EP0848403A2 - Disjoncteur de protection thermomagnétique pour installations domestiques et similaires - Google Patents

Disjoncteur de protection thermomagnétique pour installations domestiques et similaires Download PDF

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Publication number
EP0848403A2
EP0848403A2 EP97203679A EP97203679A EP0848403A2 EP 0848403 A2 EP0848403 A2 EP 0848403A2 EP 97203679 A EP97203679 A EP 97203679A EP 97203679 A EP97203679 A EP 97203679A EP 0848403 A2 EP0848403 A2 EP 0848403A2
Authority
EP
European Patent Office
Prior art keywords
switch
arc
magnetic
switch according
domestic
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.)
Withdrawn
Application number
EP97203679A
Other languages
German (de)
English (en)
Other versions
EP0848403A3 (fr
Inventor
Elio Jacovino
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 Elettrocondutture SpA
Original Assignee
ABB Elettrocondutture SpA
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 ABB Elettrocondutture SpA filed Critical ABB Elettrocondutture SpA
Publication of EP0848403A2 publication Critical patent/EP0848403A2/fr
Publication of EP0848403A3 publication Critical patent/EP0848403A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/30—Means for extinguishing or preventing arc between current-carrying parts
    • H01H9/34—Stationary parts for restricting or subdividing the arc, e.g. barrier plate
    • H01H9/36—Metal parts
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/52—Cooling of switch parts
    • 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
    • H01H71/14—Electrothermal mechanisms
    • H01H71/16—Electrothermal mechanisms with bimetal element
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H73/00—Protective overload circuit-breaking switches in which excess current opens the contacts by automatic release of mechanical energy stored by previous operation of a hand reset mechanism
    • H01H73/02—Details
    • H01H73/18—Means for extinguishing or suppressing arc

Definitions

  • the invention relates to an automatic thermo-magnetic switch for domestic and similar applications, which is able to "carry” for equal volume a nominal current greater by at least 50% than the higher nominal current "carried” by conventional automatic thermo-magnetic switches for domestic and similar applications.
  • thermo-magnetic switches for domestic and similar applications and their operation will not be described in detail here since these are well-known apparatus widely available on the market: it is merely recalled that such switches comprise:
  • the thermal means have a relatively long response time and anyway much longer than that of the magnetic means, which have to respond almost instantaneously to a short-circuit so as to protect the user from overvoltages and/or from the thermal and electrodynamic effects associated with the overcurrents due to the short-circuit.
  • thermo-magnetic switches for domestic and similar applications having a width of 1 modulus and which are able to "carry” a nominal current of not greater than 63 amperes are known and available on the market; thus the subject of the present invention is an automatic thermo-magnetic switch for domestic and similar applications having a width of 1 modulus and able to "carry” a nominal current of the order of 100 amperes, i.e. a nominal current greater by at least 50% than the higher nominal current "carried" for equal volume by conventional automatic thermo-magnetic switches for domestic and similar applications.
  • the subject of the present invention is an automatic thermo-magnetic switch for domestic and similar applications comprising: a pair of terminals to which the conductors, making up the electrical circuit into which the said switch is inserted, are connected; mechanical means able to close and to open the switch, said mechanical means being manually actuatable by the user; thermal means able to open said switch, by actuating said mechanical means in response to a current overload; magnetic means able to open said switch, by actuating said mechanical means in response to a short-circuit; and means able to extinguish the electric arc which is struck between the contacts of said switch upon opening the said switch which is able to "carry", for equal volume, a nominal current of around 100 amperes and anyway of between 80 and 125 amperes.
  • the thermal means consist of an indirectly heated bimetallic strip and the means of extinguishing the electric arc are able at least partially to dispel the heat which is developed inside the switch when the switch is closed.
  • the automatic thermo-magnetic switch of the present invention comprises:
  • Figure 1 shows a block diagram of an automatic thermo-magnetic switch for domestic and similar applications of known type; Figure 1 depicts by means of functional blocks, which are not further described since they are known per se:
  • the arc chute G 2 constitutes the extension of the fixed contact F.
  • the shape of the arc chutes G (G 1 , G 2 ) and the material, for example: iron, from which they are made are chosen exclusively on the basis of their task of making the "toes" of the electric arc travel with the greatest possible speed from the contacts (F, MO) to the vent C.
  • a top view and a cross-section of two segments of arc chutes G of known type are illustrated in Figures 3 and 4.
  • FIG. 2 shows a block diagram of an automatic thermo-magnetic switch for domestic and similar applications according to the invention, wherein the thermal means TE and the means for extinguishing SP the electric arc according to the invention are schematically illustrated, while functional blocks are used to represent the terminals M, the mechanical means MC and the magnetic means MA, substantially equivalent to the corresponding functional blocks of the switch of Figure 1.
  • a switch according to the invention is able to "carry" a nominal current of around 100 amperes and anyhow of between 80 and 125 amperes.
  • the thermal means TE consist of an indirectly heated bimetallic strip L: in Figure 2 the bimetallic strip L is illustrated; said bimetallic strip, in response to the overload current, actuates the mechanical means MC in a manner known per se and is indirectly heated by radiation from the resistive element R traversed by the current which passes through the switch.
  • the arc chute G 1 is metallically connected in a manner known per se, but not illustrated in Figure 2, to one of the terminals M, while the arc chute G 2 constitutes the extension of the fixed contact F.
  • the shape of the aforesaid arc chutes G (G 1 , G 2 ) and the materials exhibiting good magnetic characteristics and high thermal capacity (for example: iron, copper and/or their alloys) from which they are made are therefore chosen in such a way that the arc chutes G (G 1 , G 2 ) are able both to carry the "toes" of the electric arc, when present, from the contacts (F, MO) to the vent C, and to dispel the overtemperature of the current-conducting elements (mainly the fixed F and moving MO contacts and the terminal M linked to the arc chute G 1 ).
  • the overtemperature for equal volume is decreased to around the same values as may be encountered in a switch of known type. Said overtemperature is generated by the heat which is developed, when the switch is closed and traversed by current, as a consequence of the contact resistances present between the terminal M to which the arc chute G 1 is linked and the conductor adjoining this terminal M, and between the contacts (F, MO) of the switch.
  • this heat which is non-negligible in view of the relatively high nominal current and of the small dimension of the switch according to the invention, to be removed so as to be able to comply with the limits laid down by the product Standards for the particular parts (terminals, casing, etc.) and for the correct operation and reliability of the kit.
  • Figures 1 and 2 are drawn in the same scale: by comparing these figures it may be observed that the functional blocks (M, MC, MA, TE, SP) which make up the two switches have the same layout and the same dimensions. The two switches therefore have the same performance as regards response times to a short-circuit and to an overload, while the thermal means TE and the means of extinction SP made according to the invention enable the switch of Figure 2 to "carry" a nominal current of the order of 100 amperes.
  • thermal means TE The use of a indirectly heated bimetallic strip L to make the thermal means TE according to the invention is particularly advantageous since it does not entail the use of "braided wires" and/or of other flexible linking means which, if dimensioned so as to carry a nominal current of around 100 amperes, would be too rigid (for equal dimensions of the thermal means TE) to allow correct operation of the said thermal means TE and/or so bulky as to make it impossible (or, at least, extremely difficult) to place the thermal means TE in the narrow space available.
  • Figure 3 shows a top view and a cross-section view on the plane A-A of a segment of the first arc chute G of conventional type, having a rectangular cross-section.
  • Figure 4 shows a top view and a cross-section view through the plane B-B of a segment of a second arc chute G of conventional type, which exhibits a longitudinal ridge R on which one of the "toes" of the electric arc moves when the arc is carried from the zone of the contacts (MO, F) of the switch to the vent C.
  • Figure 5 shows a top view and a cross-section view through the plane C-C of a segment of a first arc chute G, made according to the invention, which exhibits a longitudinal central ridge R on which one of the "toes" of the electric arc moves and one or more series of apertures A made in each of the zones located at the sides of the longitudinal central ridge R (which are of no relevance to the "toes" of the electric arc) so as to increase the useful surface for dissipating the heat.
  • apertures A are of circular shape but, without departing from the scope of the invention, it is possible to make apertures A of square, rectangular, rhomboidal shape and/or of some other shape in the side zones of the arc chute G.
  • Figure 6 shows a top view and a cross-section view through the plane D-D of a segment of a second arc chute G, made according to the invention, which exhibits a "C" cross-section so as to increase the heat-dispersing surface and a longitudinal ridge R located at the centre of the arc chute G.
  • the side zones of the arc chute G do not have apertures A but, without departing from the scope of the invention, it is possible to make apertures A of circular, square, rectangular, rhomboidal shape and/or of some other shape in the side zones of the arc chute G.
  • arc chutes G may be given shapes and/or dimensions which differ from those illustrated by way of non-limiting examples in Figures 5 and 6.

Landscapes

  • Arc-Extinguishing Devices That Are Switches (AREA)
  • Keying Circuit Devices (AREA)
  • Cookers (AREA)
  • Thermally Actuated Switches (AREA)
EP97203679A 1996-11-27 1997-11-27 Disjoncteur de protection thermomagnétique pour installations domestiques et similaires Withdrawn EP0848403A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT96MI002474A IT1286408B1 (it) 1996-11-27 1996-11-27 Interruttore automatico termo-magnetico per applicazioni domestiche e similari
ITMI962474 1996-11-27

Publications (2)

Publication Number Publication Date
EP0848403A2 true EP0848403A2 (fr) 1998-06-17
EP0848403A3 EP0848403A3 (fr) 1998-12-23

Family

ID=11375288

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97203679A Withdrawn EP0848403A3 (fr) 1996-11-27 1997-11-27 Disjoncteur de protection thermomagnétique pour installations domestiques et similaires

Country Status (3)

Country Link
EP (1) EP0848403A3 (fr)
CN (1) CN1066567C (fr)
IT (1) IT1286408B1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1729860A (en) * 1927-02-18 1929-10-01 Condit Electrical Mfg Corp Electric switch
US3177324A (en) * 1961-12-01 1965-04-06 Allis Chalmers Mfg Co Circuit breaker employing perforated arc runners
US3575680A (en) * 1969-08-08 1971-04-20 Gen Electric Current-limiting circuit breaker
US3632932A (en) * 1969-08-08 1972-01-04 Gen Electric Current-limiting circuit breaker having a field strap assembly
FR2294529A1 (fr) * 1974-12-09 1976-07-09 Illinois Tool Works Commutateur a ressort
EP0208176A1 (fr) * 1985-06-27 1987-01-14 Mitsubishi Denki Kabushiki Kaisha Disjoncteur

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1729860A (en) * 1927-02-18 1929-10-01 Condit Electrical Mfg Corp Electric switch
US3177324A (en) * 1961-12-01 1965-04-06 Allis Chalmers Mfg Co Circuit breaker employing perforated arc runners
US3575680A (en) * 1969-08-08 1971-04-20 Gen Electric Current-limiting circuit breaker
US3632932A (en) * 1969-08-08 1972-01-04 Gen Electric Current-limiting circuit breaker having a field strap assembly
FR2294529A1 (fr) * 1974-12-09 1976-07-09 Illinois Tool Works Commutateur a ressort
EP0208176A1 (fr) * 1985-06-27 1987-01-14 Mitsubishi Denki Kabushiki Kaisha Disjoncteur

Also Published As

Publication number Publication date
ITMI962474A0 (it) 1996-11-27
EP0848403A3 (fr) 1998-12-23
ITMI962474A1 (it) 1998-05-27
CN1185015A (zh) 1998-06-17
IT1286408B1 (it) 1998-07-08
CN1066567C (zh) 2001-05-30

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