US2866044A

US2866044A - Circuit interrupting device

Info

Publication number: US2866044A
Application number: US460170A
Authority: US
Inventors: Earl F Beach
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1954-10-04
Filing date: 1954-10-04
Publication date: 1958-12-23
Anticipated expiration: 1975-12-23
Also published as: FR1139615A; CH336479A; JPS323072B1; DE1041567B

Description

Dec. 23, 1958 E. F. BEACH CIRCUIT INTERRUPTING DEVICE Filed Oct. 4, 1954 5 Sheets-Sheet 1 INVENTOR Earl F. Beach.

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Dec. 23, 1958 E, F, BEACH 2,866,044

CIRCUIT INTERRUPTING DEVICE Dec. 23, 1958 E. F. BEACH 2,866,044

CIRCUIT INTERRUPTING DEVICE! Filed 001:. 4, 1954 5 SheetsSheet 3 Dec. 23, 1958 E. F. BEACH 2,866,044

CIRCUIT INTERRUPTING DEVICE Filed Oct. 4, 1954 5 Sheets-Sheet 4 Dec. 23, 1958 E. F. BEACH CIRCUIT INTERRUPTING DEVICE 5 Sheets-Sheet 5 Filed Oct. 4, 1954 United States Patent CIRCUIT INTERRUPTING DEVICE Earl F. Beach, Penn Township, Allegheny County, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 4, 1954, Serial No. 460,170 11 Claims. (Cl. 200-446) switches that are adapted to be opened under load conditions.

In many instances it is desirable to open a high voltage disconnecting switch while load current is flowing in the circuit in which it is connected. For example, in many installations, high voltage transformers are constantly connected to the high voltage line and infrequently require servicing. It is then necessary to disconnect such a high voltage transformer from the high voltage circuit, and during such disconnecting operation it is necessary to interrupt the magnetizing current flowing from the high voltage line into the high voltage transformer.

If this magnetizing current were drawn between the blade-shaped contact and the stationary jaw contact of a conventional disconnecting switch the contact surfaces would become pitted or eroded so that following only a few such operations the contact surfaces would not be suitable for carrying the full load current. Thus the switch members would become burned or fused because of the heat of the arc depending upon the amount of current in the circuit at the particular instant that the switch is opened.

There is also the possibility, under more severe circuit conditions, that a long are may be sustained and establish itself between the switch and an adjacent circuit or ground when the attempt is made to interrupt the load current by a conventional disconnecting switch. It is a general purpose of my invention to provide an improved load-break disconnecting switch which will interrupt the load current interiorly within an arc interrupting structure and not exteriorly thereof at the open switch contacts.

A further object of my invention is to provide an improved and highly efficient load-break disconnecting switch in which the contact structure of the arc-extinguishing device is opened and closed by snap action.

Still a further object of my invention is to provide an improved operating mechanism for the arc-interrupting device of a load-break disconnecting switch.

-Yet another object is to provide a load-break disconnecting switch in which the circuit is broken within the arc-interrupting device, and, during the closing operation, the circuit is made between the contacts of the arc-interrupting device and not at the switch contact members.

It will be apparent to those skilled in the art that certain features of my invention are applicable to switches of both the indoor and outdoor type. Merely for purposes of illustration do I disclose my invention as applied to a load-break disconnecting switch of the indoor type, which is preferably mounted in a cubicle construction.

Further objects and advantages will readily become apparent upon reading the following specification taken in'conjunction with the drawings, in which:

Figure 1 is a side elevational view of a load-break disconnecting switch embodying features of my invention, and shown in the closed-circuit condition;

Fig. 2 is a plan view, partially in section, of a portion of a three-phase installation mounted in a suitable cubicle and showing how the three phases may be simultaneously opened by a single common drive shaft;

Fig. 3 is an enlarged plan view, partially in section, of my improved load-break disconnecting switch, the several parts thereof being indicated in the closed-circuit position- Fig. 4 is a fragmentary vertical sectional view through the interrupting device and mechanism of my invention;

Fig. 5 is a vertical sectional view taken substantially along the line VV of Fig. 4, the several parts thereof being indicated in the closed circuit position;

Fig. 6 is a side elevational view, partially in section, of the hinge base of my improved disconnecting switch; Fig. 7 is a fragmentary side elevational view, partially in section, of the load-break disconnecting switch of my invention in the partially open-circuit position, with the over-center spring mechanism being shown in its intoggle position; and

Fig. 8 is a fragmentary sectional view through the mechanism housing, indicating the position of the several parts in the fully open-circuit position of the interrupting device, the several parts being drawn to a reduced scale.

Referring to the drawings, and more particularly to Figs. 1 and 2 thereof, the reference numeral 1 designates a cubicle, preferably fabricated of sheet metal and enclosing a plurality of interrupting devices 2, only one of which is shown, controlling a three-phase circuit. By means of a drive shaft 3, extending through a bearing structure 4, and externally actuated by a crank arm 5, connected by a link 6 to a suitable drive mechanism, the three interrupting devices 2 may be simultaneously actuated to open and close the three-phase circuit.

The drive shaft 3 has clamped thereto a plurality of crank arms 7, preferably one for each interrupting device 2; and the outer end of each crank arm end 7 is 7 connected by an insulating link 8 to a lug 9 disposed at the upper end of each hinge mechanism housing or frame 10, as more clearly indicated in Figs. 4 and 7 of the drawings.

Thus actuation of the crank arm 5, by any suitable mechanism, will etfect rotation of the drive shaft 3 and hence a simultaneous opening movement of the three insulated links 8 to effect an opening or a closing opera tion of the three interrupting devices 2, as indicated by the full and dotted lines of Fig. 1.

Referring more particularly to Fig. 1 it will be observed that there is provided a channel base 12, which supports a pair of

insulator columns

13, 14. The insulator column or hinge base 15, more and 6 of the drawings.

bolts 16 to the upper cap particularly shown in Figs. 5 The hinge base 15 is bolted by 17 of the insulator column 13. The hinge base 15 serves not only to pivotally support the'hinge mechanism housing 10, but also to provide a terminal pad 18 for an external line connection, as is well understood by those skilled in the art.

The other insulator column 14, supported upon the base 12, is utilized to fixedly support a main contact 20, an elongated stationary auxiliary contact 21 and a second terminal pad 22, to which the other line connection may be made to the interrupting device 2. The main contact 20 cooperates with-a main switch arm or rotatable bridging contact assembly, generally designated by the reference numeral 23, and comprising a pair of cooperating contact blades 24, as more clearly indicated in Figs. 2 and 3 of the drawings. The contact blades 24 are spaced apart by a channel-shaped member 25 bolted thereto, as at 26, and their right-hand ends, as viewed in Fig. 3,

13 serves to fixedly support a terminal are: supported on the'hinge pins 27, and secured by bolts 28 to the sides 29 of the hinge mechanism housing 10.

A metallic sleeve support 30 is secured by bolts 31 to the left-hand end of the frame 10, as shown in Fig. 4 of the: drawings. The support 30 has an internally threaded recess 32;. into which: is threadedly secured the end. of an insulating interrupting tube 33, as shown in Fig.4. The base of therecess 32- is apertured, as at 34, to accommodate therethrough; a movablearcing contact rod 35, which is biasedtowardr the open position by a compression spring- 36.. The compression spring 36 seats at oneendrupomthe end1washer: 37 of a stack of washers, which collectively. define an interrupting arc passage 38, through which the movable arcing contact rod 35 moves during; the. opening operation.

The-other end of the accelerating co-mpression spring 36gseats against' a washer: 39 hearing; against a sleeve 46?, which is fixedly secured to and movable with the contact rod 35, as indicated inFig. 4 of the drawings.

Preferably, disposed internally within the interrupting tube 33 between the washers 37 and the sleeve support 30 is a spacing tube 41. A relatively stationary arcing contact 42 is secured by a threaded connection to a perforated end cap 43, the latter being threadedly secured, as at.44, to an internally threaded outer end 45 of the interrupter tube 33. The perforations or apertures 46, provided in the end cap 43, permit gases, evolved during the interrupting operation within the interrupting tube 33, to flow. thereoutof to atmosphere.

The outer end of the stationary arcing contact 42 is extended to provide a movable auxiliary contact 47, which bears against the side of the auxiliary contact 21, as indicated in-Figl of the drawings. The right-hand end of. the movable arcing contact rod 35 is enlarged, as shown-in;Fig. 3, to form a movable contact yoke 48, having a bearing aperture, 49 therethrough to accommodate a pin50. Encircling the pin50. are a pair of guide rollers 51 which are guided insl-ots, or race tracks 52. integrally formed with the mechanism. housing 10, as more clearly shown in Fig. of the drawings. Also encirclingthe pin 50 is a pair of shoulder. bushings 53, which move in slots 54 provided in the sides or furcations 55 of a U-shaped operating lever 56, the configuration ofwhich is more clearly apparent from an inspection of Fig. 5 of the drawings. The lower ends of the furcations 55 are perforated, as at 57 (Fig. 5) to. accommodate hinge pins 58 welded to the inner sides of the mechanism housing10.

The-hinge base forms a pair of upstanding supports; 59, having apertures 60 internally threaded to threadedly secure into place thehinge' pins 27, as .shown in Fig. 5. Also the hinge base 15 has an apertured lug 61, through which extendsa pin 62. The pin 62 pivotally supports a springend 63 having grooves 64 onto which ,is threaded one end of a helical tension spring 65. The; upper end of the tension spring 65'threads in a similar'manner onto a spring support 66, the latter being apertured to receive apin 67, the ends of which are journaled .in apertures provided in the furcations 55 of the U-shaped operating lever 56. Preferably spacing sleeves 68 encircle the pin 67 to maintain the upper spring support 66 in a-central position, as shown in Fig. 5'.

In the closed-circuit position of the interrupting device 2, thecurrentpasses from the terminal pad 22 through the-contact and hence through the main switch arm 23' to the metallic supports 59 and thence to the other terminal pad 18 of the hinge base 15. Another parallel path is provided by the auxiliary contact 21, the movable auxiliary contact 47, the stationary arcing contact 42, the'movable arcing contact rod to the contact yoke s Afi xi leonle to fifl ransmitsthe current from; the, contact, ,ypke. 8 o... he..- rota le housing; 19.- and; meat .o. gl,1-. 11.e.-hi ge;- Pius, 2.1 o;v hcemetallie. pp

4 59 of the hinge base 15, and thence to the other terminal ad 18. p It will be obvious that the second parallel path for current flow has a greater resistance than the first-mentioned current path, and consequently in the closed circuit position of the device practically all of the current will flow through the device by way of the main contact 20 and the main switch arm 23.

In the closed position of the switch (Fig. 4) the line of action of the tension spring 65 is to the left of thepivot 58 for the link 56 and biases it in counterclockwise direction so as to tend to move the arcing contact rod to the left and into pressure engagement with the stationary arcing contact 42.

When it is desired to open the interrupting device 2, the drive shaft 3 is rotated, which effects through the insulating link 8 clockwise rotation of the mechanism housing 10 about the hinge pins 27. This will bring the hinge pins 58 and the pin67 into line with the pin- 62 so that the tensile stress exerted by the tension spring 65 will be exerted directly axially of the U-shaped operating lever 56 in a manner more clearly illustrated in Fig; 7' of the drawings. mechanism 70 is in'toggle on dead center, and there is no force exerted by the spring 65 to efiect opening or closing motion of the contactrod 35. As shown in Fig. 7, at this time the main switch arm 23 has separated from the main contact 20 to provide a gap therebetween, as indicatedby the distance D of Fig. 1. During this time, however, the

auxiliary contacts

21, 47 have maintained contact so thatthe circuit through the interrupting device 2 extends therethroug-hby way of the auxiliaryinterrupting device 71, ,including the stationary andmovable arcing contacts 42', ,35.

Further clockwise rotationeof the mechanism housing 10 about the hingepins27, as efifected by continuedrotation of the drive shaft 3, causesmovement of 'the-hin'ge= pins 5810 the-left of astraightline drawn between pins 62 and 67, so that the line of action of thespring force, exerted by tensionspring, 65' is to the right of pins 58. This effects snap-opening movement of the contact rod35 at approximately the-position A of Fig. l, the guide rollers 51 guiding the motion of the contactrod 35 in a substantially straight-line motion.

The insulating washers 37 defining the arcing passage 28' are preferably of a suitable gas-evolving material,

such as .fiber, boric acid, or likematerials, so'thatupon separation of the stationary and

movable arcing contacts

42, 35, the are established therebetween willbedrawn within arcing passage 38 to effect evolution of consider able gas therein. This gas blast will flow axially of the" established arc, and outwardly from the arc passage 38' through the apertures 46 provided in the preforated end" cap 43. Current interruption wil quickly be brought about, andcontinued clockwiserotation of the mecha nism housing 10'to the position'B of Fig. l willlefie'ct" an adequate isolating. gap in the circuit between theauxiliary contacts21 and 47 in the fully open circuit position of the interrupting device 2, the several parts oftlie over-center spring mechanism 70 then having a disposition such as viewed inFig. 8 of the drawings withzthe line of action of'the spring lying to the right of the pivot 58 and biasing the contactrod 35 to open position;

During the-closing operation the;.events transpire in a reversed sequence, namely-the drive. shaft effectscounteh clockwise rotative motion of the mechanism housing 10 about the hinge pins 27 thereby bringing the lOCatiQH' 10ffI the pins 58 closer to a straight line drawn between the;- pins 62, 67. At about 25 angular degrees from the closed.

position the several parts of the mechanism 70 are substantially'in toggle. of the mechanism housing 10 will bring the line ofac? tionofthe tension spring-65;toithegleft of the. pins. .8, and, the=over-centen spring-=65" will efiect" snap;closing; seine movable arcing. contact-=rodi35"into; engagemenflwithitlie In this position the overcenter spring Further, counterclockwise rotation.

relatively stationary arcing contact 42. Since at this time the

auxiliary contacts

21 and 47 are in engagement, the circuit will be completed through the device by way of the auxiliary interrupter 71. Final closing rotative motion of the mechanism housing effects closing contacting engagement between the main contact 20 and the main switch arm 23. Since, as mentioned, the resistance through the

contacts

20, 23 is considerably less than that by way of the auxiliary interrupter 71, the current will be transferred to the lower resistance path between the

contacts

20 and 23.

From the foregoing description of my improved interrupting device it will be apparent that I have provided snap-opening and snap-closing motion of the movable contact rod 35. It will also be observed that the circuit is made and is broken during respective closing and opening operations by way of the interrupting device 71, and not at the main contact 20. The tension spring 65 provides a high speed of motion for the movable contact rod 35, and the construction of the over-center spring mechanism 70 is such that slight rotative movement of the drive shaft 3 effects a considerable change in the line of action exerted by the tension spring 65. This is very important in conserving floor space and in utilizing only slight rotative motion of the drive shaft 3.

It will be observed that at the time of the breaking of the circuit within the interrupting device 71 the contact 20 and the end of the main switch arm 23 are so far separated at this time that there is no chance of external breakdown or fiashover between these points upon interruption of the circuit within the interrupting device 71. In the B position of Fig. l, which represents approximately 70 of rotative travel, it will be noted that a considerable disconnecting gap is provided between parts at opposite potential.

Although I have shown and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope thereof of the invention.

I claim as my invention:

1. A circuit interrupting device including spaced terminals, a rotatable bridging contact assembly supported for rotation around an axis on one terminal and adapted to be swung around said axis into contacting bridging engagement with the other spaced terminal to complete the circuit between the terminals, an auxiliary interrupting device having a movable auxiliary contact, an operating lever pivotally supported on a movable part of the contact asembly at a point off of said axis which rotates during the opening and closing operations, means positively connecting one end of the operating lever at all times with the movable auxiliary contact, and means biasing the operating lever to one side or the other of the axis of its pivotal support.

2. A circuit interrupting device including spaced terminals, a rotatable bridging contact assembly supported for rotation around an axis on one terminal and adapted to be swung around said axis into contacting bridging engagement with the other spaced terminal to complete the circuit between the terminals, an auxiliary interrupting device having a movable auxiliary contact, an operating lever pivotally supported on a movable part of the contact assembly at a point off of said axis which rotates during the opening and closing operations, means connecting the operating lever with the movable auxiliary contact, and an over-center biasing spring for biasing the operating lever to one side or the other of the axis of its pivotal support.

3. A circuit interrupting device including spaced terminals, a rotatable bridging contact assembly supported for rotation around an axis on one terminal and adapted to be swung around said axis into contacting bridging engagement with the other spaced terminal to complete the circuit between the terminals, an auxiliary interrupting device having a movable auxiliary contact, an operating lever pivotally supported on a movable part of the contact assembly at a point off of siad axis which rotates during the opening and closing operations, means connecting the operating lever with the movable auxiliary contact, and an over-center tension spring having one end thereof connected to a point intermediate the ends of the operating lever.

4. The combination in a load-break switch of a pair of spaced terminals, a rotatable switch arm assembly mounted for rotation around an axis on one terminal, means for swinging said switch arm assembly about said axis so that the free end of the switch arm assembly makes contacting and disconnecting engagement with the other spaced terminal, an arcing horn mounted on said other spaced terminal, an auxiliary interrupting tube extending in generally the same direction as the switch arm assembly and having a protruding arcing horn which makes engagement with the first-mentioned arcing horn at least during a portion of the opening operation, a movable auxiliary contact associated with the auxiliary interrupting tube, an operating lever pivotally supported on a rotatable portion of the switch arm assembly at a point off of said axis, means operatively connecting the operating lever with the movable auxiliary contact, and means biasing the operating lever to one side or the other of the axis of its pivotal support.

5. The combination in a load-break switch of a pair of spaced terminals, a rotatable switch arm assembly mounted for rotation around an axis on one terminal, means for swinging said switch arm assembly about said axis so that the free end of the switch arm assembly makes contacting and disconnecting engagement with the other spaced terminal, ,an arcing horn mounted on said other spaced terminal, an auxiliary interrupting tube extending in generally the same direction as the switch arm assembly and having a protruding arcing horn which makes engagement with the first-mentioned arcing horn at least during a portion of the opening operation, a movable auxiliary contact associated with the auxiliary interrupting tube, an operating lever pivotally supported on a rotatable portion of the switch arm assembly at a point off of said axis, means operatively connecting the operating lever with the movable auxiliary contact and an over-center biasing spring for biasing the operating lever to one side or the other of the axis of its pivotal support.

6. The combination in a load-break switch of a pair of spaced terminals, a rotatable switch arm assembly mounted for rotation around an axis on one terminal, means for swinging said switch arm assembly about said axis so that the free end of the switch arm assembly makes contacting and disconnecting engagement with the other spaced terminal, an arcing horn mounted on said other spaced terminal, an auxiliary interrupting tube extending in generally the same direction as the switch arm assembly and having a protruding arcing horn which makes engagement with the first-mentioned arcing horn at least during a portion of the opening operation, a movable auxiliary contact associated with the auxiliary interrupting tube, an operating lever pivotally supported on a rotatable portion of the switch arm assembly at a point off of said axis, means operatively connecting the operating lever with the movable auxiliary contact, and an over-center tension spring having one end thereof connected to a point intermediate the ends of the operating lever.

7. A circuit interrupting device including spaced terminals, a rotatable bridging contact assembly supported for rotation around an axis on one terminal and adapted to be swung around said axis into contacting bridging engagement with the other spaced terminal to complete the circuit between the terminals, an auxiliary interrupting device having a movable auxiliary contact, a U-shaped operating lever pivotally mounted on a rotatable portion of said bridging contact assembly, means interconnecting the movable auxiliary contact with the U-shaped operatinglever adjacent the bight portion thereof, and anovercenter. spring connected at one end to a portion of the U-shaped operating lever intermediate the ends thereof.

8. The combination in a load-break switch of a pair of spaced terminals, a rotatable switch arm assembly mounted for rotation around an axis on one terminal, means for swinging said switch arm assembly about said axis so that the free end of the switch arm assembly makes contacting and disconnecting engagement with the other spaced'terminal, an arcing horn mounted on said other spaced terminal, an auxiliary interrupting tube extending in generally the same direction as the switch arm assembly and having a protruding arcing horn which makes engagement with the first-mentioned arcing born at least during a portion of the opening operation, a movable auxiliary contact associated with the auxiliary interrupting tube, a U-shaped operating lever pivotally mounted on a rotatable portion of the switch arm assembly at a point olf of said axis, means interconnecting the movable auxiliary contact with the U-shaped operating lever adjacent the bight portion thereof, and an over-center spring connected at one end to a. portion of the U-shaped operating lever intermediate the ends thereof.

9. A circuit interrupting device includingspaced terminals, a rotatable bridging contact assembly including a frame, the frame being pivotally supported about an axis on one terminal so that the bridging contact assembly may be swung rotatively around said one terminal into contacting bridging engagement with the other spaced terminal to complete the circuit between the terminals, the bridging contact assembly including a main contact blade and an auxiliary interrupting tube both mounted on the framev and extending outwardly therefrom. substantially parallel to oneanother, the main blade having a length substantially equal to the spacing distance between the spaced terminalsgthe aux-- saidother terminal, and means for establishing anfarc within the tube and extinguishing it' therein.

10. A circuit-interrupting device including spaced. terminals, a rotatable. bridging contact assembly including.

aframe, the frame being pivotally supported about. an axis on one terminal so that the bridging contact assem-.

bly may be swung rotatively around said' one terminal. into contacting bridging engagement with the other.

ing disengagement of the main contact blade from said.

other terminal, means for establishing an arc within' the tubeandextinguishing it therein, and the main contact blade-being shorter than the auxiliary interrupting tube.

11. A load-break disconnecting switch including a pair of spaced' terminals, relatively stationary insulatingv supporting meansfor supporting saidpair of spaced terminals a fixed distance apart, a rotatable bridging contactass'embly. supported for rotation relative to said supporting: means around: an axis on one terminal, the rotatable bridging contact assembly being adaptable to be swung around said. axis into contacting bridging engagement withthe other spaced terminal to complete the circuit betweeen the terminals, the bridging contact assembly including. a rotatable auxiliary interrupting device having a movable auxiliary contact, an operating.

lever pivo-tally'supported adjacent one end thereof on a rotatable part of the contact assembly at' apoint off of said axis which rotates during the opening and. closing operations, means connecting: said. movable auxiliary contactat all. times adjacent the other end of the oper.--

ating: lever, andmeans biasing said operating lever :05

one-side or the' other'of'the axis of its pivotal support;

References Cited in the file of this patent UNITED STATES PATENTS 2,323,241. Richardson et a1. June 29, 1943: 2,658,977 Hoye Nov. 10, 1953 2,714,144 Amundson July 26, 1955