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
  • H01H9/10—Adaptation for built-in fuses
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H81/00—Protective switches in which contacts are normally closed but are repeatedly opened and reclosed as long as a condition causing excess current persists, e.g. for current limiting
  • H01H81/02—Protective switches in which contacts are normally closed but are repeatedly opened and reclosed as long as a condition causing excess current persists, e.g. for current limiting electrothermally operated

Definitions

• the present invention relates to a power limiting device intended to limit the power delivered to an electrical installation.
• Such a device makes it possible to disconnect the electrical installation situated downstream thereof as soon as a predetermined intensity threshold is reached.
• Such a power limiting circuit breaker is easy to use because it can be reset by the customer after having tripped, but has the drawback of requiring complex assembly.
• a fuse is very easy to mount, but has the drawback of causing a definitive cut-off of the power supply if the current threshold is exceeded.
• the present invention aims to overcome the aforementioned drawbacks by proposing a power limiting device making it possible to limit the consumption of an electrical installation and to protect this installation against large and sudden increases in current.
• a power limiting device for electrical installation characteristic laughed at in that it comprises, mounted in series in a common box between two connection terminals of this box to said installation, first current limiting means, resettable automatically, adapted to intervene when the intensity of the supply current of said installation reaches a first threshold value corresponding to the maximum value of the intensity of the current authorized to circulate in said installation and of second means of breaking the current, not resettable, having a response time less than that of the first current limiting means and adapted to intervene when the instantaneous value of the supply current reaches a second threshold value greater than said first threshold value.
• the first current limiting means comprise a thermal resistance switch.
• the switch comprises, in an envelope of insulating material, a movable contact, a fixed contact and an actuating member in heat exchange relation with the thermal resistance and cooperating with the movable contact so as to move it between a closed current flow position in which the movable contact rests on the fixed contact and an open current limiting position.
• the movable contact and the fixed contact respectively comprise a conductive strip and a contact tab, each fixed by one of their ends on a support and bearing on one another in the closed position by their free end, and the actuating member comprises a snap action bimetal fixed at its median zone on a lug formed on the suppor.
• the switch has first and second pins made of conductive material sant one end of the envelope and being respectively extended inside the envelope by the conductive blade and by the contact tab, the second pin being folded from said end to an opposite end of the envelope and comprising a mechanical connection and electrical connection member with the second current cut-off means, the first pin passing through an orifice formed in a connection terminal of the housing with the installation.
• the second current cutoff means comprise a fuse provided with two connection end pieces, one of its end pieces being connected to the mechanical connection and electrical connection member of the interrupter, the other end piece passing through an orifice. formed in a connection terminal of the box with the installation.
• FIG. 1 is an exploded perspective view of a power limiting device according to the invention
• FIG. 2 is a sectional view of the first current limiting means of the device shown in Figure 1, in the closed current flow position;
• FIG. 3 shows a sectional view of the first current limiting means of the device shown in Figure 1, in the open current limiting position.
• a power limiting device according to the invention is shown, designated by the general reference 10.
• the power limiting device 10 is intended to be installed on the power supply network. upstream of an electrical installation, such as an electrical installation of a dwelling, so as to limit the power supplied to it.
• This device 10 includes first current limiting means 12 and second current cutting means 14.
• the first current limiting means 12 and the second current breaking means 14 are arranged in series and placed in a common housing 16, fictitiously broken in this FIG. 1, preferably having dimensions identical to those of a conventional fuse.
• the housing 16 comprises a cylindrical body 18, made of ceramic, surrounding the first means 12 for limiting the current and the second means 14 for cutting the current.
• the cylindrical body 18 is provided at each of its ends with two connection terminals 20 and 22 of the housing 16 with the installation, connected respectively to the first means 12 of current limitation and to the second means 14 of current cut.
• the terminals 20 and 22 are crimped hot on the body 18 of the housing 16.
• each connection terminal 20 and 22 of the housing 16 is provided with an axial orifice, respectively 24 and 26, formed in its end wall.
• the first current limiting means 12 comprise a substantially parallelepipedic envelope 28 made of insulating material, such as a plastic material, in which a switch is disposed, which will be described with reference to FIGS. 2 and 3.
• the envelope 28 is provided on one of its ends 30 with first and second pins 32, 34 made of conductive material passing through the casing 28 and each connected to the switch.
• the free end of the first pin 32 of the first current limiting means 12 passes through the orifice 24 of the connection terminal 20 of the housing 16, and is welded to the external face 36 of this terminal 20 so as to make an electrical connection between this terminal 20 and the switch.
• the free end of the second pin 34 is folded back and extends from the end 30 of the casing 28 towards an opposite end 38, shown in dotted lines, at the level of which this pin 34 comprises a mechanical connection member and electrical connection consisting of a cylindrical socket 40 intended to cooperate with the second means 14 of current cut.
• the second current cutting means 14 comprise a fuse constituted in a known manner by an alloy wire, not shown, enclosed in a cylindrical ceramic cartridge 42 and the ends of which are connected to two connection ends 44 and 46, made of material conductor, closing each end of the cartridge 42.
• the fuse constituting the second current breaking means is a fuse whose breaking capacity is above 20,000 amperes and whose nominal current is between 5 and 20 amperes, preferably 10 amperes.
• connection end piece 44 passes through the orifice 26, of the connection terminal 22 of the housing 16 so as to make an electrical connection between this terminal 22 of the housing l ⁇ and the fuse.
• the first means 12 comprise a current limiting tor interrup ⁇ , bearing the general reference 48.
• the switch 48 includes a movable contact constituted by a blade conduc ⁇ trice 50, a fixed contact, constituted by a contact tab 52 and an actuating member constituted by a snap action bimetal 54, fixed on a support 56.
• This switch 48 is arranged in the casing 28, such so that the conductive strip 50 and the bimetallic strip 54 are in heat exchange relationship.
• the conductive strip 50 of substantially rectilinear shape, is constituted by a thermal resistance. It is fixed by one of its ends to the first pin 32 and to the support 56 by means of a copper rivet 58. The other end of the conductive blade 50 carries a contact pad and cooperates with a free end of the contact lug 52, the other end of which is fixed to the second pin 34 and to the support 56 by means of a second copper rivet 60.
• the second pin 34 has a folded part 62 extending by a rectilinear part 64 and by the socket 40 for receiving the connection end piece 46 of the fuse 14.
• the support 56 comprises a lug 66 on which the bimetallic strip 54 is fixed by means of its middle part.
• the bimetallic strip 54 has an elongated shape of a substantially concave wire, the concavity of which faces the support 56 in the closed current flow position (FIG. 2), and the concavity of which faces the conductive strip 50 in the open position of current limitation ( Figure 3), in which the two ends 68 and 70 of the bimetallic strip 54 cooperate respectively with two projections 72 and 74 provided on the face of the conductive blade 50 placed opposite the bimetallic strip 54 so as to spread the free end of this blade 50 of the contact tab 52 by deformation of the blade 50.
• the thermal resistance constituting the conductive strip 50 and the material constituting the bimetal strip 54 are chosen so that the cut-off intensity of the switch 48 is substantially between 3.5 and 8 amps, of preferably 5 amps, so to limit the power supplied to approximately 1000 watts.
• the power limiting device 10 described above is arranged upstream of the electrical installation of a dwelling in place of a conventional fuse, preferably at a location not accessible by the customer.
• the current supplied by the network therefore flows in the first current limiting means 12 and in the second current cutting means 14.
• the current flows in the switch 48 and in particular in the conductive strip 50, constituted by the thermal resistance, which heats up. Due to the heat exchange relationship between the blade 50 and the bimetallic strip 54, the heat energy emitted by the thermi ⁇ resistance that is transmitted to the bimetallic strip 54.
• the switch 48 suddenly passes from its closed current flow position to its open current interruption position under the effect of the sudden change in concavity of the bimetallic strip 54.
• the concavity of the bimetallic strip 54 is turned towards the blade 50 and the ends 68 and 70 of the bimetallic strip 54 repel the projections 72 and 74 of the blade 50. Consequently, the blade 50 is deformed and its free end deviates from the contact tab 52 ce which causes a power outage.
• the bimetallic strip 54 After a second response time due to the time required for the thermal resistance and the bimetallic strip 54 cool, the bimetallic strip 54 returns to its initial position and its ends 68 and 70 move away from the blade 50 which then returns to its initial position. The current therefore again flows through the device and the power supply to the electrical installation is again ensured, the free end of the conductive strip 50 resting on the contact tab 52.
• the response times required respectively for the transition from the closed position to the open position and from the open position to the closed position are determined by appropriately choosing the materials constituting the thermal resistance and the bimetallic strip.
• the response times for opening and closing are equal and are approximately 1 minute.
• the fuse constituting the second current cutoff means 14 preserves in a known manner a very low response time and less than that of the switch 48.
• the alloy wire contained in the cartridge 42 is broken before the switch 48 opens due to the response time thereof, which causes a power cut, and makes it possible to protect the installation connected downstream and upstream of the device.
• the device which has been described therefore makes it possible to limit the power supplied to an electrical installation to a predetermined threshold value, while allowing this threshold to be exceeded for a very short time, but protecting this installation against short-circuits .
• this device is very easy to assemble and can therefore easily be installed at a customer, in the event that the latter has not paid his energy bills, replacing a conventional fuse, or be easily replaced by a conventional fuse after the customer has paid their debts.
• the box in which the first current limiting means and the second current breaking means are enclosed may comprise a body in the shape of a rectangular parallelepiped provided at each of its end faces with a knife. electrical contact. This is also how the threshold values can be modified according to the desired power limitation and protection.

Landscapes

• Emergency Protection Circuit Devices (AREA)
• Fuses (AREA)
• Control Of Motors That Do Not Use Commutators (AREA)
• Gas-Insulated Switchgears (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
• Thermally Actuated Switches (AREA)
• Crushing And Grinding (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=9467179

Family Applications (1)

Country Status (7)

Families Citing this family (2)

Family Cites Families (6)

• 1994
  • 1994-09-22 FR FR9411328A patent/FR2725082A1/fr active Granted
• 1995
  • 1995-09-21 BR BR9509174A patent/BR9509174A/pt not_active IP Right Cessation
  • 1995-09-21 EP EP95932038A patent/EP0782757B1/de not_active Expired - Lifetime
  • 1995-09-21 ES ES95932038T patent/ES2118621T3/es not_active Expired - Lifetime
  • 1995-09-21 WO PCT/FR1995/001216 patent/WO1996009634A1/fr active IP Right Grant
  • 1995-09-21 DE DE69502026T patent/DE69502026T2/de not_active Expired - Lifetime
  • 1995-09-21 AT AT95932038T patent/ATE164965T1/de not_active IP Right Cessation

Non-Patent Citations (1)

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