US3457530A

US3457530A - High-speed operating mechanism for a circuit breaker

Info

Publication number: US3457530A
Application number: US538720A
Authority: US
Inventors: Roswell C Van Sickle
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1966-03-30
Filing date: 1966-03-30
Publication date: 1969-07-22
Anticipated expiration: 1986-07-22
Also published as: FR1515768A; JPS4516486B1

Description

. Filgd March so. 1966 ly 2 1969 R. C/VAN SICKLE 3,457,530

HIGH-SPEED OPERATING MECHANISM FOR A CIRCUIT BREAKER 65hets-Sheet 1 leg a l wimessss: INVENTOR Z M Roswell C. VunS|ck|e ATTORNEY R. C. VAN SICKLE July 22, 1969 3,457,530

HIGHSPEED OPERATING MECHANISM FOR A CIRCUIT BREAKER Filed March 30, 1966 6 Sheets-Sheet 2 July 22, 1969 R. c. VAN SICKLE 3,457,530

HIGH-SPEED OPERATING MECHANISM FOR A CIRCUIT BREAKER Filed March so, 1966 s Sheets-Sheet s FIG. IO.

FIGJU.

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July 22, 1969 R. c. VAN SICKLE 3,457,530

HIGH-SPEED OPERATING MECHANISM FOR A CIRCUIT BREAKER Filed March 50, 1966 6 Sheets-Sheet 5 so FIG.5.

OPEN

CLOSED FIG.6.

L Y// vl TRIPPED Q United States Patent US. Cl. 335-21 19 Claims ABSTRACT OF THE DISCLOSURE A high-speed operating mechanism is provided for a high-voltage high-power circuit breaker. A rotatable main operating member is connected to the moving contact structure of the circuit breaker. A first toggle linkage including a knee pivot pin connects said rotatable main operating member through a second toggle linkage to a magnetically-actuated releasable holding magnet capable of being tripped or released upon excess fault current. A driving lever, pneumatically rotated on closing, has a thrust pin which is connected through a floating link to the knee pin of the first toggle linkage. Force-compensating sleeves surround the longitudinally movable operating rods between the pole-units.

This invention relates, generally, to operating mechanisms for circuit breakers and, more particularly, to high-speed operating mechanisms adaptable to circuit breakers of the high-voltage and high-power type.

As well known by those skilled in the art, it is a difficult task to provide a high-speed operating mechanism for a circuit breaker of the high-voltage type, which invariably involves heavy parts of considerable mass and component parts, which may be spaced from each other considerable distances. Moreover, it is desirable to provide an operating mechanism which is capable not only of high-speed operation, but also adaptable to trip-free operation and suitable for high-speed reclosing operations. In addition, the mechanism must be reliable, require little maintenance, preferably utilize few parts and assure trouble-free operation, since circuit breakers may stand energized for long periods of time and then suddenly be called upon to effect quick and dependable opening of the connected line, as say during a fault conditon being imposed upon the system.

It is, accordingly, a general object of the present invention to provide an improved and highly eflicient highspeed operating mechanism for a circuit breaker which will dependably assure the prompt opening of the contact structure at high speed to effectively clear the associated circuit.

Another object of the present invention is to provide an improved operating mechanism for a circuit breaker which involves few parts and utilizes a new leverage system of reliable performance.

Still a further object of the present invention is to provide an improved high-speed operating mechanism for a highspeed high-power circuit breaker which utilizes only a portion of the parts for a tripping operation, and permits other associated heavy parts, to remain stationary during the critical tripping period, and to move subsequently to their open positions.

Another object of the invention is to provide an improved mounting frame support for an operating mechanism to impose a minimum of strain upon the associated high-voltage pole-unit structure.

Another very important object of the invention is to provide a simplified type of operating leverage system for a circuit-breaker operating mechanism capable of operating all the modules of the pole unit of a high-voltage circuit breaker.

Still a further object of the invention is to provide a novel leverage system for a pneumatic-type operating mechanism in which the line of action of the applied force from the operating piston is kept on a straight line by linkage movement, rather than sliding guiding surfaces, thereby reducing friction losses.

Another object of the invention is to provide a novel lever arrangement for transmitting large forces to horizontal pull rods for closing the breaker poles characterized by limited vertical dimensions, so as to fit within a shallow space between the horizontal rods and the base of the breaker columns. This allows minimum mechanism frame height without allowing hazardous projections into the electric fields around the insulating columns supporting the elevated interrupting heads.

Another very important object of the invention is to use a special toggle linkage arranged to increase the mechanical advantage of the piston to the operating rods from an initial value of 0.3 to a final value of 9.6, or a change by the unusually high factor of 32 between the beginning and end of the operating stroke. This performs the function of matching the relatively constant applied pressure on the driving piston in the gas-filled operating cylinder to the changing load on the breaker closing rods from an initial value of 2000 pounds to a final value of 70,000 pounds, for example.

Still a further object of the invention is to provide an improved lever system for a circuit breaker operating mechanism to provide a mechanism of unusually low inertia during the tripping function, when an extremely high-speed circuit breaker opening is required. This is accomplished by trip-free action of the links, leaving the heavier parts released, but substantially stationary until the later part of the circuit breaker opening stroke.

Another object of the invention is to make a mechanism which can be mounted in line with the operating rods of the pole unit to make the operating linkage as short and as simple as possible.

Another object of the invention is to provide an improved operating mechanism for a circuit breaker having a special builtin feature for ease of maintenance such, for example, as rendering the operating cylinder removable without dismantling the rest of the operating system, rendering the retrieving springs removable without dismantling other parts of the mechanism, providing a convenient position for applying the hand-closing jack, and finally providing easy removal, remounting and positioning of a pre-tested trip assembly.

In the US. patent application filed June 12, 1964, Scr. No. 374,708, now US. Patent 3,291,947, issued Dec. 13, 1966 to Roswell C. Van Sickle, entitled Interrupting Structures and Operating Mechanisms for Compressed- Gas Circuit Interrupters, and assigned to the assignee of the instant application, there is disclosed and claimed a high-power 500 kv. 35,000 m.v.a. compressed-gas circuit breaker. In the aforesaid patent application, there is disclosed an operating mechanism for the aforesaid breaker which gives the breaker a rated interrupting time of 3 cycles. It is an additional purpose of the present application to provide an improved operating mechanism for the aforesaid breaker which reduces the operating time by one cycle to give the breaker an interrupting time of 2 cycles. It accomplishes this in a dependable and reliable manner, utilizing a magnetic holding latch for quick release, a toggle to provide the mechanical advantage between the force of a pneumatic cylinder and the load of the operating rods, and a trip-free lever system of low elfective inertia to release the operating rods quickly. A minimum of effective mass to be moved while the contacts 3 move through the first 15 or 20% of their opening stroke is most important and is obtained with this mechanism.

To assure 2-cycle interruption of an EI-IV SP breaker, the time from the energizing of the trip circuit until the contacts part must not exceed 1.2 cycles. This time is divided between the release of the breaker by an electrical tripping impulse and the mechanical movement of the linkages to separate the contacts. In this mechanism, the time from the energizing of the trip circuit until the breaker linkage starts to open is about 0.3 cycle and the time from the start of linkage movement until the are is drawn is about 0.9 cycle. Thus, the object of providing faster operation to obtain a rated interrupting time of 2 cycles is obtained.

Further objects and advantages will readily become apparent to those skilled in the art upon reading the following description, taken in conjunction with the drawings, in which:

FIGURE 1 is a side elevational view of a three-phase, high-voltage, compressed-gas circuit breaker embodying the principles of the present invention;

FIG. 2 is a longitudinal vertical sectional view taken through one of the modular interrupting heads of one of the pole units of the circuit breaker of FIG. 1, with the separable contact structure being illustrated in the closed circiut position;

FIG. 3 is a somewhat simplified diagrammatic view of the overall operating linkage and operating mechanism disposed at the base main framework of one of the pole units of the circuit breaker of FIG. 1;

FIG. 4 is a fragmentary, partially vertical sectional view of a portion of the main base framework of the circuit breaker of FIG. 1, illustrating the rotative main operating crank arm, horizontal pull rods and the force-compensating sleeves to carry the forces imposed upon the main framework;

FIG. 5 illustrates the closed position of the operating mechanism with its various parts and a sectional view through one of the force-compensating sleeves in greater detail;

FIG. 6 illustrates the tripped position of the operating mechanism, and a sectional view through the other forcecompensating sleeve in greater detail;

FIG. 7 illustrates the members of the mechanism after a tripping operation with the breaker in the open position and the slower moving parts partially retrieved;

FIG. 8 illustrates the fully-open position of the operating mechanism, with all parts retrieved and reset in readiness for a subsequent closing operation of the breaker;

FIG. 9 is a fragmentary sectional view of a portion of the operating linkage, taken substantially along the line IX-IX of FIG. 5;

FIG. 10 is another fragmentary sectional view of a portion of the operating linkage, taken substantially along the line XX of FIG. 5;

FIG. ll is a side elevational view of the electromagnetic trip mechanism which holds the roller lever in the latched position, and also illustrating the manner of positioning said electromagnetic trip mechanism, the circuit breaker being indicated in the latched closed position;

FIG. 12 is an enlarged fragmentary view of the electromagnetic trip mechanism of FIG. 11, illustrating the retrieving position of said trip mechanism; and,

FIG. 13 is a side elevational view of the magnet structure for the electromagnetic trip mechanism of FIGS. 11 and 12, with the armature being shown in the released position.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 10- generally designates a high-voltage three-phase compressed-gas circuit breaker including three pole units, only one of which is illustrated in FIG. 1. It will be observed that the pole unit A, illustrated in FIG. 1, comprises three serially related interrupting assemblies, generally designated by the reference numeral 11, and electrically connected in series.

In addition, a current transformer structure 12 is provided to measure the current flow through the pole unit A, as well understood by those skilled in the art. Reference may be made to U.S. Patent 2,504,647 for a description of a typical gas-filled type of current transformer, which could be used in the circuit breaker installation shown in FIG. 1.

The pole units are alike except for the interpole electrical control wiring, gas lines and air lines and for the house 50 on the middle pole unit, which contains the common parts of the air and gas systems. Each pole unit, such as the pole unit A of FIG. 1, for example, is mounted upon a heavy grounded supporting base frame 13 comprising heavy longitudinally-extending spaced beam members 14, upright supports 15 and angularly-extending welded, bracing members 16. In addition, each supporting base frame 13 preferably has a longitudinally-extending high-pressure main reservoir tank 17 associated therewith, extending in generally parallel relationship, having individual supply pipes extending upwardly therefrom into and through the three insulating hollow upstanding column structures 19 to supply high-pressure arc-extinguishing gas, such as sulfur-hexafluoride (SP gas to auxiliary high-pressure reservoir chambers 20* at high potential, and disposed interiorly of metallic interrupting heads 21. As shown in FIG. 1, each metallic interrupting head 21 surmounts and is supported by the upstanding insulating hollow column structure 19 the requisite distance from ground potential depending upon the line voltage to be interrupted. The circuit breaker 10 illustrated in FIG. 1 is capable of interrupting the line voltage of 500 kv. and has power rating of 35,000,000 k.v.a. For higher line voltages, such as 750 kv. or 1,000 kv., there would merely be provided more interrupting heads 21 in series having a greater distance to the grounded main base framework 13.

Interrupting structure The interrupting structure 24 disposed within each metallic interrupting head 21 will now be described, with attention specifically directed to FIG. 2 of the drawings. It will be noted that extending interiorly Within each interrupting head 21, from opposite ends thereof, is a pair of terminal bushings 25 encompassing terminal studs 26, the latter carrying stationary contact structures 27 at their interior ends. A rotating bridging contact cross-arm assem- 'bly, generally designated by the reference numeral 28, and carrying two movable contacts 29 at the outer free ends thereof, cooperates with the stationary contact structures 27 to establish during opening two arcs (not shown) in electrical series. These arcs are extinguished by a flow of high-pressure arc-extinguishing gas flowing outwardly through the hollow metallic arms 30 from the auxiliary reservoir chambers 20 and through the arc spaces. This gas flow is controlled and timed relative to contact movement by a blast valve mechanism, generally designated by the reference numeral 31, and actuated by upward opening movement of the insulating operating rods 32 within the hollow supporting columns 19. Reference may be had to the aforesaid patent application Ser. No. 374,708 for specific details of the blast valve mechanism, but it is not described in further detail here, since it constitutes no part of the present invention. A torsion bar assemblage 33 cooperates with accelerating compression springs 34, 35

(FIG. 3) to bias a pair of oppositely-movable horizontally-extending

pull rods

36, 37 in the opening direction, as indicated by the arrows 38 of FIG. 3. In more detail, the lower ends of the vertical insulating operating rods 32 are pivotally connected, as at 39, to rotatable operating crank arms 40, the latter being aifixed to rotatable shafts 43. These shafts 43 extend laterally outwardly through sealed openings in the side walls of the hollow upstanding insulating columns 19, and are driven, externally of the column 19, by a plurality of triangularly-shaped bell-crank levers 42 pivotally mounted upon the rotatable shafts 43. One arm portion 42a of each lever 42 is pivotally connected, as at 44, to one of the

horizontal drive rods

36, 37 and the other arm portions 42b of the lever 42 are pivotally connected, as at 45, to the piston rods 46 of hydraulic cylinders 47, which provide speed control and cushioning at the end of the opening operation of the breaker 10.

High-speed trip-free operating mechanism As well known by those skilled in the art, with the increasing use of extra-high-voltage transmission, many utility system engineers now desire power circuit breakers with 2 cycle interrupting times. A reduction from threecycle to two-cycle interruption provides significant improvements in power-system stability margins, minimizes voltage dips, reduces fault burning, and reduces equipment damage during faults. To provide these desirable operating margins, the SP extra-high-voltage breaker, described in the aforesaid patent application Ser. No. 374,- 708 has been modified to make it capable of two-cycle interruption. The reduction from three-cycle to two-cycle interruption was made possible by a new high-speed trip mechanism coupled to an improved leverage system of low vertical height. Referring to FIG. 1, it will be noticed that there is provided an operating mechanism compartment 49, an operating cabinet 50 enclosing a control panel, compressor equipment, and related pressure control switches. FIG. 3 illustrates, in diagrammatic fashion, the entire operating mechanism, generally designated by the reference numeral 51, comprising the operating leverage system 52 and the trip-magnet assembly 53. FIGS. 5, 6, 7 and 8, respectively, illustrate the closed position, tripped position, retrieving motion, and the open position of the operating mechanism 51; and FIGS. 11 and 12 illustrate, in detail, the trip magnet assembly 53, with FIG. 13 illustrating the holding magnet 54, per se.

The leverage system 52 comprises a thrust or actuating pin 55 operating through a floating thrust link 56 to operate a first toggle linkage, generally designated by the reference numeral 57. This toggle linkage, comprising toggle links 57a pivoted about pin 65 during a closing operation. and 57b pivoted about pin 48 in the lever 58 when extended during a closing operation, rotates a main operating crank-arm 58 attached to a main shaft 59 journaled in the two spaced vertical

heavy side plates

60, 61 of the stationary main mechanism frame, generally designated by the reference numeral 62, to the closed position shown in FIG. 5. As shown in FIG. 5, the main operating crankarm 58 has one arm thereof 58a pivotally connected, as at 63, to the left-hand end of the horizontal operating pull rod 37. In addition, the main operating crank-arm 58 has another integral arm portion 58b pivotally connected, as at 64, to the right-hand extremity of the horizontal operating pull rod 36. Thus, clockwise rotation of the main operating crank-arm 58 and its attached shaft will effect closing of the breaker 10, as effected by the extending of the first operating toggle linkage 57.

It will be observed that in connection with the first operating toggle linkage 57, that the toggle link 57a has the upper end thereof, as viewed in FIG. 5, pivotally mounted upon a releasable pivot 65. This releasable pivot is provided on the lower end of a rotatable support arm 66, itself pivotally mounted about a stationary pivot pin 67 extending through the vertical

side support plates

60, 61 of the main mechanism support frame 62. The releasable pivot 65 for the first operating toggle linkage 57 is normally maintained in its thrust-transmitting, or set position, as shown in FIGS. 5 and 8, by the operation of a second operating toggle linkage, generally designated by the reference numeral 68, and comprising a pair of toggle links 68a, 68b pivotally interconnected by a knee pivot pin 69. The toggle link 68a constitutes an arm portion of a roller lever R pivotally supported about a stationary pivot shaft '70, the latter journaled within bearing openings 71 provided in the vertical

side support plates

60, 61 of the main mechanism support frame 62 as shown more clearly in FIG. 9 of the drawings. The roller lever R carries a latching roller 72, which is latched during closing and in the closed circuit position of the circuit breaker 10', by releasable latching means, in the particular example shown comprising a trip magnet assembly 53, more fully described hereinafter.

The roller lever R is positioned as described later to control the force F exerted on the trigger 104. To have the same force when the mechanisms are used with pole units having two, three or four columns the mechanical advantage of toggle 68 is changed by using three different roller levers R which have their holes for pin 69 located in difierent positions so that the different forces on the mechanism will produce the same moment about pin 70' and consequently the same force on roller 72. For example, if a 700 k.v. breaker pole unit with four columns has a load on

rods

36 and 37 which is twice the corresponding loads for a 345 k.v. breaker pole unit with two columns, the roller lever R for the 700 k.v. breaker will have a hole so located that the lever arm of toggle 68 about pin 70 is about half as long as for the lever R used for a 345 k.v. breaker.

Driving means for operation of thrust or actuating pin 55 In the particular example shown, the driving means DM for operation of the thrust or actuating pin 55 comprises a pneumatic motor 74. As shown more clearly in FIG. 5 of the drawings, the pneumatic motor 74 comprises an operating cylinder 75 with upper and

lower end plates

76, 77 forced toward each other and against the intervening cylinder by tie bolts, not shown. An operating piston 78 is forced downwardly within the operating cylinder 74 in a breaker closing direction by the admission of highpressure air from the compressed air reservoir 79 by the operation of an air inlet control valve 80, more clearly shown diagrammatically in FIG. 3 of the drawings. A two-way closing control valve 80 is illustrated in FIG. 3, whereby energization of the closing solenoid 81 by closing the closing button CB, will admit high-pressure operating air into the upper end of the operating cylinder 74, while at the same time closing the exhaust opening 81. This will rapidly drive the piston 78 downwardly in a closing direction with the connected piston rod 82 rotating a pair of main driving levers 83 in a counterclockwise closing direction about a stationary support shaft 84 journaled in bearing openings 85 provided in the vertical

side support plates

60, 61 of the main mechanism support frame 62, as more clearly shown in FIG. 10 of the drawings. This closing driving motion exerted upon the main driving levers 83 by the piston rod 82 takes place through a straight-line mechanism, generally designated by the reference numeral 86, and comprising a straight-line lever 87 pivotally connected, as at 88, to the upper end of the piston rod 82, and also pivotally connected by a drive pin 89 to the two main driving levers 83. In addition, the two straight-line levers 87 are connected, as at 90, to the upper ends of guide links 91, the latter being pivotally supported at the lower ends there of by a stationary support pin 92. The net result of this straight-line guiding mechanism 86 for the upper end of the piston rod 82 is that the piston rod can be surrounded by a packing to prevent leakage of high-pressure operating air out of the piston rod opening 93 provided in the upper end plate 76.

It will be observed that the thrust or actuating pin 55 is carried at the left-hand free end of the main driving levers 83, and toward the end of the closing operation of the circuit breaker 10, the thrust pin 55 cams aside a mechanical holding latch 94 and moves thereunder to be latched thereby, as shown in FIGS. 3 and 5 of the drawings. The mechanical holding latch 94 is pivotally mounted about a stationary mounting pin 95, and is biased in a latching direction by a compression spring 96.

A tripping operation causes the second toggle linkage 68 to collapse first during the first and important period of the opening operation of the pole-unit 10.

To effect a retrieving operation of the main driving levers 83 and also of the first and second

operating toggle linkages

57, 68 following a trip-open operation of the circuit breaker 10, as more fully described hereinafter,

' there is provided a pair of retrieving compression springs 97, disposed within spring housings 98, only one being shown in the drawings. The two retrieving compression springs 97 act between the right-hand end plates 98a of the spring housings 98 and a spring seat 99 driving a spring rod 100, pivotally connected, as at 101, to a depending lug portion 83a of each main driving lever 83-. It will be obvious that the retrieving compression springs 97 will bias the main driving levers 8-3 in a clockwise opening direction about the stationary pivot shaft 84 to retract the operating piston 78 upwardly within the pneumatic operating cylinder 74 so as to be in readiness for the next closing operation of the circuit breaker 10. Simultaneously, the springs 97 acting through these levers retrieve the

toggles

57 and 68, the latch roller 72 and the trigger 104 as described in more detail later.

It will be obvious to those skilled in the art that other means than the pneumatic motor 74 may be utilized to drive the thrust or actuating pin 55 to the closed latched position, as shown in FIG. 5, to thereby extend the first toggle linkage 57 to effect closing clockwise rotation of the main operating crank-arm 58. The pneumatic motor 74 is merely one way, and other means for effecting this function will readily suggest themselves to one skilled in the art.

Trip magnet assembly 53 The trip magnet assembly 53 for releasably magnetically latching the roller 72 of the roller lever R in the closed circuit position of the circuit breaker 10 will now be described. Generally, the trip magnet assembly 53 comprises a holding magnet 54 and a toggle latch structure 101 pivotally mounted about a stationary pivot shaft 102 and carrying a movable armature 103 at one end thereof, and a trigger 104 at the other end thereof. As shown more clearly in FIG. 13, the holding magnet 54 comprises a generally U-shaped magnet structure 105 and a permanent magnet member 106. The U-shaped magnetic structure 105 comprises a base part 107 and two pole pieces, or leg parts 108, 109. A thin layer of nonmagnetic material 110 separates the pole pieces 108, 109 from the base part 107. Each of the pole pieces 108, 109 is provided with a generally flat pole face 108a, 109a, against which the armature 103 seats in the closed position, as shown in FIG. 12. The pole pieces 108, 109, base part 107, and armature 103, are made of a suitable magnetically permeable material, such as soft iron. The permanent magnet 106 is of the ceramic type.

With reference to FIG. 13, which shows the holding magnet 54 in the released position, it 'will be noted that the two-piece pole assembly 108, 109 provides two parallel magnetic paths for flux from the ceramic permanent magnet 106. With the armature 103 in the reset position (FIG. 12), most of the flux concentrates in the lowreluctance path provided by the moving armature 103. The magnet holds this armature with a force of 200 pounds, for example, opposing a 100 pound force as applied by the roller load 72 through the trigger mechanism 104. Thus, there is provided a 100 percent safety factor, for example, to prevent accidental tripping by mechanical shocks.

To initiate a tripping operation of the pole-unit 10, the trip coil assembly 111 is energized by pressing the manual trip button TB thereby completing the tripping circuit through the battery 112. Or, as well known by those skilled in the art, the tripping may be initiated by means of the trip relay 113 upon the occurrence of an overload current through the line L L controlled by the breaker 10, which overload or fault current causes the relay 113 to close its contacts 114, thus completing the tripping circuit through the battery 112.

There are provided two trip coils 111a, 111b, one around each pole piece 108, 109, which are connected in series and Wound so that the magnetomotive force produced by the coils 111a, 111b opposes the permanentm agnet flux in the moving armature 103. This opposition decreases the magnetic flux in the moving armature circuit (the permanent-magnet flux transfers fro-m the moving armature loop to the parallel upper air-gap loop). The holding force on the armature 103 is reduced, allowing the pound trigger force to initiate motion for release of the armature trigger mechanism 101.

As brought out in more detail hereinafter, once the armature-trigger mechanism 101 is tripped, the magnet 54 can be reset before the main circuit breaker mechanism arm R returns to its original starting position, as shown in FIG. 11. Trip coil current is cut off by an auxiliaryswitch after a small movement of the breaker mechanism. The armature 103 is attracted magnetically to the pole faces and resets. This resetting action is done without the need of supplying any electrical or mechanical energy.

The toggle-latch structure 101 will now be described, with particular attention being directed to FIGS. 11 and 12 of the drawings. It will be noted that the roller lever R with the latching roller 72 at the outer end thereof, is latched in the closed position, as shown in FIG. 11, by means of the toggle-latching structure 101 comprising a bifurcated trigger toggle link 104 pivotally mounted on a moving knee pivot pin 114 to the free end of a second toggle link 115 afiixed to, and rotatable with, the sta tionary pivot shaft 102. The stationary pivot shaft 102 is journaled in bearing openings provided in two spaced vertical support plates 116, secured fixedly together by suitable transverse braces, and collectively constituting a pivotally-mounted supporting frame 117 for adjustable location of the trigger 104 relative to the position of the latching roller 72 on the roller lever R. A stop pin 118 is carried in a tight fit through the end portion of the second toggle link 115, and also extends, with clearance, through enlarged holes 120 provided in the bifurcated lefthand end of the trigger toggle likn 104. As shown in FIGS. 11 and 12, the trigger toggle linkage 101 is erected, or overset so that the force F (FIG. 11) exerted by the operating mechanism (acelerating springs 333 5) acts in a direction to rotate the trigger 104 about pin 114 until the sides of hole 120 engage pin 118 and also acts to bias the trigger toggle linkage 101 in a counterclockwise direction about the stationary pivot shaft 102. This force F is resisted by the magnetic holding force exerted by the holding magnet 54 upon the armature 103.

As stated hereinbefore, when the trip coil 111 is energized, either by manually pressing the tripping button TB, or by automatic operation of the overload current relay 113, the trip-coil magnetomotive force opposes the magnetomotive force of the permanent magnet in the magnetic path through the armature, thereby reducing the flux through the armature. The magnetic flux of the parmanent magnet itself remains almost constant and transfers from the armature 103 to the path through the air gaps 110 and the base part 107, thereby reducing the force by which the armature 103 is attracted to pole faces 108a and 109a and following the armature 103 to be opened by the 100 pound force resulting from the trigger load. The trigger toggle latch structure 101 will rotate, as a unit, in the counterclockwise direction about the statioanry pivot shaft 102 until the force F exerted by the latching roller 72 collapses the trigger toggle linkage 101, at which time the armature 103 will be free to reset against the pole faces 108a, 109a.

When the latch is tripped, roller 72 moves counterclockwise and no longer restrains the small lever 150. Lever is biased clockwise by spring 151 and these parts now move to the position shown in FIG. 12. An integral arm portion 150a of lever 150 presses against an arm portion of a lever 153 and causes it to rotate clockwise. The other integral arm portion 15312 of lever 153 engages pin 155 and forces it upward against the biasing force of spring 122. Pin 155 also passes through trigger 104 which it holds out of the way of the roller 72 and in the position shown in FIG. 12. The pull of the magnet on armature 103 resets it against the pole faces 108a, 109a ready for the next operation.

After the latch has released roller 72, the roller lever rotates counterclockwise collapsing the toggle 68 and permitting pivot pin 65 to rotate clockwise about pin 67. This releases the toggle 57 and lever 58 is no longer held in the closed position. It rotates counterclockwise permitting the operating

rods

36 and 37 and the attached linkage and contacts to move to the open position. The first fifth of the opening stroke is made while the contacts are moving to draw an arc and consequently must be made in 0.9 cycle or less. During this time the parts which are moving at speeds comparable to the speed of the contacts or faster are relatively small and light. Consequently, the movement is made in the available time.

Further opening movement moves the contacts to their fully open position. Meanwhile, the holding latch 94 has been released and the retrieving action of pin 55, straightline linkage 86 and pneumatic motor 74 can take place.

When the retrieving of the pneumatic operator resets the lever system 52, the roller 72 is brought back into position thereby rotating lever 150 counterclockwise against the action of spring 151. This releases lever 153 and permits spring 122 to move lever 153 counterclockwise and trigger 104 clockwise about pin 114 until the sides of the holes 120 in trigger 104 engage the stop pin 118 as shown in FIG. 11. -In this position trigger 104 is behind the roller 72 and ready to restrain the roller 72 when the forces of the operating mechanism or pole unit 10 tend to rotate lever R counterclockwise.

United States patent application, S. N. 436,601, filed March 2, 1965, now United States Patent 3,391,358, issued Iuly 2, 1968, to Walter V. Bratkowski, Raymond J. Radus and Erling Frisch entitled Circuit Breaker, and assigned to the assignee of the instant application, describes and claims this trip magnet operation and structure in detail, and reference may be made to this application for additional description. The details of the trigger toggle linkage and method of magnetic flux transfer constitute no part of the present invention; consequently, a further description thereof appears unnecessary.

It is desirable to be able to properly position the trip magnet and latch assembly 53, and specifically the particular position of the latching roller 72 carried by the roller lever R and the position of the trigger 104 relative to the roller 72. To effect this end, it will be noticed with particular attention directed to FIG. 11 of the drawings, that the entire trip magnet assembly 53 is carried by a supporting frame 117, which is pivotally mounted on a pivot pin 123 to a laterally-extending boss portion 124 welded to a transverse adjustable cross-plate 125, secured by supporting bolts, not shown, to a main cross-brace 127 of the main mechanism frame 62. By inserting metallic shims 128 between the main crossbrace 127 and the movable adjustment cross-plate 125, the laterial position of the trip magnet assembly 53 relative to the main mechanism frame 62 may be adjusted. This controls the position of the lever R when the roller 72 engages trigger 104. Also, by the provision of the pivotal mounting of the trip magnet assembly 53 upon the pivot pin 123, and by the use of adjustment nuts 129 threaded upon a stud portion 130, in turn secured to a lateral support member 131 of the trip magnet assembly 53 the angular position of the trip magnet assembly 53 may also be adjusted. This will determine the line on which the latching roller 72 engages the trigger 104.

In more detail, with the circuit breaker 10 in the open position, a straight round locking bar, not shown, is inserted in accurately-located holes 132 (FIG. provided in the vertical

side support plates

61, 62 of the main mechanism frame 62. A clearance distance of say .015 inch to .020 inch between the locking bar and a gauge portion 133 of the roller lever R is desired when the roller 72 is exerting a force on the trigger 104. By adjusting the shims 12-8, the position of the trigger 104 can be moved. This moves the roller 72 and the roller lever R and controls this dimension. By using antifriction bearings in lever R and link 68b, it is possible to bring the toggle formed by them into a position close to center and by this adjustment to have the position held in the desired permissible range. This adjustment controls the mechanical advantage gained by this toggle and thereby controls the load exerted by roller 72 on trigger 104.

It is also important that the roller 72 engage the flat surface on the end of the trigger 104 at a short distance from the radius on the corner. This assures positive latching and a very short travel of the trigger 104 before the roller 72 is released. This condition is obtained by rotating the trip assembly 53 by adjusting the nuts 129 on stud 130. The flat surface on trigger 104 is approximately perpendicular to the line between the center of roller 72 and pin 123' so this adjustment does not interfere with the previous setting obtained by varying shims 12 8. The nuts 129 are adjusted until the desired position of the trigger 104 with respect to the roller 72 is obtained. Since this is diflicult to determine at the actual line of contact, a machined gauging surface 135 is provided on roller lever R at a position which assures the desired engagement, if the dimension between the gauging surface 135 and trigger 104 is within the desired range, e.g. .4l7.422.

The closing bumpers 134 engage the ends of the knee pivot pin 69 and support it in the open overtravel position. The bumpers 134 are adjusted to give a desired clearance, such as .016-020 between the roller 72 and trigger 104. This is the general manner of determining adjustment of the trip magnet assembly 53.

Stress-compensating frame support The

horizontal operating rods

36, 37 for the pole-unit 10 are surrounded by stress-compensating

pipes

136, 137, which carry forces approximately equal and opposite to the operating rod forces. These

pipes

136, 137 are welded to the column bases 22, which in turn are welded to and form an integral part of the main base frame 13. Spacers 138 are fitted and bolted between the

pipes

136, 137 and the frame 62 of the mechanism. The unbolting of these connections, the removal of the spacers 138, and the removal of the top of the housing 49 (FIG. 1) permit the mechanism 51 to be lifted from the pole unit 10 without removing the housing 49. When the mechanism 51 is in place, much of the force on the mechanism frame 62 resulting from the loads on the operating

rods

36 and 37 is transmitted to the pole unit base frame 13 through these

pipes

136, 137 surrounding the operating

rods

36, 37. This means that the principal forces which are exerted on or by the mechanism 51 during an operation are nearly in line and relatively little force has to be carried down to the beam members 14 of the pole unit 10. The use of the

horizontal pipes

136, 137 around the operating

rods

36, 37, as a means of balancing the forces of the operating

rods

36, 37, also reduces the flexing of the base frame 13 under the relatively high operating forces and contributes to the speed of operation.

Opening operation of circuit breaker 10' FIGS. 2, 3 and 5 illustrate the circuit breaker 10 in the closed circuit position. If manual opening is desired, push button TB is pressed, or if a fault condition is present, the current transformer 12 and the trip relay 113 will measure the fault or overload current and initiate tripping. In either event, the trip coil assembly 111 will become energized, and will oppose the permanent-magnet fiux in the moving keeper 103. The opposition decreases the magnetic flux in the moving keeper circuit, thereby releasing the keeper or armature 103. This will release the latching roller 72 and the second toggle linkage 68', which in turn releases the first toggle linkage 57, to permit the main operating crank 58 to rotate in a counterclockwise direction with its pivot shaft 59. The heavy accelerating spring loading 33-35 effects opening of the breaker at high speed, whereas the thrust pin 55 and the heavy masses of the drive levers 8'3, and associated linkage, remains relatively stationary during this short trip opening time of the breaker. The circuit breaker is now open, the arcs, not shown, having been extinguished by a blasting of high-pressure sulfur-hexafluoride (SP gas.

As explained hereinbefore, the armature 10'3 quickly resets. Also, a release member 140 rotating in a clockwise direction with thrust link 56, pushes off the springbiased holding latch 94 to release pin 55 and to permit the two retrieving springs 97 to raise

parts

78, 88, and 83 to the open position. FIG. 6 shows the tripped open position of the circuit breaker 10 with the release member 140 releasing the holding latch 94; and FIG. 7 shows the position of the several parts at a slightly later time with the retrieving operation of the linkage in progress.

FIG. 8 illustrates the position of the several parts of the mechanism 51 with the breaker in the fully open position, all linkage parts retrieved, and in readiness for a subsequent closing operation. It will be observed that not only do the retrieving springs 97 reset the main driving levers 83-, but that also these retrieving springs 97 straighten the second toggle linkage 68, thereby rotating the roller lever R clockwise to its latched condition, as clearly shown in FIG. 8. The roller lever R and link 68b are purposely made of a light material, such as an aluminum casting, so that only light parts of little mass are involved in the initial tripping operation. Moreover, the initial movement of pin 160 is about pin 55 instead of 65, which greatly increases the speed of opening of the pole unit. By these and other changes about 0.6 cycle was gained in the mechanical linkage. This gain plus the gain with the holding magnet trip reduced the rated interrupting time of the breaker by one cycle.

Closing operation of circuit breaker 10 To close the circuit breaker 10 from the position shown in FIG. 8-, one merely needs to press the closing button CB. Naturally, this could be done electrically, as well simplicity, the simple two-way control valve 80 and the energizing pushbutton CB have been utilized in FIG. 3 of the drawings. This action will open the inlet valve 80 to permit high-pressure air from reservoir 79 to flow into the upper end of the pneumatic cylinder 74-, forcing the piston 78 downwardly in a closing direction, and driving the thrust or actuating pin 55 downwardly to a latched position. As mentioned hereinbefore, the provision of a straight-line linkage 86 assists in guiding the piston rod 82 in a straight line direction. The downward closing movement of the thrust pin 55 will extend the first toggle linkage 57, thereby rotating the main operating crank 58 in a clockwise direction about its pivot shaft 59 and causing closing movement of the

horizontal drive rods

36, 37. This action will close the pole unit contacts to the position shown in FIG. 2, and the mechanism parts will assume the position shown in FIGS. 3 and 5. The pole unit 10 is now fully closed, and the exhaust opening of the two-way control valve 80 is open, so as not to oppose subsequent upward retracting motion of the piston 78, as caused by the retrieving springs 97, should the circuit breaker 10 be immediately opened.

Slow manual closing of the circuit breaker pole unit may be achieved by use of a hydraulic jack 144 (FIG. 8) during servicing and maintenance operations.

From the foregoing decn'ption, it will be apparent that there is provided an improved high-speed operating mechanism 51 particularly adapted for a high-power circuit breaker. The leverage system is such that initially, only few parts of lightweight are needed to trip the breaker open, and the other parts of heavier mass may be moved at a later time in the opening operation. Forces are balanced to a considerable degree and adjustment of the trip magnet assembly 53 is easily and accurately achieved. The number of parts involved are few in number and the construction is such that long operational life is achieved.

The locking bar, not shown, but previously mentioned, may be inserted in the holes 132 to make the mechanism non trip-free during servicing operations.

For reclosing operations, as soon as the mechanism piston 78 has been retrieved, the roller lever R returned to the latched position, and the trigger 104 dropped into latched position, the mechanism 51 is ready to reclose the breaker 10. The last of these operations closes the latch checking switch 147 to signify readiness to close the breaker 10.

With the improved mechanism, the air cylinder 74 may readily be removed without dismantling the mechanism 51. Also, the retrieving springs 97 may similarly be removed with little effort and without disturbing the mechanism components. Finally, the particular arrangement of the mechanism 51 results in reduced height which is important in minimizing the height of the entire circuit breaker pole-unit 10.

Although there has been illustrated and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the invention.

I claim as my invention:

1. A high-speed circuit breaker having separable contact structure, means biasing said separable contact structure to the open-circuit position, a high-speed operating mechanism for the circuit breaker including a movable main operating member (58) mechanically related to said separable contact structure to cause the closing movement thereof, means for closing the breaker including a thrust pin (55) and actuating means (74) therefor, means defining a toggle linkage (57) for causing closing movement of said movable main operating member (58), means including said thrust pin (55) for extending said toggle linkage (57) during the closing operation, means (94) for releasably latching said thrust pin (55) in the closed circuit position of the circuit breaker, said toggle linkage (57) having a releasable pivot (65), and tripping means (53) for releasing said pivot (65) of the toggle linkage (57) to effect releasing movement of the toggle linkage and thereby permit opening movement of said main movable member by virtue of the biasing means.

2. The circuit breaker of claim 1, wherein a second toggle means (68) supports the releasable pivot (65) of the first toggle means (57).

3. The circuit breaker of claim 1, wherein releasing means responsive to the release of the toggle linkage (57) is effective to release said latching means (94) and free said thrust pin (55).

4. The circuit breaker of claim 3, wherein a pivotally supported lever (83) supports said thrust pin (55) adjacent a free end thereof, and fluid driving means (78) are )used to effect closing rotative motion of said lever (83 5. The circuit breaker of claim 4, wherein a straightline linkage is used to guide the piston rod of the fluid driving means (78).

6. The circuit breaker of claim 1, wherein opening biasing means (96) provide a retrieving action of the linkage parts, and a resetting of the releasable pivot (65) of the toggle linkage (57) 7. The circuit breaker of claim 2, wherein a roller lever (R) constitutes one of the toggle links of the second toggle means (68) and carries a latching roller (72), and said tripping means (53) releasably latches said roller.

8. The circuit breaker of claim 7, wherein the tripping means includes a holding magnet (54) and a movable keeper (103), and a trip coil (111) carrying a control 13 current is used to shift the magnetic flux within the holding magnet to eifect release of the movable keeper.

9. The circuit breaker according to claim 7, wherein a trigger (104) is provided and is actuated by a toggle latch structure (101) associated with the tripping means.

10. An operating mechanism for a circuit breaker including a main frame support (62) for supporting the parts of the mechanims linkage, one of said parts being a latching roller (72), an adjustable trip magnet assembly (53) having its own adjustable frame support (117) and carrying a latching trigger, and means pivotally mounting the adjustable frame support (117) of the adjustable trip magnet assembly (53) relative to the main frame support (62) to obtain adjustment between the latching roller and the latching trigger.

11. The operating mechanism of claim 10, wherein metallic shims are used to obtain lateral positioning of the frame support (117), and the angular position of the trip magnet may be determined by one or more adjustment means (129).

12. A circuit breaker of the high-voltage type including a pair of spaced upstanding column structures (19) mouted upon a lower base frame, means including an operating mechanism supported in a main mechanism frame (62) for transmitting high forces through horizontal operating rods (36, 37) to said column structures (19) to cause actuation of the contact structures at the upper ends of the columns, and force-compensating members (136, 137) braced rigidly between the main mechanism frame ('62) and the column bases (22) to relieve the bending stresses exerted upon the base frame (13).

13. The circuit breaker according to claim 12, wherein the force-compensating members comprise metallic pipes which surround the horizontally-extending operating rods (36, 37).

14. The combination according to claim 1, wherein the thrust pin 55 is disposed adjacent the free end of a pivot ally-supported lever (82), and a pneumatic operating cylinder and piston movable therein has a mechanical connection to said lever (83) for causing rotative motion thereof, and the pneumatic cylinder being situated laterally of said toggle linkage for minimizing vertical height of the mechanism.

15. The circuit breaker of claim 14, wherein the mainoperating member (58) is a pivotally-mounted rotatable crank-arm and is disposed below the toggle linkage (57).

16. The circuit breaker of claim 14, wherein the tripping means (53) includes a second toggle linkage (68) which is disposed laterally of the first toggle linkage on the other side of said toggle linkage from the pneumatic operating cylinder.

17. A high-speed operating mechanism for a circuit breaker comprising, in combination, a main rotatable crank-arm (58) adapted to be connected to the separable contact structure of the circuit breaker, means pivotally I mounting said rotatable crank-arm, first toggle means having a pivotal connection at one end with said rotatable crank-arm and a releasable pivot at the other end of said first toggle means, means including a thrust pin acting at the knee pin of said first toggle means to extend said first toggle means and so effect closing rotative motion of said first toggle means, and releasing means for releasing said releasable pivot for the first toggle means including releasable latching means, whereby even though said thrust pin remains substantially stationary, nevertheless the rotatable crank-arm may rotate to the open position upon release of said releasable pivot by release of said latching means.

18. The combination according to claim 17, wherein said releasing means includes a second toggle means for positioning said releasable pivot of said first toggle means.

19. The combination according to claim 17, wherein main lever means (83) actuated by a fluid motor drives said thrust pin.

References Cited UNITED STATES PATENTS ROBERT S. MACON, Primary Examiner U.S. Cl. X.R. 200-148, 169