Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
  • H01H85/02—Details
  • H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
  • H01H85/041—Fuses, i.e. expendable parts of the protective device, e.g. cartridges characterised by the type
  • H01H85/044—General constructions or structure of low voltage fuses, i.e. below 1000 V, or of fuses where the applicable voltage is not specified
  • H01H85/045—General constructions or structure of low voltage fuses, i.e. below 1000 V, or of fuses where the applicable voltage is not specified cartridge type
  • H01H85/0456—General constructions or structure of low voltage fuses, i.e. below 1000 V, or of fuses where the applicable voltage is not specified cartridge type with knife-blade end contacts
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
  • H01H85/02—Details
  • H01H85/38—Means for extinguishing or suppressing arc
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
  • H01H85/02—Details
  • H01H85/38—Means for extinguishing or suppressing arc
  • H01H2085/383—Means for extinguishing or suppressing arc with insulating stationary parts
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
  • H01H85/02—Details
  • H01H85/38—Means for extinguishing or suppressing arc
  • H01H2085/388—Means for extinguishing or suppressing arc using special materials

Definitions

• the invention concerns an electric fuse with knife-blade contacts.
• Such inventions belong to electricity, namely to basic electric elements, namely to fuses in which the electric current flows through a part of fusible material and this current is interrupted by means of displacement or interruption thereof in the case of excessive current, namely to fuses with knife-blade-end contacts, and at the same time such invention may also concern the construction concept of the melting member as such.
• the purpose of the invention is to prevent a fuse with knife-blade contacts from formation of electric arc in the area between said knife-blade contacts instead of increasing the length of the melting member and the casing of the fuse.
• an electric fuse with knife-blade contacts is among others disclosed in EP 1 403 894 Al as well as in DE 197 23 540 Al .
• the fuse comprises a tubular casing, which consists of an electric insulating material and is on its both terminal portions closed with rigid covers.
• Each of said covers is furnished with a so-called knife-blade contact, which is made of an electric conductive material and is insertable into appropriate fork-shaped seat, which consists of an electric conductive material and is integrated into each electric circuit, which is protected against the electric overloading by means of said fuse.
• a melting member is mounted within said casing between said apart from each other protruding knife- blade contacts, and is electrically interconnected with each of said contacts and surrounded with a granulated non-flammable means, in the practice usually with a sand on the basis of silica.
• Said melting member is conceived as a relatively thin band and consists of a metallic material having a pre-determined electric resistance, and is moreover furnished with throughout passages, which are equidistantly arranged along said band and by means of which weak zones are formed due to obtaining a pre-determined cross-section of said melting member, which together with said material with a pre-defined electric resistance defines the nominal capacity of the fuse i.e.
• the state of the art fuse is usually furnished with an indicator, by means of which interruption of the melting member can be visually detected from the outside.
• the present invention refers to an electric fuse, which generally comprises a tubular casing, which consists of electric insulating material and is on its both terminal portions closed by means of rigid covers, wherein each of said covers is furnished with a knife-blade contact, which consists of electric conductive material and is firmly connected therewith, while a melting member is mounted inside of said casing and is conceived as a flat band consisting of electric conductive material having a pre-determined electric resistance as well as a pre-determined length and thickness, wherein said band is on the one hand in the area of its terminal portions electrically interconnected with said blade-knife contacts and is on the other hand furnished with a plurality of weak zones, which are formed as perforations in said band between both dominant surfaces thereof and arranged equidistantly along the band and each per se extend in the transversal direction of the band.
• Each of said weak zones is formed as a plurality of throughout passages, which are equidistantly arranged in the transversal direction of the band, so that the cross-section of the melting member in each weak zone is pre-defined and is smaller than the cross-section of any other area of said melting member, and at the same time the interior of said casing is filled with a granulated non-flammable means, in particular with a sand on the basis of silica, by which said melting member is surrounded.
• the invention proposes that at least on each terminal portion of said melting member, namely between each belonging blade-knife contact and each neighboring weak zone, on both apart from each other facing dominant surfaces of said melting member, at least one barrier is arranged, which consists of a flexible and at least short-term thermally resistant material and which is adapted to prevent progression of the electric arc and extends along each of said dominant surfaces in the transversal direction of said melting member along the complete width thereof.
• a preferred embodiment of the invention provides that at least one further barrier consisting of flexible and at least short-term thermally resistant material is arranged on both apart from each other facing dominant surfaces of the melting member between at least two further weak zones thereof.
• a pre-determined distance between each of the terminal barriers, which are arranged closest to the belonging knife-blade contacts, and each knife-blade contact, is at least approximately 15% of the length of the melting member. It is particularly preferred, if in addition to said terminal barriers at least one barrier is available between each pair of each neighboring weak zones of the melting member.
• each barrier has at least approximately semi-circular profile with a diameter of 2 - 6 mm, preferably 3 - 4 mm, and consists of silicone, which is at least short-term thermally resistant up to 2000°C.
• Fig. 1 is a schematic cross-section of the fuse according to the invention along the first diametrical plane thereof; and Fig. 2 is also a schematic cross-section of the fuse according to Fig. 1 along the second diametrical plane thereof, which is perpendicular with respect to previously mentioned plane.
• the electric fuse as shown in Fig. 1 and 2 comprises a tubular casing 1, which consists of electric insulating material, in this particular case of ceramics.
• Said casing 1 is on its both terminal portions 11, 12 closed by means of rigid covers 21, 22, which are in the shown embodiment made of relatively thick metallic plates.
• Each of said covers 21, 22 is furnished with a knife-blade contact 210, 220, which consists of electric conductive material and is firmly connected with it, wherein said knife-blade contacts 210, 220 are arranged to extend along the central geometric axis of said casing 1 of the fuse and protrude apart from each other.
• a melting member 3 is mounted inside of said casing 1 and is conceived as a flat band consisting of electric conductive material having a pre-determined electric resistance as well as a pre-determined length L (Fig. 1) and thickness, wherein said band is on the one hand in the area of its terminal portions 31, 32 electrically interconnected with said blade-knife contacts 210, 220 and on the other hand furnished with a plurality of weak zones 30, 30', 30", which are arranged equidistantly along the band and each per se extend in the transversal direction of the band. Thickness of said band is usually between 0,04 and 0,24 mm.
• Said weak zones 30, 30', 30" are similarly like in the state of the art fuses available as perforations on said band extending between both dominant surfaces 33, 34 thereof, and each of said weak zones 30, 30', 30" is formed as a plurality of throughout passages 300, which are equidistantly arranged in the transversal direction of the band. Consequently, the cross-section of the melting member 3 in each weak zone 30, 30', 30" is pre-defined and is smaller than the cross-section of any other area of said melting member 3. Moreover, the interior of said casing 1 is filled with a granulated non-flammable means, in particular with sand on the basis of silica, by which said melting member 3 is surrounded.
• each barrier 51, 5 ⁇ , 51"; 52, 52', 52" is arranged, which is adapted to prevent progression of the electric arc and extends along each of said dominant surfaces 33, 34 in the transversal direction of said melting member 3 along the complete width thereof, and which consists of flexible and at least short-term thermally resistant material.
• At least one further barrier 51, 5 ⁇ , 51"; 52, 52', 52" consisting of flexible and at least short-term thermally resistant material is arranged on both apart from each other facing dominant surfaces 33, 34 of the melting member 3 between at least two further weak zones 30, 30', 30" thereof.
• a pre-determined distance T between each of the terminal barriers 51, 5 , 51"; 52, 52', 52", which are arranged closest to the belonging knife-blade contacts 210, 220, and each knife-blade contact 210, 220, should be at least approximately 15% of the length L of the melting member 3.
• a further embodiment of the fuse provides that in addition to said terminal barriers 51, 51', 51"; 52, 52', 52" at least one barrier 51, 51', 51"; 52, 52', 52" is available between each pair of each neighboring weak zones 30, 30', 30" of the melting member 3.
• the invention further provides that each barrier 51, 5 , 51"; 52, 52', 52" has at least approximately semi-circular profile, wherein the diameter D of each barrier 51, 51', 51"; 52, 52', 52” should be 2 - 6 mm, preferably 3 - 4 mm.
• Each barrier 51, 5 , 51"; 52, 52', 52" consists of silicone, which is at least short-term thermally resistant up to 2000°C.
• a material, which is suitable for producing said barriers51', 51"; 52, 52', 52" is at present commercially available under the commercial name »3M Fire Barrier 2000+ « or »FIRESTOP «, and is actually a silicone with added aluminium trihydrate Al(OH) 3 and/or boron nitride BN.

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• Fuses (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

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ID=52469268

Family Applications (1)

Country Status (6)

Cited By (2)

Citations (3)

Family Cites Families (1)

• 2014
  • 2014-10-24 SI SI201400387A patent/SI24871B/sl active Search and Examination
  • 2014-12-05 PL PL14835723T patent/PL3210231T3/pl unknown
  • 2014-12-05 PT PT148357239T patent/PT3210231T/pt unknown
  • 2014-12-05 WO PCT/SI2014/000072 patent/WO2016064352A1/en active Application Filing
  • 2014-12-05 EP EP14835723.9A patent/EP3210231B1/en active Active
  • 2014-12-05 ES ES14835723T patent/ES2819289T3/es active Active

Patent Citations (3)

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