US2813179A - Disconnecting switch - Google Patents

Description

Nov. 12, 1957 H. H. RUGG DISCONNECTING SWITCH,

6 Sheets-Sheet 1 Filed Oct. '4. .1954

Nov. 12, 1957 H. H. RUGG 2,813,179

DISCONNECTING SWITCH Filed Oct. 4, 1854 6 Sheets-Sheet 2 Nov. 12, 1957 H. H. RUGG DISCONNECTING SWITCH e sheets-sheet? Filed OOt. 4, 1954 4 Nov. 12, 1957 H. H. RUGG 2,813,179

DISCONNECTING SWITCH Filed Oct. 4, 1954 6 Sheets-Sheet 4 WITNESSES. INVENTOR 4Mwg Harold H.Rugg. 2%.; gym

ATTORNEY Nov. 12, 1957 H. H. RUGG DISCONNECTING SWITCH 6 Sheets-Sheet 5 Filed Oct. 4, 1954 Fig-IO.

Nov. 12, 1957 Filed Oct. 4, 1954 H. H. RUGG DISCONNECTING SWITCH 6 Sheets-Sheet 6 2,813,179 Patented Nov. 12, 1957 ice DISCONNECTING SWITCH Haroid H. Rugg, Penn Township, Aliegheny County, Pa,

assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsyivania Application October 4, 1954, Serial No. 460,171

12 Claims. (Cl. 200-463) My invention relates generally to disconnecting switches and more particularly to disconnecting switches of the enclosed, telescoping type.

One of the problems encountered in building a disconnecting switch of the telescoping type is that of conducting current between the moving or telescoping member and the fixed or stationary members of the switch. When the switch is enclosed in a metal housing, another problem is that of withstanding high impulse voltages without increasing the dimensions of the housing greatly beyond those required ior an isolated-phase bus housing of a similar rating.

Qne object of my invention is to provide contact members suitable for conducting current between the stationary members and the moving member or" a switch in which the moving member telescopes inside the stationary em e Another object of my invention is to provide electrostatic shielding for the contact members of a disconnecting switch.

A further object of my invention is to provide electrostatic shields for both the stationary and the moving contact members of a telescoping switch which will not interfere with the closing of the switch.

Still another object of'my invention is to provide for retaining a plurality of rigid contact fingers around the periphery of a cylindrical conductor.

A still further object of my invention is to provide an electrostatic shield for a conductor which dead ends inside a metal housing.

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

in accordance with one embodiment of my invention, a plurality of rigid contact fingers are equally spaced aroundthe periphery of a hollow cylindrical conductor inside of which is disposed one end of a cylindrical switch blade which moves longitudinally of the conductor d r n cpe cticn of h witc he finger are e n in spaced relation by a spacing ring having openings therein for the fingers. A flanged retaining ring is secured inside the conductor and has openings therein corresponding to the pening n he pacing i g t ro gh which otiset portions of the fingers extend to engage the switch blade. An electrostatic shield is threaded onto the flange of the retaining ring to substantially enclose the fingers. Another shield is attached to the blade to extend beyond the end of the blade when the switch is open and overlap. the first shield when the switch is closed.

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:

Figure lis a view, partly in section and partly in side elevation, of a disconnecting switch structure embodying the principal features of the invention;

Fig. 2 is a view, in section, taken along the line IIII in Fig. 1;

Fig. 3 is an enlarged view, in section, taken along the line HIIII in Fig. 4;

Fig. 4 is an enlarged View, partly in section and partly in elevation, of one of the contact members utilized in the switch structure;

Fig. 5 is an enlarged view, in section, of one of the contact fingers utilized in the contact members;

Fig. 6 is an enlarged view, in perspective, of one of the contact springs utilized in the contact members;

Fig. 7 is an enlarged View, partly in section and partly in elevation of a contact member and electrostatic shields utilized in the switch structure;

Fig. 8 is a view, in side elevation, of an enclosed conductor which dead ends inside the enclosing housing, a portion of the structure being broken away for clearness;

Fig. 9 is an enlarged view, in side elevation of an electrostatic shield for the end of the conductor shown in F g- Fig. 10 is an enlarged view, in section, of the shield shown in Fig. 9; and

Fig. 11 is an enlarged view, partly in elevation and partly in section, of a modified contact and shield structure.

Referring to the drawings, and particularly to Figs. 1 and 2, the structure shown therein comprises a box-like metal housing 10 having axially spaced, hollow, cylindrical conductors 11 and 12 terminating within the housing. As is fully described in a copending application of P. R. Pierson, H. Rugg and R. R. Jank, Serial No. 455,972, filed September 14, 1954, the conductors 11 and 12 are supported in axial alignment by a plurality of pairs of oppositely disposed insulators 13. The insulators 13 are fully described in a copending application of B. P. Baker and P. R. Pierson, Serial No. 455,958, filed September 14, 1954.

As shown, the spaced ends of the conductors 11 and 12 are connected by a cylindrical switch blade 14 when the blade is in the closed position. The blade 14 is carried by an insulator 15 which, in turn, is mounted on a reciprocating carriage 16. The structure and operation of the carriage 16 is fully described in the aforesaid application of Pierson, Rugg and J ank. As shown by the broken lines, the blade 14 telescopes into the conductor 12 when the blade is actuated to the open position of the switch.

The structure of the housing 10 is also fully described in the aforesaid application of Pierson, Rugg and Jank. Briefly, the housing 10 comprises angle frame members 17 and 18, which are welded together to form a rigid frame, and sheet metal cover plates 19 which are attached to the frame members 17 and 13. An end member 21 having a circular flange 22 thereon is provided at each end of the housing. The flanges 22 are provided for attaching circular enclosures (not shown) for the conductors 11 and 12 which extend beyond the confines of the housing 10 and are connected to similar conductors which constitute part of an isolated-phase bus structure. A hinged door 23 is provided on the bottom of the housing It to permit access to the disconnecting switch.

in order to conduct current between the switch blade 14 and the conductors 11 and 12, a contact member 24 is mounted on the end of the conductor 11 and a contact member 25 is mounted on the end of the conductor 12. The contact member 25 is similar to the contact member 24 except that it is mounted in the opposite direction.

As shown more clearly in Figs. 3-6, the contact member 24 comprises a plurality of contact fingers 26 which are disposed around the outer periphery of the hollow vided in each opening 29 of the ring 28 to bias the finger 26 toward the conductor 11 and the blade 14, thereby obtaining the desired contact pressure between the finger 26 and the conductor 11 and blade 14. As shown most clearly in Fig. 6, the spring 31 has oppositely disposed notches 32 therein which engage the sides of the opening 29 in the ring 28 to retain the spring in position.

In order to prevent longitudinal movement of the fingers 26 on the conductor 11, a flanged retaining ring 33 is secured inside the conductor 11 by means of screws 34. The r1ng 33 has openings 35 which are in alignment with the openings 29 in the spacing ring 23 to receive the offset portions 27 of the fingers 26. As shown, the offset portions 27 extend throu h the o enin s switch blade 14. b p g 35 to engage the As explained hereinbefore, it is necessary to provide an electrostatic shield for the contact fingers 26 in order to enable the switch to withstand high impulse voltages without causing a flashover between the switch and the housing 10. As shown most clearly in Fig. 4, a curved shield 36 is threaded onto the flanged retaining ring 33. The shield 36 may be secured on the ring 33 by means of a set screw 37. As shown, the shield 36 is so sha ed that it substantially encloses the contact fingers 2 6. The outer surface of the shield 36 is smooth and rounded ihetreby preventing fiashover during high impulse voltage es s. V

As also explained hereinbefore, it is necessary to provide a shield on the one end of the switch blade 14 which is separated from the break jaw member 24 when the switch is in the open position. As shown most clearly in Fig. 7, a metal shield 38 is attached to the switch blade 14 by means of set screws 39. The shield 38 base curved portron 41 which extends beyond the one end of the blade 14 when the blade is in the open position, and ovelaps'the shield 36 when the blade is in the fully closed position. In this manner, the shield 38 does not interfere with the closing of the switch. However, the curved portion 41 of the shield extends a sufficient distance beyond the end of the switch blade 14 to prevent fiashover during high impulse voltage tests.

In the construction of an isolated-phase bus structure for such a dead end portion in order to prevent fiashover between the end of the conductor and the enclosing housmg. As shown in Fig. 8, the conductor 12 is enclosed in a generally circular housing 42 which is supported by a framework 43; An enclosure 44 for enclosing the dead end of the conductor 12 is supported by a bracket 45 which is attached to the framework 43 by bolts 46.

A generally spherical electrostatic shield 47 is attached to the dead end of the conductor 12 by means of set screws 48. As shown most clearly in Figs. 9 and 10, the shield 47 comprises two halves which are secured together by a screw 49. Dowel pins 51 are provided for retaining the two halves in position. An opeing 52 is provided to permit the shield to be installed on the end of the conductor 12.

As previously stated, the shield 47 is generally spherical in shape. For the most efiective shielding, the radius of the sphere should be within the range of one fourth to one third of the radius of the cylindrical housing 42 in which the shield 47 is installed. In this manner, the structure is enabled to withstand the high voltage impulse tests without it being necessary to increase the size of the housing 4 for the conductor beyond that required for the normal voltage rating of the conductor.

In the modification of the invention shown in Fig. 11, the shield 38 is replaced by an electrostatic shield 55 which is slidably mounted on the switch blade 14. The shield 55 is of the same general size and shape as the shield 36 and it is so mounted on the blade 14 that it abuts the shield 36 when the blade 14 is in the closed position.

A spring 45 is disposed inside the hollow cylindrical blade 14- to bias the shield 55 toward the exposed end of the blade 14 when the blade is in the open position. The outward movement of the shield 55 is stopped by a crossbar 57 disposed in a slot 58 in the blade 14 to engage the inner end of a plug 59 which is threaded into the end of the blade 14. One end of the spring 56 engages the crossbar 57 which may be welded to the shield 55 and the other end of the spring 56 engages a pin 61 secured in the blade 14.

As shown by the full lines, the spring 56 is compressed to permit the shield 55 to slide back along the blade 14' when the end of the blade enters the conductor 11 during closing of the switch. Thus, the shield 55 does not interfere with the closing of the switch. As shown by the broken lines, the spring 56 causes the shield 55 to slide along the blade 14' until the curved portion of the shield extends beyond the end 59 of the blade 14 when the switch is in the open position. Thus, the shield 55 functions in the same manner as the shield 38 to prevent flashover during high-voltage impulses.

The shield 55 may be assembled on the blade 14' by first inserting the spring 56 inside the blade 14', then placing the shield 55 on the blade with the crossbar 57 in the slot 58, and then screwing the plug 59 into the end of the blade, thereby retaining the shield on the blade. In this manner, electrostatic shielding may be provided for enclosed high-voltage conductors without increasing the shields beyond a reasonable size in comparison with the size of the housing required for the normal voltage rating of the structure.

From the foregoing description it is apparent that I have provided contact members which are particularly suitable for conducting current between the members of a disconnecting switch of the telescoping type which is enclosed in a metal housing. I have also provided electrostatic shields for the switch members which enable the structure to withstand the required high-voltage impulse tests. The various parts of the present structure are relatively simple in construction and they may be economically manufactured and installed. The present structure is particularly suitable for utilization in high-voltage isolated-phase bus structures.

Since numerous changes may be made in the abovedescribed construction, and difierent embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In a disconnecting switch, in combination, a hollow cylindrical conductor, a second conductor having one end disposed inside the hollow conductor, a plurality of rigid contact fingers disposed around the outer periphery of the hollow conductor, each contact finger having a portion engaging the outer circumference of the hollow conductor and an offset portion extending inwardly beyond the inner circumference of the hollow conductor to engage the second conductor, a floating spacing ring having an opening therein for each of said fingers, a substantially flat spring disposed in each of said openings between the finger and the ring, and retaining means disposed inside the hollow conductor and cooperating with the ofiset portions on the fingers to prevent longitudinal movement of the fingers, said second conductor being movable longitudinally wi h n sa d retaining means.

2. In a disconnecting switch, in combination, a hollow cylindrical conductor, a second conductor having one end disposed inside the hollow conductor, a plurality of rigid contact fingers disposed around the outer periphery of the hollow conductor, each contact finger having a portion engaging the outer circumference of the hollow conductor and an offset portion extending inwardly beyond the inner circumference of the hollow conductor to engage the second conductor, a floating spacing ring having an opening therein for each of said fingers, a substantially flat spring disposed in each of said openings between the finger and the ring, and retaining means secured to the hollow conductor and cooperating with the ofiset portions of the fingers to prevent longitudinal movement of the fingers, said second conductor being movable longitudinally within said retaining means,

3. In a disconnecting switch, in combination, a hollow cylindrical conductor, a second conductor having one end disposed inside the hollow conductor, a plurality of rigid contact fingers disposed around the outer periphery of the hollow conductor, each contact finger having a portion engaging the outer circumference of the hollow conductor and an ofiset portion extending inwardly beyond the inner circumference of the hollow conductor to engage the second conductor, a floating spacing ring having an opening therein for each of said fingers, a substantially fiat spring disposed in each of said openings between the finger and the ring, and a retaining ring secured inside the hollow conductor and having openings therein for the 0&- set portions of the fingers to prevent longitudinal movement of the fingers, said second conductor being movable longitudinally within said retaining ring.

4. In a disconnecting switch, in combination, a hollow cylindrical conductor, a second conductor having one end disposed inside the hollow conductor, a plurality of rigid contact fingers disposed around the outer periphery of the hollow conductor, each contact finger having a portion engaging the outer circumference of the hollow conductor and an offset portion extending inwardly beyond the inner circumference of the hollow conductor to engage the second conductor, a floating spacing ring having an opening therein for each of said fingers, a substantially fiat spring disposed in each of said openings between the finger and the ring, a flanged retaining ring secured at one end of the hollow conductor, said ring having openings therein for the ofiset portions of the fingers to prevent lon itudinal movement of the fingers, and a metal shield supported by the flanged ring, said shield having a curved portion substantially enclosing said contact fingers, said second conductor being movable longitudinally within said retaining ring.

5. In a disconnecting switch, in combination, a hollow cylindrical conductor, a second conductor having one end disposed inside the hollow conductor, a plurality of rigid contact fingers disposed around the outer periphery of the hollow conductor, each contact finger having a portion engaging the outer circumference of the hollow conductor and an offset portion extending inwardly beyond the inner circumference of the hollow conductor to engage the second conductor, a floating spacing ring having an opening therein for each of said fingers, a substantially flat spring [disposed in each of said openings between the finger and the ring, a flanged retaining ring secured at one end of the hollow conductor, said ring having openings "herein for the offset portions of the fingers to prevent longitudinal movement of the fingers, and a metal shield having one side threaded onto the flange on the retaining ring, said shield having a curved portion substantialiy enclosing said contact fingers.

6. in a disconnecting switch, in combination, a housing, a hollow cylindrical break jaw contact disposed in the housing, a hollow cylindrical sliding jaw contact spaced axially from the break jaw contact, a cylindrical switch blade having its ends disposed inside said contacts when the blade is in closed position, said blade telescoping into the sliding jaw contact to open the switch, a plurality of rigid contact fingers disposed around the periphery of each cylindrican contact, each contact finger having an offset portion extending inwardly to engage the switch blade, spring means for biasing said fingers inwardly, a flanged retaining ring secured at one end of each cylindrical contact and having openings therein for the ofiset portions of the fingers to prevent longitudinal movement of the fingers, and a metal shield supported by each flanged ring, each shield having a curved portion substantially enclosing the contact fingers on one of the cylindrical contacts.

7. In a disconnecting switch, in combination, a housing, a hollow cylindrical break jaw contact disposed in the housing, a hollow cylindrical sliding jaw contact axially from the break jaw contact, a cylindrical switch blade having its ends disposed inside said contacts when the blade is in closed position, said blade telescoping into the sliding jaw contact to open the switch, a plurality of rigid contact fingers disposed around the periphery of each cylindrical contact, each contact finger having an offset portion extending inwardly to engage the switch blade, spring means for biasing said fingers inwardly, a flanged retaining ring secured at one end of each cylindrical contact and having openings therein for the offset portions of the fingers to prevent longitudinal movement of the fingers, a metal shield supported by each flanged ring, each shield having a curved portion substantially enclosing the contact fingers on one of the cylindrical contacts, and an additional metal shield carried by the switch blade, said additional shield extending beyond one end of the switch blade when the switch is open.

8. In a disconnecting switch, in combination, a housing, a hollow cylindrical break jaw contact disposed in the housing, a hollow cylindrical sliding jaw contact spaced axially from the break jaw contact, a cylindrical switch blade having its ends disposed inside said contacts when the blade is in closed position, said blade telescoping into the sliding jaw contact to open the switch, a plurality of rigid contact fingers disposed around the periphery of each cylindrical contact, each contact finger having an offset portion extending inwardly to engage the switch blade, spring means for biasing said fingers inwardly, a flanged retaining ring secured at one end of each cylindrical contact and having openings therein for the oifset portions of the fingers to prevent longitudinal movement of the fingers, a metal shield supported by each flanged ring, each shield having a curved portion substantially enclosing the contact fingers on one of the cylindrical contacts, and an additional metal shield attached to the switch blade, said additional shield overlapping the shield on the break jaw contact when the switch is closed.

9. In a disconnecting switch, in combination, a housing, a hollow cylindrical break jaw contact disposed in the housing, a hollow cylindrical sliding jaw contact spaced axially from the break jaw contact, a cylindrical switch blade having its ends disposed inside said contacts when the blade is in closed position, said blade telescoping into the sliding jaw contact to open the switch, a plurality of rigid contact fingers disposed around the periphcry or each cylindrical contact, each contact finger having an offset portion extending inwardly to engage the switch blade, spring means for biasing said fingers inwardly, a flanged retaining ring secured at one end of each cylindrical contact and having openings therein for the offset portions of the fingers to prevent longitudinal movement of the fingers, a metal shield supported by each flange ring, each shield having a curved portion substantially enclosing the contact fingers on one of the cylindrical contacts, and an additional metal shield slidably disposed on the switch blade, said additional shield abutting the shield on the break jaw contact when the switch is closed and extending beyond the end of the switch blade when the switch is open.

10. In a disconnecting switch, in combination, a housing, a hollow cylindrical break jaw contact disposed in the housing, a hollow cylindrical sliding jaw contact spaced axially from the break jaw contact, a cylindrical switch blade having its ends disposed inside said contacts when the blade is in closed position, said blade telescoping into the sliding jaw contact to open the switch, a plurality of rigid contact fingers disposed around the periphery of each cylindrical contact, each contact finger having an offset portion extending inwardly to engage the switch blade, spring means for biasing said fingers inwardly,'a flanged retaining ring secured at one end of each cylindrical contact and having openings therein for the ofiset portions of the'fingers to prevent longitudinal movement of the fingers, a metal shield supported by each flanged ring, each shield having a curved portion substantially enclosing the contact fingers on one of the cylindrical contacts, an additional metal shield slidably disposed on the switch blade, said additional shield abutting the shield on the break jaw contact when the switch is closed and extending beyond the end of the switch blade when the switch is open, a spring disposed inside the blade for biasing the additional shield toward the end of theblade, and said blade having a removable end portion for limiting the movement of the additional shield in one direction on the blade.

11. in a switchgear structure, in combination, a cylindrical housing, a cylindrical conductor having one end terminating on the longitudinal centerline of the housing, a generally spherical shield enclosing said end of the 8 conductor and having an opening therein for receiving the end of the conductor, the radius of said sphere being Within the range of one fourth to one third of the radius of said housing; and threaded means inserted into the shield and engagingthe conductor at said opening for removably attaching the sphere to the conductor.

12. In a switchgear structure, in combination, a cylindrical housing, a cylindrical conductor having one end terminating on the longitudinal centerline of the housing, a generally' spherical shield enclosing said end of the conductor and having an opening therein for receiving the end of the conductor, the radius of said sphere being within the range of onewfourth to one third of the radius of said housing, said sphere being divided into two halves, threaded means for secun'ng said halves together, and additional threaded means inserted into the shield and engaging the conductor at said opening to removably attach the shield to the conductor.

References Cited in the file of this patent UNITED STATES PATENTS Owens Feb. 14,

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