker actuating device, and means Within said pole unit for disconnecting said movable contact member from said actuating element to allow movement of said contact member independentlyv of said actuating element.

21. In a circuit interrupter, a pole unit including a stationary contact member, a movable contact member and an operating rod for actuating said movable Contact member, an actuating element extending out of said pole unit for connection to a circuit breaker actuating device, and an electro magnetic device mounted Within the pole unit for opening said contact members by disconnecting said movable contact member from said actuating element.

22. In a circuit interrupter, a pole unit including a stationary contact member, a movable Contact member and an operating rod for actuating said movable contact member, a lever system Within said pole unit for actuating said operating rod, an actuating element extending from said lever'system out of said pole unit for connection to a circuit breaker actuating device, and a releasable connection between said operating rod and said lever system. 23. ln a circuit interrupter, a pole unit including a liquid filled container, a pair of stationary contacts immersed in said liquid, a conducting member for bridging said contact members and a lift rod for actuating said bridging member, a pivoted lever Within said pole unit for transmitting motion to said lift rod, and a releasable connection between said lift rod and said pivoted lever for allowing movement of said lift rod independently of said pivoted lever.

In testimony whereof, We have hereunto subscribed our names this 8th day of April, 1925.

CHRISTIAN AALBORG. JOHN B. MACNEILL.

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