US3036184A - Grounding switch - Google Patents

Description

May 22, 1962 v. F. SABOL ET AL GROUNDING SWITCH Filed DeC. '7, 1959 3 Sheets-Sheet 1 WITNESSES1 INVENTORS Victor E Sobol 8 aim/ g George Siviy.

ATTORNEY v. F. SABOL ET AL May 22, .1962

GROUNDING SWITCH 5 Sheets-Sheet 2 Filed Dec. '7, 1959 Fig. 2.

May 22, 1962 v. F. SABOL ET AL GROUNDING SWITCH 3 Sheets-Sheet 3 Filed Dec. 7, 1959 3,036,184 GROUNDING SWITCH Victor F. Sabol, East Pittsburgh, and George Siviy, Monroeville, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Dec. 7, 1959, Ser. No. 857,632 7 Claims. (Cl. 200163) This invention relates to high voltage switchm and, more particularly, to switches commonly known as grounding switches.

Disconnect switches are utilized in electric power systems to isolate transmission lines and high voltage electrical apparatus before handling for inspection or repair. To prevent injury to personnel in the event the apparatus becomes reenergized, it is common practice to provide auxiliary grounding switches to ground the transmission lines to drain off any static charge that may remain after an isolation operation of the disconnect switch.

Heretofore, grounding switches have been simple, pivotal blades. However, with the advent of larger disconnect switches for operation on very high power systems, the pivotal blade type of grounding switch is impractical because the increased size of the disconnect switches necessitates a corresponding increase in length of the auxiliary grounding pivotal blade, which, in turn, necessitates a larger operating force, particularly under severe icing conditions. Thus, it is apparent that to merely increase the size of present pivotal blade type grounding switches becomes impractical.

Accordingly, it is an object of this invention to provide a grounding switch having a reciprocating member carrying the movable contact.

More specifically, it is an object of this invention to provide a grounding switch having telescoping means carrying the movable contact.

Still more specifically, it is an object of this invention to provide a pair of vertically aligned members carrying a movable contact and wherein the upper member telescopes over the lower member to prevent ice from forming upon the bearings between the members when the grounding switch is in a closed position.

It is a further object of this invention to provide novel operating means for actuating a reciprocating grounding switch.

Other objects of my invention will be explained fully hereinafter or will be apparent to those skilled in the art.

For a better understanding of the nature and objects of the invention, reference may be had to the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an elevational view of a disconnecting switch and grounding switch showing the general relationship therebetween, and showing the grounding switch in the open condition;

FIG. 2 is a fragmentary end elevational View of the combined disconnect switch and grounding switch taken from the left of FIG. 1, but showing the grounding switch in the closed condition;

FIG. 3 is a side elevational view of the grounding switch, taken partly in section to show the operating mechanism of one embodiment of this invention;

FIG. 4 is a sectional view of the grounding switch taken from the right of FIG. 3 substantially along the lines IVIV, showing the switch in the open condition;

FIG. 5 is a sectional view of the grounding switch shown in a partially closed condition.

Referring to the drawings, and particularly to FIGS. 1 and 2, the structure shown therein comprises a disconnecting switch assembly and a grounding switch 11. The disconnect switch 10 may be of the type described in copending application No. 842,486, tiled September 25, 1959 which is assigned to the same assignee as the present application.

As shown, the disconnect switch structure comprises three spaced tripodic insulator stacks 12, 12, 12, each mounted on a single elongated base member 13 by means of brackets 14 and 15 associated with each tripod. The base member 13 is comprised of galvanized steel, preferably tubular in form, to provide maximum rigidity. The base 13 is rigidly mounted upon the upper end of a pair of spaced base support members 16, 16. A terminal pad 17, a surge suppressor 18 and contact jaws 19 are fixed to the apex of each one of the two end tripods 12, 12. A contact cluster 20 is fixed to the bottom of and are electrically connected to the pad 17 to the left of FIG. 1, and serves to cooperate with the grounding switch in a manner hereinafter described. The center tripod 12 serves as a rigid support for each of a pair of switch blades 21, 21 arranged in back to back relationship, each having an end rigidly fixed to one of a pair of housings 22, 22 pivoted to the top portion of center tripod 12, each housing having a switch operating mechanism enclosed therein. As described in the aforesaid copending application, the operating mechanisms within the housings 22, 22 each includes an input shaft 23, which may be rotated to effect rotation of blade 21 within contact jaws 19 to disengage the blades from the contact jaws, and subsequently pivot the blades from the horizontal position shown in FIG. 1 in full lines to the vertical position shown in FIG. 1 in broken lines. Similarly, rotation of input shafts 23, 23 in the opposite direction will reverse the procedure described. The rotation of input shafts 23, 23 is achieved by a gear mechanism 24 which operates in response to rotation of an insulator stack 25 serving as a drive shaft. A reversible motor 26 mounted below the base member 13 is connected to the lower end of the drive shaft 25 to provide the prime driving force. Reverse operation of the motor serves to close the disconnect switch.

As explained hereinbefore, it is desirable to ground the line or apparatus which may be connected to the terminal pad 17 at the left of FIG. 1 after it has been isolated in order to drain oil? a static charge that may remain and to prevent injury to operating personnel in the event that the apparatus accidentally becomes reenergized. The grounding switch 11 is provided to perform the grounding operation.

As shown in detail in FIGS. 3, 4 and S, the grounding switch 11 comprises a tubular contact carrying member 28 which is mounted telescopically upon a carrier column 29 having a diameter smaller than that of contact carrier member 28 so that the contact carrying member 28 en closes the carrier column 29 when the grounding switch is in the open position as shown in FIGS. 3 and 4. The contact carrying member 28 and the carrier column 29 are spaced from each other, and maintained in alignment with respect to each other, by means of bearing means 30 laterally fixed at the upper end of carrier column 29 to engage the interior surface of contact carrying means 28 and by means of bearing means 31 fixed to the lower end of contact carrying member 28 to engage the carrier column 29. The bearing means 30 and 31 may be of any suitable type, as desired.

The carrier column 29 is rigidly mounted upon a column support plate 32 which is adjustably fixed within a grounding switch housing 33 by means of leveling screws 34 connecting the support 32 and the housing base 35. The upper end of the housing 33 includes a restricted neck portion 36 which is fixed to and extends upwardly through the tubular base 13 of the disconnect switch 10 to a height substantially equal to that of the carrier column 29. Thus, the neck portion of the housing 33 cooperates with the base 13 to fixedly align the ground- 3 ing switch 11 with respect to terminal pad 17 and the previously described grounding switch fixed contact 20 (FIG. 1) fixed thereto, and .at the same time serves as an all weather protector for the contact carrying member 28 and the carrier column 29 in a manner to be hereinafter described.

There is provided at the upper end of contact carrying member 28 a peripheral flangeportion 38 having a downwardly extending peripheral lip 39 for effectively closing the opening between the upper end of the neck portion 36 of housing 33 and the upper end of contact carrying mem: ber 28 when the contact carrying member is in the open position as shown in FIG. 4. This construction prevents accumulation of ice or the entry of other foreign matter which may inhibit or prevent reciprocal movement of the contact carrying member 28 with respect to the carrier column 29. A finger contact mechanism 40 is fixed to the upper end of the contact carrying member 28 and extends upwardly of the flange 38 so as to be readily inserted into the cluster contact 20 on pad 17 (FIG. 1') when thecontact carrying member 28 is fully extended. It is seen that when the contact carrying member 28 is in the fully extended or closed condition so that flange 38 does not cover the opening between housing neck 36 and contact carrying member 28, the position of the bearings 30 and 31 between the larger diameter contact carrying member 28 and the smaller diameter carrier column 29 providessubstantial isolation of the bearings from the atmosphere to thus prevent the formation of ice upon the bearings, which formation might inhibit or prevent a contact opening operation of the grounding switch.

The operating mechanism for providing reciprocal movement of the contact carrying member 23 with respect to the carrier column 29 is comprised of a chain and sprocket mechanism. Specifically, a pair of parallel continuous chains 45, 45 are arranged on opposite sides of the contact carrier member 28, each chain ridingover one of a pair of upper sprockets 46, 46 attached to the top of the housing 33 by any suitable bracket means, and one of a pair of lower sprockets 47, 47 attached tothe support member 32 by any suitable bracket means. Each chain 45, 45 is connected to the contact carrying member28 by means of one of a pair of studs 48, 48 laterally affixed to the lower end of the contact carrying member 28. The chains 45, 45 are simultaneously driven by a pair of drive sprockets 49 connected to the housing by suitable bracket means (not shown) and, each engaging one of the chains. The sprockets 49 are rigidly connected together by a common shaft 50. A worm'gear 1 is driven by a reversible motor 52 to turn the shaft 50 for operating the chains 45, 45 to raise or lower the contact carrying member 28. A pair of idler sprockets 53,

53 are fixed-to the housing by suitable bracket means (not shown) and are positioned adjacent the drive sprockets .49 to provide appropriate tension on the chains 45, 45

and to assure meshing engagement between chains 45, 45 and drive sprockets 49, 49. A hand crank 54 isprovided as an alternate mechanism for operating the worm drive mechanism 51 in the event the motor 52 is inoperable.

The provision of a pair of chainsprevents'theQoccurrence of a bind which might occur between the contact carrying member and the carrier member if only one chain were used. 7

An auxiliary grounding contact blade 41 is carried at 'the lower end of the contact carrying member '28 to engage contact jaws 42 when the contact carrying member 28 is fully extended. The contact jaws 42 may be supported on the housing 33 by any suitable means such as a bracket 43, and maybe connected to ground by suitable conductor means 44. V

As shown in FIG. 4, a guide bar 55is provided adjacentthe contact carrying member 28'forpreventing rotation of the contact'carrying member about the longitudinal axis during reciprocal movement thereof. A pair of brackets 56, 56 .fix the guide bar to the housing. A

rider 57 is slidably attached to the guide bar, and is fixedly attached to the lower end of the contact carrying member 28 by means of arconnecting stud 58. A pair of limit switches 59, 59 are provided at opposite ends of the guide bar 55 for engagement with the rider 57 and may be electrically connected in obvious manner to provide operation of position indicators (not shown) and to shut 01f the motor 52 to thus define the limits of travel of the contact carrying member 28 with respect to the carrier member 29. It is seen that the guide bar 55 maintains alignment between the limit switches and the rider 57.

A spring clip 27 is attached to the lower end of contact carrying member 28 and rides against carrier member 2-9 to assure that contact is continuously connected to ground in the event an arcing condition should occur between contacts 20 and 40 during a closing operation of the grounding switch but before the switch is completely closed. The presence of the spring clip permits the use of insulating type bearings, if desired, between'the reciprocable members and between the rider 57 and guide bar 55.

From the foregoing, it is apparent that there has been provided a grounding switch comprised of reciprocable members carrying a grounding contact vertically into contact with mating contacts on the line side of a main switch 2 such structure minimizing the forces which would be required to operate a large pivotal type of switch. The telescopic nature of the reciprocable memher, with the member having the larger diameter supported by the other member, protects the bearings between the members frcm icing, to thus minimize the force necessaryto initiate operation of the grounding switch.

It is to be understood that in a polyphase system, the hereinhefo're described grounding switch mechanisms may be provided in each phase, and that the operating motors may be electrically interconnected to operate simultaneously in response to a single control. It is also to be understood that a hydraulic drive mechanism may be sub- .a limiting sense.

We claim as our invention:

1. In a switch mechanism: a-housing having an opening at the top; a first member mounted in said housing and extending axially upward toward said opening; a second member telescopically enclosing said first member for movement between upper and lower extremities along the axis of said first member and extending upwardly through said opening when the second member is at the lowermost extremity; a peripheral flange on the upper portion of said second member and extending outwardly beyond the diameter of the upper portion of the housing; peripheral lip means on said flange and extending downwardly below the top of the housing when the second member is in the lower extremity; contact means on the upper end of the second member; and, means operable to provide recipro cal movement between the first member and the second member.

2. In a switch mechanism: a base, a carrier column extending upwardly from said base; a contact carrying tubular member having a closed end and having a diameter larger than that of said carrier column; said contact carrying member fitted telescopically over said carrier column; bearing means between the carrier column and the contact carrying member; and, means operable to provide reciprocating movement between the contact carrying member and thecarrier column. Y

3. In a switch mechanism: a base, a carrier column extending upwardly from said base, a contact carrying tubular member having a closed end and having a diameter larger than that of said carrier column; said contact carrying member fitted telescopically over said carrier column; bearing means on the upper portion of the carrier column engaging the contact carrying member; bearing means on the lower portion of the contact carrying member engaging the carrier column; and means operable to provide reciprocating movement between the carrier column and the contact carrying member.

4. In a grounding switch: fixed contact means; movable contact means for engaging said fixed contact means; reciprocable means for carrying said movable contact means into and out of engagement with said fixed contact means; grounded contact means; auxiliary contact means carried by said reciprocable means to engage said grounded contact means only when said movable contact means is engaged with said fixed contact means; and means for operating said reciprocable means.

5. In combination: a base; means supporting the base above ground; insulator means supported on the base; a disconnect switch including contact means mounted on terminal means and mounted at the top of the insulator means; fixed grounding switch contact means mounted on the terminal means; a movable contact for mating with the fixed contact means; reciprocable means connected to ground and operable to carry the movable contact into and out of engagement with the fixed contact means; independently supported means for housing the reciprocable means and attached to the base member to provide alignment between the movable contact means and the fixed contact means; and means for operating the reciprocable means.

6. In combination: a tubular base; means supporting the base above ground; insulator means supported on the base, a disconnect switch including contact means mounted on terminal means and mounted at the top of the insulator means; fixed grounding switch contact means mounted on the terminal means; a movable contact for mating with the fixed contact means; reciprocable means connected to ground and operable to carry the movable contact into and out of engagement with the fixed contact means; independently supported means for housing the reciprocable means below the base and extending through the base to provide alignment between the movable contact means and the fixed contact means; and means for operating the reciprocable means.

7. In a switch mechanism: a fixed carrier column; a

contact carrying member telescopically fitted on the carrier column; a pair of spaced sprocket means on opposite sides of the carrier column, each pair of sprocket means aligned parallel to the axis of telescopic movement; a continuous chain on each pair of sprocket means; means connecting the lower end of the contact carrying member to each chain; means engaging both chains and operable to simultaneously move both chains over the corresponding sprocket means to raise and lower the contact carrying member with respect to the carrier member.

Koppitz Dec. 1, 1936 Owens Dec. 14, 1954

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