GB2337838A

GB2337838A - Remote switching system

Info

Publication number: GB2337838A
Application number: GB9811515A
Authority: GB
Inventors: Roy Derek Gregory
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-05-28
Filing date: 1998-05-28
Publication date: 1999-12-01
Also published as: GB9811515D0

Abstract

An electronic system allows continuous auxiliary power to be supplied to and communication with a device which is normally intermittently disconnected from the mains by the action of an on-off switch. The on-off switch is replaced with or connected to a device, named a switch commuter, which modulates the mains wave-form according to the condition of the switch The modulation and therefore the condition of the switch is sensed by a device, named a commuter controller, which is normally but not necessarily situated near the switched device which is switched on or off, by the commuter controller.

Description

2337838 REMOTE SWITCHING SYSTEM This invention relates to a switching

system which allows continuous auxiliary power to and communication with a switched device.

1 Fire alarms, intruder alarms and the like often employ separate wiring. This often takes the form of a low voltage loop which is driven from a power supply in the main control box which, in turn, is driven from the mains. Rechargeable batteries or large capacitors are often incorporated to provide auxiliary power in the event of mains failure. In particular fire alarm sounders must be driven via wiring which is heat resistant for compliance with BS5839. Separate wiring increases installation costs and is unsightly. Radio systems are available but sufFer from the disadvantage of requiring battery checking and replacement. Wiring for mains driven electrical devices such as incandescent light bulbs is often in an ideal physical position for detector heads such as smoke and heat detectors audible alarms and emergency lighting but cannot be used because it is disconnected from the mains by the action of the on-og switch e.g. light switch. Whilst the switch is off, no charging current for aamiliary power and no communication is Dossible via the mains wiring.

According to the present invention a normal electrical switch is replaced by a device, henceforth referred to as a switch commuter which is controlled by a switch (which may or may not be an integral part of the switch commuter) and continues to supply power but wts a switching signal, along the mains wiring, to the switched device, by modifying the shape and therefore frequency spectrum of the mains voltage wave-form. The switched device (e.g. light bulb) is now electronically switched by a commuter controller which is nornWly but not necessarily in close proximity to it and which receives the switching signal from the switch commuter. Power supplies and sensors which are connected on the switch commuter side of the commuter controller are now constantly connected to the mains.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: - Figure 1 shows a lighting circuit modified to include a smoke detector driving an alann sounder with rechargeable batteries providing au power in the event of a mains failure.

Figure 2 shows a lighting circuit modified to include a smoke detector and alarm driven from a fire alarm panel with power and signalling via the existing mains wiring.

Figure 3 shows an electrical pre payment energy meter modified to provide continuous power for circuitry.

Referring to figures 1 and 2 the light switch is operated by the consumer to switch the light on and off. The switch commuter transmits normal mains when the switch is in the on position and a modified wave shape when the switch is in the off position. The commuter controller and associated circuitry responds to three conditions:1. normal mains which the commuter controller directs to the light bulb 2. modified mains which the commuter controller disconnects from the light bulb 3. No mains which indicates a fault condition. The emergency light is switched on driven from a rechargeable battery. Further visual or audible fault indication of mains failure may be provided within the commuter controller and associated circuitry or a fault signal may be Utted along the mains cabling from the commuter controller and associated circuitry, via the commuting switch, to a control unit, depending on system requirements.

1 2

Claims

1. A remote switching system comprising of a device (named a switch commuter) which replaces or works in conjunction with an electrical switch and a companion device (named a commuter controller) which together enable a switched electrical circuit to function in the normal way whilst continuously supplying power to an auxiliary circuit.

2. A remote switch system as claimed in Claim 1 wherein the switch commuter responds to a mechanical or electronic switch and represents the state of that switch by a signal which modulates the mains wave-form.

3. A remote switch system as claimed in Claim 1 wherein the commuter controller responds to a signal modulating the rnain and provides electromechanical or electronic switching of an electrical device.

4. A remote switch system as claimed in Claim 2 wherein a closed switch is represented by the normal wave-form and an open switch is represented by a rectified, chopped or squared wave-form or vice versa.

5. A remote switch system as claimed in Claim 2 or claim 4 wherein the switch commuter is powered by the live line without connection to the neutral line.

6. A remote switch system as claimed in Claim 3 wherein the commuter controller switches the controlled device on when receiving a normal waveform and olf when receiving a rectified, chopped or squared wave-form.

7. A remote switch system as claimed in any preceding claim wherein the auxWary power supply will respond to both normal and modified wave-forms and produce constant voltage or current within limits and tolerances dictated by the auxiliary system or systems.

8. A remote switch system as claimed in claim 1 or claim 2 or claim 4 or claim 5 wherein the switch commuter passes continuous or discontinuous main born intelligence in one direction or both directions, over the whole or part of each cycle of main voltage whilst communicating with the switch controller.

1