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
  • H01H71/14—Electrothermal mechanisms
  • H01H71/142—Electrothermal mechanisms actuated due to change of magnetic permeability
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/081—Magnetic constructions
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H50/00—Details of electromagnetic relays
  • H01H50/16—Magnetic circuit arrangements
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/16—Rectilinearly-movable armatures
  • H01F7/1607—Armatures entering the winding
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F7/00—Magnets
  • H01F7/06—Electromagnets; Actuators including electromagnets
  • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
  • H01F7/16—Rectilinearly-movable armatures
  • H01F7/1638—Armatures not entering the winding
• • 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
  • H01H71/24—Electromagnetic mechanisms
  • H01H71/2454—Electromagnetic mechanisms characterised by the magnetic circuit or active magnetic elements
• • 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
  • H01H71/24—Electromagnetic mechanisms
  • H01H71/2463—Electromagnetic mechanisms with plunger type armatures

Definitions

• the invention relates to the triggering of electrical protection equipment such as circuit breakers, particularly in the field of low voltage. More generally, the invention relates to an electromagnetic actuator that can be used as a single trigger of a switchgear.
• a circuit breaker makes it possible to protect an electric line by cutting the current in the event of a fault, in particular on short circuit, when the intensity exceeds a high threshold, or in case of overload, when the intensity remains in values close to the rated current but over a long period.
• an electromagnetic actuator 2 separates contacts 4 , 6 in the event of a short-circuit
• a bimetallic thermal trigger 8 reacts to overloads: see, for example, FR 2 682 533.
• the electromagnetic actuator 2 may take various forms, in particular with a plunger core such as presented in connection with Figure 1 or paddle as described in FR 2 772 981.
• the invention aims to overcome the drawbacks of existing circuit breaker trip units, in particular by proposing a new type of electromagnetic actuator to ensure tripping over short circuit and overload.
• the invention thus relates to an electromagnetic actuator that allows the mobilization of a contact which is secured to it both when the current exceeds a nominal value over a long period, than when the current exceeds a threshold punctually.
• the invention relates in particular to an electromagnetic actuator in which a magnetic shunt device is set up at the coil, in series with respect to the path of the magnetic flux, said shunt device comprising a magnetothermic (or magnetocaloric) material, that is to say a material whose magnetization increases with the temperature above a first temperature greater than or equal to 330 K, and in particular has a peak whose maximum is greater than 40 emu / g, with rapid increase in magnetization between 350 and 420 K under a magnetic field of 0.2 to 2 T.
• the magnetocaloric material is in particular an alloy of nickel and manganese, preferably of the NiCoMnX type, with X selected from aluminum, indium, antimony or tin.
• the actuator as such is conventional, with a magnetic circuit comprising a fixed magnetic casing, a coil capable of being connected to an electrical circuit at its terminals. ends, and a magnetic element movable relative to the carcass as a function of the intensity of the current flowing in the coil.
• the movable magnetic element may be a plunger which moves within the coil, the core and the coil being housed in the carcass; alternatively, the movable magnetic element may be of the pallet type, with a U-shaped casing of which at least one of the branches is surrounded by the coil, and the pallet moving relative to the branches of the U to close it.
• the shunt device may extend along the axis of the coil, especially indoors for a plunger actuator; preferably in the form of a cylinder, it can be composed entirely of the magnetocaloric material or its effects can be dimensioned by adapting the rate of magnetocaloric material within it.
• the dimensions of the cylinder are also adapted to the desired force for the shunt device relative to the current flowing in the coil.
• the electromagnetic actuator may be implemented in a switchgear, such as a molded case modular circuit breaker, wherein one of the switchgear contacts is coupled to the actuator movable member to open or close the line. depending on the current flowing in the coil.
• the actuator may form a device for tripping such a switchgear device, the coil then being coupled to the line that the breaking device is made to protect and the movable element being able to be coupled to a moving contact of the switchgear.
• apparatus for example rigidly.
• FIG. 1 already described, illustrates a low-voltage circuit breaker with a molded case in which the actuator according to the invention can be put in place.
• Figure 2 shows the characteristics of the material that can be used in the shunt of an actuator according to the invention.
• FIG. 3 represents an actuator according to one embodiment of the invention, with illustration of the magnetic induction forces according to the current flowing therethrough.
• Figure 4 shows another embodiment of a circuit breaker according to the invention.
• the action of the bimetallic strip in a tripping system is replaced according to the invention by a saturable magnetic shunt system, which is integrated with a conventional electromagnetic actuator, which retains its role of triggering on a short circuit.
• the shunt associated with actuator thus takes the overload trip function.
• the material of the shunt is chosen for its magneto-thermal or magnetocaloric properties. More precisely, as illustrated in FIG. 2, the material is such that its degree of magnetization M has a peak as a function of the temperature. In particular, at low temperature, the material is little, if any, magnetic. When the temperature increases, beyond a first temperature T 0 , the magnetization M of the material increases rapidly, to reach a maximum at a second temperature T 1; beyond which the magnetization decreases to zero for the Curie temperature Te of the material. These different temperatures To, T 1; Te themselves depend on the applied magnetic field H (see the variations obtained for a field of 0.2 T and a field of 7 T in Figure 2).
• the first temperature To is chosen to be greater than 330 K, preferably close to 350 K.
• This choice is made possible by the use of materials of the NiCoMnX family, with X e ⁇ Al, In, Sb, Sn ⁇ , preferably aluminum or tin: for these materials, the transition is well marked with a temperature Ti close to To (difference of 10 to 30 K) and a high magnetization, of the order of 70 emu / g.
• T 0 347 K
• Mmax 90 emu / g.
• the actuator according to the invention thus comprises a shunt associated with the coil.
• an actuator 10 comprises a magnetic circuit with a fixed magnetic casing 12 housing a longitudinal coil 14 within which a magnetic plunger core 16 can be moved.
• the coil 14 is connected. to a power supply line and, depending on the current flowing therein, induces a magnetic field B in the magnetic circuit which moves the core 16 along the axis of the coil 14.
• a device 18 comprising the magnetocaloric material is set in place around the coil 14, within the carcass 12, to form a magnetic shunt in the magnetic circuit.
• the shunt device 18 preferably forms a cylinder housed in the carcass 12.
• the shunt can be provided by the device 18 in its entirety, then composed in its entirety of magnetothermic material; preferably, the shunt device 18 is thus formed of stacked washers, or even juxtaposed bars or cut sheets.
• the shunt device 18 may comprise a support which is associated, or in which is integrated, a part of magnetocaloric material, which allows a simplified form such as a cylinder; the shunt device 18 may also form a part of the carcass 12 to which are associated, for example inserted in grooves or contiguous, elements of suitable material.
• the temperature of the assembly 10 remains low, close to the ambient temperature.
• the temperature of the shunt device 18 remains lower than the first temperature To: the shunt is in its non-magnetic state and the reluctance of the magnetic circuit is strong, similar to that of the same actuator without shunt device.
• the force of the field B induced on the magnetic core 16 remains low and below the trigger threshold: the core 16 remains in its rest position.
• the temperature at the shunt device 18 increases to be at least transiently, in the range of magnetization, between To and ⁇ : the magnetothermic material goes into its magnetic state.
• the shunt device 18 then channels the induced flux B and the reluctance of the circuit decreases.
• the force on the mobile core 16 increases progressively, to become greater than the trigger threshold: the mobile core 16 moves, and it can unlock the mechanism of the circuit breaker 1 to open the line in which it is placed.
• a direct thermal contact is provided between the shunt 18 and the coil 14.
• the shunt in magnetocaloric material sees its magnetic state depend on the temperature and the magnetic field to which it is subjected, values which, in turn, depend on the value of the current I flowing in the winding 14.
• the dimensioning of the system 10 makes it possible to position the corresponding value of the overcurrent current I s to locate the induced temperature in the nonmagnetic / magnetic phase transition region [To, Ti] of the material, and size the field induced by the shunt to allow the displacement of the core 16 and therefore the tripping of a circuit breaker 1 associated with the actuator 10.
• the amount of material of the shunt notably via the length and the section, or even the composition, of the device 18, as well as the length and the section of the windings of the winding 14. It should be noted that if the t I exceeds the value of the short-circuit current I cc , it causes a magnetic saturation of the entire circuit, whatever the state of the magnetothermic material of the shunt 18: sufficient flow B passes in all cases by the mobile core 16 to cause its movement and therefore the tripping of the circuit breaker 1 ( Figure 3C).
• the shunt device 18 therefore has little influence on the operation of the actuator 10 in the event of a short circuit. In addition, since it is positioned in the leakage flux of the winding 14, the shunt 18 has little influence on the attraction force of the mobile core 16 at rated current I nom .
• the actuator 10 can therefore maintain the current dimensions and design according to the cut-off and operating parameters required for its short-circuit cut-off functions, even if the characteristics of the tripping system according to the invention can allow optimization.
• an actuator 10 according to the invention set up in a switchgear device, in particular a molded and / or modular 1-BT circuit-breaker as illustrated in FIG. 1, makes it possible to perform both protection functions by a single component. , exclusively magnetic and without the need to heat a bimetallic strip.
• volume is released by the absence of bimetallic, volume that becomes available within the housing for new features.
• the overall heat dissipation of the apparatus 1, 10 is also restricted, which increases its reliability and energy efficiency.
• the disappearance of the thermal adjustment allows a reduction in industrial costs, as the reduction in the number of parts to assemble.
• the switching device comprises two movable contacts 4, 6 relatively to each other, at least one of the two contacts being associated with the moving part of an electromagnetic actuator. 20 whose magnetic circuit comprises:
• a coil 24 connected to the current line by its ends and flanking at least one branch of the magnetic U-22:
• a pallet 26 movable relative to the carcass 22 as a function of the current flowing in the coil 24, between a rest position in which an air gap exists between the U 22 and the paddle 26, and a breaking position in which the paddle 26 closes said U 22;
• the heating of the shunt 28 is achieved by thermal contact with the coil 24 traversed by the current and / or by the Joule effect by circulating all or part of the current in the active material.
• the two functions of the circuit breaker are thus provided by a single triggering and actuating device 20, in a more efficient manner from the technical, economic, environmental and industrial point of view.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Electromagnets (AREA)
• Breakers (AREA)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

Country Status (5)

Families Citing this family (4)

Family Cites Families (10)

• 2012
  • 2012-12-03 FR FR1261532A patent/FR2999014B1/fr not_active Expired - Fee Related
• 2013
  • 2013-11-25 EP EP13808100.5A patent/EP2926355B1/de active Active
  • 2013-11-25 US US14/647,363 patent/US9355803B2/en active Active
  • 2013-11-25 WO PCT/FR2013/052836 patent/WO2014087073A1/fr active Application Filing
  • 2013-11-25 CN CN201380058281.XA patent/CN104781902B/zh active Active

Non-Patent Citations (1)

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