US2419447A - Electric circuit interrupter - Google Patents

Description

April 22, 1947. J GAYER ETAL 2,419,447

ELECTRIC CIRCUIT INTERRUPTER Filed Feb. 26, 1943 SSheets-Sheet l /i /.9 Pi 81.

Inventors: 36 if John D. Gaye)",

E dward J. Frank, .Alexander C.Boi eau, by 29 j Th ir" Att orney.

April 22,1947- J. D. GAYER EI'AL ELECTRIC CIRCUIT INTERRUPTER Filed Feb. 26, 1943 s Shgets-Sheet 2 Inventors: John D Gayer",

Edward. J. Fran k, Alexander C. Boisseu, by

Their Attorney April 22, GAYER ETAL 2,419,447

ELECTRIC CIRCUIT INTERRUPTER Filed Feb. 26, 1943 3Sheets-Sheet 3 Inventors: John D. Sayer, Edward J. Frank, Alexander C.Boisseau;,

19 )VM 4% y Their Attorney.

Patented Apr. 22, 1947 ELECTRIC CIRCUIT INTERRUPTER John D. Gayer and Edward J. Frank, Springfield, and Alexander 0. Boisseau, Lansdowne, Pa., assignors to General Electric Company, a corporation of New York Application February 26, 1943, Serial No. 477,247

8 Claims. 1

Our invention relates to electric circuit interrupters and particularly to improvements in electric circuit breakers of the fluid blast type. Speciflically, our invention is an improvement on the invention disclosed and claimed in United States Letters Patent 2,287,578Thu.mim et al., granted June 23, 1942, and assigned to the same assignee as the present application.

Circuit breakers which do not utilize oil or other inflammable liquid for are extinguishing purposes, but instead employ a blast of fluid such as airor other gas, to extinguish the are formed, have become quite popular in recent years. Many such fluid blast circuit breakers are designed with independently controlled opening and closing fluid blasts. The above mentioned United States Letters Patent is such an example.

It will be understood by those skilled in the that fluid blast circuit breakers, such as air blast circuit breakers, for example, require air storage facilities the size of which is mainly dependent upon the air used for the air blast for are ex tinguishing purposes. From a cost standpoint it would be desirable to limit these facilities to a minimum and this can be accomplished by conserving the air required for the fluid blast. It has been discovered that during the circuit opening operation of a fluid blast circuit breaker it i preferable for the fluid blast to be in existence at the instant the contacts separate and continue for a longer period of time than would be required during the circuit closing operation where it is merely necessary to prevent the arc from striking and not necessary to extinguish the arc. Our invention is primarily concerned with new and improved means for controlling the fluid blast of circuit breakers employing a fluid or air blast for are extinguishing purposes.

It is an object of our invention to provide a new and improved circuit breaker of the fluid blast type which will function to control the quantity of fluid, the interval over which the fluid is supplied, the point of application of the fluid to the circuit interrupter, and the point at which the flow of fluid is stopped on either the opening or closing stroke of the circuit breaker entirely independent of one another and which arrangement will permit reversing the motion of the circuit interrupter at any point in the cycle while still maintaining the proper sequence of operation.

It is a further object of our invention to provide a new and improved circuit breaker in which the initiation and duration of both the opening and closing fluid blasts are independently and accurately adjustable whereby an economical consumption of fluid results and the fluid storage facilities may be maintained within reasonable limits. I

Still another object of our invention is to provide a new and improved fluid blast control arrangement for. a fluid blast circuit breaker.

Further objects and advantages of our invention will become apparent as the following description proceeds and the features of novelty which characterize our invention will be pointed out with particularity in the claims annexed to and forming a part or this specification.

For a better understanding of our invention reference may be had to the accompanying drawings in which Figs. 1, 2, 3 and 4 are schematic diagrams partly in section illustrating one form of our invention at various positions during the operating stroke of the circuit breaker, Figs, 5, 6 and 7 are similar views of another modification of our invention, Fig. 8 is a similar view of still another modification of our invention and Figs. 9, 10 and 11 are schematic diagrams of still another modification of our invention.

Although our invention is applicable to any fluid blast circuit breaker, single phase or polyphase, for purposes of clearness and simplicity in the disclosure, we have illustrated our invention schematically in Figs. 1 to 4 as applied to a fluid operated circuit breaker III of the cross gas-blast type, comprising a stationary contact II and a movable contact l2 arranged to be operated to draw an arc an arc chute l3. It will be understood by those skilled in the art that contacts II and I2 which are relatively movable with respect to one another, are arranged to be connected with suitable line terminals not shown, lhe stationary or fixed contact is provided with spring pressed contact fingers I la and longer arcing contact fingers Il', while movable contact I2 is provided with an arcing tip I2 so that when the contacts separate an arc occurs between arcing tips H and I2. Immediately after separation of. the contacts one terminal of the arc is transferred by a blast of fluid such as air or any other gas issuing from conduit M which is suitably connected through blast valve [5 to be described hereinafter, with a source of fluid under pressure It, from contact fingers H to the contact H" which is provided with a tip ofare resistant metal. The fluid blast from conduit l4 upon the opening of circuit breaker Hl drives the arc gap and the ends of which extend close to the path of movement of the arcing tip l2 of movable contact |2 This circuit breaker I3 is illustrated by way of example only in order to aid in understanding our invention which is applied thereto, The circuit breaker described thus forms no part of our invention but it is disclosed and claimed in United States Letters Patent 2,284,842-Prince et al., granted June 2, 1942, and assigned to the same assignee as the present application.

Any suitable means for providing relative movement between contacts and i2 may be provided. In Fig. l we have chosen to illustrate such means as including a fluid operated motor comprising a cylinder 18 and a piston l3 which latter is operatively connected to movable contact l2 by means of a connecting rod 29, link means 2|, bell crank 22 pivotally mounted at 23 and circuit breaker operating rod In order to operate piston l9 and consequently also movable contact |2, fluid pressure tank or source [6 is connected to one end of cylinder l3 through conduit 25 and circuit breaker closing valve 23. The other end of cylinder I8 is connected to fluid pressure source itby means of conduit 2'] and circuit breaker opening valve 23.

The link means 2| which is included in the means for producing relative movement between contacts and I2, is so constructed and arranged that movement of piston I!) may cause limited movement of link means 2| without corresponding relative movement between contacts H and |2. This is accomplished by means of a lost motion connection between link 2| and bell crank 22. Link 2| is provided with an elongated slot 28 through which passes pin 30 fixed to one end of bell crank 22. Initial movement of link 2| to the left as viewed in Fig. 1 will not cause any movement of bel1 crank 22 by virtue of the lost motion connection comprising slot '29 and pin 33. The lost motion connection described above as will become apparent from the following description, permits operation of blast valve l to insure a fluid blast in the arc chute or arc chamber l3 adjacent contacts H and I2 prior to any relative separation of said contacts. Accordingly, we provide a pivotally mounted opening air blast cam 3| and a pivotally mounted closing air blast cam 32 which are pivotally mounted on pin 30 associated with bell crank 22. In the position indicated in Fig. 1 the cam 3| normally rests on a roller 33 mounted on one end of a bell crank 34 which has a roller 35 at the other end thereof for engaging valve stem 33 of blast valve l5. Blast valve |5 is normally biased to the closed position by means of spring 31 as well as by the pressure of the fluid contained in source l6 acting against the valve member 38 of blast valve #5. When bell crank 34 which is pivotally mounted at 33 is rotated in a clockwise direction as viewed in Fig. 1, valve stem 35 and valve member 38 of blast valve l5 are moved to the left to the open position indicated in Figs. 2 3, Fig. 2 indicating the partially open position of blast valve l5 while Fig. 3 indicates the completely open position.

Preferably opening air blast cam 3| is shaped so as to have a high point as indicated at 43 on the upper edge thereof, and an operating surface at the lower edge thereof between the points 4| and 42.

In order to cause opening fluid blast cam 3| to force bell crank 34 to rotate in a clockwise direction about pivotal support 39, we provide means on link means 2| indicated as a roller 43 which is adapted to engage the point 40 on cam 3| so that movement of link means 2| to the left will cause the cam face between points 4| and 42 of cam 3! to depress roller 33 and consequently open blast valve 38 for a period of time depending upon the distance between the points 4| and 42.

In order to provide an independently controlled closing fluid blast, cam 32 is also provided with a high point 44 which is engageable by roller 43 during the circuit closing operation when cam i in the position indicated in Fig. 4 so that cam face 45 of cam 32 will cause roller 33 of bell crank 34 to be depressed with the consequent opening of blast valve l5. In order to hold closing cam 32 from falling to a vertical position as viewed in 1, we support it from opening cam 3! as by means of a pin 46 supported by cam 3| which engages a cooperating opening 41 in cam 32.

Suitable guide means indicated at 48 are provided for movable contact H to insure straight line motion thereof.

With the above arrangement we have provided a blast valve operating mechanism which will function to control the quantity of air, the interval over which air is supplied, the point of application of air to the circuit interrupter I0 and the point at which blast valve I5 is closed, on either the opening or closing stroke of circuit breaker I0 entirely independent of one another and which arrangement will permit reversing of the motion of the circuit breaker while still maintaining the proper sequence of operation. It will be observed that the roller 43 mounted on link means 2| really acts as a selector means for selecting which of the cams 3| or 32 is to engage roller 33 and consequently operate blast valve I5. It will furthermore be observed that the relative shifting or relative motion of the cams 3! and 32, or the cam surfaces, one with the other causes the proper selection of the fluid blast.

In View of the detailed description included above, the operation of the valve control means and circuit breaker described above will be obvious to those skilled in the art. With the circuit breaker in the closed position as indicated by the solid lines of Fig. 1, opening operation of the circuit breaker l0 may be initiated by opening circuit breaker opening valve 28. It will be understood by those skilled in the art that any suitable means for controlling valve 28 which is schematically illustrated may be provided. As soon as valve 28 is opened, fluid under pressure from source !3 enters the right hand end of cylinder i8 indicated by the arrows in Fig. 2 whereupon piston |9 moves to the left as is also indicated by the arrow in Fig. 2. Such initial movement of piston I3 will cause connecting rod 20 and link means 2| to move to the left, but by virtue of the lost motion connection comprising slot 29 and pin 30, cams 3| and 32, bell crank 22, circuit breaker operating rod 24 and movable contact 52 remain stationary until the mechanism reaches the position indicated in Fig. 2. By this time, however, roller 43 has engaged the high point 4|! of opening cam 3| so as to cause roller 33 associated with bell crank 34 to be depressed and consequently to cause opening of blast valve l5; thereafter relative movement between contacts ii and |2 can occur. However, prior to such movement a blast of fluid is assured in arc chute l3 and consequently adjacent relatively movable contacts H and I2. As piston l9 continues to move toward the left in cylinder l8, the cam face between points 4| and 42 of opening cam 3| maintains blast valve |5 in the maximum open position as indicated in Fig. 3. When the circuit breaker l6 reaches the fully open position, shown by dotted lines in Fig. 1, the point 42 of cam 3| has ridden to the left beyond roller 33 as shown in Fig. 4 so as to permit closing of blast valve I5. It will be obvious that the shape of cam 3| may be varied in any manner so that the extent of opening of blast valve l5 or the point of opening or the point of closing relative to the opening stroke of circuit breaker l may be chosen to suit any preferred opening blast characteristics.

During the closing operation of the circuit breaker it is, of course, not necessary to have a blast of fluid in arc chute |3 before relative movement of contacts II and I2 occurs. Upon closing of circuit breaker 0 the blast valve operating mechanism is initially in the position indicated in Fig. 4. Initial movement of link 2|, in the direction of the arrow in Fig. 4, by virtue of the lost motion connection comprising slot 29 and pin 30 will cause roller 43 to engage the high point 44 of cam 32, whereupon cam face 45 will cause opening of blast valve l to provide a short fluid blast at a desired point during the circuit breaker closing operation. The amount of this blast, the duration, and the point of application, as well as the instant of closing of blast valve l5 during the closing stroke of the circuit breaker, may be controlled in any manner desired by properly shaping the closing cam 32.

The arrangement of Figs. 1 to 4 which gives complete flexibility in every respect of the opening and closing fluid blasts, may be simplified as is indicated in Figs. 5, 6 and '7 which correspond to Figs, 1, 3 and 4. by omitting closing cam 32. The corresponding parts of Figs. 5, 6 and 7 are designated by the same reference numerals as in Fig. 1 except that link means 2| is marked with a prime to distinguish it from the link means 2| of Fig. 1. In order to provide a short closing air blast, link 2| is provided with a cam surface 50 which engages roller 33 of bell crank 34 during the circuit closing operation to provide a short closing fluid blast in arc chamber l3. The operation of the arrangement in Figs. 5, 6 and 7 will be obvious to those skilled in the art. The fact that the cam face 5|! of link 2| operates during both the opening and closing stroke, detracts somewhat from the flexibility of this scheme relative to the scheme of Figs. 1 to 4 since it is necessary that cam 3|, during the opening stroke, overlaps the functioning of cam surface 50. As a practical matter, however, this is permissible in most situations.

Where no closing fluid blast is desired, the arrangement of Fig. 1 may be simplified by dispensing with cam 32 entirely and using the conventional link 2| of Fig. 1. Such an arrangement is disclosed in Fig. 8 which indicates the parts in the same position as in Fig. 4.

It will be obvious that the shape of cam 3| of Fig. 8 could be so modified that a single cam will control both the opening and closing of blast valve I5 during both the opening and closing strokes of circuit breaker ID. This is accomplished by the relative location of roller 43 with reference to the high point 4|! of cam 3|. In this arrangement the roller 43 of Fig. 8 would be positioned so that during the closing stroke roller 43 would be on point 40 of cam 3| to hold the portion of the cam face between points 4| and 42 in a position to cause a slight opening operation of blast valve l5. Consequently, during the closing stroke of the circuit breaker, only partial operation of blast valve l5 occurs. On the opening stroke, due to the reversal of the position of pin 30 in slot 29, roller 43 completely depresses cam 3| causing blast valve l5 to be fully opened.

ince this arrangement is so obvious in view of Fig. 8, merely necessitating a different arrangement of roller 43, no illustration of this arrangement has been provided.

In Figs. 9, l0 and 11 we have illustrated still another modification of our invention in which the corresponding parts thereof are designated by the same reference numerals as in Figs. 1 and following. In this case the link 2| is replaced by a pair of links and 53 which are pivotally connected at 54. The pivotal movement between links 52 and 53 is limited by means of a slot 55 in link 53 in which is adapted to move pin 56 supported from link 52. This double link arrangement with the slots 55 and pin 56 provides a lost motion connection similar to that shown in connection with Figs. 1 and following. However, an additional feature is obtained with this arrangement in that a floating pivot point 54 is provided which moves upwardly or downwardly depending upon the position of pin 56 in slot 55. For example, when connecting rod 20 moves in the direction of the arrow indicated in Fig. 9 to cause opening of the circuit breaker by upward movement of rod 24, no movement of rod 24 occurs until pin 56 has moved in slot 55 to the position indicated in Fig. 10. Such initial movement will cause a roller 51 fastened to pin, or pivot 54, upwardy to an extreme upper position indicated by the dotted position of Fig. 9 to engage a cam 58 pivotally mounted at 59. Upward movement of cam 58 will cause engagement with a roller 60 fastened to the lower end of valve stem 36 with the consequent opening of blast valve l5. It will be obvious to those skilled in the art, that the mechanism in Fig. 9 may be so arranged that the initial opening movement of the mechanism which causes movement of pin 56 in slot 55 without any movement of operating rod 24, may be caused to open blast valve |5 in the same manner as the initial movement of link 2| to the position indicated in Fig. 2 causes opening of the blast valve. The cam 53 is provided with a cam-face 5|, the height and length of which controls the opening air blast of the circuit breaker. A suitable stop 52 is provided on cam 58 which engages a pin 63 to limit the downward movement thereof. Fig. 10 indicates an intermediate position of the mechanism. during the opening stroke of the circuit breaker with the blast valve |5 in the maximum open position.

During the closing operation of the circuit breaker, the pin 56 of link 52' will be moved to the left hand end of slot 55 as is indicated in Fig. 11 so that roller 5'! is at a somewhat lower level in Fig. 11 than is indicated in Fig. 10. Consequently,

- when cam 55 is engaged by roller 51 the blast valve 5 is not opened to as great an extent during the closing operation of the circuit breaker during the opening operation. It will be observed that the arrangement disclosed in Figs. 9, 3.0 and ll is in some respects quite similar to Fig. 8 modified to provide a closing blast in that con.- trolling or the length of slot 55 will permit any required amount of air to be obtained on the closing stroke from zero to the equivalent of the amount of air supplied on the opening stroke.-

In view of the detailed description included above, the operation of the fluid blast control mechanism indicated in Figs. 9, l0 and 11 will be obvious to those skilled in the art. The solid lines of Fig. 9 disclose the mechanism just prior to opening the circuit breaker opening valve 28 while the dotted lines indicate the closed position of the circuit breaker. Fig. 10 discloses the apparatus at an intermediate point in the opening operation of the circuit breaker, and Fig. 11 discloses the apparatus during an intermediate point during the closing stroke of the circuit breaker.

From the foregoing explanations of the different embodiments that our invention might assume, it will be apparent that all are comparable in that in each case we have provided a linkage structure intermediate the actuating mechanism and the contacts, and that this linkage structure, by virtue of lost motion slots such as 2:! or 53, an efiective driving length when closing the breaker that is diiierent from the effective driving length of the linkage structure when opening the breaker. Also apparent is that we have provided cam means associated with this linkage structure for producing a predetermined valve opening for providing a blast of limited intensity at the con tacts during a closing operation of the circuit breaker; and that furthermore, we have arranged the cam means so that its eifect is responsive t or dependent upon, the change in the above mentioned effective driving length of the linkage structure whereby an increased valve opening is produced for delivering a blast of maximum intensity at the contacts for extinguishing the arc drawn during an opening operation of the circuit breaker. Also made apparent is that we prefer to arrange the valve opening cam means so that, coincident with the change in effective driving length of the linkage structure at the initiation of circuit breaker opening operation, the valve is caused to open so as to insure the arc extinguishing blast being delivered at the contacts before they separate to draw any are thereat.

Accordingly, it will be appreciated that we have disclosed a novel and useful mechanical arrangement for producing blasts of dilIerent intensities for the closing and opening operations of a circuit breaker which is simple in construction, effective in operation and economical to manufacture.

It will be apparent to those skilled in the art that our invention is not limited to the particular constructions shown, but that changes and modifications may be made without departing from the spirit and scope of our invention, and we aim in the appended claims to cover all such changes and modifications.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In an electric circuit breaker of the fluid blast type comprising means defining an arc chamber, relatively movable contacts separable to draw an arc in said chamber, a source of fluid under pressure for supplying a fluid blast to said are chamber, valve means for controlling the flow of fluid from said source to said are chamber, means for producing relative movement between said contacts including a reciprocally mounted link provided with means for permitting limited movement of said link without relative movement of said contacts, a pair of pivotally mounted cams adapted to engage said valve means, and means on said link for selecting the cam to engage and open said valve means in response to limited movement of said link to provide independently 8 controllable fluid blasts during both the opening and closing strokes of said circuit breaker.

2. In an electric circuit breaker of the fluid blast type comprising means defining an arc chamber, relatively movable contacts separable to draw an arc in said chamber, a source of fluid under pressure for supplying a fluid blast to said arc chamber, valve means for controlling the flow of fluid from said source to said are chamber, means for producing relative movement between said contacts including means so constructed and arranged as to have limited movement without corresponding relative movement of said contacts, a plurality of pivotally mounted cams associated with said last mentioned means, and means on said last mentioned means for selecting the cam to engage and open said valve means and provide independently controllable fluid blasts in said are chamber during both the opening and closing operations of said circuit breaker.

3. In an electric circuit breaker of the fluid blast type comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a source of fluid under pressure, means including a valve associated with said source for producing a blast of fluid adjacent said contacts during both the circuit opening and the circuit closing operations of said circuit breaker, a plurality of cam surfaces relatively shiftable with respect to one another, and means responsive to relative shifting of said surfaces for selecting either a closing or an opening fluid blast.

4. In an electric circuit breaker of the fluid blast type comprising a pluralit of relatively movable contacts, means for producing relative movement between said contacts, a source of fluid under pressure, means including a valve associated with said source for producin independent blasts of fluid adjacent said contacts during both the circuit opening and the circuit closing operations of said circuit breaker, a plurality of relatively movable cam surfaces, and means responsive to relative movement of said surfaces for selecting and causing to be produced one or the other of said independent blasts of fluid.

5. In an electric circuit interrupter of the fluid blast type comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a source of fluid under pressure, means including a valve associated with said source for producing two different types of fluid blast adjacent said contacts, a plurality of cam surfaces relatively movable with respect to one another, and means responsive to relative movement of said cam surfaces for selecting and causing to be produced one or the other of said two difierent types of fluid blast adjacent said contacts.

6. In an electric circuit breaker of the fluid blast type comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a source of fluid under pressure, means including a valve associated with said source for producing a blast of fluid adjacent said contacts during both the circuit interrupting and circuit closing operations of said circuit breaker, said first-mentioned means including valve lifting means for opening said valve to a greater extent during the circuit opening operation than during the circuit closing operation comprising a pair of interconnected members arranged for limited pivotal movement with respect to one another.

7. An electric circuit breaker of the fluid blast type comprising means defining an arc chamber, relatively movable contacts separable to draw an arc in said chamber, means for supplying a blast of arc extinguishing fluid to said are chamber, a valve for controlling the amount of said fluid supplied, actuating means for producing a closing and an opening operation of said contacts, means interconnecting said actuating means and said contacts including a linkage structure having a lost motion connection which produces a change in the effective driving length of said linkage structure for a closing operation as compared to that obtained for an opening operation, a valve operating member, and cam means interacting between said linkage structure and said valve operating member, the effect of said cam means being dependent upon the driving length of said linkage structure for producing different predetermined opening movements of said valve for said contact closing and opening operations respectively.

8. An electric circuit breaker of the fluid blast type comprising means defining an arc chamber, relatively movable contacts separable to draw an arc in said chamber, means for supplyin a blast of arc extinguishing fluid to said are chamber, a valve for controlling the amount of said fluid supplied, actuating means for producing a closing and an opening operation of said contacts,

means interconnecting said actuating means and said contacts including a linkage structure having a lost motion connection which produces a change in the effective driving length of said linkage structure for a closing operation as compared to that obtained for an opening operation, a valve operating member, and cam means interacting between said linkage structure and said valve operating member, the efiect of said cam means being dependent upon the driving length of said linkage structure for producing diiferent predetermined opening movements of said valve for said contact closing and opening operations respectively and for initiating the opening of said valve prior to the opening movement of said contacts.

JOHN D. GAYER.

EDWARD J. FRANK.

ALEXANDER C. BOISSEAU.

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

UNITED STATES PATENTS Number Name Date 2,287,578 Thumim et al June 23, 1942 2,310,779 Hall et al Feb. 9, 1943 2,218,797 Linde et a1 Oct. 22, 1940 2,294,824 Baker et al Sept. 1, 1942 597,150 Knudsen Jan. 11, 1898

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