Patent Publication Number: US-3875355-A

Title: Disconnect switch

Description:
[ Apr. 1,1975  
 United States Patent [191 Frink et al.  
 3 299 240 1/1967 200/48 A 3,566,056 2/1971 Joseph et 200/48 R P Primary Eraminer-Robert K. Schaefer Assislan! E.\&#39;aminerM. Ginsburg [73] Assignee: Westinghouse Electric Corporation, Attorney, Agent or Johns Pittsburgh, Pa.  
 Sept. 11, 1973 Appl. No.: 396,163  
 ABSTRACT A high voltage disconnect switch in which the hinged [22] Filed:  
 [52] U S Cl 200/48 A member pivotally supporting the switch blade is com- [511 In. .Cl 01h 31/00 posed of aluminum alloy, the sleeve for rotating the 200/48 R, 48 P1, 48 A 200/48 KB, 48 CB, 48 V, 48 SB blade is composed of copper alloy with copper alloy [58] Field of Search.............  
 conductors on opposite sides of the contact surface of the sleeve, and the circuit through the switch passing through the sleeve and conductors rather than through the hinged member.  
 2830 l44 Fjcllstcdt 200/48 A 8 Claims, 6 Drawing Figures Pi-EIENTEUAPR H975 SHZET 1 [IF 3 DISCONNECT SWITCH CROSS REFERENCE TO RELATED APPLICATIONS This invention is related to those disclosed in the applications of Russell E. Frink and Stanislaw A. Milianowicz, Ser. No. 469.5 86, filed May 13. 1974, Ser. No. 469.931. filed May 14, 1974. and Ser. No. 468,332. filed May 8, 1974.  
 BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to disconnecting switches and, more particularly, to rotating conducting structures which form part of such switches.  
 2. Description of the Prior Art Disconnect switches of various types are disclosed in US. Pat. Nos. 3.201.535, 3.240.887, 3,243,561, 3,366.753, and 3,544,742. A disadvantage of most disconnect switches is that they are fabricated from copper alloys which are costly and relatively heavy. As shown in Patent No. 3.544.742. disconnect switches are currently being fabricated with copper and aluminum parts. because aluminum is less costly and lighter than copper. However. other problems have been incurred with aluminum. That is particularly true where the disconnect switch is used outdoors and subject to varying weather conditions. Ordinarily, aluminum oxidizes readily in air; but in wet weather, it enters into electrolytic action with copper. Thus, there has been a problem of corrosion and therefore of deterioration of electrical contact at joints between copper and aluminum parts.  
 SUMMARY OF THE INVENTION It has been found that the foregoing problem may be overcome by providing a disconnect switch comprising a pair of stationary contacts at spaced locations, a switch blade pivotally movable between open and closed positions with one of the stationary contacts, means for pivotally mounting the switch blade at a location spaced from one of the stationary contacts and comprising a stationary frame, the other stationary contact being electrically connected to the stationary frame. the stationary frame supporting a movable sleeve in which the blade is rotatably mounted, means rotating the blade in the sleeve when the blade is pivotally moved between the open and closed positions, conductors mounted on the stationary frame and positioned with respect to the movable sleeve for engagement and disengagement with the mounting sleeve when the blade is in the closed and open positions, respectively.  
  The advantage of the device of this invention is that electric current is not conducted through a hinge joint as in disconnect switches of prior construction, but rather the current is transmitted through moving copper contacts on which the contacting areas are plated or clad with silver to provide satisfactory contacting surfaces.  
 DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of one pole of a three-pole disconnecting switch structure;  
  FIG. 2 is an enlarged plan view taken on the line 11-11 of FIG. 1;  
  FIG. 3 is a vertical sectional view taken on the line IIIIII of FIG. 2.  
  FIG. 4 is an end elevational view taken on the line IV-IV of FIG. 3;  
  FIG. 5 is a vertical sectional view of another embodiment of the invention, and  
  FIG. 6 is an end elevational view of the device shown in FIG. 5.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. I a disconnect switch is generally indicated at l0&#39;and it comprises three spaced insulator stacks 12, 14 and 16 mounted upon a common base support 18. Each of the insulator stacks l2, 14, 16 comprises a plurality of insulators which are preferably formed from porcelain or a similar material. A shaft 20 is secured to the upper end of the insulator stack 14 and the assembly of the shaft and stack are rotated by an external operating mechanism (not shown) through a crank member or operating lever 22.  
  At the upper end of the insulator stack 12 a terminal pad or stationary terminal contact 24 is provided. Likewise. a terminal pad or stationary terminal contact 26 is provided at the upper end of the insulator stack 16. As shown in FIG. 1, a stationary frame 28 is mounted at the upper end of the insulator stack 14 and the frame is spaced from the stationary contact 24 by an insulator 30. The insulator 30 houses an interrupter unit 32 which is not a part of this invention.  
  The disconnecting switch 10 comprises a switch structure 34 which includes a boom or blade 36 and a hinge structure 38. As viewed in FIG. 1, the right end of the blade 36 is in a closed position with respect to a contact jaw 40 which is an integral part of, or connected to, the stationary contact 26.  
  As shown more particularly in FIGS. 2, 3 and 4, the frame 28 comprises a yoke 42, a pair of upturned flanges 44, and an aperture 46. The yoke 42 provides means for pivotal mounting for a second or rotatable yoke 48 which is secured in the yoke 42 by pivot bolts 50. The second yoke 48 comprises a sleeve 52 in which a clamping or mounting sleeve 54 is rotatably mounted, for which purpose bushings 56 are provided and retained in place by a snap ring 58. The bushings 56 may be of either conducting or insulating material.  
  As shown in FIG. 3, the left end portion of the boom or blade 36 is seated within the mounting sleeve 54. The left end portion of the blade 36 includes a plurality of spaced radial slots 60 and an expander 62 is located within the left open end thereof. The expander 62 includes a threaded aperture 64, a bolt 66, and a tapered plug 68. An inner surface portion is tapered so that upon tightening of the bolt 66 within the aperture 64 the&#39;tapered plug 68 expands a plurality of split portions, such as portions 62a, 62b outwardly against the left end portion of the blade 36 and against the surrounding clamping or mounting sleeve 54. To help prevent rotational slipping of the cylindrical blade 36 within the cylindrical sleeve 54, a nut and bolt assembly 72 is provided therein.  
  As shown more particularly in FIG. 4, the outer surface of the left end portion of the clamping or mounting sleeve 54 has a substantially oval or elliptical crosssection with a horizontal axis, as indicated by the arrow 74, that is greater than the vertical axis, as indicated by the arrow 76. The arcuate surface portions of the surface at the ends of the longer axis 74 are covered with similar claddings 78 of silver.  
  In addition, the sleeve 54 comprises an arm 80 which extends from the lower side thereof at an angle, such as about 45, and the lower end of the arm is rotatably mounted on the end ofa rotator 82 through the bushing 115 which may be composed of electrically insulating or conducting material. Rotator 82 extends at a right angle from the arm 80 and at an angle of substantially 45 from a horizontal plane. A horizontal portion of the rotator 82 has an aperture 84 and the rotator is secured by a screw 86 to the upper end of the shaft 20 to which itis keyed at 87, whereby upon rotation of the lever 22 (FIG. 1), the rotator 82 is turned.  
  As shown in FIGS. 2, 3 and 4, conductor means, such as a pair of conductors 88 and 90, are mounted on each flange 44 and extend upwardly and at an angle to positions on opposite sides of the clamping or mounting sleeve 54. The conductors 88 and 90 have inturned portions88u and 90a (FIGS. 2 and 4) as well as upturned portions 88b and 901;. Each conductor 88 and 90 is secured firmly on the corresponding flange 44 by a bolt 92 and a dowel pin 93 and is thereby held in position for engagement with the portions of the sleeve 54 covered by the silver cladings 78. The contacting areas of the conductors 88 and 90 are also covered with similar claddings 94 of silver, where they contact the sleeve 54, and their ends which contact the aluminum flanges 44 are coated with tin to lessen the tendency for galvanic corrosion. By providing the silver claddings 78 and 94, good electrical contact is maintained between the sleeve 54 and the conductors 88 and 90. For that purpose, the conductors 88 and 90 are spring-biased inwardly so that they engage the elongated axial portion of the sleeve 54, but do not engage the shorter axial portion when the boom or blade 36 is rotated.  
  In addition, to facilitate lowering and rotation of the boom or blade 36, a lever 96 (FIG. 2) is provided in conjunction with the second yoke 48. As shown in FIG. 2 when the arm 80 is moved from the broken line position (corresponding to the erect position of the boom 36) to the solid line position, the arm touches and moves the lever 96 in the clockwise direction whereby lowering of the boom or blade 36 is facilitated at least in the initial stage ofmovement and not left entirely dependent upon the rotation of the shaft 20.  
  The several parts of the device shown in FIGS. 1-4 which are composed of an aluminum base alloy include the boom or blade 36, the frame 28, and the rotator 82. Those parts which are composed ofa copper base alloy include the clamping or mounting sleeve 54 including the arm 80, as well as the oval or elliptical contact surface, and the conductors 88 and 90.  
  Another embodiment of the invention is that shown in FIGS. and 6 in which similar reference numbers refer to similar parts as previously set forth above, such as the boom or blade 36, which is composed of aluminum. This embodiment differs from that described above in that a rod 98 provides for the mounting of the blade 36 on the right end portion thereof by a peripheral weld 100. The rod 98 includes a shank portion 102, which is seated in the sleeve 52 where it is mounted with bushings and snap ring 58 in a similar manner. The left end portion 104 of the sleeve includes a longitudinal slot 106 in which a contact 108 is seated with opposite end portions 108a and -l08b extending beyond the periphery of the portion 104. A plurality of spaced bolts 110 are provided in the portion 104 for holding the contact 108 securely in place. The rod 98 also includes an arm 112 by which the rod and the attached blade 36 are rotated and lifted in a manner similar to that of the embodiment disclosed in FIG. 3. The rod 98, including the portion 104 and the arm 112, is composed of aluminum-base alloy and the contact 108 is composed of a copper-base alloy. Like the end portions of the oval or elliptical contact surface of the sleeve 54, the opposite end portions 108a and 1081; of the contact 108 are covered with silver claddings similar to the silver claddings 78 as shown in FIG. 4. Accordingly, the contact 108, like the mounting sleeve 54, is adapted for opening and closing a circuit between terminal contacts 24 and 26 when the rod 98 is rotated.  
  As shown best in FIG. 3 for both embodiments of the invention, a lubricant is preferably provided at the joint 114 between the sleeve 54 and the bushings 56 in order to expedite rotation of the assembly within the sleeve 52. In addition, an electrical conducting grease is located in a joint 116 between the sleeve 54 and the boom or blade 36 as well as at the joints between the flanges 44 and the conductors S8 and 90. The oxide inhibiting grease has the purpose of maintaining good electrical contact between the aluminum blade 36 and the copper sleeve 54 by preventing the aluminum blade surface from being oxidized due to exposure to the atmosphere. Hence, a satisfactory electrical path between the sleeve 54 and the blade 36 is maintained.  
  In operation, the boom or blade 36 is raised or lowered between open and closed positions with respect to the contact jaw 40 primarily by rotation of the shaft 20. Upon clockwise rotation, as indicated by the arrow 118 (FIG. 3) the rotator 82 moves the arm in a clockwise direction, and the force applied thereby causes the assembly of the sleeve 54 and the blade 36 to rise about the pivot bolts 50 in the yoke 42. The rotator 82 continues to move to the left as viewed in FIG. 4 until it occupies the position shown by the broken line in FIG. 2, whereupon the blade 36 is elevated to the open position with respect to the contact jaw 40, which position is substantially vertical. Conversely, rotation of the shaft 20 in the counterclockwise direction of the arrow 120 (FIG. 3) will cause the blade 36 to rotate and lower to the closed position with respect to the contact jaw 40, whereupon the rotator 82 is again located in the position shown in FIG. 4, namely, adjacent to the righthand flange 44.  
  In the closed position of the blade with respect to the jaw, a circuit between the stationary contacts 24 and 26 includes the conductor 32, the frame 28, the conductors 88 and 90, the elliptical or oval contact portion of the sleeve 54, the blade 36, and the contact jaw 40. As was set forth above, when the sleeve 54 is rotated clockwise by the arm 80, the surface portions of the sleeve 54 at the extremities of the longer axis 74 are retated out of contact with the contactors 88a and a as the smaller portion of the sleeve is rotated into position between those conductor extremities.  
 Accordingly, the device of this invention provides so-- l. A disconnect switch comprising a pair of stationary contacts at spaced locations. a switch blade pivotally movable between open and closed positions with one of the stationary contacts. means for pivotally mounting the switch blade at a location spaced from one of the stationary contacts and comprising a stationary frame, the other stationary contact being electrically connected to the stationary frame, the stationary frame supporting a movable sleeve in which the blade is rotatably mounted, rotating means rotating the blade in the sleeve when the blade is pivotally moved between the open and closed positions, the rotating means comprising a rotatable sleeve in which the switch blade is disposed and which is rotatably mounted in the movable sleeve, a clamping sleeve within the switch blade for holding the switch blade in tight electrical contact with the rotatable sleeve, the outer surface of the rotatable sleeve having an oval cross-section, and conductor means mounted on the stationary frame and positioned externally of the clamping sleeve for engagement and disengagement with said oval cross-section of the rotatable sleeve when the blade is in the closed and open positions, respectively.  
  2. The disconnect switch of claim 1 in which the rotatable sleeve comprises a rotatable contact rotatable on the axis of the blade, the contact having long and short axis in a plane that is substantially normal to the blade, and the long axis engaging the conductor means when the blade is in the closed position with said one stationary contact.  
  3. The disconnect switch of claim 2 in which the conductor means comprises conductors disposed on opposite sides of the rotatable contact and engageable with the peripheral portions at the long axis of the contact and non-engageable with the peripheral portions at the short axis of the contact when the blade is in the open position with said one stationary contact.  
  4. The disconnect switch of claim 3 in which the peripheral portions of the rotatable Contact are covered with a cladding of silver and in which the portions of the conductor structures engageable with the rotatable contact are covered with a cladding of silver.  
  5. The disconnect switch of claim 1, in which the stationary frame comprises a first yoke, a second yoke rotatably mounted in the first yoke and comprising said movable sleeve, and the blade being rotatable in the sleeve on an axis substantially normal to the axis of rotation of the second yoke.  
  6. The disconnect switch of claim 5 in which the conductor means comprises conductors disposed on opposite sides of the rotatable sleeve. and the conductors and rotatable sleeve being composed of copper.  
  7. The disconnect switch of claim 6 in which the contacting areas of the rotatable sleeve and conductors means are covered with silver cladding.  
  8. The disconnect switch of claim 6 in which the joint between the engaging surfaces of the rotatable sleeve and the blade is coated with a conducting grease. and in which the rotatable sleeve is composed of a copper alloy and the blade is composed of an aluminum alloy.