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
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/6606—Terminal arrangements
• • 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
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/664—Contacts; Arc-extinguishing means, e.g. arcing rings
• • 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
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/664—Contacts; Arc-extinguishing means, e.g. arcing rings
  • H01H33/6642—Contacts; Arc-extinguishing means, e.g. arcing rings having cup-shaped contacts, the cylindrical wall of which being provided with inclined slits to form a coil
• • 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
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/664—Contacts; Arc-extinguishing means, e.g. arcing rings
  • H01H33/6643—Contacts; Arc-extinguishing means, e.g. arcing rings having disc-shaped contacts subdivided in petal-like segments, e.g. by helical grooves
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H2201/00—Contacts
  • H01H2201/022—Material
  • H01H2201/03—Composite
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H2203/00—Form of contacts

Definitions

• the invention relates to a vacuum interrupter with double contact arrangement within concentrically arranged contact parts at each side, th.m. on the side of the a fixed contact arrangement as well as on the side of a movable contact arrangement according to the preamble of claim 1.
• the inner contacts are responsible for nominal current conduction and thus should have a very small total resistance (contact and bulk resistances). For this reason, the inner contacts are TMF-like or Butt contacts and made from high electrical conductive material like copper or CuCr.
• the inner contacts following the state of the art description, hold the initial phase of the arc before its commutation to the outer contacts.
• the outer contacts are only responsible for the AMF field generation, thus can be designed with a thin cup-shaped layer made from hard conductive material like stainless-steel. This option offers many advantages over the conventional AMF contacts leading to lower material cost and very robust contacts assembly. These advantages are: 1. High mechanical strength
• the outer cup shaped contact is made from a single, double or multiple layer arrangement, wherein at least one layer is made from a hard steel or steel alloy and at least, in case of a multilayer arrangement, a second layer is made from material with high thermal conductivity.
• the material of high thermal conductivity is copper.
• a further advantageous embodiment is, that the hard steel or steel alloy is stainless steel.
• the inner layer of the double or multiple layer contact arrangement is made of stainless steel or another material with same stiffness, and the outer layer is made of copper.
• a further advantageous embodiment is, that in case of a cup shaped contact arrangement the inner layer of the contact arrangement is made of copper, and the other or in case of a cup shaped arrangement the outer layer is made of stainless steel.
• a further advantageous embodiment is, that the contact parts are positioned like that only the inner contacts are in touch when the vacuum interrupter is in closed position, and the whole nominal current flows through them.
• a further embodiment is, that the gap distance in opened position of the
• vacuuminterrupter between the inner contacts and the outer contacts is kept the same. But in closed position the quasitotality of nominal current flows through the inner contacts.
• a last advantageous embodiment is, that the gap distance between the outer contacts in opened position of the vacuum interrupter is smaller than the gap distance between the inner contacts. But in closed position a big part of nominal current flows through the inner contacts.
• electrode is the whole moving or fixed parts.
• An electrode in this case includes the combination of the inner and the outer contacts.
• the inner and/or outer contacts relative position can be classified according to the following variations:
• the inner part of the double contact is designed for nominal current path thus the contacts resistance should be as low as possible. This is achieved by applying high closing forces to minimize the contact resistance.
• the contact resistance Rc is inversely proportional to the square of the closing forces, i.e. decreases by increasing the closing forces.
• the electrode is designated to the whole moving or fixed parts.
• An electrode in this case includes the combination of the inner and the outer contacts.
• the inner and/or outer contacts relative position can be classified according to the following variations, like seen in figure 2.
• the inner contacts are in touch when the switch is in closed position and the whole nominal current flows through them. They are also used at the initial vacuum arcing phase while performing the current interruption.
• the inner contacts (TMF-like) of both, moving and fixed electrodes, are emerging compared to outer contacts, like shown in figure 2a.
• b. Alternatively, only one of the inner contacts (the moving or the fixed one) is emerging compared to the outer contact, while the other inner contact is at the same level as the outer contact, see figure 2b. In this case, the total forces in closed position are held by the inner contacts. This means that the nominal current flows entirely through the inner contacts.
• the arc ignites first between the inner contacts, then develops in succeeding modes as the contacts distance increased then commutes partially to the outer contacts after some milliseconds. At this time the outer contacts start to generate AMF field corresponding to the current flow through them. After that the arc takes some other milliseconds to commute to fully diffuse arc as the AMF generation starts with some delay (Note: The delay caused by the phase shift between the B-field (AMF) and the current due to eddy currents effect is not taken into account here; it's found to be negligible in this double-contact structure). 2.) In the second case, the gap distance (in open position) between the inner contacts (moving and fixed) and the outer contacts (moving and fixed) is kept the same. Two relative position cases can be distinguished. a. ) The inner contact of one electrode (moving and fixed) is rising compared to the outer contact, while the position of the inner part of the opposite electrode is lowered
• the elastic deformation propriety of the outer contacts ensures the arc ignition between the outer contacts as the last touching point is found between them.
• the third case is the inverse of the first one, i.e. the gap distance between the outer contacts (in open position) is smaller than the gap distance between the inner contacts. However this difference should be as small as 0.1 - 2.5 mm and
• the inner contacts can be either touching or not in closed position.
• the whole forces are held by the outer contact (easel ), but in case of small respective gap distance between the inner contacts and/or big outer contacts coil elesticity, a considerable amount of forces are held by the inner contacts (case2).
• the arc ignition will start at the outer contact but the contact resistance of the inner contacts (for the nominal current) is increased unless the elastic properties of the outer contacts are changed (to increase the deformation of the outer contact). It is important to notice that the elasticity of the outer contact can be influenced by the outer contact diameter, the cup thickness and the cup material as well.
• the outer contact is made from a double or multiple layers in which one layer at least is made from a strong, elastic and conductive material like stainless steel, and at least a second layer made from high thermal conductivity material like copper.
• This combination offers both robustness and cost effectiveness criteria to the contact assembly and would guarantee a better thermal management during and after arcing (fast contacts cooling).
• the multi-layer cup-shaped contact may have several various arrangements on the superposition order of the layers depending on the intended application. For example for a double-layer:
• the inner layer is made from stainless-steel (hard conductive material) and the outer one from copper (excellent thermal and electrical conductor). In this case the major part of the short circuit current passes through outer layer (copper), thus increasing the effective AMF area. This arrangement is favoured for increased high current interruption performance.
• the inner layer is made from copper and the outer one from stainless-steel.
• the outer layer of the cup-shaped contact is made from stainless-steel thus could be considered for withstanding high voltage towards the shield.
• This arrangement can be a good option for high voltage application.
• the contacts forces distribution changes slightly by using these two arrangements due to the change in the outer contact elasticity as shown, see for example figure 3.
• the force between the outer contacts decreased from 100 N in case of stainless- steel monolayer to ⁇ 70 N by using a double layer.
• the inner layer can be made from stainless-steel and a second layer made from copper; a third very thin layer can be superposed to the second outer layer and made from stainless-steel or another metal with good high voltage withstand properties (Nickel, steel-alloy, etc).
• This very thin layer can be obtained for example by coating with electroplating, electroforming or PVD processes, etc.
• an inversed arrangement of the multilayer cup-shape contact is possible.
• the inner layer is made from copper and the outer layer from stainless-steel (the stainless-steel layer is necessary for contacts robustness).
• the stainless-steel layer is superposed by a very thin layer of copper which can be obtained by coating with electroplating, electroforming or PVD processes, etc.
• Figure 3a shows a double layer system with a stainless-steel inner layer and a copper outer layer.
• Figure 3b shows a double layer system with a copper inner layer and a stainless steel outer layer.
• Figure 3c shows a multilayer system with stainless steel inner layer, plus a copper outer layer with a thin coverage by steel/nickel layer.
• Figure 3d shows a multilayer system with a copper inner layer plus a stainless steel outer layer with a thin coverage by a thin copper layer.

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• Contacts (AREA)
• High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)

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Applications Claiming Priority (4)

Related Child Applications (1)

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Citations (3)

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• 2012
  • 2012-10-18 EP EP12007203.8A patent/EP2674955B1/en active Active
  • 2012-10-18 EP EP20189894.7A patent/EP3754684A1/en active Pending
• 2013
  • 2013-06-11 JP JP2015516506A patent/JP2015519713A/ja active Pending
  • 2013-06-11 IN IN10567DEN2014 patent/IN2014DN10567A/en unknown
  • 2013-06-11 WO PCT/EP2013/001708 patent/WO2013185906A1/en not_active Ceased
  • 2013-06-11 CN CN201380038542.1A patent/CN104488057A/zh active Pending
• 2014
  • 2014-12-11 US US14/567,489 patent/US20150114931A1/en not_active Abandoned

Patent Citations (3)

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