WO1990002472A1

WO1990002472A1 - Reduced power switch

Info

Publication number: WO1990002472A1
Application number: PCT/AU1989/000363
Authority: WO
Inventors: Geoffrey Peter Harrington
Original assignee: Bowden, Brett, Antony
Priority date: 1988-08-26
Filing date: 1989-08-28
Publication date: 1990-03-08
Also published as: AU4184289A; AU582993B3

Abstract

A compact, three-way consumer electrical power switch built into a body (10) designed to fit into and to be interchangeable with existing consumer switch mechanisms, the switch has a button (10a) mounted on a pivot (11) connected to the active wire (12) of an alternating current power circuit and with a mechanical pivoting, switching pivot arm (13) having reduced or low power and full or high power switch contacts (14, 15) activating a power reduction unit, the switch has a lowermost ''HIGH'' full power position, an uppermost ''LOW'' reduced-power position and a middle ''OFF'' zero-power position and is coupled to a power reduction unit which is operated by a trigger device incorporating a triac switching circuit with triac component (16), gate connection diac (17), two capacitors (18, 19) and resistor (20) to reduce alternating current line voltage to a lower value when operating a load device, such as a lamp (21) in the circuit, so that when the switch button (10a) is moved into the reduced power ''LOW'' position, it switches the active supply contact of the circuit through the power reduction unit circuit then passes through the ''OFF'' position disconnecting the active wire and when the switch is placed in the ''HIGH'' position, the power-reduction circuit is by-passed and full line voltage is supplied to the load device.

Description

REDUCED POWER SWITCH

This invention relates generally to replacement of consumer electrical power switches within standard power switch plates and particularly relates to replacement of a standard on/off switch body within a switch plate by a reduced power switch incorporating full power, reduced power and zero poer off positions respectively, within the one switching mechanism or body.

It is_.an object of this invention to provide a combination consumer electric power and/or lighting on/off switch and power usage reduction unit within the one switch body.

The invention resides in a three-way, consumer electrical power switch incorporating a full-power position, a reduced-power position, and a zero-power-off position, the switch being coupled to a power-reduction unit operated by a trigger device to reduce line voltage, when the switch is operated at the reduced power position, the three-way switch and power-reduction unit being incorporated within a single switch body and being inter- changeable with existing switch mechanisms and being installable through and behind the aperture of power switches.

Preferably, the switch is coupled to a power reduction circuit operated by a trigger device through a triac gate to reduce line voltage to half its value, when the switch is operated.

A non-limitative example of a practical arrange- of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a schematic diagram of a power- reduction switch unit according to the invention, installed in a lighting circuit.

Figure 2 is a circuit diagram of specific elctronic components used in the invention. Figure 3 is a circuit diagram of the invention.

Figure 4 is a sinusoidal line voltage wave form diagram.

SUBSTITUTESHEET Figure 5 is a capacitor voltage wave form diagram. Referring to the example shown in the drawings, there is shown a power usage reduction switch unit for use in a 240 volts, 50 Hz alternating current mains supply circuit to control the level of domestic lighting, which in this particular non-limitative example, allows a user to switch immediately to a reduced level, such as half-power for dimming, or to switch to full lighting as required and comprises a combination switch and power reduction unit, the switch, in this example consisting essentially of a three way switch and which comprises a a switch body 10 with button 10a, adapted to be operated by a user through three positions indicated namely:

A middle "OFF" position, an upper "LOW" postion, and a lower "HIGH" position. The switch button is mounted on the pivot 11, -connected to the active wire 12 with a mechanical pivoting, switching pivot arm 13 having low and high power switch contacts 14, 15, activating a power reduction unit shown within the rectangle in broken outline and which incorporates a bi-directional triode thyristor rectifier known as a triac in a triac switching circuit, such as BT137 triac component 16 with gate connection diac 17, two capacitors 18, 19 respectively and resistor 20. The outputs from the switch and power reduction unit comprise a switch labelled "S", an active supply labelled "A" and a return loop labelled "L" , respectively. The lamp 21 is shown connected to the switch line S.

Referring to Figures 2 and 3 of the drawings, the electric components of Figure 1 of the power reduction unit are labelled with their respective ratings namely, the triac 16 of Figure 1 is a BT137 unit, the diac 17 is an ST4 unit, the capacitor 18 of Figure 1 is Ci of Figure 3 and is of 100 volt rating and 0.039 U F, capacitor 19, C₂ is of 630 volt and 0.022.U F rating connec-ted in parallel and a reistor 20, or R, is of 680 ohms and 0.5 watt capacity. -3-

It will be appreciated that the switch positions described can be interchanged to suit and the type of switch, as well as the mechanical action can be varied, for example, a slide-switch or rotary switch can be used. Applications of the combination switch and power usage reduction unit of the invention are:

Internal/External lighting of any room or area within a house or other buildings, where reduced power is required. Furthermore, the unit can be used in equipment such as fixed exhaust fans and range hoods and sweep fans. The unit is also user installable.

The value of the resistor R*^ and capacitor Cl are chosen, so that the triac will switch at the apex of the sine wave. This in RMS is half voltage. The triac will continue to conduct until the voltage passes through zero and then the triac will have to be re- triggered next half-cycle. The value of the load is irrelevant, as the trigger device is voltage dependent, not current dependent. The other capacitor Co is in the circuit to reduce the voltage spikes generated by the switching triac. The switch is a multi-position switch. When it is switched to "LOW" position, it switches the active supply through the power reduction circuit. The switch then passes through off position, when the active wire is not connected to anything. When the switch is placed in the "HIGH" position, the power reduction circuit is by-passed and full line voltage is supplied to the lamp. The circuit uses minimal parts to reduce the line voltage to half voltage switching, using a triac gate. During each half cycle of AC voltage, the capacitor C, is charged through the re-istor R_j . Once the voltage reaches the switching voltage of the trigger device, the capacitor Ci discharges into the triac gate. The trigger device is constructed, so that when it triggers initially, the triggering voltage on the next half cycle is equal to the original breakover _4_

voltage, plus the voltage decrease due to the capacitor C, discharging into the triac gate. This allows the the voltage of capacitor C, to maintain the same time relationship with the line voltage and thus the same firing angle.

The power-saver switch according to the invention, instead of using a constantly variable output of a dimmer circuit, as in the prior art, automatically allows a user to switch to reduced power whenever required. The switch incorporates power reduction circuitry within a switch body and can there¬ fore be used as a direct replacement for and is inter¬ changeable with a standard switch mechanism.

The switch and power usage reduction unit can be used as a replacement unit for standard switch bodies in switch plates, or can be manufactured as an entire switch plate, switch and power reduction unit and is applicable to 110 volt mains or alternating current supply systems. In this new energy conservation society in which we live, the consumers to reduce their power consumption have replaced high wattage incandescent lighting with much lower values. This practice has reduced power consumption, but has also reduced lighting brilliance, sometimes needed by the consumer. This invention will give the consumer many advantages by using high wattage globes they can switch to full brilliance when needed, then switch to reduced power for normal operation, thus increasing the life of the globes and decreasing power consumption and switch to off position when not in use, from the same switching mechanism.

SHEET

Claims

Claims :

1. A three-way consumer electrical power switch incorporating a full power position, a reduced-power position and zero-power-off position, the switch being coupled to a power reduction unit operated by a trigger device to reduce alternating current line voltage, when the switch is operated to the reduced power position, the three-way switch and power-reduction unit being incorporated within a single switch. body and being interchangeable with existing switch mechanisms and being installable through and behind the aperture of power switches.

2. A switch according to claim 1, installed in an alternating current circuit wi h a current load device, such as a lamp and which comprises a switch body (10) with buLtυn (10a), adapted to be operated by a user through three positions indicated on the switch as a middle "OFF" position, an upper "LOW" position and a lower "HIGH" position respec ively, the switch button being mounted on a pivot (11) connected to ah active wire (12) in the said circuit, the switch having a mechanical pivoting, switching arm (13) with low and high power switch contacts (14, 15), activating the power reduction unit, the circuit of which incorporates the trigger device, whereby when the switch is switched to the "LOW" position by a user, it switches the active supply contact of the AC power circuit through the power reduction unit circuit and the switch thenpasses through the "OFF" position disconnecting the active wire and when the switch is placed in the "HIGH" position, the power-reduction circuit is by-passed and full line voltage is supplied to the load device.

A switch according to claim 1 or 2 wherein the trigger device is voltage dependent.

4. A switch according to any one of claims 1 to 3, where^'in the switch is coupled to the power reduction incorporating and operated by the trigger device

SUBSTITUTESHEET comprising a triac switching circuit to reduce the line voltage to half its value, when the switch is operated to the reduced power "LOW" position.

5. A switch according to claim 4 wherein 'during each half cycle of AC voltage, the capacitor C, (18) is charged through the resistor R. (20), whereupon when the voltage reaches the switching voltage of the triac switching circuit, the capacitor C_j ^" (18) discharges into the triac switching circuit.

6. A switch according to claim 5 wherein when the trigger device triggers initially, the triggering voltage on the next half cycle is equal to the original breakover voltage plus the voltage decrease due to the capacitor C-, (18) discharging into a triac switching circuit, thereby allowing the voltage of the capacitor C, (18) to maintain the same time relationship with the line voltage and thus the same firing angle.

7. A switch according to any one of claims 4 to 6 wherein the triac switching circuit comprises a triac component (16), a gate connection diac component (17), two capacitors C, , C .. (18, 19)respectively and a resistor R ,(20).

8. A switch according to claim 7 wherein the triac is a BT137 triac and the diac is an ST4 diac.

9. A switch according to any one of claims 5 to 8 wherein the capacitor C, (18) is of 100 colt and 0.039 uF capacitance rating, capacitor C (19) is of 630 volt and o.o22 uF capacitance rating and is connected in parallel C. and the resistor R. (20) is of 680 ohms and 0.5 watt capacity.

10. A switch according to any one of claims 5 to 9 wherein the value of the resistor R-, (20) and capacitor C, (18) enables switching of the triac component (16) at the apex of the sine wave equal to RMS half voltage, the triac continuing to conduct until the voltage passes through zero and requiring to be re-triggered in the next-half cycle.

SUBSTITUTESHEET