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Title:
A SURGE PROTECTION DEVICE
Document Type and Number:
WIPO Patent Application WO/2015/085329
Kind Code:
A1
Abstract:
This invention relates to a surge protection device (10). More specifically, the invention relates to a surge protection device for protecting electronic equipment against damage from high voltage spikes induced in power, television/satellite and/or telecommunication lines arising mainly from localised lightning strikes. The surge protection device Includes a housing (12) with a plurality of input and output sockets(14, 16) for connecting to inputs (i.e. power, TV antenna, etc.) and outputs (i.e. electronic equipment): respectively. The device further includes a switch (18) for electrically connecting and disconnecting the input sockets (14) from the output sockets (16), the switch (18) comprising stationary contacts (20) and movable contacts (22) located on a movable switch arm (18A), the movable arm (18A) being movable between a connected state wherein the stationary (20) and movable contacts(22) are in electrical connection with one another, and a disconnected state, wherein the stationary (20) and movable contacts (22) are displaced from one another to form an air gap there between. The device (10) further includes a motor (26) for moving the movable switch arm (18A), a controller for actuating operation of the motor (26) and a detector for detecting; an event thereby to trigger operation of the controller.

Inventors:
NIELSEN JORGEN (ZA)
Application Number:
ZA2014/000053
Publication Date:
June 11, 2015
Filing Date:
September 29, 2014
Export Citation:
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Assignee:
NIELSEN JORGEN (ZA)
International Classes:
H02H3/20
Foreign References:
US6061216A2000-05-09
US20090213518A12009-08-27
US20130088310A12013-04-11
Attorney, Agent or Firm:
SIBANDA & ZANTWIJK (Houghton 2041,Johannesburg, Gauteng, ZA)
Download PDF:
Claims:
s

A surge protection device including: housing; one or more input sockets into which power, television antenna, satellite and/or data inputs are eonnecfible; one or more output sockets into which electronic -equi ment is connectible; a: switch for electrically connecting and disconneeting t e input seekeis from t e output sockets, the switch comprising: one o more stationary contacts; and one or more movable contacts, the movable contacts being located on a movable switch arm movable '' between a connected state, wh rein t e stationary and movable contacts are In electrical connection with one another; and a disconnecied state, wherein the stationary and movabl contacts are displaced from one another to form: an air gap there between; motor for moving the movable switch arm between the connected and disconnected states; a detector for detecting the presence of an electric storm, and/or for detecting an input signal at th one or more input sockets; and a controller for controlling the motor, the controller being rlggera le by the detector so as to; actuate movement of ms motor towards the disconnected: state on: (i) detection of the presence of an electric: storm; and/or

( i) detection of the absence of an input signal at the one or more input sockets; and actuate movement of the motor towards the connected slate where:

0) the presence of an electronic storm is not deteetih!e; and/or

(ii) signal to the one or more in t sockets is restored .

The surge protection device according to claim 1 Including a power scarce for powering the surge protection device.

The surge proteciiori device according to claim: 1 or claim 2, wherein the switch arm is pivoiafiy dispiaceabie, the switc arm being pivoia!i movable between: the connected and disconnected states about a pivot formation located within the housing.

The surge protection device- according to claim 3, wherein the switch arm is pivotajly- dlsplaceable between the connected and disconnected states from 0 degrees to about 90 degrees respectively.

The surge protection device according to claim 3, wherein the switch arm is pivotaHy disp!aeeabSe between the connected and disconnected states from 0 degrees to about 80 degrees respectively.

The surge protection device according to claim 3, wherein the switch arm Is pivotaHy displaceabie between the connected and disconnected states from 0 degrees to about 70 degrees respectively. -18-

7. The surge protection device according to any one of claims 3 to 6, wherein the air gap, being the distance between the stationary and movable contacts with the switch arm in the disconnected stale, is 20' millimetres. 8. The surge protection device according to any one of claims 3 to 6, wherein the air gap, being the distance between the stationary and movable contacts with the switch arm in the disconnected state, is about 115 millimetres.

9. The surge protection device according to any one of claims 3 to 6, wherein the air gap, being the distance between the stationary and movable contacts with the switch arm in the disconnected state, is between about 1 5 and 300 millimetres.

10. The surge protection device according to any one of claims 3 to 6, wherein the air gap, feeing the distanc betwee the .stationary and movable, contacts with the switch arm in the disconnected state, is betw n about 15 and 500 millimetres.

11. The surg protection device according to any one of claims 7 to 40,. wherein the switch arm is resi!iently defor abte, 12. The surge protection device according to claim 11, wherein th surge protection device may include secondary stationary contacts to which the movable contacts are electrically conneetabie in the disconnected state, thereby to connec the output sockets to a secondary circuit and/or alternative power and/or data source. 13. The surge protection device according to claim 12, wherein any one or mor of the contacts may be spring loaded.

14. The surge protection device according to claim 3,; wherein the motor comprises a pivotally displaceabie drive arm being connectibl to the switch arm directly, or indirectl by a d ive linkage.

15. The surge protection device according to claim 14, wherei the detector is an electromagnetic energy detector for detecting electromagnetic energy arising from an electric storm.

16. The surg protection device .according to claim 14 or claim 15, wherein the detector, or a secondary detector, is a detector for detecting the presence of power and/or signal at the input sockets.

5

17. The surge protection device according to claim 15 or claim 16. wherein the controller is a programmable microprocessor.

18. The surge protection device according to claim 17, wherein the surge protection0 devic further include a user input for enabling input of at least a safe zone and/or a safe time delay for triggering movement of the motor towards the connected and/or disconnected states.

19. The surge protection device according t claim 18. wherei the safe zon is5 defined by a radius about the surge protection device within which detection of the presence of an electric storm triggers movement of the motor and consequently the switch arm to move towards the disconnected state.

20. The surge protection device according to claim 19, wherein the safe time delay is0 the amount of time lapsing i use between: (!) the presence of an electric storm no longer being deteetible by the detector within the safe zone; and/or (ii) the presence of an Input signal being detected by the detector after a period of the input signal being absent; and the triggering of the moto to move the switch arm back towards the connected state, the time being resetlabie on detection of the5 presence of an electric storm or absence In Input signal.

21. The surge protection device according to claim 20, wherein the safe time delay s timed by a timer, independent of or built Into the microprocessor. Q 22. The surge protection device according to claim 21 , wherein the microprocessor comprises means for analysing an electromagnetic pulse receivabl from the detector to determine whether or not the electromagnetic pulse is as a result of a lightning strike or otherwise.

23. The surge protection device according to claim 22. wherein the analysing means is one or more algorithms.

24. The surge protection device according to claim 23, wherein the user input is a display and one or more buttons for inputting the user inputs,

25.

26.

27. Th surge protection device according to claim 26. t erein the warning signal is a visual output and or an audibl output.

28. The surge protection device according to claim 27, wherein the visual output is a warning displayed on the display or screen and/or a flashing warning light, and the audible output i an alarm.

29. The surge protection device according to any one or more of claims 26 to 28, wherein the warning signal is a telecommunications output signal outpirtted by a transmitter to a mobile telecommunications device of the user.

30. The surge protection device according to claim 29 including a receiver for receiving a telecommunications input signal from the user's mobile telecommunications device.

31. The surge protection device according to claim 3Q, wherein telecommunications input causes the microprocessor to actuate the motor to move towards the disconnected state.

32. The surge protection device according to any one of the preceding claims wherein the motor includes positional feedback control and/or a gearbox.

33. Th surge protection device according to claim 32, wherein the motor is a linear motor or a rotary motor, the motor being driven eleclricaliy or by fluid.

34. The surge protection dex'ice according to claim 33. wherein the motor is a stepper motor.

35. The surge protection device according to claim 33, wherein the motor is a.

servomotor.

36. The surge protection device as herein described and illustrated.

Description:
A SURGE PROTECTION DEVICE

BACKGROUND OF THE INVENTION THIS Invention relates to a surge protection device. Mate specificaiiy, the invention relates to a surge protection device for protecting electronic equipment against damage from high voltage spikes induced In power, television/satellite and/or teiecommonicaion lines arising from localise lightning strikes. For decades man has grappled with the unpredictable damaging effects of lightning on electrical ©Sftii men . With our dependency on connected electronic equipment ever increasing, we have continually become more vulnerable to damage caused by lightning, Lightning often induces high voltages in ground based Infrastructure, even without a direct ground strike ' .occurring. A cloud to cloud strike in the sk can i duce voltages in wires such as telecommunications and po er cables lying parallel to the ground. A direct ground strike in the vicinity of cabling will also induce high voltages at the strike point.

These high voltages then travel outwards from the source along the wiring, becoming lower in intensity as the surge travels outwardly there from, until completely dissipating. The distance required to completely dissipate the surge energy is entirely unpredictable, varying with the energy intensify of the strike, the nature of the terrain and cablin Infrastructure present.

Steps to counter the effects of lightning have not kept pace with the proliferation of devices and our dependency on technology, in fact, today's devices have become are more vulnerable than the devices of the past, with operating voltages of present day devices being far lower than in the past, making such devices more sensitive to damaging high voltage transients.

Very often the best surge protection devices availabl fail as a result of th high voltages induced b lightning arcing right through the protection devices, destroying them as well as the electronic equipment they were meant to protect. Conventional surge protectors are mere effective when the protected line is carrying higher voltages. Here a combination of discharge tubes, trsnsorbs and metai oxide varssfcors are employed to divert energy spikes safely to earth ' when th voltage increases beyond a safe .limit

However, the aforementioned devices are not as effective when protecting sensitive low voltage electronic equipment, due to their Inherently slow response and due to the fact that the effective voltage ranges remain too high for the equipmen t.

It appears that the only safe, certain way to protect electronic equipment from lighting damage is to physically unplug them, thereby disconnecting them from th sourc of lightning induced high voltages. However, this is very inconvenient and requires someone to be physicall present at the start of a lightning storm to unplug the equipment Various attempts hav been made over the years to build better surg protection devices, with some previous products using relays or solenoids to disconnect circuits and others aimed specifically at physically unplugging the electronic equipment from the wall. Some such devices are described in US patent no, 5 ; 453,890 In one embodiment described in the aforementioned patent document, the device operates to retract a plug out of the wall socket thereby physically unplugging the electronic equipment. Although effective, this solution remains inconvenient requiring someone to reconnect the equipment by physically plugging the plug back into the wail socket.

In an attempt to solve this inconvenience, subsequent embodiments described in the aforementioned patent include means for disconnecting and automatically reconnecting the plugs through the us of solenoids. However solenoids and rsfays are typically ineffective with the gap created between the contacts in a disconnected stat being too small, enabling high voltage transient simply to arc across the gap. it is therefore an object of the present invention to provide a surge protection device having a means for detecting lightning activity and means for switching contacts between disconnected and connected states, with the devic configured to enable a sufficiently safe distance to be defined between contacts in the disconnected state yet compact enough for domestic or similar use.

SUMMARY OF THE I DENTION

According to the invention there is provided a surge protection device including; a housing; one or more input sockets into which power, television antenna, satellite and/or data inputs are connectibie; one or more output sockets into whic electronic equipment Is ; connective; . a switch for electrically connecting and disconnecting the input sockets from the outptit sockets, the switch comprising: one or more stationary contacts; and one or mor movable contacts, the movable con tacts being located on a movable switch arm movable between a connected state, wherei the stationary and movable contacts are in electrical connection with one another; and a disconnected state, wherein the stationary and movable contacts are displaced from one another to form an air gap there between; a motor for moving the movable switch arm between the connected and disconnected states; a detector for defecting th presence of an electric storm, and/or for detecting an input signal at the one or more Input sockets; and a controller for controlling the motor, the controller being trlggerabt by the detector so as to: actuate movement of the motor towards th disconnected state on:

(i) detection of the presence of an electric storm; and/or ). detection of the absence of an input signal ai the one or more input sockets; and actuate m veme t of the motor towards the connected state where:

(i) the presence of an electronic storm Is not deiecibie;

and/or

(si) signal to the one or more input sockets is restored

The surge protection device includes a power source for powering the surge protection device.

Preferably, th switch arm is a oivo ai!y displaceable, the switch arm h lrsg piyol lly movable between the connected and disconnected states about a pivot formation located within the housing.

Typically, the switch arm is plvofaily displaceabie between the connected and disconnected states from 0 degrees to about 90 degrees respectively. Generally, from 0 degrees to about 80 degrees. Preferably, from 0 degrees to about 70 degrees.

The air gap, being the distance between the stationary and movable contacts with the switch arm in the disconnected state, may be as little as 20 millimetres In applications where th transient voltages are known to be limited (i.e, less than 22 kilo volts}. In applications where transient voltages are higher or unknown as in the ease of telecommunication fines, the air gap is preferably 1 15 millimetres, or where very high voitages may be found more preferably between 1 15 to 300 millimetres- and most preferably between 1 15 to 500 millimetres

It will be appreciated that the surge protection device may be scaled up to any size, but is preferably within the aforementioned dimensions for domestic or similar applications, i.e. small business.

The switch- arm is typically made from a resilleniiy deform a-hte material, flexible enough to take up any small toleranc Inconsistencies, hile stiff enoug to apply sufficient force between the contacts in the connected state. A suitable material from which th switch arm may be made is fibregiass or, specifically to ease construction, woven glass and epoxy printed circuit board■ {PCS),

The surge protection device may include secondary stationary contacts to which th movable contacts are electrically conneclabie in the disconnected state, thereby to conned the output sockets to § secondary circuit, for example, an -.alternative power and/or data source. in one alternative embodiment, any one or more of the contacts may be spring leaded. The motor comprises a pivofaily displaeeabie drive arm being connecfibie to the switch arm directly, or preferably indirectly by a drive linkage, it will be appreciated that the pivot axes of ih© drive arm and switch arm, as well as the connection points pi the drive linkage on the drive arm and switch arm are configured relative to one another such that a torque multiplier is created fo converting a rotational movement of the switch arm into a small linear movement just prior to the switch arm coming completely to rest in the connected state.

The detector is preferably an electromagnetic energ detector for detecting electromagnetic energy arising from an electric storm. The detector, or a secondary detector, may be a detector for detecting the presence of power and/or signal at the input sockets.

The controller is typically a programmable processor, preferably a microprocessor, The surge protection device further includes a user .input means for enabling input, amongst other inputs, of a safe zone and/or a safe time delay for triggering movement of the motor towards the connected and/or disconnected states. Typically, the safe zone is defined by a radius about the surg protection device within which detection of the presence of an electric storm triggers movement of the motor and consequently the switch arm to move towards the disconnected state.

Generally, the safe time delay is the amount of time lapsing in use between: (i) the presence of an electric storm no longer being detect b e by the detector withi the safe zone; and/or (si) the presence of an input signal being detected by the detector after ¾ period of th input signal being absent; and the: triggering of the motor to move the switch arm back towards the connected state, the tirne being resettab!e on detection of the presence of an electric storm or absence in input signal. Th safe time delay may e timed by a timer, independent of or built into the microprocessor.

Preferably, the microprocessor comprises means for analysing an electromagnetic pulse receivable from the detector to determine whether or not the electromagnetic pulse is as a result of a lightning strike or otherwise. Typically, the analysing means is one or more algorithms.

In a particularly preferred embodiment of the invention, detection by the detector of an electric storm, in the safe zone or otherwise, andior detection by the detector of the absence of an input signal, causes the surge protection device to output a warning signal. The warning signal may be a visual output and/or an audible output.

Typically, the visual output is a warning displayed on the display or screen, and/or a flashing warning fight, and the audible output is an alarm. Alternatively or jointly with the aforementioned visual and audible outputs, the warning signal may be a telecommunications output signal oufputted by a transmitter to a mobile telecommunications device of the user. The warning signal may include information about an incoming storm and/or the absence of Input signal, together with the ilkeiihood of impending disconnection and timing information. Preferably, the surge protection device includes a receiver for receiving a telecommunications input signal from the user's mobile telecommunications device. The telecommunications input may cause the micro processor to actuate the motor to move towards the disconnected state.

Typically, the motor includes positional feedback control. Generally, the motor includes a gearbox. The motor may be a linear motor or a rotary motor. Furthermore, the motor may be electrically driven or fluid driven. Preferably, the motor is a stepper motor. More preferably , the motor is a servomotor.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention wil now be descn ed in more detail, by way of example only, with reference to the accompanying drawings in which;

Figure 1 is a perspective view of a surge protection device in accordance wit a preferred embodiment of the present Invention;

Figure 2 is a perspective view of the surge protection- device of figure 1 wit the hsus g

lid removed there from;

Figure 3 is a top view of the surge protection device of figure 2 with the switch In the connected state;

Figure 4 is a top view of the surge protection device of figure 2 with the switch in an intermediate position between the connected- and disconnected states; and

Figure S is a top view of the surge protection device of figure 2 wit the switch in the disconnected state. DETAILED OESCRJFTfOE OF THE DRAWINGS

A surge protection device according to a preferred embodiment of the invention is designated generally in figure 1 with reference numeral 10. With reference now also to figure 2, the surge protection device includes a housing 12 with a housing lid ISA, a input socket 14, an output socket 16 and a switch 18 located between the input socket 14 and the output socket 16.

With reference now also to figures 3 to 5, the switch 18 comprises stationary contacts 20 and movable contacts 22 located on a switch arm 18A of the switch 18, the switch arm I SA being pivotally dlsp aceable abou a pi ot formation 24 betwee a connected state, wherein the stationary and movable contacts are in electrical connection with one anothe (see figure 3), a disconnected state, wherein the stationary and movable contacts are displaced from one another to form an air gap there between (see figure 5)

Although it may be possible to move the movable contacts relative to the stationary contacts in many other ways (I.e. linearly),, it is preferable that the movement is p votaf thereby to define a substantial air ga Jthat is direct distance between the movable and stationary contacts in the disconnected state), white at the same time keeping the surge protection device 10 compact for domestic and other similar applications.

The switch arm ISA is plvota!iy movabl between the connected and disconnected states by a motor, preferably a servomotor 26, having a pjvotafly displacea le drive arm 28 connected to the switch arm 18A via a drive linkage 30. it will be appreciated that the motor may be any type of iinear or rotary motor having positional feedback control. Furthermore, the motor may have a gearbox and driven electrically (i.e. a stepper motor) or by fluid (I.e. vacuum or hydraulic actuator). Servomotors inherently consists of a motor, a gearbox and feedback control for controlling angular position, acceleration and speed and as such, is a suitable choice for this application. To obtain a sufficiently sized air gap to reduce the possibility of arcing between disconnected contacts (about 20 millimetres for tow voltage transient voltages, or between 115 to 500 millimetres for higher voltage transient voiiages), the switch arm 18A is pivotaliy dispiaceable between the connected and disconnected states from 0 degrees to about 90 degress respectively. It will be appreciated that the switch arm 18A may not be required to pivot by a full 90 degrees (for example only by 70 to 80 degrees) to obtain the required air gap.

The switch arm ISA is preferably made from a .resiliency -deformaMe materia!, flexible enough to take up any small tolerance inconsistencies, while possessing sufficient tensile strength to apply sufficient force between the contacts 2 ; 22 in th connected state. A; surtabfe material from which the switch arm 18A may be made is fi reg!ass, or for example, strips of woven glass and epoxy printed circuit board (PCS).

The surge protection device 10 Includes a detector, more particularly a electromagnetic energy detector (not showR) for detecting the presence of an electric storm. Furthermore, the surge protection device 10 includes a controller, preferably i the form of a programmable microprocessor (not shown) for receiving one or more inputs and oufputting one or more outputs, for x mpl , a servomotor output to. cause the servomotor to displace the switch arm 18A towards the connected and/or discon nected states ,

One such input is user type Inputs, including a safe zone input and a safe time delay input. Typically, the surge protection device 10 includes user input means 32 through which the microprocessor is programmable. The user input means 32 may be in the form of a display 32A (i.e. a liquid crystal display) and a plurality of input buttons 328 as illustrated, or some other user Input means, for example, a touch screen.

A user, depending on his needs, the typography of his location and the cable infrastructure in his vicinity may customise the safe zone, and the safe time delay. The safe zone ma be programmed by selectin a radius around the surg protection device 10 defining the safe zone within which the microprocessor must actuate the servomotor 26 to the disconnected state where the presence of an electric storm within the safe zone is detected by the detector. It will be appreciated that the output of the detector is another form of input into the microprocessor and the trigger event causing movement of the switch arm ISA from the connected state to the disconnected state.

The safe time delay may be programmed by selecting an amount of time that should lapse between the presence of an electric storm no longer being detected in the safe zone and the triggering of the servomotor 26 by the microprocessor to move the switch arm 18A rom the disconnected state back towards the connected state.

It will be appreciated that th time will be automatically reset every time the detector detects the presenc of an electric storm within the safe zone, It will be appreciated further that the time: may be ou ted by an independent timer or a timer built into the. microprocessor, and that the output of such timer is yet another input into the microprocessor. The microprocessor further includes means for analysing the electromagnetic puls input received from the detector to determin whether or not the electromagnetic puls input is as a result of a lightning strike or otherwise. On confirmation of the electromagnetic puise input being as a result of a Lightning strike, the microprocessor ■will trigger actuation of the servomoto 26 to move the switch arm ISA towards the disconnected state. Typically, th analysing means in the microprocessor is one or more algorithms. it will be appreciated that th surge protection device 10 may be powered by an independent power source, for example a battery which is rechargeable by the mains when the surge protection device 10 Is in the connected state.

Outing installation, the incoming line{s) (i.e. telephone / data lines, television antenna, satellite antenna, etc) is connected Into the input socket 14 of the surge protection device 10. The electrical equipment to be protected (i.e. telephone, television, computer, modem, satellite tuner, etc.) is connected to the output socket 16 of the surge protection device 10. The user may the program his required safe zone and safe time delay into the microprocessor through the user input means 32A.32B. Where the device is configured to protect against surges present on electrical supply lines (i.e. mains), the power source is connected into the input socket 14 of the surge protection device 10, The electrical equipment to be protected is connected to the output socket 18 of the surge protection device 10. The user ma ? then program his required safe zone and safe time delay Into the microprocessor through the user input means 32A ; 328.

In use, and as illustrated in figure 3, the switch 18 remains in the connected state wit no electric storm being detected within the safe zone by the detector, in the connected state, the electrical equipment is connected to th power and/or data sources.

A warning signal may be outputte by the surge protection device 10 on de ection of an electric storm within the safe zone or otherwise. The warning signal may he outpufted as:

• a visual output In the form of a textual output on the displa 32A or flashing thereof;

· · a visual output in the form of a flashing light on the surge protection devloe 10; » an audible output in the form of an alarm; and/or

* a telecommunications output signal outputted b a surge protection device transmitter to a mobile telecommunications device of the user.

Furthermore, the surge protection device 10 may also include a receiver for receiving a telecommunications input signal from the user's mobile telecommunications device for, as an example, remotely actuating the servomotor to move towards the disconnected state in an event other than a lightning threat, i.e. a hacking threat,

In the event of the detector detecting the presence of an electric storm within th safe zone, the microprocessor triggers actuation of the servomotor 28 to actuate pivotal displacement of the switch arm 18A from the connected state tox^ards the disconnected state as illustrated in figure 4 and 5. The friction of the servomotor 26 is sufficient to hold the switch arm 18A in the disconnected state, thereby enabling the servomotor 26 to be optionally switched off in this position. -1.2-

In t disconnected state, the electrical equipment is disconnected from the power and/or data sources, thereby safe-guarding them from high voltage spikes i duced into the cable infrastructure by lightning activity. The detector continually scans the safe zone for the presence of an electric storm and, on the .presence of an electric storm no. longer being defectible within the safe zone, the timer begins to count down the pre-programmed safe time delay. Once the saf time delay has lapsed, the microprocessor actuates the servomotor 26 so as to caus the switc arm 18A, a large throw switch arm, to pivotalfy displace towards the connected state, thereby safely reconnecting the electrical- equipment to the power and/or data source .

The servomotor 26-, the drive arm 28, drive linkage 30, sw tch ami I SA nd the axe about which the drive arm 28 and the switch arm ISA are pivotally d splaoeahie. are confsgijred and laid out relative to on another th reby to create a very particular motion, torque and force.

The angular displacement of the drive arm 28 is converted to a reduced angular displacement of the switch arm ISA via the drive linkage 30. Furthermore, the angular displacement of the drive arm 28 and the switch arm 18A, in the final moments of movement into the connected state, is converted to a very small linear motion toward the contacts 20. Accordingly, a torque multiplier effect is created, providing the required torque to retain the switch arm 18A in the connected state. A further feature of this configuration and layout is that when the switch arm 18 · A Is in the connected state, where maximum force is required between the contacts 20,22, all moving parts are stopped in perfect alignment under compression, such that there is no load on the servomotor 26. In this position, the servomotor 28 may be turned off by the microprocessor to extend its useful life and to save power.

Although the invention has been described abov with reference to preferred embodiments, it wlli be appreciated that many modifications or variations of the invention ar possible .without departing from the spirit or scop of the invention. For example, an alternative embodiment of the device may include, as a supplementary or alternative feature of the detector described herein before, a detector for detecting the presence or absence of an nput signal (le. power) at the input sockets. On detection of an absence of input signal (i.e. power from mains being cut), the contacts are moved to the disconnected state, fro example, by an on-board reserve power supply.

On detection of restoration of input signal at the input sockets, the contacts are moved to the connected state either immediately or after a sufficient redetermined period of time, ft will be appreciated that although drive means other than a servomotor may be employed, the servomotor provides a high speed response fo disconnecting the conta ets from one another.

Although the surge protection device may be scaled up to any size. It is preferable thatt remain ' s he described dimensions for domestic use or other similar applications (i.e. for small businesses). The surge protection device may further include secondary stationary contacts to which the movable contacts are electrically conneotabie in the disconnected state, thereby to connect- the output sockets to a secondary circuit, for example, an alternative power and/or data source. The surge protection device may further include a means of monitoring power from the mains. In this manner, in the event of power being restored after a power outage, the switch might be restored to the connected state after the lapse of the safe time delay thereby to prevent exposure of the electrical equipment to any powe surges caused by the restoration of th power.