US3523261A - Current limiting circuit breakers - Google Patents

Current limiting circuit breakers Download PDF

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Publication number
US3523261A
US3523261A US701721A US3523261DA US3523261A US 3523261 A US3523261 A US 3523261A US 701721 A US701721 A US 701721A US 3523261D A US3523261D A US 3523261DA US 3523261 A US3523261 A US 3523261A
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United States
Prior art keywords
contact
contacts
circuit breaker
arm
current
Prior art date
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Expired - Lifetime
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US701721A
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English (en)
Inventor
Achille Bianchi
Angelo Mostosi
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CHALLENGER ACQUISITION Corp
CHALLENGER DPT Corp
CHALLENGER FUSE Corp
CHALLENGER LIC Corp
PROVIDENT INDUSTRIES Inc
Original Assignee
Federal Pacific Electric Co
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Publication of US3523261A publication Critical patent/US3523261A/en
Assigned to CHALLENGER ACQUISITION CORPORATION, CHALLENGER DPT CORPORATION, CHALLENGER FUSE CORPORATION, CHALLENGER LIC CORPORATION reassignment CHALLENGER ACQUISITION CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: FEDERAL PACIFIC ELECTRIC COMPANY
Anticipated expiration legal-status Critical
Assigned to PROVIDENT INDUSTRIES, INC. reassignment PROVIDENT INDUSTRIES, INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: AMERICAN CIRCUIT BREAKER CORPORATION, FORMERLY AMERICAN PROPERTIES CORPORATION, BY WHEELER FINANCIAL SERVICES, AS TRUSTEE
Assigned to PROVIDENT INDUSTRIES, INC. reassignment PROVIDENT INDUSTRIES, INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: AMERICAN CIRCUIT BREAKER CORPORATION BY WHEELER FINANCIAL SERVICES, TRUSTEE
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H73/00—Protective overload circuit-breaking switches in which excess current opens the contacts by automatic release of mechanical energy stored by previous operation of a hand reset mechanism
    • H01H73/02—Details
    • H01H73/18—Means for extinguishing or suppressing arc
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/04—Means for indicating condition of the switching device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H77/00—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting
    • H01H77/02—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism
    • H01H77/10—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism with electrodynamic opening
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/04—Means for indicating condition of the switching device
    • H01H2071/046—Means for indicating condition of the switching device exclusively by position of operating part, e.g. with additional labels or marks but no other movable indicators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10—Operating or release mechanisms
    • H01H71/12—Automatic release mechanisms with or without manual release
    • H01H71/24—Electromagnetic mechanisms
    • H01H71/2418—Electromagnetic mechanisms combined with an electrodynamic current limiting mechanism
    • H01H2071/2427—Electromagnetic mechanisms combined with an electrodynamic current limiting mechanism with blow-off movement tripping mechanism, e.g. electrodynamic effect on contacts trips the traditional trip device before it can unlatch the spring mechanism by itself
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10—Operating or release mechanisms
    • H01H71/50—Manual reset mechanisms which may be also used for manual release
    • H01H71/505—Latching devices between operating and release mechanism
    • H01H2071/507—Latching devices between operating and release mechanism being collapsible, e.g. yielding elastically, when the opening force is higher than a predetermined value
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/74—Means for adjusting the conditions under which the device will function to provide protection
    • H01H2071/7481—Means for adjusting the conditions under which the device will function to provide protection with indexing means for magnetic or thermal tripping adjustment knob
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2300/00—Orthogonal indexing scheme relating to electric switches, relays, selectors or emergency protective devices covered by H01H
    • H01H2300/046—Orthogonal indexing scheme relating to electric switches, relays, selectors or emergency protective devices covered by H01H using snap closing mechanisms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H2300/00—Orthogonal indexing scheme relating to electric switches, relays, selectors or emergency protective devices covered by H01H
    • H01H2300/046—Orthogonal indexing scheme relating to electric switches, relays, selectors or emergency protective devices covered by H01H using snap closing mechanisms
    • H01H2300/048—Snap closing by latched movable contact, wherein the movable contact is held in a minimal distance from the fixed contact during first phase of closing sequence in which a closing spring is charged
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10—Operating or release mechanisms
    • H01H71/50—Manual reset mechanisms which may be also used for manual release
    • H01H71/504—Manual reset mechanisms which may be also used for manual release provided with anti-rebound means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10—Operating or release mechanisms
    • H01H71/50—Manual reset mechanisms which may be also used for manual release
    • H01H71/52—Manual reset mechanisms which may be also used for manual release actuated by lever
    • H01H71/522—Manual reset mechanisms which may be also used for manual release actuated by lever comprising a cradle-mechanism
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10—Operating or release mechanisms
    • H01H71/50—Manual reset mechanisms which may be also used for manual release
    • H01H71/52—Manual reset mechanisms which may be also used for manual release actuated by lever
    • H01H71/522—Manual reset mechanisms which may be also used for manual release actuated by lever comprising a cradle-mechanism
    • H01H71/525—Manual reset mechanisms which may be also used for manual release actuated by lever comprising a cradle-mechanism comprising a toggle between cradle and contact arm and mechanism spring acting between handle and toggle knee
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H77/00—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting
    • H01H77/02—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism
    • H01H77/10—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism with electrodynamic opening
    • H01H77/102—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism with electrodynamic opening characterised by special mounting of contact arm, allowing blow-off movement
    • H01H77/104—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism with electrodynamic opening characterised by special mounting of contact arm, allowing blow-off movement with a stable blow-off position

Definitions

  • a circuit breaker with high interruption capacity is realized by utilizing an electromagnetic loop that expands instantly when high current develops, to part the contacts initially and to cause continued contact-opening motion to full fault-current interruption. Responsiveness to the electrodynamic force is preserved and adequately large contacts are utilized -without the corresponding consequence of contact-parting bounce at the instant of closing, by providing a gradual contact-closing operation that is completed with a short, sudden motion.
  • the contact which is operated With minimum bounce to close the circuit breaker is also the contact that is moved electrodynamically to open the breaker; and in this construction the electrodynamic force unlatches the breaker-opening mechanism.
  • one contact is actuated to close the contacts and the companion contact is electrodynamically operable for opening the circuit breaker.
  • the present invention relates to circuit breakers.
  • An object of this invention is to provide circuit breakers of novel construction having relatively high interruption capacity. This capacity is needed where the circuit breaker is connected to an electric bus or cable that is capable of delivering extremely high levels of current under shortcircuit conditions.
  • a further object of the invention is to provide novel circuit breakers Which can be made in comparatively small physical pr-oportions, which are nevertheless capable of interrupting remarkably high currents in case of shortcircuit.
  • a still further object of the invention is to provide a novel circuit breaker which will open and safely clear the circuit in response to severe short-circuit, where the shortcircuit exists at the time that the circuit breaker is closed, and also in response to a short-circuit that occurs at some time after the circuit breaker is closed.
  • the invention has broad application, but it is particularly applicable to circuit breakers of the class having an enclosure of molded insulation. Furthermore, it is particularly applicable to so-called low-voltage circuit breakers, that is, circuit breakers rated at 6010- volts or less.
  • the novel circuit breakers can be constructed in various physical sizes and with various Operating mechanisms, to open automatically when the current exceeds the overload calibration.
  • Such a circuit breaker may be rated at any value, usually at a value in the range of 15 amperes to 1,.200' amperes.
  • These circuit breakers (of whatever current rating) should have a vastly greater current-interruption capacity.
  • the blow-off current path includes a current loop which tends to expand mechanically When a short-circuit occurs and this elfect is used to cause instant separation of the contacts.
  • the high-speed blow-off contact-opening feature is an important factor in providing current-limiting 'Characteristics. Where the circuit breaker opens the circuit fast enough, in a properly proportioned arc chute, the rise of current is limited to only a fraction of the current capacity of the bus. The interruption process is made much easier than in circuit breakers that do not limit the rise of current.
  • the tendency of the loop to expand is due to the electrodynamic force that develops at the instant that a short circuit occurs. This effect is utilized to cause opening of the contacts under short-circuit conditions.
  • bouncing of the contacts would interfere with the sudden increase in current in case a shortcircuit exists at the time the circuit breaker is closed, and interference with the current rise would interfere with the electrodynamic contact-opening force that is needed to limit the rise of current.
  • the novel circuit breakers are operated into closed position with firm closing force by a mechanism that operates the -moving contacts gradually through most of the closing stroke, followed by a sudden short motion that completes the closing of the contacts, without interfering with the electrodynamic contact-opening feature.
  • circuit breakers described below is especially adapted to operate at relatively high rated-current levels, and to -withstand particularly high short-circuit current levels.
  • the contact Structures and the electrodynamic release mechanism in this circuit breaker for causing the contacts to open involve further novel features of the invention.
  • the moving contact is made of two parts, a main contact part and an arcing contact part.
  • the main contact part When the circuit breaker is in its closed condition, the main contact part is pressed firrnly against the companion contact.
  • the electrodynamic force developed by the reversecurrent loop acts to lift the main contact part. High contact pressure is maintained and even increased at the arcing contact part.
  • the arrangement is such that the arcing contact will not break the circuit unless the electrodynamic force is great enough to release a latch which restrains a spring-biased contact-opening mechanism. When the mechanism is released, the circuit breaker opens at high speed, far enough to clear the circuit.
  • the electrodynamic force first unlatches the contact-opening mechanism and then the electrodynamic force directly increases the contact-opening force of the contact-opening spring. Because the arcing contacts remain closed until the opening mechanism is unlatched there is no possibility of small arcs developing between contacts that open slightly and then close again. Without this feature, such a condition could exist in case of large currents that are not large enough to release the opening mechanism. The arcing could damage the contact surfaces, and could result in the contacts becoming welded together.
  • Circuit breakers of this construction operate in the contact opening direction With a great deal of speed.
  • moving contact structures of such crcuit breakers are massive when designed to carry high currents.
  • a massive moving contact structure having a high contact-opening speed normally tends to rebound powerfully in the contact-closing direction as soon as it reaches the limit of the opening motion.
  • a further features of this invention resides in providing a simple, effective and reliable antirebound latch for the moving contact structure.
  • FIG. 1 is a lateral cross section through the center pole of a multipole circuit breaker involving one embodiment of certain features of the invention, the crcuit breaker being shown With the contacts open;
  • FIG. 2 is a fragmentary cross section of the crcuit breaker in FIG. 1 With the contacts shown closed, and With antirebound latching parts shown in broken lines to represent an instantaneous relationship thereof during opening of the breaker;
  • FIG. 3 is another fragmentary cross sectional view of the crcuit breaker in FIG. l illustrating certain parts while under the influence of electrodynamic force and including a manual operating lever in broken lines;
  • FIG. 4 is a plan view, partly in cross section, of a second circuit breaker constituting another illustrative embodiment of certain aspects of the invention.
  • FIG. 5 is a vertical cross section of the circuit breaker viewed from the plane 5-5 in FIG. 4 with portions thereof shown in broken lines to illustrate the positions thereof assumed during a short-crcuit interrupting operation;
  • FIG. 6 is a bottom view of the crcuit breaker in FIGS. 4 and 5 as seen with a cover removed;
  • FIG. 7 is a lateral view of the Operating mechanism as viewed from the plane 7-7 in FIG. 5.
  • the crcuit breaker shown in FIGS. 1 to 3 includes an enclosure or case formed of parts of molded insulation including parts 10 and 12.
  • Part 10 contains an arc chute 14 which has side walls 16 and end wall 18 of fibre or other suitable arc resistant insulating material, supporting an assembly of V-notched arc splitter plates 19 of magnetizable metal.
  • the arc chute and part 10' of the molded enclosure have a vent opening 20 Which is shielded by a wire-mesh barrier 22 Secured in grooves in molded part 10.
  • the electric crcuit through the illustrated pole of the crcuit breaker includes a terminal 24 and an elongated conductor 26 carrying stationary contact structure 27 comprising stationary main contact 28 and stationary arcing contact 30.
  • Arcing horn 32 extends from contact 30 into arc chute 14.
  • Movable contact member 34 yincludes a main contact part 36 and an arcing contact part 38.
  • Elements 28, 30, 36 and 38 are of suitable material such as silver-tungsten.
  • a flexible elongated conductor 40* as of laminated copper, provides a current path from movable contact member 34 to a fixed block 42, and to terminal 44.
  • a current loop is formed of conductor 40, movable contact 34, the companion contact 27 and conductor 26.
  • Conductors 26 and 40 carry currents in opposite directions, and are called reverse current paths. These parts repel each other electrodynamically when they carry current.
  • Movable contact 34 is carried by an arm or contact carrier 46 which is essentially channel shaped, opening downward. Arm 46 is pivoted on a supporting shaft 48 which extends through the side walls 50 of the channel.
  • a compression spring 52 (FIG. 2) on guide rod 57 works against pivot 56 on contact carrier 46, and the opposite end of this spring presses against a fixed pin 54.
  • Multiple Springs like spring 52 may be used at opposite sides of the mechanism, only one spring being shown. Pivot 56 of spring 52 approaches the line of centers of pin 54 and shaft 48 as the contacts close, but pivot 56 does not reach this line of centers. Spring 52 provides opening bias for arm 46 about shaft 48 when the arm is in its open position. When arm 46 is in the contacts-closed position, spring 52 is compressed further, but the opening force is not greatly increased because the line of the spring force is closed to pivot 48.
  • the Operating mechanism for arm 46 includes a link 58 having one end pivoted to arm 46 and having a pin 60 at its opposite end. Pin 60 moves in a slot 62a of another link 62. Pin 60 also carries a roller 64 (see FIG. 3).
  • a heavy triangular Operating member 66 is fixed to a stationary shaft 68 rotatably mounted in side plates 69. There are two side plates 69 at opposite sides of the mechanism. Shaft 70 extends into slots 71 in the side plates. Movement of shaft 70 to the right is limited by the right-hand ends of slots 71. Shaft 68 is rotated and member 66 is operated to the right and to the left for opening and closing the crcuit, by means that is diagrammatcally represented in FIG. 3. As shown there, a manual lever 73 has a large opening 7311. that receives shaft 70 to drive the pin in each direction. The arrangement is such that shaft 70 is not restrained and can overtravel When snapping operation occurs, as Will be described.
  • Shaft 70 connects member 66 to link 62.
  • Compression spring 72 has a guide rod 74 whose slot 74a works along fiXed pin 76.
  • Pin 78 connects the opposite end of guide rod 74 to member 66.
  • Latch member 80 is pivoted on shaft 68 and has an upper edge portion 80a (FIG. 3) that is engaged by shaft 70 in the open condition of the crcuit breaker (FIG. 1).
  • Latch member 80 has a latch portion 80c that is pressed down under a hook portion 82a. of latch 82 -when the circuit breaker is open, for relatching.
  • Latch 82 restrains latch member -80 when the crcuit breaker is closed.
  • Member "80 also has an edge 80d constituting a bearing rail for roller 64. A slight depression 80e in member 80 establishes a stable end position in the leftward travel of roller 64, so that the roller is arrested in the position illustrated in FIG. 3 when the crcuit breaker is closed.
  • Latch 82 is carried on a fixed pivot 84 and has an arm carrying a pin 86.
  • Rod 88 has a slotted upper portion which receives pin 86; best shown in FIG. 3.
  • the lower end of rod 88 is cylindrical and it is threaded, and it terminates in a slotted portion Which fits about pin 98.
  • Compression spring 90 on rod 88 is confined between pin 86 and a nut 92 adjustable on rod 88.
  • Another nut 94 on rod 88 provides an adjustable lower end for rod 88 to bear against pin 98.
  • Nuts 92 and 94 have many notches around their edges, and these nuts are held in any adjusted position by bending a tongue 96a of washer 96 into such notches.
  • Pin 98 is carried by a latch part 100 which moves about a pivot 102.
  • pin 98 is shown slightly to the right of a line between the centers of pivots 86 and 102.
  • Spring 90 normally maintains pins 98 and 86 in the extended condition illustrated so that parts 86, 88, 90, 92, 94 and 96 act as if they were a simple link under normal conditions.
  • This link transmits a force from latched member -80 pressing latch 82 clockwise (FIG. 2) to apply latch pressure of latched part 100 against latch 104.
  • latch 104 has an arm 104a that can be lifted by upward movement of bimetal 108. Independently, latch arm 104a is operable by upward movement of a rod 110 that is slidable in a bore in member 26.
  • a 4U-shaped soft iron core 114 extends across the top of conductor 26 and has downward extending legs. Opposite core 114 is a soft iron armature 112a carried by a pivoted arm 112.
  • a persistent moderate overcurrent in conductor 26 causes heating sufficient to deflect bimetal 108 upwardly for releasing latch parts 100 and 104.
  • Bimetal r108 has a support pivot 1089: and an adjusting structure 108b for externally accessible adjustment of the "thermal tripping-current level.
  • armature 112a is lifted so that pin 110 pushes arm 104a. to release latch 104 and latch parts 100 in response to magnetic tripping-current levels.
  • latch 104 swings clockwise to release latched part 100. Thereafter the parts 88-90-92-94-96-98 act as a unit to swing latch part -100 clockwise about its pivot. Release of latch 104 releases latched part 80 (FIG.
  • Moving contact 34 has two pins 120 and 124. Pin 124 is received in a pair of slots 122a in a downward-facing channel element 122. Moving contact 34 is biased down- Ward by compression spring 126. A pair of links 118 pivoted to shaft 48 support pin 120, and links 118 are arrested (against bias of spring 126) by stop 127 fixed to the side Walls 50 of downWard-facing channel 46.
  • an antirebound latch 128 is provided having a tail 128a that is struck by a hooked part 130 at the top of contact arm 46. This drives latch 128 into dotted-liue position in FIG. 2. Part 130 is hooked by latch 128 and prevents arm 46 from rebounding downward.
  • spring 133 biases tail v12811 to an advanced position as shown in solid lines in FIG. 2 slightly clockwise of the position of FIG. 1, so as to be struck by part 130 when the arm 46 comes close to its full-open position.
  • circuit breaker is operative as a single pole device or with multiple poles tied together and linked by mechanically coupled trip units, in various Ways Well known in the art.
  • the circuit breaker illustrated is of a physical design suitable for carrying large amounts of rated current, for example, 1000 amperes, and accordingly the various current carrying parts may well be relatively large and massive. Consequently, when the circuit breaker is being closed there would be a tendency of the movable contact arm to rebound after striking the companion contact structure 26. Such a rebound involves an up- Ward reaction force tending to release the latch 82 from latched part 80, in this manner simulating the electrodynamic force that develops when the circuit breaker is subjected to high levels of short-circuit current.
  • Such large impact and rebound forces are avoided here by virtue of the action of the contact-closing mechanism described above which operates in the closing direction to carry the movable contact structure gradually through most .of its Operating stroke. The completion of the closing stroke is accomplished suddenly when
  • the action of the electrodynamic force which occurs under short circuit conditions may develop at a time when the circuit breaker has been closed or it may exisit before the circuit breaker is operated to close the contacts.
  • the sudden appearance of the electrodynamic force is such that contact opening motion is extremely fast, occurring during the sudden rise of the shortcircuit current. This operation takes place within a small part of a half-wave, in the case of 60-cycle alternatingcurrent circuits.
  • current interruption occurs in such a manner as to limit the rise of current well below anything that might be expected in circuit breakers of other construction, in Which no current li-miting action occurs. As a result the interruption process does not await the normal end of the half-cycle during w-hich contact opening occurred.
  • FIGS. 4 to 7 another form of circuit breaker is shown as a second illustrative embodiment of certain features of the invention found in the circuit breaker of FIGS. 1 to 3 and including additional novel features.
  • the circuit breaker shown involves three side-by-side poles having an arc chute 200 and a pair of terminals 202 and 204 in each pole; and at one end of the unit there is an Operating mechanism generally designated 206.
  • the circuit breaker is divided into a current-interrupting unit 208 which includes the arc chutes and the separable contacts (to be described) and the Operating mechanism, plus a second unit 210 which includes the overload sensing devices for the respective poles, and a coupling arrangement to control the operating mechanism 206.
  • Section 208 includes a housing portion 212 of insulation containing an arc chute involving a fibre "wrapper 214 and a plurality of ferrous V-notched arc splitter plates 216.
  • a movable contact arm 218 is shown in its fully closed position, held in this position by shaft 220. This shaft is common to all of the poles and is insulated from each of the contact arms 218.
  • a companion contact arm 222 on pivot 224, individual to each pole, is biased by a compression coil spring 226 in the closing direction so that contacts 228 and 230 are in firm pressure contact with each other. In this condition, both contact arms 218 and 222 are out of engagement with a dividing wall 232 of insulation, integral with housing 212.
  • Coil spring 226 is guided along a metal strip 227. One end of the spring presses against a disc 227a fixed to strip 227, and the other end of spring 226 presses against bracket 229. Strip 227 slides loosely in a slot in bracket 229. The other end of strip 227 is pressed into a notch 223 in arm 222. In the closed condition of the contacts, spring 226 acts on strip 227 along a line that passes above pivot 224 and in this way spring 226 provides firm contact pressure.
  • the overload sensing structure 210 in each pole includes a bimetal 234 which moves to the right When heated by a current-carrying conductor 236 of limited cross section. An overcurrent deflects bimetal 234 to the right sufiiciently to operate trip lever 238 about common trip bar 240. This trip bar extends to the mechanism 206.
  • a magnetic core 242 having a transverse portion encircled by conductor 236 is disposed to attract an armature 243 in the event of sudden high levels of overcurrent well above the tripping level of bimetal 234. Motion of armature 243 is resisted by a coil spring 244. When there is a sufiicient overcurrent, armature 242 moves to the right and operates trip bar 240.
  • a circuit may be traced through the pole represented in FIG. 5 starting at terminal 204, through conductor 236, conductive stud 246, and a flexible conductor 248, through contact arms 218 and 222, then through flexible conductor 249, to opposite terminal 202.
  • bimetal 234 deflects trip bar 240 after a substantial delay (depending on the severity Of the overcurrent) and for higher levels of excess current, armature 243 operates trip bar 240 in the tripping direction, with faster response.
  • armature 243 drives trip bar 238 in the direction to release the Operating mehcanism of contact arm 218, and this arm moves to its dotted-line position. This occurs after a short delay following the high-speed motion of contact arm 222.
  • the great separation between contact arms 218 and 222 in their dotted-line positions provides a further guarantee that any persisting arc will be interrupted.
  • FIGS. 5 to 7 show the Operating mechanism for contact arm 218, and also show two additional features, (1) the mechanism for resetting arms 222 to prepare the circuit breaker for reclosing, and (2) a mechanical arrangement for tripping the circuit breaker in case any arm 222 is opened electrodynamically.
  • Each of the contact-carrying arms 222 has an extension 222a acting on an insulating material plate 250 (FIG. 6) which is freely slidable between the rollers 256, the latter being pivoted on fixed aXes, and guided by flat surfaces 262 and 264.
  • Said plate 250 has a slot 2S0a receiving the extension 206aof the manual Operating lever of' the breaker.
  • the plate 250 by means of its extension 25017, induces the rotation of lever 252 and the latter, via a linking mechanism which is shown in FIG. 7, acts like trip bar 240 on a latching mechanism described below, and thus opens the circuit breaker.
  • the Operating mechanism is reset and, concurrently, the extension 20-6a is moved and shifts the plate 250.
  • the latter moves the extensions 222a of the contact-carrying arms 222 so that contacts 230 are brought back to their position as shown in solid lines in FIG. 5.
  • the circuit breaker cannot be closed if even a single contact of the contacts 230 is in the position indicated in dotted lines, since the two actions, relatching of the Operating mechanism and moving the contacts 230 to the position required for closing the circuit breaker take place simultaneously.
  • both the contacts 228 and 230 take the position shown in dotted lines.
  • FIG. 7 shows details of a suitable Operating mechanism for contact arms 218 on shaft 220, and for elements 206a and 252 in FIG. 6. Note that FIG. 7 shows 'the mechanism in the open condition of the 'circuit breaker.
  • Manual lever 206b has a fixed pivot 265 in metal frame 266.
  • Lever 206b drives link 268 to operate a secondary operating lever 270 about a hearing o'n shaft 220 but lever 270 does not operate shaft 220 directly.
  • FIG. 7 shows trip arm 238a that is operated by bimetal 234 or armature 243 (FIG. in case of an overload.
  • Arm 238a moves tothe right for tripping the circuit breaker, and operates secondary latch 290 on its pivot 290a, and releases latch 292 to release member 2810 in the usual manner.
  • Toggle spring 284 can then cause arm 272 to open the contacts.
  • manual level 206b is forced toward the left to operate reset pin 294 for resetting parts 280, 292 and 290 to the condition shown, the described release mechanism and contact-opening mechanism is entirely conventional.
  • FIG. 7 shows the connection of extension 206a (FIG. 6) to the manual lever 206b.
  • extension 206a moves freely in slot 250a.
  • plate 250 is shifted to the left in FIG. 7 and strikes lever 252.,This operates another lever 298, to release latch 290. So long as any arm 222 remains in its open'flposition, plate 250 and lever 252 act to prevent relatching of the circuit breaker, as previously explained in connection with FIG. 6. This arrangement prevents a dangerous condition.
  • Plate 250 is a mechancal coupling to the automatic release mechanism of the circuit breaker, and is important because it assures opening of all the contacts 228 in case of a short circuit. Plate 250 supplements the action of armature 243. In case no armature or bimetal is used, plate 250 is the only automatic control for releasing all .the contacts 228 to open when any one or more of the contacts 230 are opened electrodynamically.
  • a circuit breaker of high interrupting capacity including a pair of terminals and means including almovable contact and a companion contact providing a current path interconnecting said terminals, andmechansm for Operating the movable contact to open and close the circuit breaker, characterized in that said current path includes a blow-open loop tending instantly to enforce opening movement of one of the contacts by electrodynamic force in response to sudden high levels of current, said circuit breaker having means normally effective when the circuit breaker is closed to hold the contacts closed and said means being operable by said electrodynamic force for causing opening operation of the circuit breaker to its current-interrupting configuration, and further characterized in that said mechanism for Operating said movable contact includes means for Operating the movable contact gradually in the contact-closing direction followed by a short sudden contact-closing motion, for quickly and firmly closing the contacts with a minimum of mechancal bounce and thereby avoiding interference with the operation of the blow-open current loop.
  • An automatic circuit breaker in accordance with claim 4 including means for resetting said electrodynamically operated contacts and additionally for resetting the automatic release mechanism of the circuit breaker.
  • a circuit breaker in accordance with claim 1 including a latch having a hook portion cooperable with the moving contact structure thereof to arrest return motion thereof toward the companion contact and a biasing spring normally holding the hook portion out of such cooperation, said latch having a portion disposed to be struck by the moving contact structure as the limit of its opening motion is reached for impelling the hook portion into position to arrest the moving contact structure against said return motion.
  • a circuit breaker in accordance with claim 3 including a latch having a hook portion cooperable With the moving contact structure thereof to arrest return motion thereof toward the companion contact and a biasing spring normally holding the hook portion out of such cooperation, said latch having a portion disposed to be struck by the moving contact structure as the limit of its opening motion is reached for impelling the hook portion into position to arrest the moving contact structure against said return motion.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Breakers (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
US701721A 1967-01-30 1968-01-30 Current limiting circuit breakers Expired - Lifetime US3523261A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT1205567 1967-01-30
IT2330767 1967-11-29

Publications (1)

Publication Number Publication Date
US3523261A true US3523261A (en) 1970-08-04

Family

ID=26326460

Family Applications (1)

Application Number Title Priority Date Filing Date
US701721A Expired - Lifetime US3523261A (en) 1967-01-30 1968-01-30 Current limiting circuit breakers

Country Status (10)

Country Link
US (1) US3523261A (xx)
BE (1) BE710116A (xx)
CH (1) CH484508A (xx)
DE (1) DE1638114C3 (xx)
DK (1) DK137556B (xx)
FR (1) FR1553328A (xx)
GB (1) GB1193222A (xx)
NL (1) NL6801378A (xx)
NO (1) NO129929B (xx)
SE (1) SE348592B (xx)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1980002084A1 (en) * 1979-03-27 1980-10-02 Varian Associates Superconducting junction
US6188031B1 (en) * 1996-08-21 2001-02-13 Siemens Aktiengesellschaft Movable contact arrangement for a low-voltage circuit breaker with a pivot bearing
EP1261008A1 (en) * 2001-05-22 2002-11-27 Gewiss S.P.A. Enclosed magnetothermal electric circuit breaker
US7351927B1 (en) * 2006-10-13 2008-04-01 Eaton Corporation Electrical switch, conductor assembly, and independent flexible conductive elements therefor
US20080218296A1 (en) * 2007-03-07 2008-09-11 Weister Nathan J Electrical switching apparatus, and conductor assembly and shunt assembly therefor
WO2014044739A1 (de) * 2012-09-20 2014-03-27 Eaton Electrical Ip Gmbh & Co. Kg Kontaktsystem eines leistungsschutzschalters
CN109036985A (zh) * 2018-07-13 2018-12-18 浙江正泰电器股份有限公司 断路器
CN109950103A (zh) * 2019-04-28 2019-06-28 乐清市赛翔电气有限公司 一种断路器操作机构及断路器

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2295553A1 (fr) * 1974-12-17 1976-07-16 Saparel Appareil de coupure de courant electrique
SE448794B (sv) * 1983-07-04 1987-03-16 Asea Ab Strombegrensande elkopplare
DE3433624A1 (de) * 1984-09-13 1986-03-20 Doduco KG Dr. Eugen Dürrwächter, 7530 Pforzheim Automatisch ansprechender, strombegrenzender schalter

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3127488A (en) * 1960-07-18 1964-03-31 Ite Circuit Breaker Ltd Current limiting circuit breaker having both contacts movable
US3134879A (en) * 1962-06-20 1964-05-26 Gen Electric Electric circuit breaker with lock-open latch
FR1388664A (fr) * 1963-06-27 1965-02-12 Comp Generale Electricite Dispositif à fermeture indépendante pour appareils électriques
US3299244A (en) * 1965-10-11 1967-01-17 Ite Circuit Breaker Ltd Anti-rebound latch

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3127488A (en) * 1960-07-18 1964-03-31 Ite Circuit Breaker Ltd Current limiting circuit breaker having both contacts movable
US3134879A (en) * 1962-06-20 1964-05-26 Gen Electric Electric circuit breaker with lock-open latch
FR1388664A (fr) * 1963-06-27 1965-02-12 Comp Generale Electricite Dispositif à fermeture indépendante pour appareils électriques
US3299244A (en) * 1965-10-11 1967-01-17 Ite Circuit Breaker Ltd Anti-rebound latch

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1980002084A1 (en) * 1979-03-27 1980-10-02 Varian Associates Superconducting junction
US6188031B1 (en) * 1996-08-21 2001-02-13 Siemens Aktiengesellschaft Movable contact arrangement for a low-voltage circuit breaker with a pivot bearing
EP1261008A1 (en) * 2001-05-22 2002-11-27 Gewiss S.P.A. Enclosed magnetothermal electric circuit breaker
US7351927B1 (en) * 2006-10-13 2008-04-01 Eaton Corporation Electrical switch, conductor assembly, and independent flexible conductive elements therefor
US20080087531A1 (en) * 2006-10-13 2008-04-17 Eaton Corporation Electrical switch, conductor assembly, and independent flexible conductive elements therefor
US20080218296A1 (en) * 2007-03-07 2008-09-11 Weister Nathan J Electrical switching apparatus, and conductor assembly and shunt assembly therefor
US7646269B2 (en) * 2007-03-07 2010-01-12 Eaton Corporation Electrical switching apparatus, and conductor assembly and shunt assembly therefor
CN101303946B (zh) * 2007-03-07 2013-06-05 伊顿公司 电气开关装置及其导体组件和分流器组件
WO2014044739A1 (de) * 2012-09-20 2014-03-27 Eaton Electrical Ip Gmbh & Co. Kg Kontaktsystem eines leistungsschutzschalters
CN109036985A (zh) * 2018-07-13 2018-12-18 浙江正泰电器股份有限公司 断路器
CN109950103A (zh) * 2019-04-28 2019-06-28 乐清市赛翔电气有限公司 一种断路器操作机构及断路器
CN109950103B (zh) * 2019-04-28 2023-10-31 乐清市赛翔电气有限公司 一种断路器操作机构及断路器

Also Published As

Publication number Publication date
BE710116A (xx) 1968-05-30
DE1638114B2 (de) 1973-03-01
FR1553328A (xx) 1969-01-10
DK137556C (xx) 1978-09-04
NL6801378A (xx) 1968-07-31
CH484508A (de) 1970-01-15
GB1193222A (en) 1970-05-28
SE348592B (xx) 1972-09-04
DE1638114C3 (de) 1979-09-13
DE1788148A1 (de) 1973-05-24
DE1788148B2 (de) 1976-01-29
NO129929B (xx) 1974-06-10
DE1638114A1 (de) 1971-05-27
DK137556B (da) 1978-03-20

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