WO1985000473A1

WO1985000473A1 - Telecommunication system surge protection device

Info

Publication number: WO1985000473A1
Application number: PCT/AU1984/000129
Authority: WO
Inventors: Frank Zamburro
Original assignee: Frank Zamburro
Priority date: 1983-07-07
Filing date: 1984-07-09
Publication date: 1985-01-31
Also published as: EP0148911A4; EP0148911A1

Abstract

A surge protection device for a telecommunication system is in the form of a component (10) which may be interposed in a line of the system. Positioned across conductors (32, 34) of the component (10) which conductors (32, 34) are, in use, connected to conductors of the system line, is a gas arrestor (36) which operates to deflects surges reaching the component along the system line.

Description

TITLE: TELECOMMUNICATION SYSTEM SURGE PROTECTION DEVI

This invention relates to a device for arresting any surge or overload which may be applied to a telecommunicati system, its lines and equipment, to prevent damage to areas of the system.

It has long been known that in theory lightning may contact telephone lines and seek a path to ground through t lines, and through any equipment connected to the lines. The Australian Telecommunications Commission (Telecom Australia) , on page 8 of its 1982 White Pages (Alphabetical) Telephone Directory for the city of Melbourne, includes a warning concerning the use of telephones during thunderstor The warning states in part: "The telephone .... can be a source of electric and acoustic shock during thunderstorms" The user is advised: "Use your telephone only for calls of the utmost urgency". Recently, the public in Australia ha been made aware of damage actually caused to equipment, and of injury caused to persons, who have been in close proxim to telephone equipment when lightning has struck a part of the telephone system and has resulted in a voltage surge along the telephone lines to the equipment.

Although the protection of human life and well-being must be the most important consideration in such cases, it is also necessary to consider ways to protect expensive equipment from the results of lightning strikes. In partic it is conceivable that a fire could be started in unattende premises if an article of telephone equipment was destroyed or damaged as a result of a lightning strike. Of course, lightning surges can be caused by a direct strike, or induce in a system by a nearby strike.

Accordingly, it is an object of this invention to prov a device for isolating areas of a telecommunication system from the effects of surges.

The invention consists of a surge protection device for a telecommunication system, said device being capable of location in said system between an area where surge initiati may occur and an element of said system, characterized by a gas arrestor situated in said device such that when said dev

OMPI is located in said system, said gas arrestor is connected to a line of said system along which said surge may be propagated.

In the drawings: Fig. 1 is a side elevation of a first embodiment of a surge protection device according to the invention; and

Fig. 2 is a side elevation of a second embodiment of a surge protection device according to the invention.

Referring firstly to Fig. 1, the device is in the for of a component 10 which is capable of being inserted into a telephone line between a Telecom Australia standard telepho socket and a Telecom Australia standard telephone plug, the latter of which is used to connect a telephone to the telep system. It must be stressed that for other telephone and telecommunication systems, the component 10 would be design to fit the standard plugs and sockets of those systems, or be located permanently in a line of said systems.

The component 10 includes a plug section 12 which has three pins 14, 16, 18 and an apertured projection 20 which are adapted to be pushed into a Telecom Australia standard telephone socket, a socket section 22, which has three sock 24, 26, 28 which are adapted to receive the pin of a Teleco Australia standard telephone plug.

The component has a casing 30 which preferably is for from the same type of plastics material used in the standar plug and socket referred to hereinbefore. Within the casin there is an electrical connection 32 between pin 14 and soc 28, and another connection 34 between pin 18 and socket 24. The device 10 is shown with only two electrical connections but of course three or more wires are sometimes utilized, and this invetion is of course not limited to the arrangeme shown in Fig. 1.

Connected between connections 32 and 34 (or between sockets 24 and 28, or pins 14 and 18, or connected between sets of connections for numbers greater than two) is a gas arrestor 36. Gas arres ors are known per se; they act to "deflect" or *fiivert" voltages over a pre-set value. For example, telephones are often operated on a voltage of 50V and therefore a gas arrestor could be used, in a telephone system of that type, with a pre-set voltage of, say, 75V. As long as the maximum instantaneous voltage remained below 75V, the gas arrestor would not be active in the circuit an the article of telephone equipment would function normally. However, if a voltage surge occurred, with a voltage in excess of 75V (which would clearly be the situation if t telephone line was affected by a lightning strike, causing a direct or indirect lightning surge) gas arrestor 36 would come into operation to "deflect" the voltage back through the lines, thereby isolating the article (and any person in close proximity to it) from the surge.

The preferred gas arrestor 36 for the embodiment of F 1 is a Siemens T61-350. The third connector of the arresto may be connected to earth, as descirbed hereinafter in rela to the embodiment of Fig. 2.

This invention is of course, not limited to the kinds of voltage values referred to by way of example in the description of this embodiment.

The advantage of the device of this invention is that component 10 can be bought "off the shelf" and easily inter between a telephone plug and a telephone socket. Alternati the arrangement can be fitted more permanently in a fixed position within a system, in a telephone itself in a junctio or elsewhere in the telephone lines or system. It may well be that a severe lightning surge will dest components of the device, but such a device can be replaced more cheaply than an article of telephone equipment, and of course its destruction may have saved a life or at the very least, injury to a person. It has been suggested that the first embodiment of the invention described in relation to Fig. 1, may not protect a end user of a telephone or the like in the extremely rare situation when a voltage surge occurs on both or all incomin lines. In such a situation it may not be possible to divert the surge along the other line.

The embodiment of Fig. 2 is designed to overcome this very unlikely scenario. In the drawing, reference numerals 10 to 30 relate to the features denoted by the same referenc numerals in Fig. 1. In this embodiment, sockets 24, 26 and 28 are shown a connected to pins 18, 16 and 14, by conductors.38, 40 and 4 Connected to conductor 38 is a first gas arrestor 44 , and connected to conductor 42 is a second gas arrestor 46. The two gas arrestors are connected together by a conductor 48, to which is connected a conductor.50 to earth. in use, the conductor 50 would be connected to a dome commercial or other earth system. Preferably, the unit would be sold with the earth lead 50 attached to the earth of an electrical plug, for example the standard Australian three-pin power plug, so that the device could be connected to earth merely by plugging the plug into a power point.

In the event of a 'double surge* of voltage along bot conductors 38, 42, such as would possibly occur from a lightning strike very close to the .telephone or like instru itself, the gas arrestors 44, 46 would isolate pins 18, 14 divert the surge along conductor 50 to earth thereby protecting the user of the instrument. It is envisaged tha such an arrangment. could cope with a total voltage surge, down both lines, of 100,000 volts.

As an alternative to the dual gas arrestors 44, 46 a single Siemens T61-350 gas arrestor could be used across conductors 38, 42. The third, central connector of the gas arrestor is connected to earth lead 50.

OMPI

Claims

1. A surge protection device for a telecommunication sys said device being capable of location in said system betwee an area where surge initiation may occur and an element of said system, characterized by a gas arrestor situated in sai device such that when said device is located in said system, said gas arrestor is connected to a line of said system along which said surge may be propagated.

2. A surge protection device according to claim 1, characterized in that said gas arrestor is connected in said device such that a surge reaching it along a first conductor will be diverted to a second conductor.

3. A surge protection device according to claim 2, characterized in that said first conductor and said second conductor are connectible respectively to separate conductor forming part of a line of said system.

4. A surge protection device according to claim 2, characterized in that said first conductor is connectible to a conductor forming part of a line of said system, and said second conductor is connectible to earth.

5. A surge protection device according to any preceding claim, characterized in that the device is in the form of a component which may be interposed between a plug and a socke forming part of a line of said system.

6. A surge protection device according to any preceding claim, characterized in that said telecommunication system i a telephone system.

7. A surge protection device according to claim 6, characterized in that said element is a telephone.

8. A device for isolating an area of a system which uses electricity, characterized in that said device allows the system .to function normally at system parameters below a predetermined level, but which isolates said area when system parameters rise above said predetermined level.