US3546641A - Electric circuit breakers - Google Patents

Electric circuit breakers Download PDF

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Publication number
US3546641A
US3546641A US707536A US3546641DA US3546641A US 3546641 A US3546641 A US 3546641A US 707536 A US707536 A US 707536A US 3546641D A US3546641D A US 3546641DA US 3546641 A US3546641 A US 3546641A
Authority
US
United States
Prior art keywords
contact
coil
retractable
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
US707536A
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English (en)
Inventor
Alan Twemlow Freeman
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.)
Associated Electrical Industries Ltd
Original Assignee
Associated Electrical Industries Ltd
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Filing date
Publication date
Application filed by Associated Electrical Industries Ltd filed Critical Associated Electrical Industries Ltd
Application granted granted Critical
Publication of US3546641A publication Critical patent/US3546641A/en
Anticipated expiration legal-status Critical
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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
    • H01H71/12—Automatic release mechanisms with or without manual release
    • H01H71/42—Induction-motor, induced-current, or electrodynamic release mechanisms
    • H01H71/43—Electrodynamic release mechanisms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H3/00—Mechanisms for operating contacts
    • H01H3/22—Power arrangements internal to the switch for operating the driving mechanism
    • H01H3/222—Power arrangements internal to the switch for operating the driving mechanism using electrodynamic repulsion
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H3/00—Mechanisms for operating contacts
    • H01H3/02—Operating parts, i.e. for operating driving mechanism by a mechanical force external to the switch
    • H01H3/0253—Operating parts, i.e. for operating driving mechanism by a mechanical force external to the switch two co-operating contacts actuated independently

Definitions

  • This invention relates to electric circuit breakers and is particularly, but not exclusively, applicable to socalled high speed circuit breakers whose purpose is to achieve contact separation as rapidly as possible on the occurrence of a trip signal, especially under overload or fault conditions, in order to be able to provide eflicient protection in high power, direct current, circuit applications.
  • An object of the invention is to provide in a circuit breaker means whereby contact separation may be achieved more rapidly and with less delay after the occurrence of a trip signal than is achievable by a known high speed circuit breaker, such as a high speed circuit breaker according to our British patent specification No. 934,210, in which a certain delay is inherent in the releasing of a mechanical latch in the operating mechanism and in which the acceleration of a movable contact away from a cooperating stationary contact is limited by the inertia of a relatively massive pivoted arm carrying the movable contact.
  • the present invention makes use of the well-known principle that when a current is suddenly caused to flow in an electromagnetic coil a repulsive force will be exerted between the coil and a conductive ring or disc adjacent to and substantially coaxial with the coil.
  • an electric circuit breaker comprising a pair of cooperating contacts one of the contacts of the pair is mechanically connected, for retraction from the other contact, to one member of a combination comprising an electromagnetic coil and conductive ring or disc which, on the occurrence of a trip signal in response to which a current is suddenly caused to flow in the coil, cooperate to repel one another and thereby exert an accelerating retraction force on the retractable contact.
  • the member to which the retractable contact is connected is the ring or disc and the coil is restrained against movement, at least in the direction away from the ring or disc: this arrangement is conducive to fulfilling the desideratum of minimum inertia of parts connected to the retractable contact, as well as being more convenient for making electrical con- ICC nection to the coil, and will be assumed to subsist in order to facilitate the following description of certain other aspects of the invention.
  • a path for the current flowing through that contact under normal working conditions and during fault clearance is preferably provided by means of one or more sliding contacts.
  • the biasing force will return the contact to its closed-contact position unless means, such as a latch or toggle mechanism, is provided to retain it in a retracted position.
  • the need for such means may be avoided by providing for withdrawal of the other contact of the pair from its closed-contact position prior to such return of the first-mentioned retractable contact; alternatively provision may be made both for such retention of said retractable contact and for withdrawal of the other contact in order to achieve further separation of the contacts.
  • Withdrawal of the other contact may be initiated by a release mechanism which may be actuated by an electrical trip mechanism independently responsive to the trip signal or by a mechanical trip mechanism responsive to the motion of said retractable contact.
  • FIG. 1 is a diagrammatic representation of a high speed electric circuit breaker in accordance with the invention and FIGS. 2 and 3 illustrate modifications thereof.
  • circuit breaker represented by the drawings is of the kind previously mentioned with reference to our British patent specification No. 934,210 but with its stationary contact replaced by a retractable contact as hereinbefore defined.
  • this contact, 2 will be referred to as the fast contact
  • the normal movable contact 4 will be referred to as the slow contact.
  • the slow contact 4 is carried by a contact arm 6 which is pivoted at a fixed point 8 and has an operating mechanism 10, generally as described in said British patent specification, including a release mechanism constituted by a latch 12 which may be of the kind described in our British patent sepcification No. 849,658 with reference to FIG. 1 thereof but with the arm 14 carrying the-roller 16 inverted as shown in the present drawing.
  • the latch 12 is releasable by the armature 17 of an electromagnetic trip mechanism 18 (responsive to an overload current in a connection 20 to the contact arm 6 via the pivot at 8) mechanically connected to the C-shaped catch 22 through the inermediary of a rod or wire 24.
  • the slow contact 4 bears against the fast contact 2 which is secured coaxially to the end of a rod 26 slidably mounted in a stop 28 (fixed to the circuit breaker frame partly shown at 29) through which the rod passes. Beyond the stop, the rod passes through an electromagnetic coil 30 also fixed to the circuit breaker frame. To the other end of the rod 26 is secured, also coaxially, a copper ring 32 held as by a screw 34 and a clamping device 36.
  • the clamping device has a flange 36A against which bears a spiral spring 38, the other end of which bears against a fixed abutment 40 on the circuit breaker frame.
  • the spring may provide a force of, say, 150 lbs.
  • a main current connection 44 is connected to the fast contact 2 through the stop 28 and a plurality of radially spring loaded fingers 46 enabling the current path to be maintained while the contact 2 is retracted as will now be described.
  • the adjustment of the contacts and the closing mechanism are so arranged that the slow contact presses against the fast contact, as shown by the arrow 48, with a force which may be, say, 100 lbs.
  • a force which may be, say, 100 lbs.
  • An overload current which will operate the electromagnetic trip mechanism 18 and thereby release the slow contact 4 by means of the latch12, also causes operation of sensitive quick-acting switching means S (such as a sensitive relay, thyratron or thyristor) which serves to discharge a previously charged capacitor C through the coil 30.
  • sensitive quick-acting switching means S such as a sensitive relay, thyratron or thyristor
  • the pressure of the spring 38 retains the ring 32 in close proximity to the coil until, after a time delay which may be less than 0.1 millisecond and is determined by the time constant of the LC circuit including the inductance of the coil 30 and the capacitance of the capacitor, a large repulsive force established between the coil and the ring causes the fast contact to move very rapidly away from the slow contact with an acceleration which may exceed l000G; thus there is little delay between the occurrence of the trip signal and the initial separation of the contacts and there is a high rate of increase of the distance between the contacts.
  • the slow contact 4 initially attempts to follow the fast contact 2 under the force ap plied to it by the mechanism 10 but, owing to the inertia of the arm 6, it moves much more slowly than the fast contact.
  • the operating mechanism 10 its latch 12 having been released by the trip mechanism 18
  • the slow contact 4 will have caused the slow contact 4 to move away from its closed position towards its open position so that contact is not re-established.
  • the circuit breaker may incorporate a latch or toggle arrangement which engages the fast contact 2 (or one of the parts mechanically connected thereto) at the limit of its travel so as to prevent this contact returning to its normal position until the latch or toggle is released.
  • FIG. 2 shows such a latch arrangement in which the fast-contact rod 26 has an extension 26A which passes through the fixed abutment and through a conical hole 50A in another fixed member 50.
  • This hole tapers in the direction of return motion of the rod, opposite to the direction (indicated by the arrow 52) of retraction of the fast contact.
  • a ring of steel balls 54 surrounding the rod 26A and within the hole 50A, is pressed into the tapering aperture between the rod and the conical surface of the hole by a light spring 56.
  • the rod 26A is free to move in the direction of the arrow 52 but will be gripped and held by the balls 54 as soon as it attempts to return in the opposite direction. This action will not be affected by any variation which may occur in the travel of the fast contact due, for example, to variation in the voltage to which the aforementioned capacitor is charged.
  • FIG. 2 also shows a means of releasing such a latch.
  • This force acts through a forked lever 66, pivoted at 68, to press a tubular member 70 against the ring of balls 54 in the direction to overcome the pressure of the spring 56.
  • the retractable contact 2 is able to return to its closed-contact position.
  • circuit breaker may be provided is a lever arrangement responsive to the motion of the fast contact 2 and arranged to trip the latch 12 of the slow contact mechanism at a predetermined point in the travel of the fast contact. This would enable the electromagnetic trip mechanism 18 itself to be dispensed with. Since the acceleration of the fast contact is very high, such lever mechanism would be subject to severe shock loading.
  • FIG. 3 shows such a lever arrangement comprising a forked lever pivoted at a fixed point 82.
  • the forked end 80A of the lever (of which only one fork is shown in the cross-sectional drawing) is so shaped and positioned as to be acted upon, by the flange 36A against which the spring 38 bears, to rotate the lever clockwise (as indicated by the arrow 84) on retraction of the fast contact 2.
  • the other end of the lever is coupled, by a Bowden cable 86 or other suitable means, to the slowcontact trip mechanism arm 17A which carries the armature 17, so that the rotation of the forked lever 80- will initiate release of the slow contact 4.
  • the discharging of the capacitor C is preferably achieved by means of a thyristor whose firing circuit PC is responsive to a signal representative of the value of current flowing in the main current circuit being controlled by the high speed circuit breaker, so that when the current exceeds a predetermined value the firing circuit produces a trigger pulse which fires the thyristor.
  • a signal representative of the value of current flowing in the main current circuit being controlled by the high speed circuit breaker, so that when the current exceeds a predetermined value the firing circuit produces a trigger pulse which fires the thyristor.
  • such signal may be the output of a D0. current transformer CT included in that circuit.
  • the delay between the instant at which the main current reaches the trip value and the instant at which the thyristor is fired can be very short, typically less than one microsecond.
  • An electric circuit breaker including a combination comprising an electromagnetic coil member and a conductive ring or disc member one of which members is repellably movable away from the other by sudden flow of current created in the coil member in response to a trip signal and a pair of co-operating circuit-breaking contacts one of which is mechanically connected to said one of said members, whereby consequently upon such flow of current said one contact will be subject to an accelerating retraction force for separating it from the other contact, including means for retaining the retractable contact in its retracted position on completion of retraction thereof, and wherein the retaining means comprises a rod connected to the retractable contact for movement therewith, a fixed apertured member having an inner surface defining a tapering aperture through which the rod extends and which tapers in the direction of movement of the rod accompanying return movement of the retractable contact to its closed-contact position, a ring of balls surrounding the rod and being so dimensioned as to be able to contact both the rod and said surface, and spring means urging the balls in said direction, the arrangement
  • An electric circuit breaker including, in combination: an electromagnetic coil member and a conductive ring or disc member, one of said member being repellably movable away from the other of said members by sudden flow of current created in the coil member, a pair of co-operating circuit breaking contacts one of which is retractable and is mechanically connected to said movable one of said members, a main source of current electrically connected to each of said contacts and flowing through said contacts when said contacts are closed, a trip signal source of current electrically connected to said coil member and to said main current source and adapted to create a sudden flow of current in said coil in response to undesirable variations in said main current source, whereby consequently upon such sudden flow of current in said coil said one mechanically connected contact is subjected to an accelerating retraction force for separating it from the other contact, including means connected to said other contact for withdrawing the other contact from its closed-contact position and means for actuating said withdrawing means in response to said undesirable variations and after commencement of retraction of the retractable contact.
  • a circuit breaker as claimed in claim 2 and including means for retaining the retractable contact in its retracted position on completion of such retraction thereof.
  • circuit breaker as claimed in claim 2, wherein the circuit breaker includes automatic release means for releasing the retaining means in response to movement of said other contact on such withdrawal thereof.
  • a circuit breaker as claimed in claim 6 including a mechanical trip mechanism, said mechanism responsive to the motion of the retractable contact on retraction thereof, and means for initiating the action of the withdrawing means.
  • the said trip mechanism includes an electrical trip mechanism electrically connected to said trip signal source and a mechanical trip mechanism mechanically responsive to the motion of said retractable contact on retraction thereof, and wherein the electrical and mechanical trip mechanisms include a common lever for transmitting their initiating etfect to the withdrawing means.

Landscapes

  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
  • Breakers (AREA)
US707536A 1967-03-09 1968-02-23 Electric circuit breakers Expired - Lifetime US3546641A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB11070/67A GB1145959A (en) 1967-03-09 1967-03-09 Improvements relating to electric circuit breakers

Publications (1)

Publication Number Publication Date
US3546641A true US3546641A (en) 1970-12-08

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Family Applications (1)

Application Number Title Priority Date Filing Date
US707536A Expired - Lifetime US3546641A (en) 1967-03-09 1968-02-23 Electric circuit breakers

Country Status (8)

Country Link
US (1) US3546641A (enrdf_load_stackoverflow)
BE (1) BE711942A (enrdf_load_stackoverflow)
DE (1) DE1613974A1 (enrdf_load_stackoverflow)
ES (1) ES351371A1 (enrdf_load_stackoverflow)
FR (1) FR1555375A (enrdf_load_stackoverflow)
GB (1) GB1145959A (enrdf_load_stackoverflow)
NL (1) NL6803145A (enrdf_load_stackoverflow)
SE (1) SE326751B (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4039983A (en) * 1975-08-26 1977-08-02 Merlin Gerin High-speed high-current circuit interrupter having electrodynamically operated arcing contacts
EP1347479A1 (fr) * 2002-03-22 2003-09-24 Schneider Electric Industries SAS Appareillage électrique de coupure limiteur ultrarapide
CN120299960A (zh) * 2025-06-16 2025-07-11 三峡金沙江川云水电开发有限公司 一种锁扣装置及其使用方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2357048A1 (fr) * 1976-06-28 1978-01-27 Merlin Gerin Interrupteur electrique dote d'un propulseur electrodynamique et d'un amortisseur pneumatique
FR2512268A1 (fr) * 1981-08-27 1983-03-04 Merlin Gerin Interrupteur electrique a commande rapide

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1818801A (en) * 1929-05-25 1931-08-11 Gen Electric High speed circuit interrupter
FR740568A (fr) * 1932-07-28 1933-01-27 Telemecanique Electrique Contacteur électromagnétique à coupure accélérée
US2486104A (en) * 1942-07-28 1949-10-25 Ite Circuit Breaker Ltd Circuit breaker
US3127488A (en) * 1960-07-18 1964-03-31 Ite Circuit Breaker Ltd Current limiting circuit breaker having both contacts movable
US3178533A (en) * 1963-04-03 1965-04-13 Hi G Inc Resettable plunger switch assembly
US3215798A (en) * 1962-05-03 1965-11-02 Siemens Ag Synchronous-type circuit interrupter with synchronous-operating holding magnet for latching interrupter in closed position
US3384845A (en) * 1966-11-23 1968-05-21 Gen Electric Current-limiting electric circuit breaker

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1818801A (en) * 1929-05-25 1931-08-11 Gen Electric High speed circuit interrupter
FR740568A (fr) * 1932-07-28 1933-01-27 Telemecanique Electrique Contacteur électromagnétique à coupure accélérée
US2486104A (en) * 1942-07-28 1949-10-25 Ite Circuit Breaker Ltd Circuit breaker
US3127488A (en) * 1960-07-18 1964-03-31 Ite Circuit Breaker Ltd Current limiting circuit breaker having both contacts movable
US3215798A (en) * 1962-05-03 1965-11-02 Siemens Ag Synchronous-type circuit interrupter with synchronous-operating holding magnet for latching interrupter in closed position
US3178533A (en) * 1963-04-03 1965-04-13 Hi G Inc Resettable plunger switch assembly
US3384845A (en) * 1966-11-23 1968-05-21 Gen Electric Current-limiting electric circuit breaker

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4039983A (en) * 1975-08-26 1977-08-02 Merlin Gerin High-speed high-current circuit interrupter having electrodynamically operated arcing contacts
EP1347479A1 (fr) * 2002-03-22 2003-09-24 Schneider Electric Industries SAS Appareillage électrique de coupure limiteur ultrarapide
FR2837619A1 (fr) * 2002-03-22 2003-09-26 Schneider Electric Ind Sa Appareillage electrique de coupure limiteur ultrarapide
US6777635B2 (en) 2002-03-22 2004-08-17 Schneider Electric Industries Sas Very high-speed limiting electrical switchgear apparatus
CN120299960A (zh) * 2025-06-16 2025-07-11 三峡金沙江川云水电开发有限公司 一种锁扣装置及其使用方法
CN120299960B (zh) * 2025-06-16 2025-08-22 三峡金沙江川云水电开发有限公司 一种锁扣装置及其使用方法

Also Published As

Publication number Publication date
ES351371A1 (es) 1969-06-01
FR1555375A (enrdf_load_stackoverflow) 1969-01-24
BE711942A (enrdf_load_stackoverflow) 1968-07-15
DE1613974A1 (de) 1971-06-03
SE326751B (enrdf_load_stackoverflow) 1970-08-03
NL6803145A (enrdf_load_stackoverflow) 1968-09-10
GB1145959A (en) 1969-03-19

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