Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/02—Details
  • H01H33/04—Means for extinguishing or preventing arc between current-carrying parts
  • H01H33/20—Means for extinguishing or preventing arc between current-carrying parts using arcing horns
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/02—Details
  • H01H33/04—Means for extinguishing or preventing arc between current-carrying parts
  • H01H33/08—Stationary parts for restricting or subdividing the arc, e.g. barrier plate
• • 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
• • 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
• • 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
  • H01H9/46—Means for extinguishing or preventing arc between current-carrying parts using arcing horns

Definitions

• the invention relates to the field of arcing devices.
• an electric arc arises between the electrical contacts. This arc creates a counter-electromotive force in the network that tends to oppose the source of the network.
• the intensity of the current across the switchgear periodically goes to zero. For example, these crossings of the intensity by zero are carried out every 10ms on a network 50Hz.
• the conductive arc cools down and the arc plasma ions recombine. This recombination takes place more or less rapidly according to the cutting technique (fractionation or elongation), the degree of pollution and the type of plasma. This recombination allows the break to resist the network voltage still present at its terminals. If this is not the case, a dielectric breakdown resets an arc in the cut, until the next passage of the current by zero.
• an electric arc cutting device comprising: a contact zone in which there are present at least one fixed contact and at least one moving contact with respect to the fixed contact, the contacts being able to be brought into contact and separated from one another, and
• an arc horn present opposite the fixed contact, the height of the arc horn being greater than or equal to the height of the fixed contact and the arc horn having a folded arc switching portion extending in a direction opposite to the fixed contact.
• the arc horn Due to the presence of a folded switching portion, the arc horn makes it possible to push back the arc in the bottom of the cutoff device, to improve its splitting and to move the arc away from the fixed contact.
• the displacement of the arc from the fixed contact towards the arc horn also makes it possible to reduce the erosion of the fixed contact due to a limited contact between the electric arc and the fixed contact, which makes it possible to improve the duration life of the cut-off device.
• the arc switching portion constitutes a sacrificial element that will be consumed by the arc in place of the fixed contact thus making it possible to improve the service life of the fixed contact and thus to increase the service life of the breaking device. .
• the material forming the arc switching portion may have a state change temperature greater than the change of state temperature of the material forming the fixed contact. This is the case for example when the arc horn is steel and the fixed contact copper.
• the material forming the arc switching portion may have a melting temperature, respectively of vaporization, greater than the melting temperature, respectively of vaporization, of the material forming the fixed contact.
• the cut-off device may be present in a housing, the arc horn having a width equal to the internal width of said housing.
• the implementation of such an arc horn reduces or even avoids its lateral bypass by plasma gases. In doing so, it makes it possible to lengthen the path traveled by the gases and thus to better cool them before they are evacuated outside the cut-off device.
• Such a configuration advantageously allows the potentials to be minimized outside the cut-off device.
• the cut-off device may, in addition, comprise a breaking chamber comprising a stack of electric arc splitting plates present opposite the arc horn.
• Such a device makes it possible to further improve the breaking capacity of the device and thus to further limit the erosion of the electrical contacts due to the arc.
• the cut-off device can be devoid of a stack of electric arc splitting plates.
• Such a device advantageously provides a simple and inexpensive electric arc cutting solution.
• FIGS. 1 to 3 show a first example of a breaking device according to the invention
• FIG. 4 represents a detail of the cut-off device illustrated in FIGS. 1 to 3,
• FIGS. 5 to 8 show the evolution of an electric arc in the cut-off device of FIGS. 1 to 3, and
• FIG. 9 represents a variant of the breaking device according to the invention.
• FIG. 1 represents an example of an electric arc cut-off device 1 according to the invention.
• the cut-off device illustrated makes it possible to cut an electric arc in the air.
• the cut-off device 1 comprises a contact zone 2 in which there are present at least one fixed contact 3 and at least one movable contact 4 relative to the fixed contact 3.
• the contacts 3 and 4 can be brought into contact and separated from each other , the movable contact 4 being configured in the illustrated example to perform a rotational movement about an axis of rotation when the contacts are separated.
• the contact head 3 and the fixed support 15 form a fixed subassembly for connecting the cut-off device 1 in an electrical installation.
• the contact head 3 may be formed of a metallic material, for example copper. When the movable contact 4 is in contact with the contact head 3 a current can flow between these elements. When the movable contact 4 is separated from the contact head 3 a current can flow between these elements.
• the cut-off device illustrated is a double-cut rotary cutoff device (see FIG. 2). It is not beyond the scope of the invention when the cut-off device is of another type, for example of the simple type rotary cutting knives or double cut knife.
• the cut-off device 1 further comprises an arc horn 10 present opposite the contact head 3 on the fixed support 15.
• the arc horn 10 is fixed to the fixed support 15 by a mechanical connection.
• the horn 10 comprises a tab 14 and an arc switching portion 12.
• the arc horn is made of an electrically conductive material, the arc horn 10 being able to be formed, for example of a metallic material, for example steel.
• the tab 14 is in the illustrated example in contact with the fixed support 15 but it is not beyond the scope of the invention when the horn 10 is not in contact with the fixed support 15 but is attached to the housing constituting the outer envelope of the cut-off device. In the latter case, the distance separating the arc horn 10 from the fixed support 15 may, for example, be less than or equal to 1 mm.
• An electric arc generated from the movable contact 4 is intended to move on the arc switching portion 12 as will be detailed below.
• the height h c of the horn 10 is greater than the height h t of the contact head 3
• the arc switching portion 12 is folded down and extends in a direction opposite to the fixed contact 3 (ie extends away from the fixed contact 3).
• the switching portion 12 forms, as illustrated, a bend 12a.
• the height h c of the horn 10 and the height h ' c at which the bend 12a is present are, in the example shown, greater than the height h t of the contact head 3.
• the heights h c , hc and h t are measured from the surface S of the fixed support 15 opposite which the arc horn 10 is present and perpendicular to this surface S.
• the cut-off device 1 is present in a casing 35.
• the casing corresponds to the union of two half-casings (see FIGS. 2 and 3).
• the half-box forms with the other half-box (not shown), the outer casing of the cut-off device.
• This envelope allows the fixing of the cut-off device in the electrical installation.
• the arc horn 10 has a width equal to the internal width of the housing 35 to reduce, or even prevent, the lateral bypass of said arc horn 10 by the plasma gases.
• Figure 4 shows the arc horn and illustrates that it has a width sufficient to limit its lateral bypass by the gases.
• the width L of the arc horn 10 corresponds to its largest dimension measured perpendicularly to its height.
• the cut-off device 1 furthermore comprises, in the example illustrated in FIG. 1, a breaking chamber 20 comprising a stack of splitting plates 21.
• the splitting plates 21 of the electric arc are mounted on a plate support 22 (see Figure 3).
• the assembly of the splitting plates 21 on the sheet support 22 makes it possible to form a rigid interrupting chamber 20.
• the fractionation sheets 21 are for example mild steel.
• the sheet support 22 may, for example, be made of vulcanized cardboard.
• the splitting plates may alternatively be directly mounted on the housing constituting the outer casing of the cut-off device.
• the interrupting chamber 20 illustrated comprises a plurality of stacking plates 21 stacked, for example at least three stacking sheets 21 stacked, for example at least five fractionation sheets 21 stacked.
• the splitting plates may for example have a V-shape or a U-shape when they are observed in a direction perpendicular to their elongation plane.
• an electric arc 30 is formed after opening contacts 3 and 4.
• the arc 30 is born at the location of the last electrical contact.
• This arc 30 is subjected to the Laplace force induced by the circulation of the current, this circulation is materialized by the curves 31.
• the arc 30 is in a current loop and the Laplace forces acting on this loop tend to open the loop. This effect is commonly called loop effect.
• the Laplace force applying to the arc 30 tends to push the arc 30 towards the bottom of the cut-off device 1.
• the contacts continue their opening movement.
• the arc 30 then moves to the end 3a of the contact head 3 and to the end 4a of the movable contact 4 (see Figure 5).
• the plasma from the cooled arc can follow a predetermined path shown by the arrows 32. Due to the implementation of an arc horn 10 of sufficient width, the gases travel a longer path and are therefore better cooled. before being evacuated outside the cut-off device. This may advantageously make it possible to minimize the potential ignitions outside the cut-off device.
• the majority of the volume of these plasma gases is diverted to an exhaust port 40 and flows in the volume defined by the switching portion 12 and the fractionation sheet closest to this portion. These gases allow the medium close to the arc horn to be in more optimal conditions of dielectric breakdown (the dielectric strength decreases when the temperature increases).
• the contacts continue their opening movement.
• the arc at the end of the contact head (configuration PI shown schematically in Figure 6) then switches on the switching portion 12 of the horn 10 (configuration P2) because its length is shorter after switching.
• Such switching may be explained by the fact that it is preferable for the electric arc to extend along a path as "impedant" as possible, corresponding here to a path having the shortest possible length. This switching results from a dielectric breakdown phenomenon.
• the arc in the PI configuration is also subject to the looping effect of the current flow, which tends to distort it and give it a curved shape (see P 'dashed configuration in Figure 6). This deformation makes it even easier to switch the arc on the arc horn.
• the arc moves radially when switching on the arc horn that is to say perpendicular to the axis rotation of the movable contact.
• the switching portion 12 constitutes a sacrificial portion of the cut-off device which will be consumed in place of the fixed contact 3 This makes it possible to extend the duration during which the contacts of the cut-off device can be used and thus to improve the service life of the cut-off device.
• the contacts always continue their opening movement.
• the arc enters the breaking chamber and splits. In doing so, it maintains a certain level of fixed voltage (cathodic and anodic voltage drop at the different arc feet) and cools (exchange between the arc and the splitting plates which increases the impedance). After complete opening of the contacts, the arc is totally split in the interrupting chamber (see FIGS. 7 and 8).
• This breaking principle can also be declined without splitting plates, which allows a simplification of the cut-off device 50, as shown in FIG. 9.
• the switching of the arc of the contact head 3 on the arc horn 10 is realized as with the breaking chamber. After switching, the arc no longer stabilizes in the interrupting chamber, but extends to the bottom of the cut-off device 50. This elongation results from the efforts of Laplace resulting from the loop effect. Elongation allows the arc to increase its impedance.
• the arc extends along the inner wall of the housing, which tends to cool the arc and also to increase its impedance.
• the arch foot is stabilized at the end of the switching portion 12, this area being a sacrificial zone as described above.
• the cut-off devices according to the invention can be used to cut a DC ("DC") or alternating current. (“AC”).
• the breaking devices according to the invention can be used in the low voltage field (U_AC ⁇ 1000V and U_DC ⁇ 1500V).
• U_AC ⁇ 1000V and U_DC ⁇ 1500V The expression “comprising / containing / including a” should be understood as "containing / containing / including at least one".

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• Arc-Extinguishing Devices That Are Switches (AREA)
• Breakers (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=52465504

Family Applications (1)

Country Status (6)

Families Citing this family (8)

Family Cites Families (14)

• 2014
  • 2014-10-22 FR FR1460150A patent/FR3027728B1/fr active Active
• 2015
  • 2015-10-20 EP EP15791327.8A patent/EP3210225B1/de active Active
  • 2015-10-20 WO PCT/FR2015/052807 patent/WO2016062960A1/fr active Application Filing
  • 2015-10-20 ES ES15791327T patent/ES2872524T3/es active Active
  • 2015-10-20 CN CN201580057339.8A patent/CN107004529A/zh active Pending
  • 2015-10-20 US US15/521,368 patent/US10319542B2/en active Active

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