US3813619A - Current-limiting circuit breaker - Google Patents

Current-limiting circuit breaker Download PDF

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Publication number
US3813619A
US3813619A US00195739A US19573962A US3813619A US 3813619 A US3813619 A US 3813619A US 00195739 A US00195739 A US 00195739A US 19573962 A US19573962 A US 19573962A US 3813619 A US3813619 A US 3813619A
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US
United States
Prior art keywords
contact carrier
contacts
movable
circuit breaker
current
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00195739A
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English (en)
Inventor
L Koval
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co
Original Assignee
General Electric Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Priority to US00195739A priority Critical patent/US3813619A/en
Priority to GB16880/63A priority patent/GB1016216A/en
Priority to ES287634A priority patent/ES287634A1/es
Priority to CH623563A priority patent/CH416796A/de
Priority to FR935217A priority patent/FR1362756A/fr
Priority to DE19631463190 priority patent/DE1463190B2/de
Priority to US05/414,648 priority patent/US3935409A/en
Application granted granted Critical
Publication of US3813619A publication Critical patent/US3813619A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • 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
    • H01H73/48—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 having both electrothermal and electromagnetic automatic release
    • H01H73/50—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 having both electrothermal and electromagnetic automatic release reset by lever

Definitions

  • a circuit breaker including means for causmg opening [58] Field of Search ZOO/88.9, 87.9, 87.3, 109, of the circuit therethrough p h occurrence f 200/ 147, 144, 106, 146 R; 335/16; 17, 18, overload current conditions existing for a predeter- 19, 20, 158, 35 6 195 mined time, and (2) minor short-circuit conditions, and also including means providing a current-limiting [56'] References Cited action upon the occurrence of predetermined shortcircuit conditions above'a predetermined level.
  • circuit breakers While prior art circuit breakers have included means for causing automatic opening on the occurrence of either of the aforesaid two types of abonorrnal current conditions, such circuit breakers have not been capable of providing a current-limiting action on theoccurrence of extremely high short-circuit currents.
  • the term.current-limiting is used to mean that the electric current is not permitted to rise to the levels to which it would otherewise rise if the only impedance elements in the ,circuit'were the source impedance and the normal impedance of the circuit breaker itself. Such level may be referred to as the peak of the prospective short-circuit current.
  • the only elements tending .to limit the rise of electric current in the circuit are the impedance of the source, the impedance of the lines connecting the source to the circuit breaker, and the impedance of the circuit breaker itself, including the impedance, if any, of arcs drawn by the circuit breaker in the time which the current requires to rise to its potentially highest value.
  • Electric circuitbreakers of known prior art construction include automatic opening means which involves parts having a mass or weight such that movement thereof at a speed sufficiently high to introducea true current-limiting'action is not possible.
  • circuit breakers of medium and high current capacity such as 800-1 ,000 amperes or more, which require high contactpressure, with correspondingly large and heavy operating mechanisms.
  • It is an' object "of the present invention to provide an electric circuit breaker of medium of high capacity including thermal and magnetic means for causing automatic opening of the circuit breaker upon the occurrence of overload current conditions of predetermined magnitude and of electrical short-circuit conditions of predetermined magnitude, and also including means providing a current-limiting action upon the occurrence of predetermined short-circuit current conditions above a predetermined magnitude.
  • electric circuit breaker including contacts which are movable upon the occurrence of extremely high shortcircuit currentconditions without requiring movement of other'mechanism parts having anextremely high inertia.
  • an electric circuit breaker including relatively movable contacts and manually operable operating mechanism for operating such contacts betweenopen" and closed tripping circuit conditions.
  • Currentresponsive means is also provided for moving the contacts to open position upon the occurrence of either sustained minor overload conditions or minor shortcircuit conditions.
  • means for instantaneously causing relative opening movement of such contacts upon the occurrence of high short-circuit conditions is accomplished by movement of one or more of such contacts per so, without requiring movement of the main operating mechanism.
  • the contact so moved is mechanically held in its instantaneously opened position at least until the main operating mechanism has had time to move to its automatically-opened position following operation of its current-responsive tripping means.
  • FIG. 1 is a side elevation view, partly in section, of an electric circuit breaker in accordance with the invention, shown in the normal OFF condition;
  • FIG. 2 is a view similar to FIG. 1, the parts being shown in ON position;
  • FIG. 3 is an elevation view of a portion of the circuit breaker of FIG. 1, the parts being shown in a transient position, illustrating the current-limiting action, and
  • FIGS. 4 and 5 are representationsin graph form of current conditions which may be expected to exist in circuit breakers in accordanc'e'with the prior art, and in circuit breakers incorporating the present invention, under short-circuit conditions.
  • the invention is shown as incorporated in an electric circuit breaker comprising an insulating enclosure having a base 10 and a cover 11.
  • An incoming or line lug or cable connector 12 is fixedly mounted on the base 10 by suitable means, not shown, and is conductively connected to an elongated line terminal strap.
  • the line terminal 13 has an upright conductive member 14 attached thereto adjacent its inner end, having an extension 15 extending parallel to the terminal strap 13'.
  • the extension 15 is connected by a flexible conductor member 16 to a first movable contact arm 17, having a first movable contact member 18 supported on a contact support 18A.
  • the movable contact 18 is adapted to engage a second movable contact member 19 carried by a bridging contact carrier 20.
  • the contact carrier 20 has a third movable contact member 21 mounted thereon and .adapted to engage a fourth movable contact ,22-
  • the movable contact 22 is supported by a Contact support 22A on a second-contact arm 23.
  • the contact arm 23 is connected by a flexible conductor .24 to a conductive member 25, shown partially broken away, which is connected to an upright conductive member, not shown, which in turn is connected to an outgoing terminal strap 27.
  • the outgoing terminal strap 27, at its outer end, is connected to an outgoing or load terminal member.28.
  • the flexible conductor 16 connecting the contact arm 17 and the conductivemember 15 is vshunted by a pair of contacts 29,30, which in the closed condition of the circuit breaker serve to carry a portion of the current in parallel with the conductor 16 in a manner to be described.
  • the flexible conductor 24 has a pair of .contacts 31, 32 in parallel therewith and serv- .ing to carry a portion of the current from the contact arm 23 to the connective member 25 in closed condition of the circuit breaker.
  • the provision of the supplementary contacts 31, 32 and 29, 30, makes possible the use of lighter flexible connectors 24, 16, respectively than would otherewise be required, since a large portion of the current is carried by the contacts rather than the flexible conductor. At the same time,'arcing be tween the contacts 31, 32, when opening, is avoided by the presence of the flexible connectors conductors l6 and 24.
  • the movable contact carrier 20 is movable in rier 20 from the OFF position as shown in FIG. 1 to the ON position as shown in FIG. 2, mechanism is provided including a pivotally supported manually engageable handle member 34 rigidly carried by a-handle support member 35 pivotally supported in the cover 11 on a pivot pin 36 in the cover 11.
  • the handle support member 35 has an actuating cam member 37 pivotally supported thereon at 38 at one end, and having a releasable engagement with a pivotally supported latch member 39 at the other end.
  • the latch member 39 is supported ona pivot pin 40 on the handle support member 35, and is constantly biased to the latching position as shown in FIG. 1 by suitable spring means, not shown.
  • thecam member 37 engages a roller member 41 supported at 42 on the contact carrier 20, and earns the contact carrier 20 downwardly against the force of the compression spring 33.
  • the movablev contact arm 23 is resiliently and floatingly supported, being guided laterally. by suitable guide portions, and pivotally supported on a. pivot pin 43, extending through an elongated slot 44 in the contact arm.
  • a compression spring 45 is seated in a recess 46 in the base 11 and urges the left-hand end of the contact arm 23 upwardly.
  • a second compression spring 47 seated in a recess 48, engages the forward end of the contact arm 23 and urges it upwardly against a stop portion 49 of a catch member 50 'pivotally supported on a pin 51 in the base 11, for a purpose to be described.
  • the movable contact arm 17 is similarly pivotally supported on a pivot pin 52 extending through an elongated slot 53 in the contact arm.
  • a compression spring 54 is seated in a recess 55 of the base 11 and urges the right-hand portion of thecontact arm 17 upwardly as shown.
  • a second compression spring 56 is seated in a recess 57 and urges the left-hand end of the contact arm 17 upwardly as shown.
  • the contact arm 17 is adapted to be held in a depressed condition by means of a lever 61 which is pivotally supported on a pivot pin 58, and which is urged in a clockwise direction by a strong compression spring 61B.
  • the right-hand end 61A of the lever 61 engages the left-hand end of the movable contact 17 and depresses it to the position shown when the contact carrier 20 is in the upward position.
  • a latch member 59 is also provided, likewise pivoted on the pin 58, and having a first shoulder portion 60 adapted to overly the end of the contact arm 17 when the arm 17 is in depressed condition as shown in FIG. 1.
  • an elongated pivoted latch member 62 is provided, pivotally supported at 63 on a support bracket 64 rigidly attached to the base 11 by suitable means such as by bolt 65.
  • the latch 62 is resiliently biased to vertical, latching, position as shown in FIG. 1 by means of a compression spring 66.
  • the contact carrier 20 is provided with a catch projection 69 for cooperation with the latch 62.
  • an elongated tripping rod 67 is provided, slidably engaging a projection 68 on the latch member 62.
  • the parts are moved from the OFF position as shown in FIG. 1 to the ON position as shown in FIG. 2 in the following manner.
  • the handle member 34 is moved clockwise from the position shown in FIG. 1, causing the cam 37 to engage the roller 41 of the contact carrier 20, thereby depressing the contact carrier 20 against the force of the compression spring 33.
  • the contact carrier 20 In its continued downward movement, the contact carrier 20, through the agency of a projection 70, engages the end of the lever 61, depressing it against the force of the spring 59, and lifting the right-hand end 57A away from the movable contact member 17.
  • the circuit breaker has not yet closed at this point.
  • a further amount of remaining clockwise travel of the handle 34 causes aprojection 35A of the handle support 35 to engage an end of a lever 73 pivotally supported at 74 in the casing cover 11.
  • the lever 73 has an engagement, at an intermediate point thereof, with a vertically extending rod 75 slidably supported in a bracket 76 carried by the cover 11.
  • tripping means including a generally ring-shaped magnetic core member 80 through which the load terminal strap 27 projects.
  • the core 80 carries a short-circuited turn or loop 81 of highly conductive material such as copper.
  • a thermally responsive bimetallic strip 82 is rigidly attached to the member 81 at one side thereof by suitable means such as by brazing, and carries an adjusting or calibrating screw 83 at the outer end thereof.
  • the terminal strap 27 acts as a primary winding for the mag netic core 80, and the member 81 acts as a shortcircuited secondary winding on the same core 80.
  • a high current through the terminal strap 27, therefore induces currents in the secondary turn 81.
  • the current in the secondary'turn 81 causes heat therein, which is transmitted by conduction to the bimetallic strip 82.
  • the bimetallic strip 82 is disposed and arranged to warp toward the right as viewed in FIG. 1 upon the occurrence of predetermined high current conditions through the circuit breaker, and to engage the upper end of a trip bar 84 pivotally supported at 85 in the casing cover 11.
  • the magnetic core member 80 is provided with a pair of pole extensions 90, only one shown.
  • the pole extensions 90 include secondary extensions 91 which serve as a stop to limit counterclockwise rotation of the armature portion 86.
  • the secondary extensions 91 also serve as back drag" magnetic poles, serving normally to retain the armature86 in the position shown in FIG. 1 until certain predetermined high current conditions occur.
  • the armature 86 Upon the occurrence of predetermined high short-circuit current conditions, the armature 86 is attracted to the main pole portions 90, thereby rotating in a clockwise direction about the pivot 85, and moving the trip rod 67 to the left as viewed, causing tripping.
  • CURRENT-LIMITING ACTION For the purpose of providing ultra-rapid opening-action of the contacts in response to exceptionally high short-circuit conditions, so :as to provide a currentlimiting action, there is provided, in accordance with the invention, means for causing an initial separation of the contacts prior to movement of the main contact carrier 20.
  • means for causing an initial separation of the contacts prior to movement of the main contact carrier 20 For this purpose, there is provided, surrounding each of the movable contact arms 17 and 23 respectively, a stationary magnetic core member 95, 96, respectively.
  • the contact arm "17 is provided with an armature member '97 rigidly attached thereto by 23 is provided with an annature member 98 rigidly attached thereto by similar means.
  • each of the arrnatures 97 and 98 is drawn to its corresponding magnetic time member 95, 96, thereby moving the corresponding contact arm 17, 23, downwardly, moving the movable contacts 18 and 22 to a downwardly retracted open position, as shown in FIG. 3.
  • the contact arms 17 and 23 are drawn downwardly in this manner, they are engaged and latched in depressed position by the latches 59 and 50, respectively. This action takes place irrespective of, and ordinarily precedent to, automatic opening of the main mechanism, including the movable contact rnember 20.
  • each of the magnetic assemblies is provided with two turns energizing it.
  • the terminal strap 13 extends through the magnetic member 95, and from thence the current path is through the vertical member 14 to the horizontal member 15 through the flexible conductor 16 to the contact .arm 17, which again passes through the magnetic member 95.
  • two energizing turns are pro vided between the magnetic field piece and the armature 97.
  • the main contact carrier 20 being unlatched, moves to'its upward or tripped position, as shown in FIG. 1.
  • the contact arms 17 and 23, and their associated contacts 18 and 22 are drawn downwardly as shown in FIG. 3, electric arcs are drawn between the pairs of contacts 18, 19, and 21, 22.
  • the graph of FIG. 4 shows typical current conditions during interruption of a full-symmetrical short-circuit.
  • the graph of FIG. -5 shows typical current conditions during interruption of a full-symmetrical short-circuit.
  • Curve A in each of these graphs represents the value of actual current which may be expected to occur when the interruption is by means of conventional prior art circuit breaker.
  • Curve B in each of these graphs represents the value of actual current when the interruption is by means of a current-limiting circuit breaker in accordance with the present invention.
  • the total circuit opening time in the case of'a conventional circuit breaker, may be expected to be anywhere from 16 to 28 microseconds. In the case of the current-limiting circuit breaker, such arcing time is reduced to from 8.33 to l4 micro-seconds. More significantly, total arcing time is proportionally reduced.
  • the breaker may be used in a power system which has a short-circuit capacity greater than the interrupting capacity of the basic breaker, i.e., the breaker without the current-limiting feature.
  • the handle member 34 In order to go from the ON position shown in FIG. 2 to the OFF position'shown in FIG. 1 by manual operation, the handle member 34 is moved in counterclockwise direction. During this movement the roller member 358 is moved over the shoulder 100 of the member 101 against the bias of the spring 101A. F urther counter-clockwise movement of the handle 34 causes the roller 353 to engage the shoulder portion 110A of the lever 110. This causes the lower end of the lever 110 to engage the head portion of a plunger 111. The plunger 111 engages a bell-crank 112 which includes a portion engaging a stop 113 carried by the trip rod 67. This moves the trip rod 67 to the left, and moves the latch member 62 to disengaged position, permitting the contact carrier 20 to move to opencircuit position under the influence of the compression spring 33. The parts thereupon move to the OFF position as shown in FIG. 1.
  • the parts are in the condition as shown in FIG. 3, in which the contact arms 17 and 23 are locked in a depressed condition by the latch members 50 and 59.
  • the handle member In order to reclose the circuit breaker, the handle member must first be moved to reset position. To do this, the handle member 34 is moved to the fully counterclockwise position, permitting the cam member 37 to be reset on the latch member 39. To reclose the breaker, the handle is again rotated in clockwise direction, forcing the contact carrier 20 downwardly against the bias of the spring 33.
  • An electric circuit breaker comprising:
  • each of said relatively stationary contacts being carried by a separate second contact carrier member pivotally mounted in said enclosure,
  • latch means for latching said second contact carrier members in position away from said movable contacts when moved thereto by said electromagnetic means at least until said current responsive means has operated to cause automatic opening movement of said movable contact carrier.
  • said second contact carrier members each comprise an elongated member extending parallel to said movable contact carrier member and in a direction away from the space between said stationary contacts.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Breakers (AREA)
  • Emergency Protection Circuit Devices (AREA)
US00195739A 1962-05-18 1962-05-18 Current-limiting circuit breaker Expired - Lifetime US3813619A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US00195739A US3813619A (en) 1962-05-18 1962-05-18 Current-limiting circuit breaker
GB16880/63A GB1016216A (en) 1962-05-18 1963-04-30 Improvements in current-limiting circuit breakers
ES287634A ES287634A1 (es) 1962-05-18 1963-05-03 Perfeccionamientos introducidos en los disyuntores de circuitos eléctricos
CH623563A CH416796A (de) 1962-05-18 1963-05-17 Strombegrenzungsschalter
FR935217A FR1362756A (fr) 1962-05-18 1963-05-17 Disjoncteur à limitation de courant
DE19631463190 DE1463190B2 (de) 1962-05-18 1963-05-17 Selbstschalter mit thermischer magnetischer und schnellaus loesung
US05/414,648 US3935409A (en) 1962-05-18 1973-11-12 Current-limiting circuit breaker

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00195739A US3813619A (en) 1962-05-18 1962-05-18 Current-limiting circuit breaker

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US05/414,648 Division US3935409A (en) 1962-05-18 1973-11-12 Current-limiting circuit breaker

Publications (1)

Publication Number Publication Date
US3813619A true US3813619A (en) 1974-05-28

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Application Number Title Priority Date Filing Date
US00195739A Expired - Lifetime US3813619A (en) 1962-05-18 1962-05-18 Current-limiting circuit breaker

Country Status (5)

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US (1) US3813619A (de)
CH (1) CH416796A (de)
DE (1) DE1463190B2 (de)
ES (1) ES287634A1 (de)
GB (1) GB1016216A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3959753A (en) * 1974-01-25 1976-05-25 Westinghouse Electric Corporation Circuit interrupter with load side short circuit
US3991391A (en) * 1974-01-29 1976-11-09 Westinghouse Electric Corporation Circuit interrupter with electromagnetic opening means
US4031492A (en) * 1975-08-22 1977-06-21 Westinghouse Electric Corporation Triple break current limiter
US4039983A (en) * 1975-08-26 1977-08-02 Merlin Gerin High-speed high-current circuit interrupter having electrodynamically operated arcing contacts

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1043840A (en) * 1974-04-29 1978-12-05 Square D. Company Current limiting circuit breaker

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1724840A (en) * 1926-03-26 1929-08-13 Gen Electric Circuit maker and interrupter
US2025697A (en) * 1933-04-22 1935-12-24 Westinghouse Electric & Mfg Co Circuit interrupter
US2874247A (en) * 1953-03-13 1959-02-17 Ite Circuit Breaker Ltd Circuit breaker trip mechanism
US3012118A (en) * 1958-10-29 1961-12-05 Ite Circuit Breaker Ltd Current limiting circuit breaker
US3127488A (en) * 1960-07-18 1964-03-31 Ite Circuit Breaker Ltd Current limiting circuit breaker having both contacts movable
US3136921A (en) * 1957-12-10 1964-06-09 Westinghouse Electric Corp Circuit breakers

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1724840A (en) * 1926-03-26 1929-08-13 Gen Electric Circuit maker and interrupter
US2025697A (en) * 1933-04-22 1935-12-24 Westinghouse Electric & Mfg Co Circuit interrupter
US2874247A (en) * 1953-03-13 1959-02-17 Ite Circuit Breaker Ltd Circuit breaker trip mechanism
US3136921A (en) * 1957-12-10 1964-06-09 Westinghouse Electric Corp Circuit breakers
US3012118A (en) * 1958-10-29 1961-12-05 Ite Circuit Breaker Ltd Current limiting circuit breaker
US3127488A (en) * 1960-07-18 1964-03-31 Ite Circuit Breaker Ltd Current limiting circuit breaker having both contacts movable

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3959753A (en) * 1974-01-25 1976-05-25 Westinghouse Electric Corporation Circuit interrupter with load side short circuit
US3991391A (en) * 1974-01-29 1976-11-09 Westinghouse Electric Corporation Circuit interrupter with electromagnetic opening means
US4031492A (en) * 1975-08-22 1977-06-21 Westinghouse Electric Corporation Triple break current limiter
US4039983A (en) * 1975-08-26 1977-08-02 Merlin Gerin High-speed high-current circuit interrupter having electrodynamically operated arcing contacts

Also Published As

Publication number Publication date
DE1463190B2 (de) 1972-01-27
DE1463190A1 (de) 1968-12-12
CH416796A (de) 1966-07-15
GB1016216A (en) 1966-01-05
ES287634A1 (es) 1963-12-01

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