Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
  • H01T4/00—Overvoltage arresters using spark gaps
  • H01T4/10—Overvoltage arresters using spark gaps having a single gap or a plurality of gaps in parallel
  • H01T4/12—Overvoltage arresters using spark gaps having a single gap or a plurality of gaps in parallel hermetically sealed
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
  • H01T4/00—Overvoltage arresters using spark gaps
  • H01T4/10—Overvoltage arresters using spark gaps having a single gap or a plurality of gaps in parallel

Definitions

• the invention relates to an overvoltage protection device with a first electrode, with a second electrode, with an air breakdown spark gap existing or effective between the electrodes, and with a housing which receives the electrodes, wherein when the air breakdown spark gap is ignited, a Arc arises between the first electrode and the second electrode.
• Electrical, but in particular electronic measuring, control, regulating and switching circuits are sensitive to transient overvoltages, as can occur in particular due to atmospheric discharges, but also due to switching operations or short circuits in energy supply networks.
• This sensitivity has increased to the extent that electronic components, in particular transistors and thyristors, are used; Above all, increasingly used integrated circuits are endangered to a great extent by transient overvoltages.
• Overvoltages are all voltages that are above the upper tolerance limit of the nominal voltage. Above all, this includes the transient overvoltages, which can occur due to atmospheric discharges, but also as a result of switching operations or short circuits in energy supply networks, and which can be coupled into electrical circuits galvanically, inductively or capacitively.
• surge protection devices In order to protect electrical or electronic circuits, in particular electronic measuring, control, regulating and switching circuits, especially also telecommunication devices and systems, wherever they are used, against transient overvoltages, surge protection devices have been developed and have been in use for more than twenty years Years known.
• An essential part of the surge protection device of the type in question here is at least one spark gap, which at a certain Overvoltage, the response voltage, and thus prevent overvoltages occurring in the circuit protected by an overvoltage protection device which are greater than the response voltage of the spark gap.
• the overvoltage protection device according to the invention has two electrodes and an air breakdown spark gap which exists or is effective between the electrodes.
• surge protection devices with an air breakdown spark gap there are surge protection devices with an air flashover spark gap in which a sliding discharge occurs when activated.
• Overvoltage protection devices with an air breakdown spark gap have the advantage of a higher surge current carrying capacity compared to surge protection devices with an air flashover spark gap, but the disadvantage of a higher - and not particularly constant - response voltage.
• various overvoltage protection devices with an air breakdown spark gap have already been proposed, which have been improved with regard to the response voltage.
• Ignition aids have been implemented in the area of the electrodes or the air breakdown spark gap effective between the electrodes, for. B. in such a way that at least one ignition aid triggering sliding discharge has been provided, which at least partially protrudes into the air breakdown spark gap, is web-like and made of plastic.
• An overvoltage protection device of the type described above is known from DE 44 02 615 C2.
• the known surge protection device has two narrow electrodes, each of which is angular and each has a spark horn and an angled connecting leg.
• the spark horns of the electrodes are provided with a hole in their areas adjacent to the connecting legs.
• the holes provided in the spark horns of the electrodes ensure that at the moment the overvoltage protection element responds, that is to say the ignition, the resulting arc is "set in motion" by a thermal pressure effect, that is to say it migrates away from its point of origin. Since the spark horns of the electrodes are arranged in a V-shape with respect to one another, the distance to be bridged by the arc is thus reduced
• BESTATIGUNGSKOPIE Moving out of the arc increases, which also increases the arc voltage.
• Another way of extinguishing the arc is to cool the arc by the cooling effect of insulating material walls and the use of gas-emitting insulating materials. This requires a strong flow of the extinguishing gas, which requires a great deal of design.
• the object of the present invention is now to provide an overvoltage protection device of the type in question which is distinguished by a high line follow current extinguishing capacity, but can nevertheless be implemented in a structurally simple manner.
• the overvoltage protection device in which the previously derived and shown object is achieved, is first and essentially characterized in that a third electrode is assigned to the first electrode and the second electrode and a second air between the first electrode and the third electrode. Breakdown spark gap exists or is effective that the third electrode via at least one impedance, in particular a varistor, is connected directly or indirectly to the second electrode and that after the discharge of the surge current through the first electrode, the first air breakdown spark gap and the second electrode of the remaining arcs from the first air breakdown spark gap to the second air
• the overvoltage protection device is generally parallel to the input of the circuit to be protected or the system or device to be protected.
• the - two-pole - overvoltage protection device is thus electrically, and galvanically, connected to the lines or connections between which the operating voltage is present during operation.
• the first line or the first connection is also described as being live, while the second line or the second connection is also referred to as ground.
• the first electrode of the overvoltage device is to be or are to be connected to the live line or the live connection and the second electrode of the overvoltage device is to be connected to ground.
• the overvoltage protection device according to the invention can also be connected in reverse, and of course the overvoltage protection device according to the invention can not only be used to protect circuits in which an AC voltage is present as the operating voltage, but rather the overvoltage protection device according to the invention can also be used without further ado if the operating voltage of the device to be protected Circuit is a DC voltage.
• the third electrode is connected directly or indirectly to the second electrode via at least one impedance.
• a direct connection means that the third electrode is connected to the second electrode within the overvoltage protection device according to the invention.
• An indirect connection of the third electrode to the second electrode is to be understood to mean that this connection can be or is to be implemented outside the surge protection device according to the invention, for. B. in that the overvoltage protection device has three poles and both the second electrode and the third electrode are to be grounded or grounded.
• the air breakdown spark gap ignites between the first and the second electrode when the response voltage is applied, as is customary in the prior art.
• a known ignition aid can be implemented in the area of the electrodes or in the air breakdown spark gap effective between the electrodes.
• the surge current is now diverted via the ignited spark gap, also as is known.
• the remaining arc is now moved according to the invention from the first air breakdown spark gap to the second air breakdown spark gap.
• the third electrode is not connected directly to the ground like the second electrode, but via at least one impedance, in particular a varistor, an abruptly increased impedance is now effective for the overvoltage protection device, so that a line follow current is prevented or an existing line follow current occurs Going out.
• a voltage divider lies between the first electrode or the live line or the live connection and ground, which ensures that when the mains voltage is present, the partial voltage present between the first electrode and the third electrode is lower than the burning voltage of the arc, this partial voltage is therefore no longer sufficient to maintain the arc.
• the manner in which the arc remaining after the discharge of the impulse current is carried from the first air breakdown spark gap to the second air breakdown spark gap or from the first electrode and the second electrode to the first electrode and the third electrode can be realized by different measures, in particular, as already stated, by pneumatic or magnetic blowing.
• Pneumatic blowing can be achieved by specifically guiding the gas or plasma flow resulting from the thermal of the arc.
• a preferred embodiment of the overvoltage protection device according to the invention that realizes this measure is characterized in that the housing and / or the third electrode has or has at least one opening, through the opening a pressure equalization is created and the pressure equalization is a targeted spreading of the gas or plasma flow from the second Electrode to the third electrode. As the gas or plasma flow propagates from the second electrode towards the third electrode, the base point of the arc is moved from the second electrode to the third electrode.
• the magnetic blowing already mentioned can be achieved by arranging the electrical connections of the overvoltage protection device to one another in a known manner in such a way that the surge current generates such a magnetic field that the arc from the first air breakdown spark gap to the second air breakdown - Spunk distance or from the first electrode and the second electrode to the first electrode and the third electrode.
• the teaching of the present invention is fundamentally independent of the specific design of the overvoltage protection device, in particular of the type and shape of the electrodes, the design of the air breakdown spark gap or the use of ignition aids. Nevertheless, two preferred exemplary embodiments of the surge protection device according to the invention are to be briefly stated below.
• a first preferred embodiment of the overvoltage protection device is characterized in that the housing has an essentially cylindrical shape, the first electrode is designed as a rod-shaped central electrode, and the second electrode and the third electrode are designed as cylindrical outer electrodes and are arranged concentrically around the first electrode are and that the second electrode and the third electrode are arranged at an axial distance from one another, - so that part of the first electrode is surrounded by the second electrode and another part of the first electrode by the third electrode.
• the arc is then blown parallel to the longitudinal extent of the first electrode from the second electrode to the third electrode, for. B. in that in the third electrode or on
• BESTATIGUNGSKOPIE Transition of the third electrode to the housing at least one radial opening is provided.
• a second preferred exemplary embodiment of the overvoltage protection device is characterized in that the first electrode is designed as a flat circular disk, in that the second electrode and the third electrode are arranged opposite the first electrode and in that the second electrode is centered on the first electrode and the third electrode is arranged concentrically around the second electrode.
• the third electrode is preferably not in the form of a ring, but in the form of a ring segment, in particular semicircular, so that the third electrode only partially concentrically surrounds the second electrode.
• the axial distance between the first electrode and the second electrode is less than the axial distance between the first electrode and the third electrode. This can be achieved by different heights or arrangements of the second electrode or the third electrode. The fact that the distance between the first electrode and the second electrode is less than the distance between the first electrode and the third electrode ensures that the air breakdown spark gap between the first electrode and the second electrode ignites and the surge current is derived via this air breakdown spark gap, that is to say via the first electrode and the second electrode.
• BESTATIGUNGSKOPIE 2 shows a basic sketch of a first exemplary embodiment of an overvoltage protection device according to the invention
• FIG. 3 shows an illustration of the electrode arrangement in the embodiment of the surge protection device according to the invention according to FIG. 2, partly in section,
• FIG. 4 shows a basic sketch of a second exemplary embodiment of an overvoltage protection device according to the invention
• Fig. 5 is an overvoltage protection device according to the second embodiment in section and
• Fig. 6 is a plan view of an overvoltage protection device according to the second embodiment.
• the overvoltage protection device which initially consists of a first electrode 1 and a second electrode 2 and an air breakdown spark gap 3 which is effective between the electrodes 1, 2.
• Such an overvoltage protection device is used to protect electrical circuits or systems or devices. If a transient overvoltage occurs that is greater than the response voltage of the overvoltage protection device, this responds, i. that is, the air breakdown spark gap 3 is ignited, an arc 4 is formed between the first electrode 1 and the second electrode 2.
• the arc 4 creates a relatively low-resistance connection between the first electrode 1 and the second electrode 2, so that when the operating voltage is applied, an undesired line follow current can flow through the overvoltage protection device.
• a line follow current is prevented or an occurring line follow current is extinguished by assigning a third electrode 5 to the first electrode 1 and the second electrode 2 and a second air between the first electrode 1 and the third electrode 5 Breakdown spark gap 6 exists
• the third electrode 5 is directly or indirectly connected to the second electrode 2 via at least one impedance, in the present case via a varistor 7, and that after the surge current has been discharged via the first electrode 1, the first air breakdown Spark gap 3 and the second electrode 2, the remaining arc 4 can be moved from the first air breakdown spark gap 3 to the second air breakdown spark gap 6 or from the first electrode 1 and the second electrode 2 to the first electrode 1 and the third electrode 5 is, in particular by pneumatic or magnetic blowing.
• the first electrode 1 is designed as a rod-shaped central electrode and the second electrode 2 and the third electrode 5 are designed as cylindrical outer electrodes and are arranged concentrically around the first electrode 1.
• the second electrode 2 and the third electrode 5 are arranged at an axial distance from one another.
• the third electrode 5 has a radial opening 9 through which pressure equalization occurs, the pressure equalization causing the plasma current to spread from the area between the first electrode 1 and the second electrode 2 into the area between the first electrode 1 and of the third electrode 5.
• the direction of this plasma flow is marked with P in FIG. 2.
• This plasma flow caused by the pressure equalization, drives an arc 4 present between the first electrode 1 and the second electrode 2 or the base point 8 of the arc 4 from the second electrode 2 to the third electrode 5.
• the second electrode 2 and the third electrode 5 are separated from one another by an annular spacer element 10.
• the radial distance between the first electrode 1 and the second electrode 2 or the third electrode 5 is ensured by two ring-shaped carrier elements 11, 12, the carrier elements elements 11, 12 have a radial section 13 and an axial section 14.
• the axial section 14 of the carrier elements 11, 12, together with the annular spacer element 10, serves as a support for the second electrode 2 and the third electrode 5.
• Both the annular spacer element 10 and the carrier elements 11, 12 are preferably made of plastic , Not shown in FIGS. 2 and 3 is a housing which accommodates the electrodes 1, 2, 5 as a whole. Such a housing, like the arrangement of the electrodes 1, 2, 5, is then essentially cylindrical.
• FIG. 4 to 6 show a second exemplary embodiment of the overvoltage protection device according to the invention, the shading of the third electrode 5 with a varistor 7 being indicated in FIG. 4 corresponding to FIG. 2 to clarify the function of the overvoltage protection device.
• the first electrode 1 is designed as a flat circular disk, only part of the first electrode 1 being shown in FIG. 6.
• the second electrode 2 and the third electrode 5 are arranged opposite the first electrode 1, the second electrode 2 being arranged centrally to the first electrode 1 and the third electrode 5 being arranged concentrically around the second electrode 2.
• FIG. 5 also shows a housing of the overvoltage protection device consisting of an upper housing part 15 and a lower housing part 16. An insulating part 17 made of plastic connects to the lower housing part 16. In the interior of the housing there is a pot-shaped receiving element 18 for the second electrode 2 and the third electrode 5, which is also made of plastic. A spacer element 19 formed in one piece with the cup-shaped receiving element 18 ensures the separation of the second electrode 2 from the third electrode 5.
• the second electrode 2 is circular and the third electrode 5 is semicircular.
• openings 20 are provided in the vicinity of the upper housing part 15, these openings 20 being located on the side of the lower housing part 16 facing the third electrode 5.
• the openings 20 are thus provided in the region of the lower housing part 16 which is adjacent to the air breakdown spark gap 6 between the first electrode 1 and the third electrode 5.
• recesses 21 are provided in the upper housing part 15, through which the excess pressure generated by the plasma flow can be reduced.
• a pressure equalization occurs through the openings 20 and the recesses 21, the pressure equalization causing the plasma flow to spread from the area between the first electrode 1 and the second electrode 2 into the area between the first electrode 1 and the third electrode 5.

Landscapes

• Emergency Protection Circuit Devices (AREA)
• Thermistors And Varistors (AREA)
• Plasma Technology (AREA)
• Amplifiers (AREA)

Applications Claiming Priority (5)

Publications (2)

Family

ID=26006497

Family Applications (1)

Country Status (8)

Families Citing this family (9)

Family Cites Families (12)

• 2001
  • 2001-07-23 WO PCT/EP2001/008487 patent/WO2002009251A2/fr not_active Ceased
  • 2001-07-23 CN CNB018021298A patent/CN100355164C/zh not_active Expired - Lifetime
  • 2001-07-23 EP EP01978261A patent/EP1226638B1/fr not_active Expired - Lifetime
  • 2001-07-23 ES ES01978261T patent/ES2250488T3/es not_active Expired - Lifetime
  • 2001-07-23 DE DE50107609T patent/DE50107609D1/de not_active Expired - Lifetime
  • 2001-07-23 US US10/088,633 patent/US6671126B2/en not_active Expired - Lifetime
  • 2001-07-23 AU AU10428/02A patent/AU1042802A/en not_active Withdrawn
  • 2001-07-23 AT AT01978261T patent/ATE306134T1/de not_active IP Right Cessation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events