EP0183542A1 - Stromkreisschutzanordnungen - Google Patents

Stromkreisschutzanordnungen Download PDF

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Publication number
EP0183542A1
EP0183542A1 EP85308627A EP85308627A EP0183542A1 EP 0183542 A1 EP0183542 A1 EP 0183542A1 EP 85308627 A EP85308627 A EP 85308627A EP 85308627 A EP85308627 A EP 85308627A EP 0183542 A1 EP0183542 A1 EP 0183542A1
Authority
EP
European Patent Office
Prior art keywords
circuit
shunt
protection element
series
switch device
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Withdrawn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
EP85308627A
Other languages
English (en)
French (fr)
Inventor
John Peter Phillips
Geoffrey Ian Palmer
John Douglas Flindall
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.)
Dubilier PLC
Original Assignee
Dubilier PLC
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
Priority claimed from GB858511755A external-priority patent/GB8511755D0/en
Application filed by Dubilier PLC filed Critical Dubilier PLC
Publication of EP0183542A1 publication Critical patent/EP0183542A1/de
Withdrawn legal-status Critical Current

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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
    • H01T1/00—Details of spark gaps
    • H01T1/14—Means structurally associated with spark gap for protecting it against overload or for disconnecting it in case of failure

Definitions

  • the present invention relates to circuit protection arrangements for protecting a circuit against damaging signals, such as high voltage or current surges and transients, and which comprise both a series protection element and a shunt protection element arranged so that in the event of a damaging signal the series element tends to open circuit and the shunt element tends to short circuit.
  • damaging signals such as high voltage or current surges and transients
  • a circuit protection arrangement for protecting a circuit against damaging signals, such as surges and transients, comprising the combination of a series protection element which becomes open-circuit in the event of a damaging signal and a shunt protection element which becomes a low resistance circuit in the event of a damaging signal, wherein the series protection element is a normally-closed switch device which is actuated in response to heat generated in the shunt protection element to open-circuit the series path and provide a short circuit of the shunt path.
  • the invention also provides a circuit protection arrangement for protecting a circuit against damaging signals, such as surges and transients, comprising a changeover switch device which is noramlly restrained in one position in which it completes a series circuit and forms a series protection element, and a shunt protection element in thermal relationship with said changeover switch device such that heat generated in the shunt protection element in response to a damaging signal causes actuation of the changeover switch device to its other position in which it opens the series circuit and short circuits the shunt path.
  • damaging signals such as surges and transients
  • the invention further provides a circuit protection arrangement comprising a changeover switch device which is normally retained in one position to provide a series protection element and which is thermally actuated to its other position by heat generated in a shunt protection element associated with said changeover switch device, and wherein when in said other position the switch device open circuits a series path and short circuits a shunt path.
  • the switching action is arranged to be irreversible, so that when the thermally actuated switch device has been switched to its other position, it will remain in this position even when the heat which caused its operation is removed.
  • the switch device includes a contact which is biassed towards the short circuit shunt position but which is retained in the normally closed series circuit protection position by means of a thermally softenable material, e.g. soft solder or fusible alloy, which softens to release the contact upon the application of sufficient heat from the shunt protection element.
  • a thermally softenable material e.g. soft solder or fusible alloy
  • the switch contact may be formed of a resilient wire or strip, which may include one or more turns to impart an enhanced springiness to the contact.
  • the shunt protection element comprises a gas discharge tube and the heat generated by the tube when it is struck is employed to cause the thermally responsive operation of the switch device.
  • the protection arrangements according to the invention may be applied to both balanced and unbalanced circuits and lines and advantageously the arrangements according to the invention may be in the form of a module which can be readily attached to and replaced in a circuit arrangement which is to be protected.
  • a pair of lines L balanced with respect to earth and having input terminals L1 and L2 are connected to equipment to be protected via terminals E1 and E2.
  • a shunt protection element comprising a double gas discharge tube 1 having its common electrode connected to earth via connecting pin 2 and its outer electrodes respectively connected to the two lines L via connecting pins 3 which are also connected to the normally-closed switch contact 4 disposed in series in each line.
  • These contacts 4 are each part of a changeover switch and are activated in response to heat generated in the gas discharge tube 1 so as to open-circuit the series path between the input lines and the equipment and short-circuit the shunt path provided by the tube 1.
  • actuation of the switch contacts 4 serves to short-circuit the equipment side across terminals E1 and E2 whilst in Figure 1b, actuation of the switch contacts 4 serves to short circuit the input line side across terminals L1 and L2.
  • the changeover switch could be arranged to short-circuit both the input side and the equipment side.
  • FIGs 2a and 2b show an embodiment of the invention in which the components are mounted on a circuit board.
  • Each switch contact 4 is in the form of a shaped resilient wire or strip which may be coiled about a post 5 to increase its flexural range and which has one end soldered to a point 6 connected to the terminal E1 or E2.
  • the spring contacts 4 are tensioned so that they are biassed towards the centre earthed pin 2 of the gas discharged tube, but they are constrained into contact with the pins 3 and also into contact with posts 7 connected to the line terminals L1 and L2 by fusible joints at points P1 and/or P2.
  • both points P1 and P2 may be fusible joints or that the desired effect can be achieved if only one point is a fusible joint and the other point is merely a pressure contact between the parts.
  • the fusible joints may be formed by a soft solder or a fusible alloy.
  • the fusible joints are intended to be softened by heat generated in the gas discharge tube 1 and whilst there is direct heat transfer to a fusible joint at points P1 via the pins 3, it is desirable to provide some form of heat transfer member, such as a metal strip between the insulating envelope of the gas discharge tube 1 and the posts 7 when fusible joints are located at the points P2.
  • Figure 2b shows the arrangement mounted on a circuit board B.
  • each switch contact 4 is again a resilient wire or strip which in this case forms a generally vee-spring coiled at an intermediate point of its length about a post 5 and has one arm 4a bearing against a pin forming the terminal E1 or E2.
  • the contacts 4 are tensioned so that the other arms 4b are biassed towards the centre earthed pin 2 of the gas discharge tube, but they are constrained into contact with the pins 3 and also into contact with pins forming the input terminals L1 and L2 by fusible joints at point P1 and/or P2.
  • both points P1 and P2 may be fusible joints or the desired effect can be achieved if only one point is a fusible joint and the other point is merely a pressure contact between the parts.
  • the fusible joints may be formed by a soft solder or a fusible alloy.
  • the fusible joints are intended to be softened by heat generated in the gas discharge tube 1 and whilst there is direct heat transfer to a fusible joint at points P1 via the pins 3, it is desirable to provide some form of heat transfer member, such as a metal strip between the insulating envelope of the gas discharge tube 1 and the posts P2 when fusible joints are located at the points P2.
  • This temperature rise could occur as a result of a heavy surge caused by lightning or by induction from a power line under fault conditions, or a steady AC or DC surrent of a few amps resulting from accidental contact between the line and a power cable. It is the object of the present invention to provide effective protection from these and similar hazards.
  • the module For balanced lines comprising both L1 and L2 and a common earth, the module requires two spring contacts as indicated. The resulting configuration is known as a 5-point arrangement. For unbalanced or "line-and-earth" circuits, a 3-point arrangement with a single spring contact only is required. Either arrangement may readily be constructed as a module.
  • the spring contacts could conceivably be thin enough to be heated by an excess of current and so either cause or aid melting of the fusible alloy.
  • a study of working conditions on practical lines shows that such a level of current can only arise as a result of an intrusive voltage high enough to "strike" the gas discharge tube and hence the tube conducts and so generates enough heat unaided.
  • a further advantage of this invention is that the spring contacts may be heavy enough to (i) avoid annealing and loss of tension due to the heating effects of fault-currents, (ii) add negligible series loss resistance to the signalling circuits and (iii) provide adequate contact pressure at any contact points which are not soldered.
  • protection arrangement formed as a module which is mechanically interchangeable with existing types of protection modules, as employed for example in telephone exchange equipment.
  • metal strip contacts rather than wire, it provides better pulse current carrying capacity, due both to the larger cross-section of the conductors and the larger pressure contact areas.
  • a gas discharge tube 1 is supported from a platform 10 of insulating material by two arms 11 formed of metal strip, which are respectively attached to annular terminals 3 connected to the outer electrodes of the gas discharge tube 1.
  • the lower end of the arms 11 are connected to tag strips 12 depending below the platform 10 and forming the input connections L1 and L2.
  • U-shaped springs 4 which are biassed such that they tend to contact the ends of a bridge contact 13 having one central limb 13a in contact with the annular terminal 2 connected to the common electrode of the gas discharge tube 1.
  • a second central limb 13b is connected to an earth pin 15 extending through the platform 10 and also serves to locate and support the bridge contact 12 above the ends of the U-shaped springs 4.
  • tags strips 14 forming the output connections El and E2.
  • the springs 4 are normally held in contact with the ends of the strips 14 by means of a soft solder or fusible alloy, as shown in the drawings, thus providing a series connection between the input terminals L1,L2 and output terminals E1,E2.
  • heat is conducted via the metal strips 11 and 13 to melt the fusible alloy, thereby releasing the U-shaped springs 4 so that they break contact with the strips 14 and make contact with the bridge 13, hence effectively open-circuiting the series paths between Ll,El and L2,E2 and short circuiting the gas discharge tube.
  • the spring contacts performing the switching function may be of various other forms besides that specifically shown.
  • the shunt protection device which generates the heat could be other than a gas discharge tube.

Landscapes

  • Emergency Protection Circuit Devices (AREA)
  • Fuses (AREA)
EP85308627A 1984-11-28 1985-11-27 Stromkreisschutzanordnungen Withdrawn EP0183542A1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB8430000 1984-11-28
GB8430000 1984-11-28
GB8511755 1985-05-09
GB858511755A GB8511755D0 (en) 1985-05-09 1985-05-09 Circuit protection arrangements

Publications (1)

Publication Number Publication Date
EP0183542A1 true EP0183542A1 (de) 1986-06-04

Family

ID=26288501

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85308627A Withdrawn EP0183542A1 (de) 1984-11-28 1985-11-27 Stromkreisschutzanordnungen

Country Status (3)

Country Link
EP (1) EP0183542A1 (de)
GB (1) GB2167915B (de)
NO (1) NO854721L (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2643504A1 (fr) * 1989-02-23 1990-08-24 Mars Actel Module de protection de ligne, a parafoudre, notamment pour bloc de raccordement telephonique
EP0471167A1 (de) * 1990-08-14 1992-02-19 KRONE Aktiengesellschaft Schutzschaltung und Schutzstecker in Telekommunikationsanlagen
FR2705838A1 (fr) * 1993-05-26 1994-12-02 Pouyet Int Réceptacle de sécurité pour parasurtension tripolaire de protection de ligne téléphonique.
CN1046371C (zh) * 1993-12-17 1999-11-10 株式会社日立制作所 带保险丝的负载开关
WO2006015641A1 (de) * 2004-08-04 2006-02-16 Epcos Ag Elektrische schaltung und bauelement mit der schaltung

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9100283D0 (en) * 1991-01-07 1991-02-20 Raychem Ltd Overcurrent protection device
US5319515A (en) * 1990-10-12 1994-06-07 Raychem Limited Circuit protection arrangement
KR930702811A (ko) * 1990-10-12 1993-09-09 죤 에버레트 벤슨 회로 보호 장치 및 유니트
US5424901A (en) * 1994-01-26 1995-06-13 Illinois Tool Works Inc. Sidactor fail-safe device
US5488535A (en) * 1994-01-26 1996-01-30 Illinois Tool Works Inc. Arc suppressor for sidactors
GB2336245A (en) * 1998-04-09 1999-10-13 Universal Scient Inductrial Co Thermal fuse for fixing on a circuit board

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3947730A (en) * 1974-07-22 1976-03-30 Porta Systems Corporation Telephone line surge protecting device
US4034326A (en) * 1975-04-17 1977-07-05 Comtelco (U.K.) Limited Temperature sensitive trip device
US4477857A (en) * 1982-12-27 1984-10-16 Gte Network Systems Corporation Printed circuit fuse

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3723820A (en) * 1972-01-03 1973-03-27 Brown Radio & Tv Device for protecting against a.c. transient overloads with means for automatically resetting same
US4068277A (en) * 1976-07-19 1978-01-10 Tii Corporation Overvoltage protector
NL8006411A (nl) * 1980-11-25 1982-06-16 Philips Nv Inrichting voor het beveiligen tegen oververhitting door overspanning van een spanningsbegrenzende schakeling.
GB2136646A (en) * 1983-02-04 1984-09-19 Standard Telephones Cables Ltd Line circuit protection
GB2153609B (en) * 1984-02-02 1987-12-02 Lucas Elect Electron Syst Surge suppressor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3947730A (en) * 1974-07-22 1976-03-30 Porta Systems Corporation Telephone line surge protecting device
US4034326A (en) * 1975-04-17 1977-07-05 Comtelco (U.K.) Limited Temperature sensitive trip device
US4477857A (en) * 1982-12-27 1984-10-16 Gte Network Systems Corporation Printed circuit fuse

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2643504A1 (fr) * 1989-02-23 1990-08-24 Mars Actel Module de protection de ligne, a parafoudre, notamment pour bloc de raccordement telephonique
EP0384347A1 (de) * 1989-02-23 1990-08-29 MARS-ACTEL Société Anonyme dite: Leitungsschutzvorrichtung mit Blitzschutz für Anschluss, insbesondere Fernsprechanlagen
EP0471167A1 (de) * 1990-08-14 1992-02-19 KRONE Aktiengesellschaft Schutzschaltung und Schutzstecker in Telekommunikationsanlagen
DE4026004A1 (de) * 1990-08-14 1992-02-20 Krone Ag Schutzschaltung und schutzstecker in telekommunikationsanlagen
CN1037731C (zh) * 1990-08-14 1998-03-11 克罗内有限公司 电信设备的保护电路和保护插塞
FR2705838A1 (fr) * 1993-05-26 1994-12-02 Pouyet Int Réceptacle de sécurité pour parasurtension tripolaire de protection de ligne téléphonique.
CN1046371C (zh) * 1993-12-17 1999-11-10 株式会社日立制作所 带保险丝的负载开关
WO2006015641A1 (de) * 2004-08-04 2006-02-16 Epcos Ag Elektrische schaltung und bauelement mit der schaltung
US7737805B2 (en) 2004-08-04 2010-06-15 Epcos Ag Electrical circuit and component with said circuit

Also Published As

Publication number Publication date
GB2167915B (en) 1988-05-25
GB8529217D0 (en) 1986-01-02
NO854721L (no) 1986-05-29
GB2167915A (en) 1986-06-04

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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18D Application deemed to be withdrawn

Effective date: 19890531

RIN1 Information on inventor provided before grant (corrected)

Inventor name: PALMER, GEOFFREY IAN

Inventor name: PHILLIPS, JOHN PETER

Inventor name: FLINDALL, JOHN DOUGLAS