US2374702A - Electric switchgear - Google Patents

Description

y 1945- F. w. REILLY 2,374,702

ELECTRIC SWITCHGEAR Filed Nov. 4, 1940 4 Sheets-Sheet 1 ATTORN y 1945' F. w. REILLY 2,374,702

ELECTRIC SWITCHGEAR Filed Nov. 4, 1940 4 Sheets-Sheet 3 as 6F INVENTOR K 6 Tim 2? ATTORN EY May 1, 1945. F. w. REILLY ELECTRIC SWITCHGEAR Filed Nov. 4 1940 4 Sheets-Sheet 4 r INVENTOR ATTORNEY disconnect switch.

Patented May 1, 1945 UNITED STATES PATENT OFFICE ELECTRIC SWITCHGEAR Frank W. Reilly, Auburndale, Mass. 7 Application November 4, 1940, Serial No. 364,149

4 Claims. Cl. 175-298) movable contact by a flexible conductor, such.

as a pigtail. A plurality of such switches may be mounted on the same shaft to form a gang switch and, if desired, two or more gangs may be provided having suitable connections whereby all switches may be operated together or interlocked for independent operation. i

Although this type of switch is capable of a wide range of uses in connection with switchboards and other places where it is desired to connect and disconnect electric conductors, it has an important use with switchingapparatus which is enclosed in a compartment or cubicle.

This type of switching apparatus commonly includes a removable interrupting switch which may be of the oil or air immersed type and the In one preferred form of the invention the disconnect switch arm may be journall'ed directly upon the circuit breaker frame and coact with stationary switch contacts mounted upon the cubicle frame. In another preferred form of the invention, the disconnect switch arm may be journalled upon the cubicle frame and may cooperate with stationary switch contacts mounted upon the terminals of the circuit breaker casing.

The invention also consists in certain new and original features of construction and combination of parts hereinafter set forth and claimed.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, and the manner in which it may be carried out, may be better understood by referring to the following description taken in connection with the accompanying drawings iorming a part thereof, in which Fig. i is a side elevation, partly in section, illustrating the new switching apparatus;

Fig. 2 is a front sectional elevation taken on the line 22 of Fig. 1, with the removable switching unit removed;

Fig. 3 is a front elevation of the removable switching unit after removal from the cubicle;

Fig. 4 is a detail showing the device for locking the disconnect switch in open and closed positions;

Fig. 5 is a side elevation, partly in section, of a modified switching apparatus;

Fig. 6 is a front elevational view taken on the line G6 of Fig. 5; and

Fig. '7 is a top plan view of the removable unit of Figs. 5 and 6.

In the following description and in the claims, various details will be identified by specific names for convenience, but they are intended to be as generic in their application as the art will permit.

Like reference characters denote like parts in the several figures of the drawings.

In the drawings accompanying and forming part of this specification, certain specific disclosure of the invention is made for purposes of explanation, but it will-be understood that the details may be modified in various respects without departure from the broad aspect of the invention.

Referring now to the drawings, and more particularly to Figs. 1, 2 and 3, the switching apparatus comprises as its main parts, a. cubicle indicated in general by it, made up of a suit able structural steel framework with steel panels, a removable unit made up of a circuit breaker, denoted generally by H, carrying a framework l2 which in turn carries the movable contacts of a disconnect switch, indicated generally by it. The cubicle has horizontal ways H on which the removable unit ii, i2, shown in Fig. 3, normally rests and from which it may be moved outwardly outof the front of the cubicle by a suitable truck (not shown). The framework E2 of the removable unit carries individual insulating panels or barriers 59, 60, Si, Bland a handle it for operating the disconnect switch E3. The cubicle it) is provided with a vertical space, indicated by H, to accommodate the handle IE. it will be understood that, if desired, a series of such cubicles may be placed side by side in a manner known to those skilled in the art, with their fronts in line, available for operation, inspection, and repairs. These cubicles may be used for general switching purposes, for connecting and disconnecting any suitable electrical apparatus and a source of electricity.

The cubicle l comprises a suitable steel framework denoted in general by 22, covered by suitable steel panelling, the front being indicated by I8, the back by I9, and the sides by and 2|. The steel framework is arranged to provide the operating space H. Secured to the framework are the pair of ways It extending from the front to the back of the cubicle. These ways support the removable unit II, I 2, as described hereinafter more in detail. The front 83 may be provided with a removable closure such as a door (not shown).

Mounted within the upper part of the cubicle II] are three conductors 2d, and 26, forming part of a three-phase line. This line may be the incoming line supplying the electricity to the load through the switching apparatus forming part of this invention. Similarly, three outgoing conductors, all indicated by 21, are provided for su lying electricity to the load. All of the condugirs 23, 25, 26 and 2'? are mounted upon suitab e pest insulators, indicated in-general by 28, these insulators being mountedupon the framework of the cubicle. These several conductors may lead to suitable busses or to feeders, or, in fact, the conductors 23 to 23 may be busses in themselves.

Circuit breaker H may be of any well known type, as for an example, an oil or air circuit breaker of high interrupting capacity, 1, e., adapted to break the circuit under load. In the form shown, oil circuit breaker I I is of the three-phase type having six terminals, three incoming terminals and three outgoing terminals. The incoming terminals are denoted by 38, 39 and 33 and the outgoing terminals are all indicated by 3|.

The circuit breaker II comprises a switch frame 33 from which is detachably suspended the oil tank 3|. The switch frame has secured thereto a pair of cross heads 32 adapted to rest on the ways It when the removable unit II, I2 is in place within the cubicle. The ways id have a series of holes I5, two on-each side, in which are seated dowel pins 23 depending from cross heads 32. The operating mechanism for operating the circuit breaker II is denoted diagrammatically by 33. Supported on top of the switch frame 30 are bushings 48 supporting the terminals 38, 33, 60 and ti.

Forming part of the removable unit and supported by the circuit breaker II is the framework I 2. The framework l2 carries bearings 32 and 53 for disconnect switch shafts 3d and 35, which carry insulators for the various movable forked prongs indicated by 33 and 31. There are three prong contacts, all indicated by 35, corresponding to the three conductors of the threee phase system forming part of the incoming line, and three prongs, all indicated by 37 for the corresponding outgoing line. All of these forked prongs form part of a multiple gang, multiple pole switch. The poles are all identical so that it is only necessary to describe the one in detail.

The shaft 33' carries a support 43 which in turn carries a post type insulator 45 which carries the prongs 3B. Secured to the prongs 36 is a plate 43 which has a Pigtail 37 secured thereto extending to the terminal 40 of the circuit breaker II. Secured to the insulator 28 and in electric contact with the conductor 23 is a contact blade 49 adapted to enter between the prongs 36 when the disconnect switch is closed. The constructional details of the blades and forked prongs are discussed more in detail hereinafter.

For operating the gang switch, the handle I6 is secured to the end of an arm 50 secured to shaft 36. An arm 5| is secured to shaft 35 and the wo arms 50 and 5| are connected by a connecting rod 52. Thus by pulling down on the handle I3 in Fig. 1, the both gangs of prongs 36 and 31 are raised upwardly in the direction of the arrows A, contacting their respective blades 39 to close both gangs of the disconnect switch. It will be noted that the supports 34 swing into engagement with the adjacent structural members 53 in Fig. 1 to provide a positive stop to limit the downward movement of the disconnect switch.

For locking the disconnect switch in both open and closed positions, a suitable locking device may be provided. This may take the form of a plate 55 suitably secured to the framework and having holes 53 and 57. A spring-pressed plunger 58 is secured to arm 53 which is adapted to engage in the hole 56 and 51. Thus a single looking device locks both gangs of switches in both open and closed positions.

For thoroughly insulating the several phases from each other and from the grounded cubicle, a series of insulating barriers 59, 63, SI and 82 may be provided. These barriers may be of any well known dielectric material, such as transite, asbestos ebony, slate, Bakelite, etc., and are suitably secured as by angle irons, angles, or the like, to the framework I2, as shown. These barriers all have clearance spaces 33 in their upper front and rear corners to clear the insulators 35. In

addition, the two middle barriers fill and SI have clearance spaces 34 in their lower corners to clear the operating mechanism 33 of the oil circuit breaker II. The barriers eliminate all possibility of flash-over and also prevent the possibility of the flexible pigtail conductors 31 from swinging against each other or against the rounded cubicle frame.

In the ordinary use of the switching device, assuming that it is desired to withdraw the circuit breaker II out of the cubicle for inspection or repairs, the circuit breaker II will first be opened to open the circuit. Locking member 58 will then be removed from hole 51. The disconnect switch will then be opened by operating the handle I 6 to open position, after which thelocking device 58 is engaged in hole 56 to hold the switch in open position. A truck (not shown) will be wheeled into the cubicle and the entire removable unit I I, I2 raised slightly to raise the cross heads 32 off the ways It to remove the dowel pins 29 from their holes I5. The removable unit will then be withdrawn on the truck out of the front of the cubicle where the circuit breaker will be inspected or repaired. To put the cubicle back into use, the removable unit II, I2 is then replaced by wheeling it in on the truck to position the cross heads 32 on top of the ways It and against the back of the cubicle. This aligns the dowels 29 with holes I5. The truck is then lowered and removed and the dowels 29 seat'in the holes I5. This insures that the prongs 35, 31 will be in proper position to engage their blades 49 when the switch is closed. The disconnect switch is then closed by lowering handle I6 in Fig. 1 and engaging the locking device 58 with hole 51 to'hold the disconnect switch in closed position. The circuit breaker II is then also closed and the cubicle is back in servlce.

Referring now to Figs. 5, 6 and 7, a somewhat different type of switching apparatus is ,shown.

circuit breaker I I.

made up of suitable structui'al steel work with steel panels and having a removable unit. The removable unit here is made up merely of the The swinging arms carrying the movable contacts of the disconnect switch I8 are carried by the cubicle frame instead of by the circuit breaker frame. barriers are also carried by the cubicle frame instead of by the circuit breaker frame. g,

The cubicle I8 comprises a suitable steel framework 12 covered by suitable steel panelling, the front being indicated-by I8, the back by I8, and the sides by 88, and 8|. The steel framework is made to provide a clearance space 11 to accommodate the handle I8 of the disconnect switch.

, The cubicle framework is also provided with ways I4 on which the removable unit It rests.

Mounted within the upper part of the cubicle I8 are the three conductors, indicated by 84, 85 and 88, forming part of a three-phase line. These conductors may be the incoming line which supplies electricity to the load through the switching apparatus forming part of this invention. The three corresponding outgoing conductors are all indicated by 81. All of these conductors 84. 85, 86 and 81 are mounted upon suitable post type insulators indicated by 83 mounted upon the framework of the cubicle. These conductors may form part of suitable busses or may be connected to busses.

The circuit breaker II may be of any well known type as in the case of circuit breaker II in the first. form, having three incoming terminals, indicated by 88, 89 and 98, and three outgoing terminals, indicated by 9|. The circuit breaker operating mechanism is indicated diagrammatically by 93, the switch frame by 98, and the detachable oil tank by 95. Secured to the switch frame are cross heads 98 adapted to rest upon the ways I4. Cross heads 98 carry dowel pins H8 disposed in holes II9'in ways I4 to imsure holding the circuit breaker II in correct position. Circuit breaker TI is removable by means of a truck (not shown) in a manner similar to the removable unit in the first form.

The cubicle frame 12 carries bearings 88 and 89 for the disconnect switch shafts I84 and I85 which carry insulators for the various movable blades, indicated by I88 and I81. There are three blades, indicated by I88, corresponding to the three conductors of the incoming line. There are three blades, indicated by I81, for the corresponding outgoing line. All of these blades form part of the multiple gang, multiple pole disconnect switch I3. The poles are all identical so it is only necessary to describe one'set in detail.

Suitably secured to the shaft I84 is a support I88 which has anchored thereto a post type insulator I89 which in turn carries a blade I88. The insulator I89 also supports a plate H8 in electric contact with blade I88. Plate H8 is secured to a pigtail conductor III which in turn is secured to the conductor 88. Blade I88 is adapted to engage with forked prongs II2 secured to the terminal 98 of circuit breaker II.

The handle I8 for operating the disconnect switch is connected to arm II4 aflixed to the shaft I84. A similar arm H5 is secured to a shaft I85 and connecting rod H8 connects the arms II 4 and H5. Thus it will be seen that by moving the handle I8 to the left in Fig. 5, both gang switches will'move in the direction of the arrows B to open the disconnect switch. It will be noted that the supports I88 swing into en- In the present case the gagement with the adjacentstructural members I88 to provide a positive stop to limit the downward movement of the disconnect switch. A suitable locking device may be provided for holding the disconnect switch in either open or closed position, similarly to that described in the first form.

A series of barriers of suitable insulating materials such as used in the first form are provided, these barriers being mounted by suitable angle irons or angles directly on the framework 12 of the cubicle. Four barriers are provided, the two middle barriers 98 and 98 being disposed between the blades of the disconnect switch and preventing arcing over between the several phases, and the two end barriers 917 and I88 providing protection against ground. comparatively large recesses I8I are provided in the upper edges of all barriers to provide clearance for the disconnect shafts I84 and I85 and for the insulators I89, and the lower front edges of the intermediate barriers 98 and 99 are provided with notches I82 to clear the operating mechanism 98. These barriers provide protection against flash-over either between phases or between the several phases and ground, and also prevent any possible accidental swinging together of the several flexible pigtail conductors Iii.

It is thought that the use of this switching apparatus will be obvious to those skilled in the art from the explanation given above in connection with the first form. To remove the circuit breaker it it is first opened by operation of mechanism 93, as will be understood by those skilled in the art, The disconnect switch is then opened by swinging the handle 16 to the left in Fig. 5, the dsconnect switch being locked open for safety by engaging the spring-pressed member in the locking hole. The circuit breaker II is then removed by placing a truck (not shown) in the cubicle under the circuit breaker and raisin the cross heads slightly off the ways to disengage dowels I I8 from holes I I9 so that the circuit breaker can be easily withdrawn from the cubicle. After the circuit breaker is withdrawn, it may be inspected and repaired, if necessary, and then replaced. Stops I I3 are provided on the ways I4 to assist in aligning the dowel pins H8 and holes H9. This insures locating the circuit breaker in the proper position so that the prongs of the disconnect switch will be properly aligned with its blades. Before the circuit breaker 'II is closed, the disconnect switch must be closed by swinging the handle I8 to the right into the position shown in Fig. 5.

The pigtail conductors 41 and III may be of flexible flat ribbon stock and so connected at their ends that. when the disconnect switches I3 or 13 are open, they will bend only in a plane parallel to the plane of movement of the switch arms and F'g.' 1), These pigtails assume a moderately taut 'ing apparatus with a minimum of change.

forked prongs. The blades 48 and M6, M1 will be of suitable construction to cooperate with the forked prongs to make good electrical connections.

It will be understood that, if desired, various safety interlocks may be provided between the disconnect switches and the circuit breakers in both the above forms.

There are many 'advantagesin the present invention, both from a structural standpoint and from the standpoint of safety and operation. Although the disconnect switch is show used in a cubicle with a circuit breaker, it is obvious that it may be used alone to connect and disconnect any two terminals or conductors in any circuit. For general application, the disconnect switch may be arranged so that its rotating contacts may swing in a vertical plane'either up or down, as shown in the drawings, or it may be arranged to swing in a horizontal plane or at an angle, as for example 45 with the horizontal.

The disconnect switch may be adapted to exist- For example, the stationary switch contacts may be located on existing bus bars, as shown in Fig. 1, or on existing stationary terminals, as shown in Fig. 5. The contact arms may be adjusted along their shaft to correspond to the spacing of the stationary contacts. I

All of the several poles are separated by insulating barriers which may be mounted upon a stationary part of the frame as shown, or the barriers may be mounted upon the disconnect switch shaft so as to rotate with the switch, thus protecting the poles and eliminating arc-over.

The operating shafts'may be of metal and may be thoroughly grounded, entirely eliminating the necessity for insulated operating linkage. The operating shafts may be grounded through their bearings as shown or by any other suitable means. Since there are no insulators directly surrounding the switch contacts, full visibility of the contacts is enjoyed at all times. The switch is esp cially strong since both the stationary and movable contacts are directly mounted upon post type insulators and, when the switch is closed, increased cantilever strength is obtained.

The disconnect switch lends itself admirably to use with metal enclosed switch gear. The stationary contacts of the switch may be mounted upon the existing terminals of the oil circuit breaker, as in Fig. 5, or they may be mounted upon the existing bus bars, as in Fig. 1. The rotating contact arms may be carried by the stationary cubicle frame or they may be carried by the removable'unit. In both cases they may be adequately grounded.

The use of this disconnect switch in a metal cell or cubicle has many advantages. It permits the withdrawal of the breaker without breaking any cable connections. The breaker can also be electrically opened without withdrawal. The breaker tank may be removed without withdrawal of the breaker. In case the swinging arm of the disconnect switch is mounted on the breaker frame, as in Fig. 1, it becomes removable with the circuit breaker for inspection and mainte nance. In addition, theprongs 36, 31, which require attention from time to time, are exposed for convenient adjustment and repair. Also, in Fig. l, the movable blades fall away from the upper contacts. which makes the disconnect switch doubly safe. Furthermore, the fixed contacts may be mounted directly upon the bus or upon the insulator supporting bus, as shown in asvcyoa when the swinging arm of the disconnect switch is mounted upon the stationary cubicle frame, when the switch is thrown to open position, the breaker is freed for removal. This construction also facilitates the use of a. horizontal barrier between the bus and the disconnect switch.

While certain novel features of the invention have been disclosed and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. In enclosed electric switching apparatus, a cubicle, a circuit breaker in said cubicle and bodily removable horizontally therefrom, said circuit breaker and said cubicle each having thereon a set of fixed disconnect switch terminals, said cubicle terminals being mounted above said circuit breaker terminals to provide generally vertical air gaps, disconnect switch contacts movable in paths generally lengthwise of said air gaps to engage and disengage one set of terminals, said movable switch contacts including conductors extendible to the other set of terminals, a. grounded metal operating shaft extending horizontally across the cubicle, post insulators rigidly attached to said shaft and to their respective movable contacts forming cantilever switch arms, operating devices secured to said shaft, said shaft being offset from points intermediate the length of said air gaps at such distance that, upon force being applied to said operating devices, said cantilever arms carry their movable contacts in the paths aforesaid.

2. In enclosed electric switching apparatus, a cubicle, a circuit breaker in said cubicle and bodily removable therefrom, said circuit breaker and said cubicle each having mounted thereon a set of stationary disconnect switch terminals, disconnect switch contacts movable to engage and disengage one set of terminals constituting stationary contacts, said movable switch contacts having flexible linear conductors secured thereto and to the other set of terminals, an operating shaft extending across the cubicle, insulators rigidly attached to said shaft and to their respective movable contacts to form cantilever switch arms, operating devices secured to said shaft to rotate said shaft to cause said cantilever to carry their movable contacts to open or close the disconnect switch, said cantilever arms being individually bodily adjustable lengthwise of said shaft during assembly to align said movable and stationary contacts, said flexible linear conductors yielding to permit such adjustment.

3. In enclosed electric switching apparatus, a cubicle, a multi-phase circuit breaker mounted in said cubicle and removable horizontally therefrom, said circuit breaker having mounted thereon incoming and outgoing switch contacts corresponding to the phases, said cubicle having corresponding terminals mounted above saidcircuit breaker. switch contacts to provide generally vertical air gaps, movable switch contacts movable upwardly lengthwise of said air gaps to disengage said circuit breaker contacts, fiexible linear conductors depending from said cubicle terminals and securednto said movable contacts, an incoming metal operating shaft and an outgoing metal operating shaft both joumaled in, and extending horizontally across, the cubicle above said circuit breaker contacts, post insulators rigidly attached to their respective shafts and to their respective movable contacts to form cantilever switch arms, operating devices secured to said shafts, said shafts being offset from points intermediate the length of their respective air gaps at such distance that, when force is applied to said operating devices, said cantilever arms carry their movable contacts in the paths aforesaid, and plate-like insulating barriers adjacent said able contacts and located between the phases and between theend phases and the adjacent wall of the cubicle to prevent said flexible conductors swinging together or against the cubicle.

4. In enclosed electric switching apparatus, a cubicle, a multi-phase circuit breaker mounted in said cubicle and removable horizontally through the front thereof, said circuit breaker having mounted thereon three forward and three rearward switch contacts corresponding to the phases, said cubicle having corresponding forward and rearward terminals mounted above said circuit breaker switch contacts to provide generally vertical air gaps, forward and rearward movable switch contacts movable upwardly lengthwise of said air gaps to disengage said circuit breaker contacts, flexible linear conductors depending from said cubicle terminals and secured to said movable contacts, a forward metal operating shaft and a rearward metal operating shaft both journaled in, and extending horizontally across, the cubicle from left to right, post insulators rigidly attached to their respective shafts and to their respective movable contacts to form cantilever switch arms, operating devices secured to said shafts, said shafts being offset from points intermediate the length of their respective air gaps at such distance that, when force is applied to said operating devices, said cantilever arms carry their movable contacts in the paths aforesaid, and plate-like insulating barriers adjacent said movable contacts and located between the phases and between the end phases and the adjacent wall of the cubicle, said barriers being seicured to said cubicle and extending from front 0 rear.

FRANK W. REILLY.

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