US2573234A

US2573234A - Circuit interrupter

Info

Publication number: US2573234A
Application number: US608580A
Authority: US
Inventors: James M Wallace; Earl F Beach
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1945-08-02
Filing date: 1945-08-02
Publication date: 1951-10-30
Anticipated expiration: 1968-10-30

Description

Patented Oct. 30, 1951 UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER James M. Wallace, Braddock, and Earl F. Beach, Wilkinsburg, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application August 2, 1945, Serial No. 608,580

8 Claims. 1

This invention relates to electric circuit interrupting devices, and especially to automatic reclosing circuit breakers.

One object of this invention is to provide in an automatic reclosing circuit breaker, novel means for causing closely successive circuit interrupting operations of the breaker to have difierent time characteristics, and for preventing reclosure of the breaker in response to a predetermined number of closely successive circuit interrupting operations.

Another object of this invention is to provide in an automatic reclosing circuit breaker, fluid dashpot means adapted to determine the circuit opening time of the breaker and being controlled in a novel manner to cause closely successive circuit opening operations of the breaker to have different opening times, and which dashpot means actuates integrating means for preventing reclosure of the breaker in response to a predetermined number of closely successive circuit opening operations thereof.

Another object of this invention is to provide in an automatic reclosing circuit breaker, a single fluid dashpot means for controlling at least a circuit opening operation of the breaker and being provided with means varying'the freedom of ilow of fluid displaced by the dashpot means on closely successive operations of the breaker, together with means operated by said displaced fluid for preventing reclosing of the breaker in response to a predetermined number of closely successive breaker operations.

These and other objects of this invention will becom more apparent upon consideration of the following description of preferred embodiments thereof when taken in connection with the attached drawing, in which:

Figure 1 is a longitudinal section view of a circuit breaker constructed in accordance with this lustrated as being enclosed in a tubular casing '2' of insulating material, such as porcelain or the like, which is adapted to be supported intermediate its ends as by a supporting bracket 4, having packing material 6 interposed'between the bracket and casing. The lower end of easing 2 is provided with a closure disk 8 secured in position as by cementing or the like, and has a central aperture for receiving a terminal bolt I0. An enlarged head [2 is provided on terminal bolt Hi to be seated on the upper side of closure disk 8, with interposed packing material l4, and the terminal bolt is provided with a nut i6 for securing the bolt in position, and for also securing a terminal fixture I 8 thereto.

A channelled supporting ring 2| is adapted to ,be secured about the upper end of easing 2 as by cast metal 2% or the like, which enters the channel portion of the ring and interlocks with peripheral grooves provided about the upper end of casing 2. A cover casting 22 is adapted to be secured over the upper end of casing 2 by means of bolts or the like (not shown) for securing the casting to sup-porting ring 2|. Cover casting 22 is provided with a hollow chamber portion 24 which opens into casing 2, and it is also provided with an integral hood 26, for a purpos to be described.

A shaft 28 extends transversely of cover chamber 24 and has its ends mounted in opposite sides of the chamber for supporting a generally U-shaped spring support 30 which has the legs thereof apertured for rotatably receiving shaft 28. Spring support 30 is normally biased in a counterclockwise direction by a coil compression spring 38, which is mounted on a rod 32 pivotally mounted at one end at 36 on one leg of support 30, and slidably mounted at its other end in an apertured lug 34 integral with cover casting 22. Spring 38 reacts between lug 34 and a washer 40 secured to or integral with rod 32. Spring support 30 is normally prevented from rotating in a counterclockwise direction under the influence of spring 38 by a pair of toggle levers 42 and 44, with lever 42 pivotally connected with one leg of support 30 at one end, and at its other end being pivoted to lever 44, which is in turn pivotally mounted as at 46 in the cover casting. Toggle lever 44 is provided with an integral handle extension 48 beneath hood 26, and a hook eye 56 is located at the outer end of the handle extension for the reception of a hook stick or other operating member. Toggle levers 42 and 44 are normally held at their over-center position shown in Fig. 1 by spring 38, due to engagement of handle extension 48 with an adjustable stop bolt 52 provided beneath hood 26'.

A coil reclosing spring 54 is also mounted on shaft 28 within chamber 24, and reacts at one end against the bight portion of support 30, and at its other end against the inner end of an operating lever 56 which is also pivotally mounted on shaft 28. A pair of links 58 of insulating material, such as fiber or the like, pivotally connect operating lever 56 to the upper end of a contact rod 69 which extends downwardly through casing 2 and into an interrupting chamber '52 provided in the lower portion of casing 2. Interrupting chamber 62 is formed of a tube 64 of insulating material, such as fiber or the like, having a bottom cap 96 secured thereon in any desired manner, with a fixed contact 68 mounted on the bottom cap so as to be positioned within interrupting chamber 62. Fixed contact 68 is adapted to cooperate with a contact head 69 provided on the lower end of contact rod 59 to open and close the circuit through the breaker upon appropriate movement of contact rod 99. Bottom cap 66 of the interrupting chamber is adapted to be electrically connected with terminal fixture I8 by means of a coil compression spring 79, reacting between the cap and head I2 of terminal bolt I9. Spring I9 is of a good electrical conducting resilient material, such as' a copper alloy.

An upper end cap I2 is provided for tube 64 of the interrupting chamber being secured thereto in any desired manner, and is centrally apertured to slidably receive contact rod 69 and a sleeve I4 of insulating material provided on the rod to insulate it from cap I2. Sleeve 74 may be of any desired insulating material, such as fiber or a molded insulating material. Interrupting chamber 62 is adapted to be maintained in the position shown in Fig. l by a pair of spaced supporting plates I6 which may be integral with upper cap I2 of the interrupting chamber at one end, and at the other end they are integrally joined by a transverse supporting plate Tl. A generally U-shaped solenoid supporting frame "I8 has the lower leg thereof secured to supporting plate 'Il', as by bolts 69, and the upper leg thereof is adapted to be secured to cover casting 22 ,as'bysupports 8|.

An annular coil 82 is adapted to -be supported by frame I8, with the coil preferably being provided with a coating 84 of insulating material.

,Coil 82 is held in position substantially in alignment with opposed openings formed in the'legs of supporting frame I8 by a dashpot sleeve 86,

which is held in position by a shoulder provided on supporting plate 11. Contact rod 69 has an actuating sleeve 88 provided thereon in the region of coil 82, and this sleeve is provided with a collar 99 threaded into the upper end thereof for engagement with a shoulder 92 on the contact rod, for a purpose to be described. A tubular solenoid core 94 is also slidably mounted ,on'contact rod 69 between

sleeves

86 and 88 to form therewith a dashpot structure. Vent openings 96 are provided through the side wall of core 94 adjacent its lower end, to permit'the free escape of liquid trapped within core 94. A light fcoil compression spring 98 is provided on contact 10d 69 within actuating sleeve 88, and it reacts fb'etween 'collar 99 of the actuating sleeve and the closed end of core 94, to normally maintain the core at its lowermost position shown on the Tdrawing.

'The circuit through the breaker thus far described extends from a terminal fixture 99 provided on cover casting 22, by way of a conductor I99 to one side of coil 82, and then by a flexible conductor I92 to a supporting plate I94 secured on contact rod 69 against the upper end of insulating sleeve 74. The circuit then continues in the closed position of the breaker to fixed contact 68 and terminal fixture I8. It will thus be observed that solenoid coil 82 is connected in series in the circuit. Supporting plate I94 on the contact rod also serves the purpose of pivotally supporting one end of a latch plate I96 having an opening for receiving contact rod 69 to permit limited pivotal movement of plate I98, and having a smaller opening adjacent the pivot point for receiving a latch rod H9.

When current fiows through the circuit greater than a value predetermined by the rating of coil 82, solenoid core 94 will be attracted upwardly by coil 82. Initial upward movement of core 94 will compress spring 98 but will not separate the contacts until the bottom of the core engages the lower end of actuating sleeve 88 and moves the sleeve upwardly until collar 99 engages shoulder 92 of the rod. As soon as contact head 69 separates from fixed contact 68, an arc will be drawn which will create pressure within interrupting chamber 62 to further separate the contacts. As soon as the arc is extinguished, the chamber may be automatically vented or the pressure therein otherwise dissipated so that reclosin spring 54 will be free to move contact rod 69 downwardly to cause engagement of contact head 69 with fixed contact 68. The structure and operation thereof described above is quite similar to that disclosed in J. M. Wallace Patent No. 2,333,604, issued November 2, 1943, on Circuit Interrupter, and assigned to the same assignee of this invention. In the Wallace patent, separation of the contacts is delayed a predetermined time after the occurrence of an overload sufiicient to cause coil 82 to attract core 94 upwardly by the dashpot action of the core working between

sleeves

86 and 88. Moreover, in reclosing, the circuit, downward movement of contact rod 69 is also adapted to be correlated with downward movement of core 94 and, consequently, be delayed by the dashpot action thereof. This correlation of the movement of contact rod 69 and core 94 in closing the circuit is accomplished by latch plate I96 which wedges on latch rod II9 upon attempted downward movement of the contact rod, due to the action of spring I98, to thus latch the contact rod in the uppermost position to which it is moved during a circuit opening operation, and this latch is released by engagement with the outer end of latch plate I96 of core 94 in its downward movement. Contact rod 69 will thus move downwardly toward closed circuit position at the turned flange at its upper end held against the.

upper leg of solenoid supporting frame I8, by a coil compression spring I I4 reacting between this flange and the upper end of sleeve 86. The lower end of sleeve H2 is provided with a relatively large fluid inlet opening IIB which is normally closed by a check valve disk I I8 held against the opening by a coil compression spring I29. The

upper leg of supporting frame 18 is provided with.

a fluid passage I22 leading from the upper endof sleeve II2 to an openin in which is threaded a cylindrical sleeve I24. The upper end of sleeve I24 has secured therein a plug disk I26 provided with a small opening I28 of a size to receive a rod I32 secured to a piston member I30 which is slidably mounted in sleeve I 24. Rod I 32 may extend below piston I30 as at I36, to form a stop for downward movement of the piston. The upper end of rod I32 may be tapered as at I34 so that it may readily enter aperture I28 in disk I26.

It will now be observed that in operation, with casing 2 filled with an armextinguishing liquid, preferably up to the level L, that when solenoid coil 82 becomes energized sufficiently to attract core 34 upwardly and effect a circuit opening operation, such upward movement of core 34 will displace liquid trapped above the core between

sleeves

86 and 88 up through sleeve I I2, by displacement of check valve disk H8, through passage I22, and will cause upward movement of piston I30in a relatively unrestrained manner. Now when the circuit is reclosed, downward movement of core 94 will be restrained, because check valve disk H8 will close inlet H6, and liquid can enter the dashpot space between

sleeves

86 and 88 only through the relatively small clearances between these sleeves and core 94. Upon reclosure of the circuit if the fault or other condition which caused the opening operation has cleared, piston I30 will gradually sink back to the position shown in Figs. 1 and 2. However, if the fault or condition still remains on the circuit upon the first reclosure of the breaker, core 94 will be immediately attracted upwardly again. Depending upon the length of sleeve I24, the upper end of rod I 34 may this time be moved into opening I28 in the upper end of sleeve I24 to thereby restrict the flow of liquid from the upper end of sleeve I24, and thus slow down upward movement of core 94 inasmuch as it is necessary that fluid displaced by such upward movement of the core be forced through the relatively small clearance between rod I32 and opening I28, and thus delay opening of the contacts. If desired, sleeve I24 may be made longer so that rod I32 will not enter opening I until the third closely successive circuit opening operation, so that the first twoclosely successive circuit opening operations will occur relatively rapidly, and the third opening will be delayed. In-any event, when the breaker automatically recloses the second time, resetting of piston I may occur as described above if the fault or condition causing opening of the breaker hasv disappeared. However, if it has not disappeared, the breaker will immediately reopen and upward movement of the core 94 will again be delayed as rod I32 will be in opening I28.

Inasmuch as rod I32 is advanced a predetermined amount each time the breaker operates toopen the circuit, this is made use of by positioning sleeve I24 substantially directly beneath toggle lever 42, so that when rod I32 has been advanced an amount due to a predetermined number of closely successive circuit interrupting operations, it will be moved into engagement with toggle lever 42 and cause this lever together with the lever 44- to be moved upwardly overcenter, and thus release spring 38 to rotate spring support 30 in a clockwise direction to maintain the contacts in an open circuit position. Following such an automatic lockout of the breaker contacts, they can be reclosed only by manually returning handle 48 from its lockout position where it projects below hood 26 to the position shown in Fig. l, to move the toggle levers back overcenter and permit spring 54 assisted by the force of gravity to reclose the contacts.

The breaker described above may be provided with various accessories such as a receptacle I38 integral with the cover structure within chamber 24 for mounting a lightning arrester unit therein to be electrically connected with coil supporting frame 78, as by a conductor I40. An operation counter I42 may be mounted beneath hood 26 if desired, and be actuated by a connecting rod I44 from a lever I45 which moves in accordance with movement of contact operating lever 56. Such a counter I42 should be positioned beneath hood 26 so that the number of operations registered thereon is readily visible. A filler plug I48 may also be provided for the cover casting to obtain communication with chamber 24 and permit replenishing the supply of arc extinguishing liquid within casing 2.

Instead of providing for the first, or the first two circuit opening operations in any series of closely successive circuit opening operations to occur relatively rapidly as in the embodiment of the invention illustrated in Figs. 1 and 2, with the circuit opening operations following these being delayed a predetermined time after the occurrence of the predetermined conditions or overload causing the opening operation, it may be desirable to provide some other sequence of relatively fast and slow opening operations, and this may be accomplished by varying the form of rod I32. Thus, in Fig. 3, there is illustrated a rod I50 provided with a portion I52 beneath piston I30 forming a stop, and provided intermediate its ends with a portion I54 reduced in cross-section area so that a relatively large upper end I58 of substantially the same size as opening I28 in disk I26 is provided normally closely adjacent the opening so that the tapered end I58 is partially in the opening.

In the operation of this embodiment of the invention, it will be observed that the first circuit opening operation in any series of closely successive circuit opening operations will be delayed because enlarged portion I56 of rod I53 will be positioned within opening I 28 in the upper end of sleeve I24 so as to restrict flow of liquid displaced by upward movement of solenoid core 94. In the event the breaker opens immediately after a first reclosure, the reduced part I 54 of rod I50 will be within opening I28 so that a relatively free flow of the fluid displaced by upward movement of core 34 will occur on the second circuit opening operation, so that this operation will occur relatively rapidly. It will be apparent that a third closely succeeding operation will occur relatively slowly as will subsequent operations until lockout occurs.

It is apparent that with this invention there is provided a simplified means for controlling the time characteristic of circuit opening and closing operations of automatic reclosing circuit breakers, which is adapted to provide a predetermined sequence of relatively fast and slow circuit opening operations in any sequence of a predetermined number of closely successive circuit opening and closing operations. Moreover, in the event a lesser number of circuit opening and closing operations occurs, the device will reset so that the breaker will operate through the same sequence of relatively fast and slow circuit openings in the event the predetermined conditions appear on the circuit at a later time. In addition to the above, the same device is also adapted to integrate closely successive circuit interrupting operations so as to operate lockout means to maintain the circuit breaker contacts amazes open after the occurrence of a predetermined number of such closely successive circuit interrupting operations. The very simple mechanism disclosed herein for obtaining these various results may be made to provide any desired sequence of relatively fast and slow circuit opening operations merely by varying the shape of rod I32, as illustrated, for example, in Figs. 2 and 3. It is obvious that the breaker can thus be made to open with time delay on the first operation and with instantaneous characteristics on subsequent operations, or to open substantially instantaneously on the first or.first and second operations and with time delay on subsequent operations, or in other sequences of relatively fast and slow circuit opening operations.

Having described preferred embodiments of this invention in accordance with the patent statutes, it is desired that the invention be not limited to the particular structures disclosed,

'inasmuch as it will be apparent particularly to persons skilled in this art that many modifications and changes may be made in these particular Structures without departing from the broad spirit and scope of this invention.

We claim as our invention:

1. An automatic reclosing circuit breaker comprising, separable contacts, means responsive to a predetermined condition of the circuit for causing separation of said contacts to open the circuit, means responsive to a circuit opening operation for automatically closing said contacts, fluid dashpot means for delaying separation of said contacts a predetermined time after the occurrence of said predetermined condition, vent means for said dashpot means normally :ireeiy passing an amount of fluid equal to that displaced by said dashpot means during a circuit opening operation, a member which. is advanced a predetermined amount from a normal position in response to each circuit opening and closing cycle of operation of the breaker for restricting the flow of fluid through said vent means in response to a predetermined operation in any series of closely successive operations to delay the following circuit opening operation of such a series of operations, said member being biased to return to its normal position and having means for delaying such return movement, and

means responsive to advancement of said memher an amount greater than that required to restrict said vent means. for terminating such a series of operations.

2. An automatic reclosing circuit breaker comprising, separable contacts, means responsive to a predetermined condition of the circuit for causing separation of said contacts to open the circuit, means responsive to a circuit opening operation for automatically closing said contacts, fluid dashpot means for delaying separation of said contacts a predetermined time after the occurrence of said predetermined condition, vent means for said dashpot means normally freely passing an amount of fluid equal to that displaced by said dashpot means during a circuit opening operation, a member which is advanced a predetermined amount in response to each circuit opening and closing cycle of operation of the breaker for restricting the flow of fluid through said vent means in response to a predetermined operation in any series of closely successive operations to delay the following circuit opening operation of such a series of operations, means responsive to advancement of said member an amount greater than that required to restrict said vent means tion, and fluid dashpot means delaying said return movement of said member.

3. An automatic reclosing circuit breaker comprising, separable contacts, means responsive to a predetermined condition of the circuit for causing separation of said contacts to open the circuit, means responsive to a circuit opening operation for automatically closing said contacts, fluid dashpot means for delaying separation of said contacts a predetermined time after the occurrence of said predetermined condition, vent means for said dashpot means normally freely passing an amount of fluid equal to that displaced by said dashpot means during a circuit opening operation, a member which is advanced a predetermined amount in response to each circuit opening operation of the breaker for restricting the flow of fluid through said vent means in response to a predetermined circuit opening operation in any series of closely successive circuit opening operations to delay the following circuit opening operation of such a series of operations, means responsive to advancement of said member an amount greater than that required to restrict said vent means for terminating such a series of operations, means for delaying return movement of said member and means for automatically closing said vent during at least a portion of each circuitclosing operation of the breaker to delay closing of said contacts.

4. An automatic reclosing circuit breaker comprising, separable contacts, means responsive to a predetermined condition of the circuit for causing separation of said contacts to open the circuit, means responsive to a circuit opening operation for automatically closing said contacts, fluid dashpot means for delaying separation of said contacts a predetermined time after the occurrence of said predetermined condition, vent means for said dashpot means normally freely passing an amount of fluid equal to that displaced by said dashpot means during a circuit opening operation, a member which is advanced a predetermined amount in response to each cir cuit opening operation of the breaker for restricting the flow of fluid through said vent means in response to a predetermined circuit opening operation in any series of closely successive circuit opening operations to delay the following circuit opening operation of such a series of operations, means responsive to advancement of said member an amount greater than that required to restrict said vent means for terminating such a series of operations, means for automatically closing said vent during at least a portion of each circuit closing operation of the breaker to delay closing of said contacts, said member being biased to return to a normal position, and fluid dashpot means delaying said return movement of said member.

5. An automatic reclosing circuit breaker comprising, separable contacts, means responsive to a predetermined condition of the circuit for causing separation or" said contacts to open the circuit, means responsive to a circuit opening operation for automatically closing said contacts, fluid dashpot means for delaying separation of said contacts. a predetermined time after the occurrence of said predetermined condition, a vented chamber for receiving fluid displaced by operation of said dashpot means, one-way valve means permitting flow of displaced fluid into said chamber but preventing outflow thereof. piston means in said chamber, said piston means biased to a normal position in said chamber free of the chamber vent and from which it is advanced a predetermined amount by said displaced fluid at least on each circuit opening operation of the breaker, said piston means being advanced sufliciently to restrict said chamber vent on a predetermined circuit opening operation in any series of closely successive circuit opening operations, and means responsive to still further advancement of said piston means for terminating such a series of operations.

6. An automatic reclosing circuit breaker comprising separable contacts, means responsive to a predetermined condition of the circuit for causing separation of said contacts to open the circuit, means responsive to a circuit opening operation for automatically closing said contacts, fluid dashpot means for delaying separation of said contacts a predetermined time after the occurrence of said predetermined condition, a vented chamber for receiving fluid displaced by operation of said dashpot means, piston means in said chamber, said piston means biased to a normal position in said chamber free of the chamber vent and from which it is advanced a predetermined amount by said displaced fluid at least on each circuit opening operation of the breaker, said piston means being advanced sufiiciently to restrict said chamber vent on a predetermined circuit opening operation in any series of closely successive circuit opening operations, means responsive to still further advancement of said piston means for terminating such a series of operations, and check valve means permitting flow of said displaced fluid solely in a direction into said chamber.

'7. An automatic reclosing circuit breaker comprising, separable contacts, means responsive to a predetermined condition of the circuit for causing separation of said contacts to open the circuit, means responsive to a circuit opening operation for automatically closing said contacts, fluid dashpot means for delaying separation of said contacts a predetermined time after the occurrence of said predetermined condition, a vented chamber for receiving fluid displaced by operation of said dashpot means, one-way valve means permitting flow of displaced fluid into said chamber but preventing outflow thereof, piston means in said chamber, saw piston means biased to a normal position in said chamber from which it is advanced a predetermined amount by said displaced fluid at least on each circuit opening operation of the breaker, said piston means having a portion normally spaced from the chamber vent but adapted to enter said chamber vent when said piston means is advanced an amount determined by a predetermined circuit opening operation in any series of closely successive circuit opening operations to delay the next opening operation of such a series of operations, and means positioned to be engaged by said portion when advanced a predetermined further amount to prevent reclosure of said contacts.

8. An automatic reclosing circuit breaker comprising, separable contacts, means responsive to a predetermined condition of the circuit for causing separation of said contacts to open the circuit, means responsive to a circuit opening operation for automatically closing said contacts, fluid dashpot means for delaying separation of said contacts a, predetermined time after the occurrence of said predetermined condition, vent means for said dashpot means normally freely passing an amount of fluid equal to that displaced by said dashpot means during a circuit opening operation, a member which is advanced a predetermined amount from a normal position in response to each circuit opening and closing cycle of operation of the breaker, said member being biased to return to its normal position and having means for delaying such return movement, vent opening and closing means operated by said member for altering the time characteristic of successive circuit opening operations, and means responsive to advancement of said member a greater amount for terminating such a. series of operations.

JAMES M. WALLACE. EARL F. BEACH.

REFERENCES CITED UNITED STATES PATENTS Name Date Scott Feb. 25, 1930 Number