US3751617A

US3751617A - Vacuum type circuit breaker

Info

Publication number: US3751617A
Application number: US00262582A
Authority: US
Inventors: A Bohlinger; R Miller
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1972-06-14
Filing date: 1972-06-14
Publication date: 1973-08-07
Anticipated expiration: 1990-08-07
Also published as: CA943587A

Abstract

For converting a particular existing oil circuit breaker into a vacuum-type circuit breaker, a conversion assembly is provided which can be easily incorporated into the circuit breaker after the circuit breaker has been stripped of certain key components. The conversion assembly comprises a frame on which vacuum interrupters, their operating mechanism, and an interconnecting linkage are mounted and suitably adjusted in the factory. Conversion is effected by attaching this frame to the top of an existing cell of the circuit breaker in place of the previouslyused cap and thereafter electrically connecting the vacuum interrupters in circuit with existing lead-in conductors.

Description

United States Patent Bohlinger et al; 1 Aug. 7, 1973 i 1 VACUUM TYPE C lRCUlT BREAKER 2,469,203 5 1949 Palme et al. 200 144 B t 4 3 303,309 2 1967 Fl h t l 200 144 [75] Inventors: Arthur L. Bohlinger, Newtown I ursc em 6 a l B EW si z ir; Mlner Primary Examiner-Robert S. Macon er o o Attorney-J. Wesley Haubner, William Freedman [73] Assignee: General Electric Company, et

Philadelphia, Pa. I

[57] ABSTRACT [22] Fil d Jvlilille 717090742" 7 For converting a particular existing oil circuit breaker 21 A L N .1 262,582 into a vacuum-type circuit breaker, a conversion as- 1 pp 0 sembly is provided which can be easily incorporated into the circuit breaker after the circuit breaker has [52] U.S. CI 200/144 B, 200/150 R been tripped 0f certain key eomponen[s The conver- [51] Int. Cl. 01h 33/66 ign assembly comprises a frame on which vacuum in- [58] Field Of Search R, 150 E, ter upte s their perating mechanism and an inter- Z 144 150 G connecting linkage are mounted and suitably adjusted in the factory. Conversion is effected by attaching this [56] References Cited frame to the top of an existing cell of the circuit UNITED STATES PATENTS breaker in place of the previously-used cap and there- 1 113 ()87 10 1914 Ball 200 150 E afterelectrically connectingthe Vacuum imerruPmi" 1,720,413 7 1929 Greenwood 200/144 B Circuit with misting lead-in Conductorsl,783,279 12/1930 Burnham ZOO/144 B 1,801,736 4 1931 Greenwood 200 144 B 5 5 Drum F'gures 1,936,492 ll/l933 Whitehead ZOO/I50 G PATENIEDMJB H915 3,751,617

summra PR/OR 2/ 2/ ART /2 VACUUM TYPE CIRCUIT BREAKER BACKGROUND This invention relates to a vacuum-type circuit breaker and, more particularly, to a conversion assembly that can be used for converting a particular existing oil circuit breaker into a modern vacuum-type circuit breaker and also to a method of making such a converson.

A type of oil circuit breaker that has been in widespread use since the early 1900s is General Electric Companys II-type circuit breaker, an example of which is disclosed in U.S. Pat. No. 1,113,087-Ball, assigned to the assignee of the present invention. There have been many variations in this I-I-type circuit breaker, but the basic organization of the circuit breaker has remained essentially the same. This basic organization has comprised: (I) an enclosing cell made either of masonry or metal and having a horizontallyextending base near the bottom of the cell, (2) horizontally-spaced insulators supported on the base, (3) oiltype interrupters mounted atop said insulators, (4) generally vertically-extending contact rods within said cell extending into said interrupters, (5) a cross-bar within said cell mechanically connecting said contact rods, (6) a frame mounted atop said cell, (7) an operating mechanism mounted atop said frame, and (8) an operating rod extending between said mechanism and said cross-bar.

Beginning with the successful development in the late 1950s of vacuum interrupters capable of handling short circuit currents, there has been a progressively increasing shift from oil to vacuum-type circuit breakers. The vacuum-type circuit breaker has many advantages over the oil-type circuit breaker, some of which as pointed out in US. Pat. Nos. 3,025,375-Frank, 3,163,735-Miller, and 3,594,524- Heintz, all assigned to the assignee of the present invention. Among these advantages are the fact that the vacuum interrupter is a sealed device and there are thus no hot arcing products which must be vented or which could impair insulating properties outside the interrupter, noise and mechanical shock are much reduced, and maintenance is easier and is required less frequently.

Certain owners of the I'l-ty'pe oil circuit breaker may wish to avail themselves of these advantages, but they may not be willing to completely discard their I-l-type circuit breaker and replace it with a vacuum-type circuit breaker. Such complete replacement is expensive, involves time-consuming major reconstruction, and results in the loss of many components which maybe entirely adequate for continued long-term service, e.g., the cell itself, insulators within the cell, instrumentation, associated buses, and bus compartments.

SUMMARY Accordingly, an object of our invention is to provide a conversion assembly which can be used for easily and quickly converting an oil circuit breaker of the abovedescribed l-I-type to a modern vacuum-type circuit breaker.

Another object is to provide for such a conversion without necessitating replacement of the cell itself, insulators within the cell, and associated bus equipment.

Still another object is to provide a conversion assembly which can be assembled and adjusted as a unit in the factory, and then, in the field, can easily be incorporated in a stripped-down existing circuit breaker to effect the desired conversion.

Another object is to construct the conversion assembly in such a manner that once it is located as a unit in the stripped-down circuit breaker, all that is basically required to complete the conversion is to electrically connect it to the lead-in conductors of the circuit breaker.

In carrying out our invention in one form, we first remove from the existing oil circuit breaker referred to hereinabove under Background the components numbered (3) through (8). We replace these components with a conversion assembly comprising: a replacement frame adapted to be mounted atop the remaining cell, a replacement operating mechanism mounted atop said replacement frame, a post insulator projecting downwardly from said replacement frame and having its upper end secured to said frame, a vacuum interrupter mounted on the lower end of said insulator with its envelope extending generally horizontally in a position beneath said frame, and an operating linkage interconnecting said operating mechanism and said vacuum interrupter. When the replacement frame is mounted atop the cell, a pair of conductive bars are respectively connected between the tops of the insulators numbered (2) and terminals of the vacuum interrupter, and this substantially completes the conversion operation.

BRIEF DESCRIPTION OF DRAWINGS For a better understanding of the invention, reference may be had to the following description taken in conjunction with the accompanying drawings, wherein:

FIG. I is a side elevational view, partly in section, of a prior art oil circuit breaker that it is desired to convert into a vacuum-type circuit breaker.

FIG. 2 is a front view, reduced in size, of the circuit breaker of FIG. 1 with certain portions thereof removed for simplicity.

FIG. 3 is a side elevational view, partly in section, of a circuit breaker originally like that of FIG. I but after having been converted into a vacuum-type circuit breaker,

FIG. 4 is an enlarged view showing in section a portion of the circuit breaker of FIG. 3 in a closed position;

FIG. 5 is an end view of the vacuum-type circuit breaker of FIG. 4.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Referring now to FIG. 1, there is shown an existing oil circuit breaker 10of the l-I-type referred to hereinabove. This circuit breaker comprises a protective cell 12 made in the illustrated device primarily of masonry. More specifically, the illustrated cells back wall 14, its bottom wall 15 and its side walls 17 are of concrete. Its front wall is a metal or wooden door 18, shown closed, but suitably mounted for opening movement to permit access to the interior of the cell. The top of the cell is a frame 19 of slate or some similar material suitably attached to side wall 17.

Typically the cell is divided into three side-by-side compartments 21, one for each phase unit of the circuit breaker, as shown in the front view of FIG. 2. The vertically-extending concrete sidewalls 17 are disposed between these compartments 21. The cap or frame 19 covers all three compartments, and the back wall 14 extends across the three compartments. Since the circuit breaker structure in each compartment is essentially the same, only that in one of the compartments will be described.

Referring now to FIG. 1, in the lower portion of the cell is a horizontally-extending base 22 on which two horizontally spaced-apart

insulators

24 and 26 are mounted. in FIG. 1, insulator 24 is depicted as being the tubular insulating shell of a lead-in bushing 27 that comprises a lead-in conductor 28 extending vertically through tubular shell 24. lnsulator 24 has a metal end cap 25 at its upper end to facilitate the making of an electrical connection to any part mounted thereon. lnsulator 24 also has a mounting flange 29 around its mid portion suitably bolted to the base 22. A horizontallyextending bus bar 30 is electrically connected to the lead-in conductor 28 at its lower end. This bus bar 30 extends through back wall 14 via a suitable lead-in bushing 32.

The other insulator 26 is a post-type insulator suitably secured at its lower end to base 22. Bonded to the upper end of insulator 26 is a metal end cap 33. Electrically connected to end cap 33 is the terminal of a bus bar 34 that extends horizontally through the back wall 14 via a suitable insulatinb bushing 36.

Mounted atop each of the

insulators

24 and 26 is an oil-type circuit interrupter 40 of the type shown, for example, in the aforesaid US. Pat. No. l,l13,087-Ball. Each of these interrupters comprises an oil-containing housing 41, a stationary contact 42 within the housing electrically connected to the metal end cap of the supporting insulator at the lower end of the interrupter, and a cooperating movable contact supported on a movable contact rod 43 at its lower end. The two contact rods 43 extend vertically and are mechanically connected together by a cross bar 45 at their upper ends.

For actuating the cross bar 45 to open and close the I breaker, an operating mechanism diagrammatically shown at 50, is provided, mounted upon the cap 19. This operating mechanism comprises an output crank 52 that is driven in a clockwise direction from its position of FIG. 1 to open the circuit breaker. Crank 52 is connected to cross-bar 45 through an insulating operating rod 54 that extends through cap l9.

The'electrical circuit through the breaker extends from lead-in conductor 28, through one of the interrupters 40, through cross bar 45, and through the other interrupter 40 to the other lead-in conductor 34. Interruption of this circuit is effected by causing the operating mechanism 50 to drive cross-bar 45 in an upward direction into a dotted line open position of FIG. 1. Such interruption vaporizes oil within the interrupters, which is suitably vented from the interrupters.

Assume now that it is desired to convert this existing oil circuit breaker of FIG. 1 into a vacuum-type circuit breaker. This is accomplished, first of all, by stripping the existing circuit breaker by removing the operating mechanism 50 and the cap, or frame 19, on which it is mounted, the operating rod 54, cross-bar 45, and interrupters 40. Then our conversion assembly 60 of FIGS. 3-5, soon to be described, is mounted atop the cell 12 in place on the frame 19, following which the conversion assembly is electrically connected to the lead-in

conductors

28 and 34 through

conductive bars

130 and 132. This conversion operation will be referred to in more detail hereinafter.

Referring now to FIGS. 3-5, the conversion assembly 60 comprises three vacuum-type circuit interrupters 62, one for each phase of the circuit breaker, and a common operating mechanism, diagrammatically shown at 64, for the three vacuum interrupters. For supporting both the operating mechanism 64 and the vacuum interrupter 62, a horizontally-extending rigid frame 65 is provided. Suspended from frame 65 are three downwardly-projecting post insulators 68 that are horizontally-spaced from each other so that each is located within one of the compartments 21 approximately midway between its sidewalls 17. Each of these insulators is suitably attached at its upper end to frame 65 and at its lower end to its associated vacuum interrupter 62, as will soon appear in more detail.

Each vacuum interrupter 62 is of a conventional design such as shown, for example, in the aforesaid US Pat. No. 3,163,735-Miller. Referring to FIG. 4, each of these interrupters comprises a highly evacuated envelope 70 comprising a tubular casing 72 of insulating material and

end caps

74 and 75 joined thereto by vacuum-tight seals. Within the sealed envelope are a pair of relatively

movable contacts

77 and 78. One of the contacts 77 is a stationary contact supported on a stationary conductive contact rod 77a extending in sealed relationship through end plate 75. The other contact 78 is a movable contact supported on movable contact rod 78a extending through the other end cap 74. Flexible metallic bellows79 provides a seal about the movable contact rod 78a which allows it to be moved axially without impairing the vacuum inside the envelope.

Suitably attached to tthe left-hand end cap 74 is a casting 80 of a highly conductive material such as copper or a copper alloy. Casting 80 has a mounting portion 82 at its upper end that is suitably bolted to the lower end of insulator 68. Thus casting 80 supports interrupter 62 on insulator 68. The casting 80 further comprises a downwardly-projecting lug 83 to which an electrical connection is adapted to be made, as will soon be described. Casting 80 is electrically connected to movable contact rod 78a by suitable means such as flexible copper braid 84 which does not interfere with free longitudinal movement of contact rod 78a..

The two terminals of the vacuum'interrupter 62 may be thought of as being constituted by the outer end of movable contact rod 78a and by the outer end of stationary contact rod 770, respectively.

The operating mechanism 64 that is provided for operating the three vacuum interrupters can be of any suitable conventional design and, hence, it is shown in block form only. This operating mechanism comprises a rotatably-mounted output shaft that is rotatable in a clockwise direction from its position of FIG. 4 to open the interrupters and is returnable in a counterclockwise direction into its position of FIG. 4 to close the interrupters. Coupled to this output shaft 90 are three cranks 92, one for each interrupter. These cranks 92, which are respectively aligned with the three interrupters, have their outer ends connected to the movable contact rod 78a of the interrupters through insulating linkages 95.

Each linkage comprises an operating rod 97 of insulating material, the upper end of which is pivotally connected at 98 to crank 92 and the lower end of which is pivotally connected at 99 to a guide link 100. Guide link 100 is pivotally mounted on a stationary pivot 101 carried by casting 80.

Between the lower pivot 99 and the movable contact rod78a there is a wipe mechanism 105 of conventional form through which opening and closing force is transmitted to the movable contact rod 78a. A wipe mechanism of this kind is described in greater detail and claimed in the aforesaid Miller US Pat. No. 3,163,735. In general, this wipe mechanism comprises an intermediate link 106 of rod form, the end of which is pivotally connected at 108 to the contact rod 78a and the other end of which is pivotally connected with lost motion to the operating rod 97. The connection to operating rod 97 is through the previously-described pivot 99. Pivot 99 has a transversely-extending hole therethrough slidably receiving intermediate rod 106 to permit motion of pivot 99 along the length of rod 106. Disposed between pivot 99 and the other end of intermediate rod 106 is a compression spring 109 encircling the intermediate rod. This compression spring 109 tends to urge pivot 99 against a stop 110 fixed to the intermediate rod 106.

When operating rod 97 is driven downwardly toward the

contacts

77 and 78 are firmly driven into engagement and held in engagement with a predetermined force despite loss of contact material through wear and arc-erosion and without blocking the contacts of the other interrupters from engaging should the contacts of one of the interrupters engage ahead of the contacts of the others.

For insuring substantially straight line motion of con tact rod 78a during the above-described closing operation, another guide link 112 is pivotally connected by pivot 108 at one end to the contact rod and at its opposite end is pivoted on the pin 101'. In addition, a slide bearing (not shown) is provided about contact rod 78a and is suitably fixed to end cap 74. t

Contact-opening is effected by driving operating rod 97 upwardly from its solid line position of FIG. 4. During initial movement of operating rod 97 in this upward openingldirection, no opening force is applied to the movable'contact rod since the pivot 99 is merelysliding along the intermediate rod 106 without driving the intermediate rod. This lost motion continues until pivot 99 strikes stop 110. When this occurs, an abrupt opening force is applied to movable contact rod 78a, and it separates contact 78 at high speed from contact 77 to produce interruption of the circuit.

For supplying force for an opening operation, an opening spring 115 is provided. This spring 115, which constitutes a part of operating mechanism 64, is a compression spring bearing atone end on a stationary member 116 and at its opposite end on a stop 118 fixed to a rod 119 connected to crank 92. When output shaft 90 is driven in a counterclockwise direction into its position of FIG. 3, it acts to compress opening spring 115.

At the end of the closing operation, shaft 90 is latched in its closed position by a suitable latch (not shown). When such latch is released at the start of an opening operation, opening spring 115 expands to drive crank 92 clockwise and operating rod 97 in an upward opening direction.

The rigid frame 65 may be thought of as constituting a skeleton for the assembly on which all of the interrupters 62, the post insulators 68, the operating mechanism 64, and the insulating linkages 95 are mounted. While the assembly 60 is still in the factory, these

components

62, 68, 64, 95 can be supported on the frame and suitably located and adjusted with respect to each other. The result is a self-sustaining assembly built around frame 65 as a skeleton, which assembly can be shipped as a unit to a field site and there incorporated into a stripped-down circuit breaker without requiring any additional adjustments of its

major operating components

62, 68, 64 and 95. Should any minor adjustments be needed at the field site, these can be readily effected in view of the self-sustaining character of the assembly and the easy access that can be had to its components. It will be noted that thiseasy access is available even when the conversion assembly 60 is mounted on cell 12 since all the key parts inside the cell can be easily reached when cell door 18 is opened.

Returning to the conversion operation, it was pointed out hereinabove that the first step in making the conversion at the field site is to remove from the oil circuit breaker of FIGS. 1 and 2 the operating mechanism 50, the frame 19 on which it is mounted, operating rod 54, the cross bar 45, and the interrupters 40. Then, the above-described conversion assembly 60 of FIG. 3 is placed atop cell 12, with its frame 65 being in substantially the same location as the original frame 19. The new frame 65 is then bolted to the walls of the cell, thus fixing the frame to the cell and locating one of the vacuum interrupters in each compartment of the cell midway between the sidewalls of the compartment. The

next step is to electrically connect the lead-in

conductors

28 and 34 of each phase to the respective terminals 78a and of the vacuum interrupter in the associated phase. Referring to FIG. 3, this is accomplished in each phase of the breaker by connecting between end cap 25 of insulator 24 and the lug 83 on casting an electroconductive bar and by connecting between the exposed outer end of stationary contact rod 77a and end cap 33 of insulator 26 another electroconductive bar 132. Suitable clamping bolts are relied upon for interconnecting

parts

130 and 83, and a suitable clamp 137 is relied upon for interconnecting

parts

132 and 77a. Bar 130 includes an angle conductor 133 at its lower end shaped to facilitate making the connection to conductive end cap 25 of insulator 24; and bar 132 includes a similar angle conductor 134 shaped to facilitate making the connection with the conductive end cap of insulator 26. This basically completes the conversion operation, though a few finishing touches may be needed, such as attaching a shield to the right hand end of each vacuum interrupter and also electrically connecting the control wiring for the operating mechanism.

It will be seen from the above that once the original oil circuit breaker has been stripped, all that is required, basically, to effect the conversion is to mount the conversion assembly 60 atop the cell 12 and to electrically connect it to the lead-in

conductors

28 and 34 through the

bars

130 and 132. All the mechanically interconnected parts of assembly 60 have already been located and adjusted with respect to each other at the factory, thus eliminating the need for assembling and adjusting these parts in the field and thus greatly simplifying the conversion operation.

It will also be apparent that the above-described conversion can be effected without disturbing the basic structure of cell 12, or

insulators

24 and 26, or the

buses

30 and 34, or any switches or instrumentation (not shown) combined with the bus, thus reducing the cost of converting from oil to vacuum interruption.

While we have shown and described particular embodiments of our invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from our invention in its broader aspects; and we, therefore, intend herein to cover all such changes and modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A conversion assembly for use in converting into a vacuum-type circuit breaker an existing oil circuit breaker that comprises: l a cell having a horizontallyextending base in the lower region of the cell, (2) horizontally-spaced insulators supported on said base, (3) oil-type interrupters mounted atop said insulators, (4) generally vertically-extending contact rods within said cell extending into said interrupters, (5) a cross-bar within said cell mechanically connecting said contact rods, (6) a framemounted atop said cell, (7) an operating mechanism mounted atop said frame, and (8) an operating linkage extending between said mechanism and said cross bar, after said existing circuit breaker has been stripped by removal of said interrupters, contact rods, cross bar, frame, operating mechanism, and linkage; said conversion assembly comprising:

a. a replacement frameadapted to be mounted atop said cell,

b. a replacement operating mechanism mounted atop said replacement frame,

c. a vacuum interrupter comprising: an evacutated envelope having spaced-apart opposite ends, separable contacts within said envelope, a movable contact rod extending through one end of said envelope and supporting one of said contacts, and spaced terminals at opposite ends of said envelope electrically connected to said contacts,

d. a post insulator projecting downwardly from said replacement frame and having its upper end secured to said replacement frame,

e. means mounting said vacuum interrupter on the lower end of said first insulator in such a manner that said envelope extends generally horizontally in v a position beneath said frame,

f. a replacement operating linkage at least partially of insulating material extending between and interconnecting said replacement operating mechanism and the movable contact rod of said vacuum interrupter,

g. and a pair of conductive bars for connection, re-

spectively, between the tops of said base-supported insulators and the terminals of said vacuum interrupter.

2. A polyphase conversion assembly as defined in claim 1 in which one phase of the assembly comprises (c), (d), (e), (f) and (g) of claim 1, and another phase of the assembly comprises additional parts constructed as defined in (c), (d), (e), (f) and (g) of claim 1, said replacement frame and said replacement operating mechanism being common to both phases, the vacuum interrupters of said phases being horizontally spaced from each other.

3. An electric circuit breaker comprising:

a. a cell having a horizontally extending base in its lower portion,

b. a pair of horizontally-spaced insulators supported on said base,

0. a frame mounted atop said cell,

d. an operating mechanism mounted atop said frame,

e. a vacuum interrupter comprising: an evacuated envelope having spaced-apart opposite ends, separable contacts within said envelope, a movable contact rod extending through one end of said envelope and supporting one of said contacts, and spaced terminals at opposite ends of said envelope electrically connected to said contacts,

f. a post insulator projecting downwardly from said frame and having its upper end secured to said frame,

g. means mounting said vacuum interrupter on the lower end of said post insulator in such a manner that said envelope extends generally horizontally in a position beneath said frame,

h. an operating linkage at least partially of insulating material extending between and interconnecting said operating mechanism and the contact rod of said vacuum interrupter,

i. and a pair of conductive bars respectively connected between the tops of said base-supported insulators and the terminals of. said vacuum interrupter.

4. A polyphase circuit breaker as defined in claim 3 in which one phase of the circuit breaker comprises (e), (f), (g), (h), and (i) of claim 3, and another phase of the circuit breaker comprises additional parts constructed as defined in (e), (f), (g), (h), and (i) of claim 3, said frame and said operating mechanism being common to both phases, the vacuum interrupters of said phases being horizontally spaced from each other.

5. A method of converting into a vacuum-type circuit breaker an existing oil circuit breaker that comprises: l) a cell having a horizontally-extending base in the lower region of the cell, 2) horizontally-spaced insulators supported on said base, (3) oil-type interrupters mounted atop said insulators, (4) generally verticallyextending contact rods within said cell extending into said interrupters, (5) a cross bar within said cell mechanically connecting said contact rods, (6) a frame mounted atop said cell, (7) an operating mechanism mounted atop said frame, and (8) an operating linkage extending between said mechanism and said cross-bar; said conversion method comprising the following steps:

a. stripping said circuit breaker by removing therefrom said interrupters, contact rods, cross-bar, frame, operating mechanism and linkage,

b. providing a conversion assembly comprising a replacement frame, a replacement operating mechanism mounted atop said frame, a vacuum interrupter comprising an evacuated envelope containing separable contacts and having terminals at its opposite ends respectively connected to said contacts, a first insulator projecting downwardly from said replacement frame and having its upper end c. mounting said replacement frame atop said cell with said vacuum interrupter within said cell,

(1. providing a pair of conductive bars,

e. and electrically connecting said bars between the tops of said base-supported insulators and the terminals of said vacuum interrupter.

. (5/621) i J x I I (115.1117 Mil/x1321) ()ir (1Q il-i iiifi'fiUf-J Patent: No- 1.617 I -])ntcd August 7, 1973 n Arthur L. Bohlinge'r & Richard H. Miller It is cortifiod that error appbars in the nbovca-idontificd patent and that said Letters Patent are hereby corrected 3:; shown below:

Column 1 line 36, change "as" to are Column 3-, line G3,;chn'ge "'on" :to of Column 5, line 66, after "counterclockwise" insert --closing-- Column 5, Line 67, change "3" to=-.14

Signedain'd sealed this 'l th day of'March 1974.

(SEAL) Attest:

EDWARD M.FLETCHER, J R. v C. MARSHALL 'DANN 'Attesting Officer v Commis sioner of Patents CEik'ii z. i-ij/.'i.iil O 2. CO Ell-39811.04!

Patent: No. 3. 751.617 Dated August 7, 1973 Invcnmflg) Axjtl ur L. Bohlinger &' Richard H. Miller .t is certified that error appears in the abovcwidentified patent and that; said Letters Patent arc: hereby corrected as; shown below:

Column 1, line 36, change "as" to are Column 3, line 63, cnnge '"on" to of Column 5, line 66, after "counterclockwise" insert --closing-- Column 5, line 67, change "3" to -,4

Signed and sealed this' 19th day of March 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. C. MARSHALL DANN Attesting Officer Commis sioner of Patents

Claims

1. A conversion assembly for use in converting into a vacuumtype circuit breaker an existing oil circuit breaker that comprises: (1) a cell having a horizontally-extending base in the lower region of the cell, (2) horizontally-spaced insulators supported on said base, (3) oil-type interrupters mounted atop said insulators, (4) generally vertically-extending contact rods within said cell extending into said interrupters, (5) a crossbar within said cell mechanically connecting said contact rods, (6) a frame mounted atop said cell, (7) an operating mechanism mounted atop said frame, and (8) an operating linkage extending between said mechanism and said cross bar, after said existing circuit breaker has been stripped by removal of said interrupters, contact rods, cross bar, frame, operating mechanism, and linkage; said conversion assembly comprising: a. a replacement frame adapted tO be mounted atop said cell, b. a replacement operating mechanism mounted atop said replacement frame, c. a vacuum interrupter comprising: an evacutated envelope having spaced-apart opposite ends, separable contacts within said envelope, a movable contact rod extending through one end of said envelope and supporting one of said contacts, and spaced terminals at opposite ends of said envelope electrically connected to said contacts, d. a post insulator projecting downwardly from said replacement frame and having its upper end secured to said replacement frame, e. means mounting said vacuum interrupter on the lower end of said first insulator in such a manner that said envelope extends generally horizontally in a position beneath said frame, f. a replacement operating linkage at least partially of insulating material extending between and interconnecting said replacement operating mechanism and the movable contact rod of said vacuum interrupter, g. and a pair of conductive bars for connection, respectively, between the tops of said base-supported insulators and the terminals of said vacuum interrupter.

3. An electric circuit breaker comprising: a. a cell having a horizontally extending base in its lower portion, b. a pair of horizontally-spaced insulators supported on said base, c. a frame mounted atop said cell, d. an operating mechanism mounted atop said frame, e. a vacuum interrupter comprising: an evacuated envelope having spaced-apart opposite ends, separable contacts within said envelope, a movable contact rod extending through one end of said envelope and supporting one of said contacts, and spaced terminals at opposite ends of said envelope electrically connected to said contacts, f. a post insulator projecting downwardly from said frame and having its upper end secured to said frame, g. means mounting said vacuum interrupter on the lower end of said post insulator in such a manner that said envelope extends generally horizontally in a position beneath said frame, h. an operating linkage at least partially of insulating material extending between and interconnecting said operating mechanism and the contact rod of said vacuum interrupter, i. and a pair of conductive bars respectively connected between the tops of said base-supported insulators and the terminals of said vacuum interrupter.

5. A method of converting into a vacuum-type circuit breaker an existing oil circuit breaker that comprises: (1) a cell having a horizontally-extending base in the lower region of the cell, (2) horizontally-spaced insulators supported on said base, (3) oil-type interrupters mounted atop said insulators, (4) generally vertically-extending contact rods within said cell extending into said interrupters, (5) a cross bar within said cell mechanically connecting said contact rods, (6) a frame mounted atop said cell, (7) an operating mechanism mounted atop said frame, and (8) an operating linkage extending between said mechanism and said cross-bar; said conversion method comprising the following steps: a. stripping said circuit breaker by removing therefrom said interrupters, contact rods, cross-bar, frame, operating mechanism and linkage, b. providing a conversion assembly comprising a replacement frame, a replacement operating mechanism mounted atop said frame, a vacuum interrupter comprising an evacuated envelope containing separable contacts and having terminals at its opposite ends respectively connected to said contacts, a first insulator projecting downwardly from said replacement frame and having its upper end secured to said replacement frame, means mounting said vacuum interrupter on the lower end of said first insulator in such a manner that said envelope extends generally horizontally in a position beneath said frame, and linkage means interconnecting said operating mechanism and one of the contacts of said vacuum interrupter, c. mounting said replacement frame atop said cell with said vacuum interrupter within said cell, d. providing a pair of conductive bars, e. and electrically connecting said bars between the tops of said base-supported insulators and the terminals of said vacuum interrupter.