WO2007041788A1

WO2007041788A1 - A load switching arrangement

Info

Publication number: WO2007041788A1
Application number: PCT/AU2006/001496
Authority: WO
Inventors: Jeff Elliott
Original assignee: Rheem Australia Pty Limited
Priority date: 2005-10-14
Filing date: 2006-10-11
Publication date: 2007-04-19

Abstract

The present invention provides an arrangement for switching a first load (216) from a continuous load meter (214) to an intermittent load meter (226), including a first switch (218) connected in series with the first load (216) and the continuous load meter (214), and a second switch (236) connecting the first load (216) to the mains supply (206,208) via the intermittent load meter (226), wherein the first switch (218) is closed and the second switch (236) is opened when the intermittent load meter (226) is quiescent, and wherein the first switch (218) is opened and the second switch (236) is closed when the intermittent load meter (226) is activated. The present invention also provides a method of switching a load (216) from a continuous load meter (214) to an intermittent load meter (226), including a first switch (218) connected in series with the first load (216) and the continuous load meter (214), and a second switch (236) connecting the first load (216) to the mains supply via the intermittent load meter (226), the method including the steps of: switching the first switch (218) to its closed state, switching the second switch (236) to its opened state when the intermittent supply is quiescent, and switching the first switch (218) to its opened state, and switching the second switch (236) to its closed state when the intermittent load meter (226) is activated.

Description

A load switching arrangement

Field of the invention

[001] This invention relates to the switching of electrical loads. Background of the invention

[002] Off-peak switching of electrical loads has been used for many years. In one arrangement, two electricity meters are provided with one load capable of being operated through the first meter at all times, and a second load, usually a storage hot water system, only enabled to operate during off-peak periods. The off-peak load can be controlled by the use of a ripple controlled switch which is operated by transmitting a ripple signal at a frequency different from the mains frequency. The ripple signal is detected by a ripple detector which operates a relay to connect the off-peak load to the mains via the off-peak meter during off-peak periods. A second ripple signal is used to disconnect the off-peak loads at the end of the off-peak period.

[003] Any reference herein to known prior art does not, unless the contrary indication appears, constitute an admission that such prior art is commonly known by those skilled in the art to which the invention relates, at the priority date of this application.

Summary of the invention

[004] This invention provides a method and arrangement for switching loads between a continuous operation meter and an off-peak meter. The switching can be triggered by an off-peak signal transmitted over the power lines, by an off-peak signal transmitted over a communications link, or by a local time clock controlled switch or other suitable triggering means.

[005] In a first embodiment there is provided an arrangement for switching a first load from a continuous load meter to an intermittent load meter, including a first switch connected in series with the first load and the continuous load meter, and a second switch connecting the first load to the mains supply via the intermittent load meter, wherein the first switch is closed and the second switch is opened when the intermittent load meter is quiescent, and wherein the first switch is opened and the second switch is closed when the intermittent load meter is activated.

[006] The second switch can be arranged to close before the first switch opens during a change from quiescent state to activated state of the intermittent load meter.

[007] The first switch can be arranged to close before the second switch opens when switching from the activated state to the quiescent state of the intermittent load meter. [008] The invention also provides a method of switching a load from a continuous load meter to an intermittent load meter, including a first switch connected in series with the first load and the continuous load meter, and a second switch connecting the first load to the mains supply via the intermittent load meter, the method including the steps of: switching the first switch to its closed state, switching the second switch to its opened state when the intermittent supply is quiescent, and switching the first switch to its opened state, and switching the second switch to its closed state when the intermittent load meter is activated.

[009] The second switch can be arranged to close before the first switch opens during a change from quiescent state to activated state of the intermittent load meter.

[010] The first switch is arranged to close before the second switch opens when switching from the activated state to the quiescent state of the intermittent load meter.

[011] The inventive switching arrangement can readily be retro-fitted to an existing off- peak metering arrangement in domestic, commercial or industrial sites to provide a cost effective means of spreading loads to low demand periods. The switching arrangement can be readily fitted by an electrician.

[012] The switching arrangement can be connected to connect at least some of the power-point outlets to the off peak meter.

[013] The switching arrangement can be used in conjunction with appliances using 24 hour standby power supplies.

Brief description of the drawings

[014] An embodiment or embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[015] Figure 1 represents a known off-peak arrangement;

[016] Figure 2 represents an off-peak switching arrangement according to an embodiment of the invention.

[017] Figure 3 represents an off peak switching arrangement according to a further embodiment of the invention.

Detailed description of the embodiments

[018] With reference to Figure 1 , a known off-peak switching arrangement is shown.

The mains electricity supply is represented by a three-phase supply 102, 104, 106, with neutral 108. At a customer premises a continuous supply meter 114 measures the power consumed by a load 116. Load 116 can be a plurality of appliances each with individual on/off switches.

[019] An off-peak meter 122 is connected to an off-peak load 124, such as a storage hot water system via a switch 128. Switch 128 is controlled by ripple controller 126. Ripple controller 126 detects the off-peak ripple signal transmitted by the electricity supply utility and closes the switch 128 at the commencement of the off-peak period. Similarly, at the end of the off-peak period, the ripple controller detects a second ripple signal from the mains supply and switches the switch 128 to the open position.

[020] In the embodiment of the invention shown in Figure 2, the continuous load meter

214 is connected to a load 220 via switch 218. The continuous load meter 214 can also be connected to a second load 216 on the "upstream" side of switch 218. Switch 218 is closed during periods when the off-peak circuit is not powered so that load 220 is supplied via continuous load meter 214 during this time.

[021] The off-peak meter 226 is associated with an off-peak circuit including off-peak switch 230 and off-peak load 232. In an alternative arrangement, load 232 may not exist. Similarly load 216 may not exist, so that all the continuous load is switched to the intermittent load meter 226 during periods when the intermittent load meter is activated, and all the load is switched to the continuous load meter when the intermittent load meter is quiescent.

[022] A ripple controller 228 detects the ripple control signals as for the arrangement in

Figure 1. The ripple controller can thus close switch 230 to supply power to load 232.

[023] In addition, the ripple controller 228 is arranged to close switch 236 and open switch 218. The closing of switch 236 and the opening of switch 218 causes the load 220 to be switched to the off-peak meter 226.

[024] Thus, according to an embodiment of the invention, at least part of the continuous supply load can be switched to off-peak tariff rates during off-peak periods.

[025] Some electronic equipment is sensitive to switching spikes or momentary power interruptions, and such equipment can be included in load 220. According to a further embodiment of the invention, the invention can be modified to reduce switching spikes and interruptions in the load 220 by providing a make-before arrangement between switch 236 and switch 218. Thus switch 236 is arranged to close before switch 218 is opened. This feature is illustrated by the inclusion of a time delay 238 between switch 236 and switch 218. Of course, make-before-break switches are available commercially. [026] At the end of the off-peak period, the ripple controller 228 causes switch 230 to open to disconnect supply to the off-peak load 232. In this case, the supply to load 220 can be interrupted momentarily.

[027] Accordingly, the embodiment shown in Figure 3 illustrates a further arrangement in which the ripple controller 328 is shown as having a first output 342 to switch the off-peak loads on, and a second output 344 to switch the off-peak load off. In this arrangement, a further delay 340 is used to ensure that the switch 318 for the load 320 is supplied with power via the continuous load meter 314 before the supply from the off-peak meter 326 is switched off via switch 330 and switch 336.

[028] The switching on of the off-peak meter loads is as for Figure 2, with only the prefix number of each element of Figure 3 which corresponds to an element of Figure 2 being changed from 2 to 3.

[029] Where ever it is used, the word "comprising" is to be understood in its "open" sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of. A corresponding meaning is to be attributed to the corresponding words "comprise", "comprised" and "comprises" where they appear.

[030] It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text. All of these different combinations constitute various alternative aspects of the invention.

[031 ] While particular embodiments of this invention have been described, it will be evident to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. The present embodiments and examples are therefore to be considered in all respects as illustrative and not restrictive, and all modifications which would be obvious to those skilled in the art are therefore intended to be embraced therein.

Claims

1. An arrangement for switching a first load from a continuous load meter to an intermittent load meter, including a first switch connected in series with the first load and the continuous load meter, and a second switch connecting the first load to the mains supply via the intermittent load meter, wherein the first switch is closed and the second switch is opened when the intermittent load meter is quiescent, and wherein the first switch is opened and the second switch is closed when the intermittent load meter is activated.

2. An arrangement as claimed in claim 1, wherein the second switch is arranged to close before the first switch opens during a change from quiescent state to activated state of the intermittent load meter.

3. An arrangement as claimed in claim 1 or claim 2, wherein the first switch is arranged to close before the second switch opens when switching from the activated state to the quiescent state of the intermittent load meter.

4. A switching arrangement as claimed in any one of claims 1 to 3 adapted to be connected to connect at least some of the power-point outlets to the off peak meter.

5. A method of switching a load from a continuous load meter to an intermittent load meter, including a first switch connected in series with the first load and the continuous load meter, and a second switch connecting the first load to the mains supply via the intermittent load meter, the method including the steps of: switching the first switch to its closed state, switching the second switch to its opened state when the intermittent supply is quiescent, and switching the first switch to its opened state, and switching the second switch to its closed state when the intermittent load meter is activated.

6. A method as claimed in claim 5, wherein the second switch is arranged to close before the first switch opens during a change from quiescent state to activated state of the intermittent load meter.

7. A method as claimed in claim 5 or claim 6, wherein the first switch is arranged to close before the second switch opens when switching from the activated state to the quiescent state of the intermittent load meter.

8. A kit including a switching arrangement as claimed in any one of claims 1 to 3 adapted to be retro-fitted to an existing off-peak metering arrangement.

9. A switching arrangement substantially as herein described with reference to the embodiments illustrated in the accompanying drawings.

10. A method of switching loads substantially as herein described with reference to the embodiments illustrated in the accompanying drawings.