WO1999001917A1

WO1999001917A1 - Overvoltage protection device for electric/electronic appliances

Info

Publication number: WO1999001917A1
Application number: PCT/IL1998/000309
Authority: WO
Inventors: Benzi Shemesh; Oved Tal
Original assignee: Girit Communication Engineering Ltd.
Priority date: 1997-07-04
Filing date: 1998-07-02
Publication date: 1999-01-14
Also published as: AU7929898A; IL121233A0

Abstract

A modular overvoltage protection device (10, 40, 50, 60) for protecting at least one electric or electronic appliance from a voltage surge, the device comprising an overvoltage protection module (16, 30, 30a, 46) for connecting in-line to a connection cable (11, 22, 24, 36) of the device. The module has a ground coupling means (18, 18a, 32, 38, 42) in form of either a jack socket or a jack pin for coupling to ground.

Description

Overvoltage protection device for electric/electronic appliances

FIELD OF THE INVENTION

The present invention relates to the protection of electric apparatus, computers, telephones, etc. from random overvoltages appearing on a data or power line coupled thereto. In particular, the invention relates to a device for preventing damage to a group of electronic appliances from overvoltages induced by lightning.

BACKGROUND OF THE INVENTION

Electronic circuits and devices are l iown which are capable of protecting electronic appliances from random voltages exceeding predetermined nominal magnitudes. Such protecting devices may be installed inside the electronic appliance, or built-in as an integral module within an electrical plug or socket for use therewith. Another lαiown type of the protection device is manufactured as a discrete module which may be installed in an office or other building for local protection of electronic appliances from sudden outages and overvoltages, etc.

Electrical distribution switchboards with automatic safety fuses are also lαiown. However, such switchboards are neither sufficiently sensitive nor those electronic appliances which are grounded.

Protection of low-current telephone lines or data transmitting computer lines from induced overvoltages is problematic, since the low-current circuits are usually not connected to the earth electrode. Attempts to provide grounding to such lines have resulted in somewhat bulky auxiliary protective devices connectable to an electrical plug or socket of the appliance.

None of the known modifications of protecting devices of the kind described suggests an effective and inexpensive arrangement for overvoltage protection of a group of different electronic appliances some of which may include low current data transmitting lines.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide an inexpensive device for overvoltage protection of an electric or electronic appliance from overvoltage appearing on a power and/or data line thereof.

Another object of the invention is to provide a system for overvoltage protection of a group of such appliances located close to one another.

The above object is achieved in accordance with the invention by means of a modular overvoltage protection device for protecting at least one electric or electronic appliance from a voltage surge, the device comprising an overvoltage protection module for connecting in-line to a connection cable of the device and having a ground coupling means for coupling to ground.

The connection cable may be provided at opposite ends thereof with a plug and socket, respectively, connected to phase, neutral and ground conductors for connecting via the plug to respective phase, neutral and ground feeders of an electrical supply, said ground coupling means being coupled to the ground conductor.

However, in an auxiliary modification said connection cable may comprise two portions, - the first portion intended for connecting the overvoltage protection module to electrical supply and including the phase, neutral and ground conductors,

- the second portion, including the phase and neutral conductors only, being intended for connecting said overvoltage protecting module to an electric appliance, said ground coupling means being electrically connected to the ground conductor of the first portion of the connector cable.

The ground coupling means may include at least one jack connector accessible from an exterior of the device. If desired, at least two jack connectors may be provided each being accessible from an exterior of the device and being electrically coupled to said ground conductor. This permits a first device described above, having a ground point and being connected to a ground conductor of the connecting cable, to be coupled to an electrical supply having a ground feeder, and one or more other devices to be mutually interconnected thereto such, that the ground points of all devices are commonly connected to the ground feeder coupled to the first device.

According to the preferred embodiment of the invention each of the jack connectors of the first device comprises, a jack socket. In the above-mentioned another embodiment of the device, the connection cable may be either a cable of an electric appliance including a phase conductor and a neutral conductor only, or a data cable of an electronic appliance including data-in and data-out conductors, and the ground coupling means may include at least one jack connector accessible from an exterior of the device for electrically coupling to the ground conductor of the first device. Such a data cable may be a telephone cable having tip and ring conductors, a computer cable, or the like. The connection cable of the described type may be provided with a plug and socket at opposite ends thereof, respectively. However, the opposite ends of the cable may be equipped by two respective plugs or two respective sockets.

According to one embodiment of the invention the jack connector of such other device is formed as a jack pin. However, it may comprise a socket shaped identically to that of said first device, said two sockets being interconnectable with one another by an electrically conductive connecting pin having two contact ends snap-fittingly insertable into said respective sockets.

According to another aspect of the invention, there are provided two main types of novel cables having integral therewith an overvoltage protection device according to the invention. A first such cable thus includes a ground conductor for connecting to the ground feeder of a supply line and including at least one ground jack socket electrically connected to the ground conductor and being accessible from an exterior of the overvoltage protection device, said ground jack socket being adapted for connecting thereto either a jack pin of a mating device, or a connecting pin. Said connecting pin being an electrically conductive structure having at least two contact ends snap- fittingly connectable to said respective sockets.

A second such cable has no ground conductor and is usually intended for connection to a low-current line. The device in such a cable is usually provided with at least one jack pin for coupling to the grounded jack socket of a mating device, both the jack pin and socket being accessible from an exterior of the respective devices.

However, said second cable may be provided with at least one jack socket shaped identically to that of said first cable, accessible from the exterior of the protective device and intended for coupling to the grounded jack socket of said first cable or to the jack pin of another second cable. In the embodiment, where said second cable has said jack socket, the respective sockets of the first and second cables are interconnectable with one another by an electrically conductive connecting pin having two contact ends snap-fittingly insertable to said respective jack sockets.

The second type cable may constitute a connection cable of an electric appliance having only a phase and a neutral conductors; in another embodiment it may be a cable for connecting a telephone extension unit or a computer modem to a telephone socket. Alternatively, the second type cable may constitute a computer data communication line (screened or unscreened) with two or more channels.

According to yet another aspect of the invention, an overvoltage protection system is provided, comprising a first and a second said modular overvoltage protection devices, each comprising an overvoltage protection module for connecting in-line to a respective connection cable and having a ground coupling means for coupling to ground; the ground coupling means of said first protection device being electrically coupled to a ground conductor of the respective connection cable, while the ground coupling means of said second protection device being mechanically and electrically coupled to the ground coupling means of said first protection device.

According to the preferred embodiment of the overvoltage protection system, it may comprise at least one first type cable and at least one second type cable mutually interconnected via respective jack connectors thereof. It should be appreciated, that the system may include, inter alia, a number of auxiliary cables intended for telephone lines, or a set of cables required for a number of computers, and many other variations.

In one particular embodiment of the system most or all said jack connectors are in the form of jack sockets, and the system additionally comprises a set of connecting conductive elements each having at least two contact pins snap-fittingly connectable to said jack sockets.

The system is effective for electronic appliances located in one room, especially where electric sockets of these appliances are positioned in close proximity to one another. According to one particular application of the invention, the device, the cables and the system are adapted for protecting electronic appliances from overvoltages induced by a lightning.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and see how the same may be carried out in practice, some preferred embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Figs, la, lb and lc show respectively pictorial, schematic and functional representations of an in-line cable protection device according to a first embodiment of the invention;

Figs. 2a, 2b and 2c show respectively pictorial, schematic and functional representations of an in-line cable protection device according to a second embodiment of the invention;

Figs. 3a, 3b and 3c show respectively pictorial, schematic and functional representations of an in-line cable protection device according to a third embodiment of the invention;

Figs. 4a, 4b and 4c show respectively pictorial, schematic and functional representations of an in-line cable protection device according to a fourth embodiment of the invention;

Figs. 5a and 5b show respectively schematic and functional representations of a pair of mutually connected in-line cable protection devices;

Figs. 6a and 6b show respectively schematic and functional represen- tations of three mutually connected in-line cable protection devices;

Figs. 7a and 7b show respectively schematic and functional representations of four mutually connected in-line cable protection devices. DET AILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figs, la and lb show pictorially and schematically, respectively, a modular overvoltage device depicted generally as 10 for protecting at least one electronic appliance (not shown) from a voltage surge. The device 10 comprises a cable 11 having at opposite ends thereof a respective plug 12 and socket 14 for connecting to an electrical supply feeder. The cable 11 has integral therewith an in-line overvoltage protection module 16 having a jack socket 18 (constituting a ground coupling means) for coupling to ground.

Fig. lc is a block-diagram of the cable 11 including the in-line protection module 16 being an overvoltage protection circuit 20. The overvoltage protection circuit 20 is grounded via a ground conductor 21 which is itself connected to the jack socket 18.

Figs. 2a to 2c illustrates a cable 22 according to a second embodiment having an in-line protection module 16. The cable 22 differs from the cable 11 of the first embodiment 10 in that the protection module 16 includes an additional jack socket 18a being electrically connected to the ground conductor 21 of the cable 22. Although not shown, the additional jack socket 18a may be replaced by a jack pin.

Figs. 3a, 3b and 3c show respectively pictorial, schematic and functional representations of a cable 24 having an integral in-line overvoltage protection module 30 according to a third embodiment of the invention. The module 30 has a jack pin 32 (constituting a ground coupling means) for coupling to ground. The jack pin 32 comprises a conductive core.

Fig. 3b is a schematic representation of the cable 24, and Fig. 3c shows its block-diagram, where LI and L2 are a pair of low-current telephone wires. The cable 24 is provided with two plugs 26 and 28 at its two ends. It should be noted, that the cable may be screened or unscreened, and that it may comprise more lines; a conductor of the cable screen may also be connected to a respective protection circuit. The overvoltage protective module 30 includes an overvoltage protection circuit 34, and the jack pin 32 is shown as an ungrounded lead of the overvoltage protection circuit 34. It will be appreciated that the cable 24 may be any other suitable low-current line as well, such as a computer data transmitting line as will be shown in the following drawings.

Figs. 4a, 4b and 4c show respectively pictorial, schematic and functional representations of a cable 36 having an integral in-line protection module 30 according to a fourth embodiment of the invention. The cable 36 differs from the embodiment shown in Figs. 3a to 3c of the drawings in that the overvoltage protection module 30 further includes an additional jack socket 38 which is dimensioned for accommodating the jack pin 32 of a mating module. By such means, several such devices may be mutually interconnected as will be described below with reference to Figs. 7a and 7b of the drawings. Figs. 5a and 5b show respectively schematic and functional representations of a compound overvoltage protection system 50 having a first in-line cable protection device 10 coupled to a second in-line cable protection device 40 being a computer data transmitting line. In the block-diagram of Fig. 5b the cable 40 is schematically shown as having a transmitting channel L3 and a receiving channel L4. However, in practice the data transmitting cable may comprise a much more complicated system of channels. The interconnection between the cables 10 and 40 is accomplished by a mechanical/electrical coupling between the ground jack socket 18 of the cable 10 and a jack pin 42 of the cable 40. As a result, a protective circuit 44 integral with the cable 40 becomes grounded through the protective ground conductor PG, thus providing overvoltage protection to the data transmitting line of a computer (not shown) coupled to the cable 40. It should be mentioned, that in an alternative embodiment of the second in-line protection cable device 40 it may have a jack socket instead of the jack pin 42. Such an ungrounded jack socket can be shaped identically to the jack socket 18. For interconnecting the two cables 10 and 40 a connecting conductive pin (not shown) would be required which has two contact ends snap-fittingly engageable with the grounded jack socket 18 of the cable 10, and the jack socket of the cable 40, respectively.

Figs. 6a and 6b show respectively schematic and functional representations of a compound overvoltage protection system 60 having three mutually connected devices 22, 24 and 40 containing integral in-line protection modules 16, 30 and 46, respectively. The overvoltage protective devices 34 and 44 are commonly grounded through the ground conductor PG of the device 22 via respective ground jack sockets 18 and 18a coupled to corresponding jack pins 42 and 32 of the respective modules 46 and 30. In order to facilitate connection of the jack pins to the respective jack sockets, the jack pins may be formed of a plastic material strengthened by an inner axial reinforcing conductive core.

Figs. 7a and 7b show respectively schematic and functional representations of a compound overvoltage protection system 70 having four mutually connected devices 22, 24, 36 and 40 containing integral in-line protection modules 16, 30, 30a and 46, respectively. The overvoltage protective circuits 34a and 44 are commonly grounded through the ground conductor PG of the device 20 via respective ground jack sockets 18 and 18a of the device 20 which are coupled to corresponding jack pins 42 and 32 of the respective circuits 44 and 34a. Likewise, the overvoltage protective circuits 34 is commonly grounded through the ground conductor PG of the module 16 via the ground jack socket 18 of the module 16 which is coupled to the jack pin 32 of the module 30a.

It should be noted, that each one of the described overvoltage protection modules such as 16, 30 and 46 may additionally comprise an interference suppressor filter. Such a filter can be adjusted to a specific range of frequencies from which an appropriate appliance should be protected.

It will readily be appreciated that, in similar manner, any number of cables having in-line integral overvoltage protection devices may be mutually interconnected. It will further be understood that the invention contemplates both the separate use of the modular protection devices as described as well as their in-line connection to a cable having integral overvoltage protection.

Claims

CLAIMS:

1. A modular overvoltage protection device for protecting at least one electric or electronic appliance from a voltage surge, the device comprising an overvoltage protection module for connecting in-line to a connection cable of the device and having a ground coupling means for coupling to ground.

2. The device according to Claim 1, wherein the connection cable is provided at opposite ends thereof with a plug and socket, respectively, for connecting to electrical supply and to electric appliance; at least a portion of said cable connecting said plug and said overvoltage protection module includes phase, neutral and ground conductors for connecting via the plug to respective phase, neutral and ground feeders of an electrical supply; said ground coupling means being electrically coupled to the ground conductor.

3. The device according to Claim 2, wherein the ground coupling means includes at least one jack connector accessible from an exterior of the device.

4. The device according to Claim 2, wherein the ground coupling means includes at least two jack connectors each accessible from an exterior of the device.

5. The device according to Claims 3 or 4, wherein each said jack connector comprises a jack socket.

6. The device according to Claim 1, wherein said connection cable does not comprise a ground conductor, and the ground coupling means includes at least one jack connector accessible from an exterior of the device for electrically coupling to the ground conductor of the device according to any one of Claims 3 to 5. 7.

7. The device according to Claim 6, wherein said connection cable includes a plug and socket at opposite ends thereof.

8. The device according to Claims 6 or 7, wherein one of said jack connectors is a jack pin for coupling to a corresponding jack socket of a device according to Claim 5, thereby allowing said devices to be mutually interconnected.

9. The device according to Claims 6 or 7, wherein one of said jack connectors is a jack socket shaped identically to the grounded jack socket of the device according to Claim 5, said two jack sockets being interconnectable with one another by an electrically conductive connecting pin having two contact ends snap-fittingly insertable into said respective jack sockets.

10. The device according to any one of Claims 6 to 9, wherein the ground coupling means includes at least two jack connectors each accessible from an exterior of the device for electrically coupling to said ground conductor.

11. The device according to Claim 10, wherein said two jack connectors include a jack socket and a jack pin for coupling to a corresponding jack pin and socket, respectively, of another of said devices thereby allowing several of said devices to be mutually interconnected.

12. The device according to any one of Claims 6 to 11, wherein the connection cable is a telephone cable having tip and ring conductors.

13. The device according to any one of Claims 6 to 11, wherein the connection cable is a computer data transmitting line cable.

14. The device according o any one of Claims 6 to 11, wherein said connection cable is a cable of an electric appliance including a phase conductor and a neutral conductor.

15. The device according to any one of the preceding claims adapted for protection from overvoltages induced by a lightning.

16. A cable having integral therewith the overvoltage protection device according to any one of the preceding claims.

17. A modular overvoltage protection system comprising a first and a second modular overvoltage protection devices, each comprising an overvoltage protection module for connecting in-line to a respective connection cable and having a ground coupling means for coupling to ground; the connection cable of said first device including a ground conductor, while the connection cable of said second device having no a ground conductor; the ground coupling means of said first protection device being electrically coupled to a ground conductor of the respective connection cable, while the ground coupling means of said second protection device being mechanically and electrically coupled to the ground coupling means of said first protection device.

18. The modular system according to Claim 17, wherein said first device is a device according to any one of Claims 3 to 5, 15 and said second device is a device according to any one of Claims 6 to 15, said devices being mutually interconnected via respective jack connectors thereof.

19. The modular system according to Claim 18, wherein most of or all said jack connectors are in the form of jack sockets, the system additionally comprising a set of connecting conductive elements each having at least two contact pins snap-fittingly insertable into said jack sockets.

20. The modular system according to Claim 18 or 19, wherein each of said devices is integral with an appropriate cable according to Claim 16.