US3211876A

US3211876A - Pressure contact disconnect switch

Info

Publication number: US3211876A
Application number: US143744A
Authority: US
Inventors: Carl A Christian; Zwingle J Dragar
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1961-10-09
Filing date: 1961-10-09
Publication date: 1965-10-12
Anticipated expiration: 1982-10-12

Description

Oct. 12, 1965 c. A. CHRISTIAN ETAL 3,211,876

PRESSURE CONTACT DISCONNECT SWITCH 5 Sheets-Sheet 1 Filed 001;. 9. 1961 Oct. 12, 1965 c. A. CHRISTIAN ETAL 3,211,876

PRESSURE CONTACT DISCONNECT SWITCH 3 Sheets-Sheet 3 Filed Oct. 9, 1961 United States Patent 3,211,876 PRESSURE CONTACT DISCONNECT SWITCH Carl A. Christian, Monroeville, and Zwingle Ii. Dragar, Penn Hills, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa, a corporation of Pennsylvania Filed Oct. 9, 1961, Ser. No. 143,744 3 Claims. (Cl. 200-168) This invention relates, generally, to electric switches and, more particularly, to disconnect switches capable of conducting relatively large amounts of electric current.

Prior high current disconnect switches have been of a friction or sliding contact type in which switch blades engage contact jaws with a sliding action. The current carrying capacity of prior disconnect switches has been increased by providing switches having multiple blades and contact jaws. The friction between the blades and the contact jaws makes the switches diflicult to operate. Furthermore, prior switches having a current rating of 4000 amperes and above have been of a relatively large size.

An object of this invention is to provide a high current disconnect switch which shall be relatively easy to operate and which is relatively small in size.

Another object of the invention is to provide a disconnect switch having contact members of the pressure or abutting type.

A further object of the invention is to provide a disconnect switch having a plurality of pole units connected in parallel-circuit relation.

Still another object of the invention is to provide a high current disconnect switch having contact members which are actuated by an operating mechanism of the type utilized in automatic circuit breakers.

A still further object of the invention is to provide a disconnect switch having a plurality of individually insulated pole units mounted on a metal base common to all of the units.

Another object of the invention is to provide for utilizing certain parts of an automatic circuit breaker in a high current disconnect switch, thereby reducing the manufacturing cost of the switch.

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

In accordance with one embodiment of the invention one or more pole units of a high current disconnect switch are mounted on the front of a metal panel which may be mounted in a supporting structure. Each pole unit comprises an insulating base to which an upper terminal stud and a lower terminal stud are attached in spaced relation. A moving contact arm is hinged on the lower stud and has contact surfaces which abut against contact members resiliently mounted on the upper stud when the contact arm is closed by a toggle lever mechanism.

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 drawing, in which:

FIGURE 1 is a view, in front elevation, of a disconnect switch embodying the principal features of the invention;

FIG. 2 is a view, in side elevation, of the switch shown in FIG. 1;

FIG. 3 is an enlarged view, partly in section and partly in elevation, of one of the pole units utilized in the switch, and

FIG. 4 is an enlarged view, in perspective, showing a manner of making electrical connections to the switch.

Referring to the drawings and particularly to FIGURES 1 and 2, the structure shown therein comprises a metal panel 10, a platform 11 attached to the panel 10, an operating mechanism 12 mounted upon the platform 11, an actuating handle 13, and a plurality of pole units 14 which 'ice are mounted on the front of the panel 10. The panel 10 is preferably composed of sheet steel or sheet aluminum and it may be mounted in a switchboard or other structure by means of supporting members 15, shown in FIG- URE 4. The platform 11 comprises a horizontal cross member 16 supported by two vertical side members 17. The side members 17 may be attached to the front of the panel 10 by means of bolts 18.

The operating mechanism 12 is preferably of the type utilized in automatic circuit breakers such as the one disclosed in Patent 2,883,585, issued Apr. 21, 1959 to A. E. Maier et al. and assigned to the Westinghouse Eelectric Corporation. As described in the aforesaid patent, the operating mechanism is of the toggle type and includes a lever 21 pivotally mounted on a pivot pin 22 supported in a frame 23 which is mounted on the cross member 16 of the platform 11. The lever 21 is actuated about its pivot point by a toggle linkage 24, only a portion of which is shown in the present drawing. The linkage mechanism is fully described in the aforesaid patent. Therefore, it will not be described in detail in this specification. As described in the aforesaid patent the mechanism is operated by the actuating handle 13 to close the switch. The switch may be opened by pressing on a trip button 25 shown in FIGURE 1.

A brace 26, which is attached to the panel 10 and to the top of the frame 23, may be utilized to provide additional support for the operating mechanism. Auxiliary switches 27 may be mounted on the cross member 16 at one side of the operating mechanism. The auxiliary switches may be operated by the mechanism in a manner well known in the art.

As shown most clearly in FIGURE 3, each pole unit 14 includes an insulating base 31, an upper terminal stud 32, a lower terminal stud 33, and a movable contact arm 34. The base 31 is preferably composed of a molded insulating material and it is provided with

projections

35 and 36 which extend through openings provided in the panel 10.

The

terminal studs

32 and 33 are preferably composed of copper or other good electrical conducting material. The upper terminal stud 32 is generally of a U-shape having two spaced legs or arms 37 which extend through openings provided in the projection 35 of the base 31. The stud 32 is attached to the base 31 by means of bolts 38 which are threaded into the base of the U-shaped stud.

Likewise the lower terminal stud 33 is generally of a U-shape and has two spaced legs 39 which extend through openings provided in the projection 36 of the base 31. The stud 33 may be attached to the base by means of bolts 38.

Two rows of

contact members

41 and 42 are movably mounted in grooves provided'in the upper terminal stud 32. Each contact member 41 is retained in position by a pin 43 which engages a pressure plate 44. Likewise, each contact member 42 is retained in position by a shorter pin 45 which engages the pressure plate 44. A plurality of springs 46 are disposed between the pressure plate 44 and a bracket 47 attached to the terminal stud 32 by bolts 48. Thus, when the

contact members

41 and 42 are engaged by the contact arm 34, as will be described hereinafter, a high contact pressure is maintained between the

contact members

41, 42 and the contact arm by the force exerted by the springs 46. The

contact members

41 and 42 are retained in the grooves in the stud 32. by a plate 49 attached to the end of the stud by a screw 51.

The contact arm 34 is pivotally mounted on the lower terminal stud 33 by means of a hinge comprising a support member 52 and a pin 53 which extends through the member 52 and the lower end of the contact arm 34. The support member 52 is attached to the terminal stud 33 by a bolt 54.

Current is conducted between the terminal stud 33 and the contact arm 34 by means of a plurality of contact fingers 55 which bridge the hinged connection for the contact arm 34. The contact fingers 55 are arranged in pairs with the two fingers of each pair disposed at opposite sides of the hinge support 52. One end of each upper contact finger 55 engages a curved surface 56 on the contact arm 34. The other end of each upper contact finger engages the upper surface of a projection 57 on the terminal stud 33. Likewise, one end of each lower contact finger 55 engages a curved surface 58 on the contact arm 34. The other end of each lower contact finger 55 engages the lower surface of the projection 57. The two fingers of each pair of fingers are biased towards each other by a spring 59 which is disposed on a bolt 61 extending through the two fingers. In this manner, contact pressure is maintained between the contact fingers and the contact arm 34 and the terminal stud 33, thereby providing a low resistance path for the flow of current between the contact arm 34 and the terminal stud 33.

As shown in FIGURE 3, the contact arm 34 is provided with contact members or surfaces 62 and 63 which engage the

contact members

41 and 42, respectively, when the contact arm is actuated to the closed position. Thus, all of the current flowing through the switch is conducted through the

contact members

41, 42 and the contact surfaces 62, 63 of the pole units of the switch. In order to increase the current capacity of the switch two or more pole units may be connected in parallel-circuit relation as will be described more fully hereinafter.

As shown in FIGURES l and 2, the lever 21 of the operating mechanism 12 carries a cross bar 64 which is connected to each one of the contact arms 34 by an insulating link 65. The link 65 is pivotally attached to the contact arm 34 between the contact surfaces 62 and 63 by means of a pin 66. Thus, maximum pressure may be applied on the

contact members

41 and 42 when the contact arm is closed since the force of the operating mechanism is applied between the contact surfaces 62 and 63.

The operating mechanism 12 may be operated to close all of the contact arms of the switch by rotating the handle 13. The closing force is transmitted through the lever 21, the cross bar 64 and the connecting links 65 to the contact arms 34 of the switch.

As shown in FIGURE 3, springs 67 are disposed between the contact arm 34 and the base 31 to bias the contact arm to the open position. Thus, the contact arms are actuated to the open position when the trip button 25 is pushed to release the operating mechanism from the closed position.

As shown in FIGURE 4, the legs 37 of the upper terminal studs 32 may be connected in parallel-circuit relation by means of a plurality of

electrical conductors

71, 72. The conductors 71 are attached to opposite sides of the legs 37 by bolts (not shown). The conductors 72 are attached to the conductors 71 by bolts (not shown). Spacing members 73 may be provided between the

conductors

71 and 72. Additional conductors (not shown) may be disposed between the conductors 72 and attached thereto by bolts, thereby continuing the electric circuit. Likewise, the legs 39 of the lower terminal studs 33 may be connected in parallel-circuit relation by

conductors

74, 75. Additional conductors 76 may be connected to the conductors 75, thereby connecting the parallel-connected terminal studs 33 in an electric circuit. A plurality of bolts (not shown) may be utilized to connect the conductors together.

Thus, by utilizing pole units of different ratings and operating mechanisms of different sizes, and by utilizing a single pole unit or two or more units connected in parallel-circuit relation in the manner shown disconnect switches having a wide range of current ratings may be provided. By way of example, switches having current ratings from 2000 to 12,000 amperes DC. or 1600 to 9000 amperes A.C. may be built. 7

It will be noted that an upwardly extending projection 77 is provided on the contact arm 34. A disconnect switch of the load break type may be provided by attaching arcing contact members to the upper portion 77 of the contact arm 34 and by attaching fixed contact members to the upper portion of the terminal stud 32 which are engaged by the arcing contact members when the switch is closed. An arc chute may be attached to the upper portion of the insulating base 31. In this manner a switch having current interrupting ability may be provided. It should be understood that the switch illustrated in the present drawings has no interrupting capabilities. It is intended to be utilized as a high current disconnect switch.

Certain parts of the present switch, such as the indi vidual pole units, the operating mechanism, and the platform are so constructed that they may be utilized in automatic circuit breakers. In this manner the cost of manufacturing and stocking these parts is reduced.

From the foregoing description it is apparent that the present high current disconnect switch has the following advantages as compared with existing switches of the friction type:

(a) The complete pole unit asembly can be installed on a metal panel instead of on a panel composed of impregnated fibrous material or an ebony asbestos panel.

(b) Lower cost of manufacturing.

(c) Easier to close and open.

(d) Smaller in size, therefore easier to install in metal enclosed switch gear units.

(e) Easy to adapt or modify for a load break switch.

Furthermore, when switches of the present type are utilized for conducting high currents no skin etfect will be encountered as is the case with prior switches having blades in parallel. In such switches the center blades do not carry their proportionate share of the current thereby reducing the current rating of the switch.

Since numerous changes may be made in the above described construction, and different 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.

We claim as our invention:

1. A high current disconnect switch comprising, a metal panel, a platform attached to the front of the panel, an operating mechanism mounted on the platform, a plurality of pole units mounted in side by side spaced relationship on the front of the panel, each pole unit including an insulating base supporting a pair of spaced terminal studs extending through said panel, a contact arm for each pole unit, said contact arm being hinged on one of the terminal studs and actuated into abutting engagement with the other terminal stud with a high contact pressure by the operating mechanism, a cross bar mechanically con necting all of the contact arms to the operating mechanism, and conductors disposed at the rear of the panel for electrically connecting the pole units in parallel-circuit relation only at the corresponding terminal studs.

2. A high current disconnect switch comprising a metal panel, a platform attached to the front of the panel, an operating mechanism mounted on the platform, a plurality of pole units mounted in side by side spaced relationship on the front of the panel, each pole unit including an insulating base supporting an upper terminal stud and a lower terminal stud extending through the panel and insulated therefrom by the base, a contact arm hinged on each lower terminal stud,a cross bar having a plurality of insulating members mounted thereon for mechanically connecting the respective contact arms to the operating mechanism to actuate the contact arms against the upper terminal studs, conductors disposed at the rear of the panel electrically connecting only the upper terminal studs in parallel-circuit relation, and additional conductors disposed at the rear of the panel electrically connecting only the lower terminal studs in parallel-circuit relation, said pole units being electrically connected in parallel only at the upper and lower terminal studs.

3. A high current disconnect switch comprising, a metal panel, a platform attached to the front of the panel, an operating mechanism mounted on the platform, a plurality of pole units mounted in side by side spaced relationship on the front of the panel and spaced from one another, each pole unit including an electrically insulating base supporting a generally U-shaped upper terminal stud and a generally U-shaped lower terminal stud extending rearwardly through the panel and insulated therefrom by the base, a contact arm hinged on each lower terminal stud, a cross bar having a plurality of insulating members mounted thereon for mechanically connecting said contact arms to the operating mechanism to actuate the contact arms against the upper terminal studs, each contact arm having a portion extending above the point of engagement with the terminal stud for supporting additional References Cited by the Examiner UNITED STATES PATENTS 2,707,732 5/55 Ortwig 200-170 X 2,770,701 11/56 Yarrick 200-168 X 2,809,252 10/57 Lingal et al. 200-108 X 2,813,170 ll/57 Horn et al 200--108 BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

Claims

1. A HIGH CURRENT DISCONNECT SWITCH COMPRISING, A METAL PANEL, A PLATFORM ATTACHED TO THE FRONT OF THE PANEL, AN OPERATING MECHANISM MOUNTED ON THE PLATFORM, A PLURALITY OF POLE UNITS MOUNTED IN SIDE BY SIDE SPACED RELATIONSHIP ON THE FRONT OF THE PANEL, EACH POLE UNIT INCLUDING AN INSULATING BASE SUPPORTING A PAIR OF SPACED TERMINAL STUDS EXTENDING THROUGH SAID PANEL, A CONTACT ARM FOR EACH POLE UNIT, SAID CONTACT ARM BEING HINGED ON ONE OF THE TERMINAL STUDS AND ACTUATED INTO ABUTTING ENGAGEMENT WITH THE OTHER TERMINAL STUD WITH A HIGH CONTACT PRESSURE BY THE OPERATING MECHANISM A CROSS BAR MECHANICALLY CONNECTING ALL OF THE CONTACT ARMS TO THE OPERATING MECHANISM, AND CONDUCTORS DISPOSED AT THE REAR OF THE PANEL FOR ELECTRICALLY CONNECTING THE POLE UNITS IN PARALLEL-CIRCUIT RELATION ONLY AT THE CORRESPONDING TERMINAL STUDS.