US3558991A - Circuit breaker with high speed tripping system - Google Patents

Circuit breaker with high speed tripping system Download PDF

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Publication number
US3558991A
US3558991A US756479A US3558991DA US3558991A US 3558991 A US3558991 A US 3558991A US 756479 A US756479 A US 756479A US 3558991D A US3558991D A US 3558991DA US 3558991 A US3558991 A US 3558991A
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United States
Prior art keywords
movable contact
breaker
circuit
circuit breaker
high speed
Prior art date
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Expired - Lifetime
Application number
US756479A
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English (en)
Inventor
Thomas P Brandt Jr
Frank J Pokorny
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.)
ABB Inc USA
Original Assignee
ITE Imperial Corp
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Filing date
Publication date
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Publication of US3558991A publication Critical patent/US3558991A/en
Assigned to BROWN BOVERI ELECTRIC INC.; A CORP OF DE reassignment BROWN BOVERI ELECTRIC INC.; A CORP OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: I-T-E IMPERIAL CORPORATION
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
    • 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
    • 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
    • H01H2071/506—Latching devices between operating and release mechanism using balls or rollers in the latching device
    • 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
    • H01H71/123—Automatic release mechanisms with or without manual release using a solid-state trip unit
    • H01H71/125—Automatic release mechanisms with or without manual release using a solid-state trip unit characterised by sensing elements, e.g. current transformers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H83/00—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current
    • H01H83/20—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by excess current as well as by some other abnormal electrical condition

Definitions

  • circuit breakers which protects the entire system and the various components being operated thereby in the event of overloads and short circuit fault conditions. Furthermore, because of the magnitudes of current flowing in these higher rated distribution systems, circuit breakers must be designed to be much quicker acting than those presently available.
  • the instant invention is in fact directed to a quickacting circuit breaker which is particularly useful in the higher rated systems coming into extensive use in the electrical distribution industry.
  • the circuit breaker can be of minimum size, compact construction, reliable over extended periods of use, and have such high speed tripping characteristics as to be especially useful for current limiting applications during the occurrence of short circuit fault conditions in a line or lines being monitored.
  • the instant invention proposes a tripping system which, upon the occurrence of predetermined fault conditions, will free the movable contact of the circuit breaker from the conventional restraining and/or closing mechanism normally associated therewith such that the movable contact arm can rapidly snap open under the inuence of the opening springs free of the relatively high inertial parts of the restraining system.
  • the movable contact arm used to interrupt current is conventionally restrained or latched against the bias of the opening springs by means of a jack shaft and other parts rotatable therewith.
  • the aforenoted restraining mechanism customarily a toggle arrangement, collapses such that its parts rotate with the movable contact arm during the opening sequence. Because the opening springs must rotate relatively heavy portions of the restraining mechanism, in addition to the movable contact arm, the opening sequence is relatively slow.
  • the high speed tripping system although applicable for initiating rapid interruption in response to any type of fault, is preferably utilized to initiate interruption in response to short circuit current faults where the need for quick opening is especially acute.
  • the invention includes an electronic sensing subsystem for quickly detecting the presence of a short circuit fault in the circuit being protected.
  • Such subsystem preferably comprises a Hall crystal located in the eld generated by the current ilow through the conductor being monitored. The output of the Hall crystal, upon reaching a predetermined magnitude, actuates an electronic switching circuit which discharges a capacitor storage tripping supply to energize an impulse tripping coil which rotates a break-away latch to free the movable contact arm for independent rotation.
  • Another object of the instant invention is to provide such a lhigh speed tripping system which includes means for freeing the rotatable contact ar-m of a circuit breaker from the relatively heavy and complex restraining mechanism normally associated therewith in response to predetermined current conditions flowing in the line being protected.
  • Another object of the instant invention is to provide such a tripping system for a circuit breaker which frees the movable contact arm from the relatively complex and heavy mechanism normally associated therewith, such that the opening springs of the circuit breaker need only rotate the movable contact arm of the breaker and essential linkage elements associated therewith in order to effectuate circuit interruption.
  • Yet another object of the instant invention is to provide such a high speed tripping mechanism for a circuit breaker which employs a novel electronic sensing subsystem utilizing a Hall crystal, the output of which is response to current ilow in such a manner as to eliminate the necessity of current transformers previously utilized in such circuit breakers to provide an indication of current ow.
  • Yet another object of the instant invention is to provide such a circuit breaker with a high speed tripping system which can be utilized in combination with conventional circut breakers in such a way as to add extremely quickacting tripping characteristics to the relatively slower tripping characteristics of the existing breaker.
  • FIG. l is a somewhat schematic side view of a circuit breaker embodying the instant invention.
  • FIG. 2 is an exploded, perspective detailed view of a portion of the high speed tripping 4mechanism of the instant invention.
  • FIG. l there is shown a circuit breaker 10 incorporating the high speed tripping system of the instant invention.
  • the breaker includes an upper and lower primary conductor 412 and '14, respectively, which are to be electrically connected in the line being protected.
  • the upper conductor 12 terminates in a stationary contact arrangement I16 including a main and arcing contact surface 18 and 20, respectively.
  • the lower conductor 14 is provided with a pivot 22 at one extremity, about which is rotatable the movable contact arm 24 of the breaker.
  • the movable contact arm 24 includes main and arcing surfaces 26 and 28, respectively, which cooperate in a well known manner with contact surfaces 18 and 20, respectively, to assure that upon circuit interruption, that is, ⁇ rotation of the movable contact arm 24 in a counterclockwise direction, the main contact surfaces 18 and 26 will separate prior to the separation of arcing contacts 20 and 28. In this manner an arc which is nally drawn across the separating arcing contacts 20 and 28 will be transferred to the arc runners 30 and 32, respectively, whereby such arc may rise into the arc chute 34 to be expeditiously extinguished with the aid of arc plates such as 36.
  • the delayed separation of the arcing contacts 20 and 28 with respect to the main contacts 18 and 26 is etfectuated by providing that the movable arcing contact 28 be situated on a sub-portion 37 of the movable contact arm 24 continually biased clockwise about a pivot point 38 by a spring 40.
  • the movable contact arm 24 is linked by means of a pull rod 42. to one end 44 of a contact operating lever arm 46 which, as best shown in FIG. 2, is provided with an enlarged central aperture 48 such that it is freely rotatable with respect to a pivotal axis constituted by the jack shaft 50.
  • the contact operating lever arm is normally biased in a counterclockwise direction, as viewed in FIG. 1, by an opening spring 52, one end of which 54 bears against a xed stop 56 while the second end of which 58 bears against the contact operating lever arm at a point above the pivotal axis defined by the jack shaft 50.
  • the defeatable restraining system 60 illustrated in FIG. 1, is not the only type of restraining system which can be utilized to counteract the bias of the opening spring 52.
  • the only essential operating characteristics of a restraining system such as 60 is that in normal operation it maintains or latches the movable contact arm 24 in a closed circuit position and that upon being defeated, the entire restraining mechanism or portions thereof can be collapsed or otherwise made movable, in which case the opening springs will be free to rotate contact operating le'ver arm 46 and hence the movable contact arm 24, and additionally those portions of the restraining system 60 which previously presented a rigid obstruction to such movement.
  • the restraining mechanism includes a support plate 62 which is keyed to and rotatable with the jack shaft 50. As best illustrated in FIG. 2, one end 64 of the support plate 62 pivotally carries a latch 66. As will be explained, the latch 66 is an integral portion of a high speed releasing system, the function of which will be explained in greater detail. For the immediate purposes of describing the restraining system 60, it is sufficient to note that latch 66 is normally biased by a spring 68 in a clockwise direction with respect to FIG. 2 such that one end 70l thereof is normally in blocking relationship with respect to a roller 72 carried on the second end 74 of the contact operating lever arm 46.
  • cam member 76 having a cammed surface 78 engaged by a following roller 80 carried by a bell-crank type of lever 82 pivotally mounted on one end 84 of an L-shaped link 86 pivotally mounted on a xed pivot pin 88.
  • a cam member 76 having a cammed surface 78 engaged by a following roller 80 carried by a bell-crank type of lever 82 pivotally mounted on one end 84 of an L-shaped link 86 pivotally mounted on a xed pivot pin 88.
  • the bell-crank type lever ⁇ 82 l would tend to rotate clockwise about the pivot 84, and indeed the L-shaped lever 86 would tend to rotate counterclockwise about the xed pivot 88 (from the bias of the opening spring 52 transmitted through the aforenoted rigid linking arrangement and cammed surface 718) were it not for a second bellcrank type lever 90 pivotally mounted at 92, such that one end 94 thereof prevents movement of the bell-crank lever 82 and the L-s'haped link 86.
  • the restraining system 60 does in fact counteract the bias developed by the opening spring 52 and thereby retain the movable contact arm 24 in a closed circuit position of FIG. 1.
  • circuit breakers include some means for manually tripping the circuit breaker and additionally customarily include some means for automatically tripping the circuit breaker upon the occurrence of predetermined conditions within the line to which the primary conductors 12 and .14 are connected.
  • current sensing means which will detect the presence of overload currents in the line being monitored and, upon the occurrence of a predetermined magnitude, produce as an output some type of motion which can be utilized to initiate the tripping operation.
  • the circuit breaker of FIG. l preferably includes such a current sensing means (not shown) which might comprise, for example, a magnet and armature trip device, the armature of which would be moved upon the occurrence of a predetermined current occurring within the line '12, 14, Upon the occurrence of such armature movement, a latch 94, shown in FIG. l, is rotated out of engagement with a roller '96 provided on the second end 98 of the second bell-crank lever 90.
  • a current sensing means (not shown) which might comprise, for example, a magnet and armature trip device, the armature of which would be moved upon the occurrence of a predetermined current occurring within the line '12, 14, Upon the occurrence of such armature movement, a latch 94, shown in FIG. l, is rotated out of engagement with a roller '96 provided on the second end 98 of the second bell-crank lever 90.
  • the bell-crank lever 90 is free to rotate such that the L-shaped lever 86 and the bell-crank lever 82 are free to rotate counterclockwise and clockwise, respectively, and consequently the cam member 76, and the rigid arrangement comprising the jack shaft 50, support plate 62 and the contact operating lever arm 46 (through the latch 66) is free to rotate in a counterclockwise direction under the bias of the opening spring 52 to rotate the movable contact arm 214 counterclockwise to its open circuit position.
  • circuit breakers are additionally provided with some sort of closing mechanism for rotating the movable contact arm back to the closed circuit position after the fault which initiated interruption has been cleared.
  • closing mechanism (not shown) which could, if desired, rotate the bell-crank type lever 82 in a counterclockwise direction such that the roller 80 bearing against the cam surface 78 would rotate the cam member 76 which eventually (through the jack shaft 50, support plate 62, latch 66 and roller 72) would rotate the ⁇ contact operating lever arm 46 and hence the movable contact arm 24 against the bias of opening spring 52 to return the breaker to the closed circuit position.
  • a prop latch such as 99 may be conveniently provided to prevent a closing operation unless the fault has been cleared.
  • the instant invention provides a quick-acting tripping system which, upon the occurrence of predetermined short circuit fault conditions occurring in the line, will bring about circuit interruption much quicker than was heretofore possible.
  • the instant invention provides that upon the occurrence of a high current fault condition, the movable contact arm 24 (and the contact operating lever arm 46) will be freed and allowed to rotate independent of those portions of the restraining mechanism 60 which customarily are rotated during what is conveniently classified as the semi-high speed tripping operation described above.
  • the instant invention includes a trip coil 100, which, as will be further explained, is energized in response to the occurrence of a short circuit fault flowing in the line 12, 14.
  • the trip coil 100 includes a member 102 which would be linked to the armature of the coil (not shown), which member 102 strikes the latch 66 and rotates it counterclockwise against the bias of spring 68 in response to energization of the coil 100.
  • the latch 66 is rotated counterclockwise, the aforementioned rigid arrangement which was effectuated between the contact operating lever arm 46 and the support plate 62 (through the engagement of the end 70 of the latch 66 and the roller 72) is defeated such that the contact operating lever arm 46 is now free to rotate independently about the jack shaft 50 under the influence of the opening spring 52.
  • the sensing system for energizing the impulse trip coil 100 upon the occurrence of predetermined short circuit fault conditions takes advantage of the well known Hall effect which permits the development of an electrical potential when a magnetic field is applied transversely to a current in a suitable material.
  • current flow through the line 12, 14, generates a magnetic field about the conductor 14 which is conveniently concentrated by means of an iron structure 104 which has located in its gap a Hall crystal of suitable type, 106, which is excited with a constant current source (not shown).
  • the crystal 106 supplies a signal which will be proportional to a magnetic field in turn proportional to the current owing through the line 14.
  • This signal is amplied by DC amplifier 108 and used to actuate or turn on an electronic switch of suitable design, 110, at predetermined levels of forward and reverse current.
  • the electronic switch will serve to connect a capacitor storage tripping supply 112 to the impulse trip coil 100 which, as noted previously, will initiate the high speed tripping operation.
  • the high speed opening operation afforded by the instant invention permits breakers employing the invention to have higher interrupting capabilities than previously possible, With increased interrupting capabilities, smaller circuti breakers can be utilized to service equipment previously requiring higher rated breakers. For example, in one situation it was found that a 4000 kw. rectifier in a singled ended substation required an 8000 amp. main breaker and a 3000 amp. feeder breaker for adequate short circuit capabilities. Using circuit breakers embodying the instant invention, it was found that the same protection could be afforded using a 6000 amp. main breaker and a 1200 amp. feeder breaker for substantial reductions in size and cost.
  • a circuit breaker for interrupting the flow of current through a conductor upon the occurrence of predetermined conditions, said circuit breaker comprising:
  • a movable contact rotatable between a closed circuit and an open circuit position with respect to said stationary contact
  • defeatable restraining means for normally preventing rotation of said movable contact means, said restraining means including members which are rotated in response to rotation of said movable contact under the bias of said means when said restraining means is defeated in response to lirst predetermined conditions;
  • release means for permitting said -movable contact to rotate to its open circuit position independent and free of said members of said restraining means in response to occurrence of second predetermined conditions
  • bias means need not overcome the mass of said members in rotating said movable contact to its open circuit position
  • said movable contact is linked to a contact operating lever arm freely rotatable on a first rotatable axis, and further including support means rigidly mounted on said first rotatable axis and rotatable therewith, said release means including a latch carried by said support means, said latch normally preventing rotation of said contact operating lever arm independent of said support means, energization of said release means rotating said latch out of the path of rotation of said contact operating lever arm such that said contact operating lever arm and said movable contact can rotate free of said support means and said first rotatable axis.
  • the circuit breaker of claim 1 and further including camming means rigidly mounted on said rst rotatable axis and rotatable therewith, said camming means constituting one of said members of said restraining means which is rotated in response to rotation of said movable contact arm when said restraining means is defeated, whereby with said latch in blocking relationship with respect to said contact Operating lever arm, rotation of said contact operating lever arm will cause rotation of said support means which, through said iirst rotatable axis, will bring about rotation of said camming means, and when said latch is moved out of blocking relationship with respect to said contact operating lever arm, said contact operating lever arm will be free to rotate independent of said camming means and the remainder of said restraining means.
  • circuit breaker of claim 3 and further including sensing means for monitoring the current flow in said conductor, said second predetermined condition being when said current reaches a predetermined magnitude.
  • circuit breaker of claim 3 and further including a normally non-energized trip coil which réellees rotation of said latch when energized, energy storage means for energizing said trip coil, and switching means for permitting said energy storage means to energize said trip coil when said predetermined magnitude of current is sensed.
  • sensing means is a crystal device located in the magnetic iield generated by said conductor, said crystal device producing an output signal which is proportional to the current liowing in said conductor.
  • T. R. BRANDT, JR In the first and second sheets of drawings containing Figures l and 2 at the top thereof, the inventor, "T. R. BRANDT, JR.” should be listed as T. F. BRANDT, JR.

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  • Breakers (AREA)
  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
US756479A 1968-08-30 1968-08-30 Circuit breaker with high speed tripping system Expired - Lifetime US3558991A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US75647968A 1968-08-30 1968-08-30

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US3558991A true US3558991A (en) 1971-01-26

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US756479A Expired - Lifetime US3558991A (en) 1968-08-30 1968-08-30 Circuit breaker with high speed tripping system

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US (1) US3558991A (enrdf_load_stackoverflow)
FR (1) FR2016634A1 (enrdf_load_stackoverflow)
GB (1) GB1232721A (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3914667A (en) * 1972-03-27 1975-10-21 Ite Imperial Corp Rate of rise tripping device
US4090156A (en) * 1976-04-12 1978-05-16 I-T-E Imperial Corporation Circuit breaker having solid state and thermal-magnetic trip means
US4425596A (en) 1980-09-26 1984-01-10 Tokyo Shibaura Denki Kabushiki Kaisha Electric circuit breaker
US4594634A (en) * 1983-09-08 1986-06-10 Bbc Brown, Boveri & Company, Ltd. High-voltage direct-current supply with over-current protection
US4616207A (en) * 1984-10-12 1986-10-07 Gould Inc. Electric fuse holder having a Hall-effect current sensor
CN101752149B (zh) * 2008-12-12 2013-01-16 三菱电机株式会社 电路断路器

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE9414333U1 (de) * 1994-09-03 1994-11-03 Abb Patent Gmbh, 68309 Mannheim Leitungsschutzschalter oder Fehlerstromschutzschalter

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3914667A (en) * 1972-03-27 1975-10-21 Ite Imperial Corp Rate of rise tripping device
US4090156A (en) * 1976-04-12 1978-05-16 I-T-E Imperial Corporation Circuit breaker having solid state and thermal-magnetic trip means
US4425596A (en) 1980-09-26 1984-01-10 Tokyo Shibaura Denki Kabushiki Kaisha Electric circuit breaker
US4594634A (en) * 1983-09-08 1986-06-10 Bbc Brown, Boveri & Company, Ltd. High-voltage direct-current supply with over-current protection
US4616207A (en) * 1984-10-12 1986-10-07 Gould Inc. Electric fuse holder having a Hall-effect current sensor
CN101752149B (zh) * 2008-12-12 2013-01-16 三菱电机株式会社 电路断路器

Also Published As

Publication number Publication date
DE1944062A1 (de) 1970-10-01
FR2016634A1 (enrdf_load_stackoverflow) 1970-05-08
DE1944062B2 (de) 1972-10-12
GB1232721A (enrdf_load_stackoverflow) 1971-05-19

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Legal Events

Date Code Title Description
AS Assignment

Owner name: BROWN BOVERI ELECTRIC INC.; SPRING HOUSE, PA. 1947

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:I-T-E IMPERIAL CORPORATION;REEL/FRAME:004103/0790

Effective date: 19820428