US3764946A - Current-limiting electric switch - Google Patents

Current-limiting electric switch Download PDF

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Publication number
US3764946A
US3764946A US00222953A US3764946DA US3764946A US 3764946 A US3764946 A US 3764946A US 00222953 A US00222953 A US 00222953A US 3764946D A US3764946D A US 3764946DA US 3764946 A US3764946 A US 3764946A
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United States
Prior art keywords
contacts
movable
release
current
switch
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Expired - Lifetime
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US00222953A
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English (en)
Inventor
A Mostosi
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C E SpA CONSTR ELETTROMECCAN
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C E SpA CONSTR ELETTROMECCAN
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    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/12—Contacts characterised by the manner in which co-operating contacts engage
    • H01H1/14—Contacts characterised by the manner in which co-operating contacts engage by abutting
    • H01H1/20—Bridging contacts
    • H01H2001/2091—Bridging contacts having two pivotally and electrically connected halve bridges

Definitions

  • a current-limiting electric switch is disclosed, of the kind having at least one release per pole, each release comprising two contacts carried by respective supporting members, said contacts being electrically connected to a feed and a load terminal through a current path of which said supporting members form, when the contacts are closed, two parallel branches through which currents of opposite sign flow, so that a current increase beyond a preselected limit produces in said two branches electrodynamic repulsion forces to overcome the bias of resilient supporting members and to cause the supporting members to be set apart for separating the contacts, the improvement consisting in the fact that said parallel branches are a part of -a closed loop which is made up by said current path in correspondence with each release.
  • the switch according to s more reliable operability.
  • This invention relates to a current-limiting electric switch, which is particularly adapted to apparatus intended to operate in the field of low voltages (up to 1,000 volts) and with currents in the order of magnitude of a few hundreds of amperes on continuous duty, wherein the switch release under overcurrent conditions due to short circuiting is automatically brought about by the electrodynamic repulsion forces as produced by the flow of strong currents of opposite signs through two parallel and properly approached branches of the current path which connects the movable and the fixed contacts of the switch to the feeding and loading terminals, said parallel branches being usually the supporting members themselves for the movable and the fixed contacts,
  • An object of the present invention is to provide a current-limiting electric switch having a higher interrupting capacity. That is, a current-limiting electric switch wherein the electric connection between the fixed and movable contacts and the feed and load terminals is obtained in such a way as to produce higher repulsion forces and thus a higher contact-separation speed, the impressed currents being equal, or equal repulsion forces when the impressed current is lower.
  • the object of the invention is achieved by means of a current-limiting electric switch equipped with at least a release per pole, each release comprising two contacts carried by the respective supporting members, said contacts being electrically connected to a feed and a load terminal through a current path of which, when the contacts are closed, said surpports form two parallel branches through which currents of opposite signs flow, so that a current increase above a predetermined limit produces in said branches electrodynamic repulsion forces capable of overcoming the bias of resilient retaining members and of causing the supporting members to be driven apart from one another for the separation of the contacts, characterized in that said parallel branches are a part ofa closed loop as formed by said current path in correspondence with each interruption.
  • the switch according to the present invention permits to construct apparatus which are characterized, as compared with the conventional constructions, by shorter operation times and thus, the arcextin-guishing means being the same, by a higher ability to limit the maximum value of the current and energy that the switch allows to be established under shortcircuit conditions.
  • FIGS. 1, 2, 3 and 4 are vertical cross-sectional views showing, in four different working conditions, a pole of a two-release switch according to a preferred embodiment of the invention.
  • FIG. 5 is a partial cross-sectional view taken along the line VV of FIG. 1.
  • FIGS. 6, 7 and 8 are diagrammatical elevational views showing three different operative conditions of a pole of a switch having two releases per pole according to another possible embodiments of the invention.
  • FIGS. 9, 10 and 11 are diagrammatical elevational views showing three different working conditions of a pole ofa switch having two releases per pole according to still another embodiment of the invention.
  • FIGS. 12, 13 and 14 are diagrammatical elevational views showing three different working conditions of a pole of a switch having two releases per pole according to a further possible embodiment of the invention.
  • FIGS. l5, l6 and 17 are diagrammatical elevational views showing three different working conditions of a pole of a switch having a single release per pole according to still another embodiment of the invention.
  • the switch shown in FIGS. l-S comprises, above all, a fixed frame 1, of an electrically insulating material, which supports two stiff conductors 2-3 which can be connected to electric feed and load cables (not shown) by means of terminal clamps 4-5 equipped with set screws 6-7 and an annular conducting plate 8 which is the supporting member for two fixed contacts 9-10.
  • a shaped rod 11, of an electrically insulating material which is driven so as to be shifted between the position of FIG. 1 and the position of FIG; 4, by the agency of a lever 12 keyed to an actuating shaft 13.
  • two movable arms 16-17 of an electrically conducting material which are electrically connected to the rigid conductors 2-3 by means of flexible cables 18-19 and carry the respective movable contacts 20-21 cooperating with the fixed contacts 9-10.
  • the two movable arms 16-17 furthermore, carry the respective pins 22-23 which engage the corresponding ends of two compression springs 24-25, whose other ends engage, at 26-27, the slidable rod 11.
  • the two movable arms 16-17 carry the respective couples of trunnions 28-29 (FIG. 5) whose function will become clearer hereinafter.
  • a lid 30 also of an electrically insulating material,.which, along with the framing aforementioned, defines two areextinguishing chambers 31-32, within which respective arc-splitting sets of ferromagnetic plates 33-34, are housed.
  • the movable arms 16-17 are biassed by the bias of the springs 24-25; then, as the axes of the spring have attained and overtaken the line jointing the pins 26-14 and 27-15, the couple of springs is inverted and the movable-arms 16-17 are quickly driven towards the position of maximum rotation which is-defined by the abutment between the back of the arms and a central core 35 of the shaped rod 11 (FIG. 2).
  • means should also be provided which are capable of allowing the manual release by an operator, as well as the release in the case of overcurrents which are not strong enough to originate such electrodynamic forces as to overcome the bias of the springs 24-25.
  • These means are not a part of the claimed invention and are thus not described herein in detail, or shown in the drawings, either. They are intended, in any case, to act upon the driving shaft 13 so as to cause the rotation from the position of FIG. 1 to the position of FIG. 4, so as to cause the shift of the rod 11 and of the arms 16-17 from the closed position of FIG. 1 to the opened position of FIG. 4, said shift being an integral movement on account of the abutment between the trunnions 28-29 of the arms 16-17 and the bracket-like projections 39-40 of the rod 11.
  • FIGS. 6 to 8 diagrammatically show a pole of aswitch having two releases per pole, in which the two couples of fixed and movable contacts of the two releases are connected to the feeding and loading terminals (not shown) by a currentpath having two closed loops (as indicated by the arrows A) which comprises a first rigid conductor 51, a first flexible cable 53, a first movable arm 55, a first movable contact 57, a first fixed contact 59, a conducting plate 61, a second fixed contact 60, a second movable contact 58, a second movable arm 56, a second flexible cable 54 and a second rigid conductor 52.
  • the two movable arms 55-56 are pivoted to respective fixed pivot pins 62-63 and are driven towards the closed position of FIG. 6 by springs 64-65 arranged between pins 66-67 as carried by the movable arms 55-56 and pins 68-69 as carried by movable supporting members 70-71 also pivotedto the fixed pins 62-63 and linkably connected by tie rods 72-73 to a slidable rod 74 driven by a lever 75 keyed to a driving shaft 76, which is controlled in the same way as the shaft 13 of the embodiment of the FIGS. 1 to 5.
  • the switch is preset for a new closure operation (which can be effected by the reverse displacement of the rod 74).
  • FIGS. 9-11 there is the embodiment of FIGS. 9-11, in which the two couples of fixed and movable contacts of the two releases of each pole of the switch are connected to the two feeding and load terminals (not shown) by means of a current path formed by two closed loops (arrows B) which comprises a first rigid conductor 101, a first fixed arm 103, a first fixed contact 105, a first movable contact 107, a movable plate 109, a second movable contact 108, a second fixed contact 106, a second fixed arm 104 and a second rigid conductor 102.
  • the movable plate 109 which is a supporting member for the movable contacts 107-108, is held by a fixed sleeve 110 equipped with two peripheral'notches 111-112, in whose interior two rollers 113-114 can be engaged, which are carried by arms 115-116, the latter being rotatably'carried by a T-shaped rod 117 which is slidably housed within the sleeve 110 and is driven by a driving shaft 118 through a lever 119.
  • Two springs 120-121 are active upon the arms 115-116 so as to urge them against one another.
  • the two couples of fixed and movable contacts of the two releases of each pole of the switch are connected, in turn, to the feeding and loading terminals (not shown) by a current path having two closed loops (arrows C) which comprises a first rigid conductor 151, a first flexible cable 153, a first movable arm 155, a first movable contact 159, a movable conducting plate 161, a third movable contact 160, a fourth movable contact 158, a second movable arm 156, a second flexible cable 154 and a second rigid conductor 152.
  • a current path having two closed loops (arrows C) which comprises a first rigid conductor 151, a first flexible cable 153, a first movable arm 155, a first movable contact 159, a movable conducting plate 161, a third movable contact 160, a fourth movable contact 158, a second movable arm 156, a second flexible cable 154 and a second rigid conductor
  • the two movable arms 155-156 are pivoted on fixed pivots 162-163 and, when in the closure position of FIG. 12, they are maintained in such position by springs 164-165 inserted between fixed pivots 166-167 and pins 168-169 carried by the arms 155-156.
  • the movable plate 161 is rigidly connected to a slidable rod 170 which is terminated by a wedge head 171 and is driven by a driving shaft 172 through a lever 173.
  • the presetting of the switch for the subsequent closing operation can then be obtained by displacing the rod 170 so as to allow the wedge head 171 of the latter to penetrate between the two confronting backs of the arms -156, so as to overcome the initially counteracting bias of the springs 164-165 and to restore the arms 155-156 to the other end position as defined by the abutting relationship with fixed abutments 176-177 (FIG. 14).
  • the closure of the switch can then obviously be carried out by displacing the rod in the opposite direction.
  • FIGS. 15 to 17 show the case of a switch hav- I ing a single release per pole, constructed in accordance with the principles of the invention.
  • the structure of this switch is practically equal to one half of the structure of the switch as shown in FIG. 6 to 8.
  • FIGS. 6 to 8 the same reference numerals have been used herein also.
  • the only fact which deserves emphasis herein is that, in the present case, the two contacts 57 and 59 are connected to the feed and load terminals 91-92 by a current path (arrows D) formed by a single closed loop, of which the supporting members 55 and 61 are two parallel branches through which currents with opposite signs flow.
  • switches having a single release per pole which substantially corresponds to one half of the switch of FIG. 6 to 8
  • switches having a single release per pole which substantially correspond to one half of the switches shown in FIG. 1 to 5, 9 to 11 and 12 to 14.
  • These switches will be obviously characterized by a current path forming a single closed loop, in which the supporting members are two parallel branches through which currents of opposite signs flow.
  • a current-limiting electric switch having at least one release per pole, each release comprising two contacts carried by the respective supporting members, said contacts being electrically connected to a feeding terminal and to a loading terminal through a current path of which, when the contacts are closed, said supporting members form two parallel branches through which currents of opposite signs flow, so that a current increase beyond a predetermined limit produces in said branches electrodynamic repulsion forces such as to overcome the contrary bias of resilient holding means and to cause the supporting members to be set apart for separating the contacts, characterized in that said parallel branches form a portion of a closed loop formed by said current path in correspondance with each release.
  • a switch according to claim 1 equipped with two releases per pole, characterized in that said current path makes up two closed loops.
  • a switch according to claim 2 characterized in that the two releases comprise first contacts placed at the ends of a common conducting supporting member and respective second contacts placed at the ends of respective movable arms the latter being located and electrically connected to the feed and load terminals so that the two current paths which electrically connect said terminals to said second contacts may form respective open loops which, as the contacts are closed, are
  • a switch according to claim 3 characterized in that said second contacts are carried by rotatable arms and are maintained in the closed position by resilient means which are urged, by the rotation of the arms for effecting the rotation of the arms under the control of the electrodynamic repulsion forces; to switch from a biassing condition to a condition of aid to said rotation.
  • a switch according to claim2 characterized in that the two releases comprise respective fixed contacts placed at one end of respective fixed arms arranged and electrically connected to the feed and load terminals so that the two current paths which electrically connect said terminals with said fixed contacts from respective open loops, the two releases further comprising respective movable contacts arranged at the ends of a movable common conducting supporting member for closing said loops.
  • a switch according to claim 5 characterized in that said common movable conducting supporting member is fastened to a translatable supporting member which is held in the contact-closing position by resilient means of the groove and tongue type.
  • a switch according toclaim l equipped with a single release per pole, characterized in that said current path is a single closed loop.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Breakers (AREA)
  • Emergency Protection Circuit Devices (AREA)
US00222953A 1971-02-02 1972-02-02 Current-limiting electric switch Expired - Lifetime US3764946A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT2009971 1971-02-02

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US (1) US3764946A (enrdf_load_stackoverflow)
DE (1) DE2204662A1 (enrdf_load_stackoverflow)
ES (1) ES399750A1 (enrdf_load_stackoverflow)
FR (1) FR2124380B1 (enrdf_load_stackoverflow)

Cited By (7)

* 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
DE2905854A1 (de) * 1979-02-08 1980-08-21 Terasaki Denki Sangyo Kk Leistungsschalter
US4516182A (en) * 1981-01-16 1985-05-07 Ga Technologies Inc. Current limiting apparatus
US4616198A (en) * 1984-08-14 1986-10-07 General Electric Company Contact arrangement for a current limiting circuit breaker
RU2259612C2 (ru) * 2002-10-22 2005-08-27 Закрытое Акционерное Общество "Электрические Низковольтные Аппараты И Системы" Автоматический выключатель с двумя разрывами контактов
RU2368976C1 (ru) * 2008-08-04 2009-09-27 Общество с ограниченной ответственностью "Технос" Выключатель автоматический быстродействующий
US20130206729A1 (en) * 2010-06-07 2013-08-15 Eaton Electrical Ip Gmbh & Co. Kg Switch unit with arc-extinguishing units

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4012615A (en) * 1975-07-24 1977-03-15 Westinghouse Electric Corporation Latch for a circuit interrupter
FR2458887A1 (fr) * 1979-06-07 1981-01-02 Hazemeyer Sa Appareil de coupure de courant electrique du type limiteur d'intensite
FR2511542A1 (fr) * 1981-08-12 1983-02-18 Telemecanique Electrique Dispositif de liberation des contacts mobiles de contacteurs aptes a limiter les courants de courts-circuits
DE3139489A1 (de) * 1981-09-29 1983-07-07 Siemens AG, 1000 Berlin und 8000 München Kontaktanordnung fuer elektrische leistungsschalter
US4998081A (en) * 1989-05-18 1991-03-05 Siemens Energy & Automation, Inc. Power interrupter with force-sensitive contact latch
DE102005046640B4 (de) * 2005-09-29 2007-10-18 Abb Patent Gmbh Elektrisches Installationsgerät

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3317866A (en) * 1963-02-07 1967-05-02 Terasaki Denki Sangyo Kk Automatic circuit interrupter having magnetic blowoff means
US3343108A (en) * 1965-12-10 1967-09-19 Terasaki Denki Sangyo Kk High speed circuit interrupter using magnetic blowoff and means for decreasing the inertial effects during interruption
US3517356A (en) * 1967-07-24 1970-06-23 Terasaki Denki Sangyo Kk Circuit interrupter

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3317866A (en) * 1963-02-07 1967-05-02 Terasaki Denki Sangyo Kk Automatic circuit interrupter having magnetic blowoff means
US3343108A (en) * 1965-12-10 1967-09-19 Terasaki Denki Sangyo Kk High speed circuit interrupter using magnetic blowoff and means for decreasing the inertial effects during interruption
US3517356A (en) * 1967-07-24 1970-06-23 Terasaki Denki Sangyo Kk Circuit interrupter

Cited By (8)

* 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
DE2905854A1 (de) * 1979-02-08 1980-08-21 Terasaki Denki Sangyo Kk Leistungsschalter
US4516182A (en) * 1981-01-16 1985-05-07 Ga Technologies Inc. Current limiting apparatus
US4616198A (en) * 1984-08-14 1986-10-07 General Electric Company Contact arrangement for a current limiting circuit breaker
RU2259612C2 (ru) * 2002-10-22 2005-08-27 Закрытое Акционерное Общество "Электрические Низковольтные Аппараты И Системы" Автоматический выключатель с двумя разрывами контактов
RU2368976C1 (ru) * 2008-08-04 2009-09-27 Общество с ограниченной ответственностью "Технос" Выключатель автоматический быстродействующий
US20130206729A1 (en) * 2010-06-07 2013-08-15 Eaton Electrical Ip Gmbh & Co. Kg Switch unit with arc-extinguishing units
US8921728B2 (en) * 2010-06-07 2014-12-30 Eaton Electrical Ip Gmbh & Co. Kg Switch unit with arc-extinguishing units

Also Published As

Publication number Publication date
DE2204662A1 (de) 1972-08-10
FR2124380A1 (enrdf_load_stackoverflow) 1972-09-22
ES399750A1 (es) 1974-12-01
FR2124380B1 (enrdf_load_stackoverflow) 1975-02-14

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