EP0893863A1 - Tube à décharge à gas muni d'un boítier d'oxyde de métal - Google Patents

Tube à décharge à gas muni d'un boítier d'oxyde de métal Download PDF

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Publication number
EP0893863A1
EP0893863A1 EP98401806A EP98401806A EP0893863A1 EP 0893863 A1 EP0893863 A1 EP 0893863A1 EP 98401806 A EP98401806 A EP 98401806A EP 98401806 A EP98401806 A EP 98401806A EP 0893863 A1 EP0893863 A1 EP 0893863A1
Authority
EP
European Patent Office
Prior art keywords
voltage
electrodes
varistor
gas
current
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP98401806A
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German (de)
English (en)
Inventor
Neil Mcloughlin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Harris Corp
Original Assignee
Harris Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Harris Corp filed Critical Harris Corp
Publication of EP0893863A1 publication Critical patent/EP0893863A1/fr
Withdrawn legal-status Critical Current

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    • 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

Definitions

  • the present invention relates to electrical voltage surge suppression devices. Suppression devices are widely used for protection of electrical equipment from overvoltage conditions caused by electrical surges, lightning, high voltage line contact and the like.
  • Crowbar devices include plasma surge arrestors, spark gap devices, gas discharge tubes (GDTs), and silicon controlled rectifiers (SCRs). These devices limit the current flow into the protected circuit by abruptly switching from a high impedance state, e . g ., an open circuit, to a low impedance state, e . g ., a short circuit, responsive to the circuit voltage exceeding a set impedance switching threshold level.
  • GDTs gas discharge tubes
  • SCRs silicon controlled rectifiers
  • crowbar devices When in a high impedance state, no current flows through the crowbar device and no power is consumed. Once switched into the low impedance state, the voltage across the crowbar device is at a relatively low level and the device does not dissipate a significant portion of the power delivered during the overvoltage event but rather passes the power from line to ground. For example, once the voltage across a GDT exceeds a characteristic gas breakdown voltage (the GDT threshold voltage), the GDT switches to a low impedance state where the voltage across the GDT is less than 15 volts.
  • the GDT threshold voltage a characteristic gas breakdown voltage
  • Clamping devices include zener (avalanche) diodes and metal oxide varistors (MOVs).
  • clamping devices limit the voltage transient to a specified voltage level by varying the clamping device's intemal resistance responsive to the applied voltage.
  • Clamping devices advantageously provide rapid response and protect against fast rising surge conditions.
  • the zener diode presents an open to the circuit until a voltage surge in excess of the diode breakdown voltage is present in the circuit. With the zener diode conducting, the voltage across the circuit is limited to the zener breakdown voltage. Zener diodes are typically used in low voltage applications and, due to capacitive effects, are generally not suitable to RF applications.
  • the clamping device With a MOV device, the clamping device's internal resistance changes with the applied voltage so that the MOV acts as a voltage sensitive, nonlinear resistive element in parallel with the circuit being protected. As a clamping device must absorb the surge energy at the clamped voltage, clamping devices cannot withstand the same high level of surge current as a gas discharge tube. MOVs suffer from high current surges causing cumulative degradation and performance changes. Thus, while suitable for higher voltage applications than zener diode devices, fuses may be required to protect the MOV from damage by exposure to excessive voltage levels.
  • An object of the invention is to provide protection against both fast rising voltage levels and protection at relatively high voltages for an extended period, crowbar and clamping devices have been used in combination.
  • the present invention improves on the prior art with a simpler, less complex to manufacture, electrical over-voltage suppression device integrating crowbar protection with clamping protection in a single component form.
  • An object of the present invention is to provide a gas discharge tube suppressor with both crowbar and clamping protection without the use of a varistor separate from the gas discharge tube, and to provide a voltage arrestor using a gas discharge tube for crowbar protection and an integral varistor for clamping protection.
  • Another object is to provide a voltage suppression device providing both crowbar protection and clamping protection in single component form.
  • Another object is to provide a voltage surge suppression device having a gas discharge tube and varistor formed as a single component, and also to provide a gas surge arrestor using varistor ceramic as component of a sealed gas housing.
  • the present invention includes an electrical suppression device integrating crowbar protection with clamping protection in a single component, comprising first and second spaced-apart electrodes, a gas medium positioned between the electrodes and having both a relatively low current conducting state and a relatively high current conducting state, said high conducting state corresponding to application of a characteristic breakdown voltage between the first and second electrode, a voltage variable resistor connected between the first and second electrodes, in which the resistor is a body extending from the first electrode to the second electrode and shaped to form in combination with the electrodes a sealed housing to retain the gas medium.
  • the invention also includes a circuit over-voltage protective device with voltage-dependent current paths comprising, an envelope containing a volume of gas, said envelope having varistor ceramic portions with terminations, arcing targets attached to said envelope and exposed to said gas, device contacts for connecting said envelope into a circuit, attached to said envelope and operatively connected to apply a circuit voltage to said arcing targets and said terminations, whereby upon applying circuit voltage to said contacts the protective device provides a voltage sensitive, nonlinear current path through said varistor ceramic portions until said applied circuit voltage ionizes said gas between said arcing targets and provides a current path between the arcing targets.
  • a circuit over-voltage protective device with voltage-dependent current paths comprising, an envelope containing a volume of gas, said envelope having varistor ceramic portions with terminations, arcing targets attached to said envelope and exposed to said gas, device contacts for connecting said envelope into a circuit, attached to said envelope and operatively connected to apply a circuit voltage to said arcing targets and said terminations, whereby upon applying circuit voltage to said
  • Figure 1 illustrates a prior art GDT surge arrestor.
  • Figure 2 is an equivalent circuit of the Figure 1 GDT arrestor.
  • FIG. 3 is an illustration of one embodiment of the present invention.
  • Figure 4 is the equivalent circuit of the Figure 3 device.
  • FIG. 5 illustrates another embodiment of the present invention.
  • Figure 6 is an equivalent circuit of the Figure 5 embodiment.
  • FIG. 1 shows prior art GDT surge arrester 10 and consists of housing 20, electrodes 30, device leads 40, and fill gas 50.
  • Housing 20 may be metal, glass, or ceramic and holds electrodes 30 at a proper spacing distance.
  • the volume defined by housing 20 and electrodes 30 may contain ionizable fill gas 50.
  • Electrodes 30 act as arcing targets and may be shaped to optimize current arcing at fill gas 50 breakdown voltage.
  • Electrodes 30 may include metal end caps 35 sealing against housing 20 to contain and prevent leakage of fill gas 50.
  • FIG. 2 provides an equivalent circuit of prior art GDT surge arrester 10.
  • Prior art GDT 10 functions as a crowbar device, triggered at fill gas 50 characteristic breakdown voltage value, e . g ., 400-600 volts, shorting line to ground across gap 80.
  • Figure 3 refers to an embodiment for surge suppressor 60 includes electrodes 30, device leads 40, fill gas 50, and varistor housing 70.
  • Varistor housing 70 in combination with electrodes 30 define a gas discharge tube containing fill gas 50.
  • Varistor housing 70 may serve to hold electrodes 30 spaced apart at a optimized distance for current arcing.
  • Electrodes 30 may include end caps 35 forming part of the gas discharge tube and providing a mounting surface for device leads 40.
  • Figure 4 provides an equivalent circuit diagram Surge suppressor 60 functions as varistor 90 in parallel with a arc gap 80.
  • varistor 90 serves as a transient suppressor providing clamping protection up to a specified voltage, after which crowbar protection is provided by arc gap 80.
  • Arc gap 80 trigger voltage is pre-set at a value to complement the operation of varistor 90, yet sufficiently low to avoid damaging varistor 90.
  • fill gas 50 ionizes, changing from a nonconducting state to a conducting state, and current arcs across gap 80, both shorting line to ground to provide crowbar protection and shorting out varistor 90 to avoid subjecting varistor 90 to a voltage, and the resulting high current, in excess of a level that would cause damage to varistor 90.
  • This arrangement thus provides both crowbar and clamping protection in a single component device and further obviates the need for a fuse to protect the varistor.
  • Varistor housing 70 comprises a zinc oxide ceramic and acts as a metal oxide varistor.
  • surge suppressor 60 is in the form of a cylinder having an exterior length of 0.196 inches and diameter of 0.316 inches, an interior volume of 7.45 x 10 -3 cubic inches filled with a gas of consisting principally of Argon results in a GDT having a breakdown voltage of 600 volts. With a typical zinc oxide ceramic, this embodirnent would exhibit a clamping voltage of 400 volts at 10 amps.
  • FIGS 5 and 6 depict a three terminal, 2 GDT surge arrestor embodiment of the present invention is depicted.
  • Three terminal arrestor 100 includes three spaced apart electrodes 30 and varistor housing 70 defining 2 gas discharge tubes.
  • An electrical over-voltage suppression device integrating crowbar protection with clamping protection in a single component form, a gas volume defined by a gas discharge tube with spaced-apart electrodes acting as arcing targets providing crowbar protection, and a varistor integral to the gas discharge tube providing clamping protection.

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  • Emergency Protection Circuit Devices (AREA)
  • Thermistors And Varistors (AREA)
EP98401806A 1997-07-21 1998-07-17 Tube à décharge à gas muni d'un boítier d'oxyde de métal Withdrawn EP0893863A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US897644 1992-06-11
US89764497A 1997-07-21 1997-07-21

Publications (1)

Publication Number Publication Date
EP0893863A1 true EP0893863A1 (fr) 1999-01-27

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP98401806A Withdrawn EP0893863A1 (fr) 1997-07-21 1998-07-17 Tube à décharge à gas muni d'un boítier d'oxyde de métal

Country Status (2)

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EP (1) EP0893863A1 (fr)
JP (1) JPH11126674A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2345390A (en) * 1998-12-10 2000-07-05 Bettermann Obo Gmbh & Co Kg Compact varistor and spark gap surge arrester
ES2195743A1 (es) * 2001-09-27 2003-12-01 Diseno Sistemas Silicio Sa Circuito protector frente a sobretensiones.
WO2004034545A1 (fr) * 2002-10-08 2004-04-22 Diseño De Sistemas En Silicio, S.A. Circuit de protection contre les surtensions
US10673187B2 (en) * 2017-01-06 2020-06-02 Citel Integrated component for protecting against overvoltages, in particular for a coaxial-cable system

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101779349B (zh) * 2007-06-21 2013-05-29 埃普科斯股份有限公司 用于防雷电及过压保护的装置和模块
JP5252272B2 (ja) * 2008-05-28 2013-07-31 貴康 金村 放電ノイズ吸収素子及びこれを利用した放電ギャップ式避雷器並びに放電跳ね返り波回避回路及びノイズ回避ボックス

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2355426A1 (de) * 1973-11-06 1975-05-15 Siemens Ag Ueberspannungsableiter
DE2641514A1 (de) * 1976-09-15 1978-03-16 Siemens Ag Ueberspannungsableiter
US5289335A (en) * 1989-01-21 1994-02-22 Central Lightning Protection Co. Ltd. Compound lightning arrester for low voltage circuit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2355426A1 (de) * 1973-11-06 1975-05-15 Siemens Ag Ueberspannungsableiter
DE2641514A1 (de) * 1976-09-15 1978-03-16 Siemens Ag Ueberspannungsableiter
US5289335A (en) * 1989-01-21 1994-02-22 Central Lightning Protection Co. Ltd. Compound lightning arrester for low voltage circuit

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section Ch Week 9123, Derwent World Patents Index; Class L03, AN 91-164576, XP002078484 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2345390A (en) * 1998-12-10 2000-07-05 Bettermann Obo Gmbh & Co Kg Compact varistor and spark gap surge arrester
ES2195743A1 (es) * 2001-09-27 2003-12-01 Diseno Sistemas Silicio Sa Circuito protector frente a sobretensiones.
WO2004034545A1 (fr) * 2002-10-08 2004-04-22 Diseño De Sistemas En Silicio, S.A. Circuit de protection contre les surtensions
US10673187B2 (en) * 2017-01-06 2020-06-02 Citel Integrated component for protecting against overvoltages, in particular for a coaxial-cable system

Also Published As

Publication number Publication date
JPH11126674A (ja) 1999-05-11

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