GB2080050A

GB2080050A - Reduction of electrical power consumption

Info

Publication number: GB2080050A
Application number: GB8021766A
Authority: GB
Original assignee: QUISEAR Ltd
Current assignee: QUISEAR Ltd
Priority date: 1980-07-02
Filing date: 1980-07-02
Publication date: 1982-01-27

Abstract

An electric power consumption reduction circuit receives power from an AC electricity supply and provides power output to an electrical appliance via switch 14 and semiconductors 12, 13. The circuit is cyclically controlled to reduce power by periodically terminating the supply of power to the output. The control may provide reduced power by allowing only one half cycle from an output via diode 12 and/or by allowing only a predetermined number of whole AC cycles in a given period to be passed to the output via thyristor 13 dependent on the period determined by pulse generating timer 10 and the position selected for switch contacts 14. Diode 12 and thyristor 13 may be replaced by a triac. <IMAGE>

Description

SPECIFICATION Reduction of electrical power consumption The invention relates to a device suitable for use on the standard mains electricity supply for reducing the power consumed by heating elements, such as electric fires for example.

According to the invention there is provided an electric power consumption reduction device including input means for receiving power from an electricity supply, output means for providing power output to an electrical appliance in use when connected thereto, and cyclically operating control means for reducing power to said output means by periodically terminating the source of supply to said output means.

The control means may provide reduced power by allowing only one half cycle from an ac supply to be passed to the output means and/or by allowing only a predetermined number of cycles in a given period to be passed to the output means.

The invention will now be described by way of example with reference to the accompanying drawings, in which: FIGURE 1 shows one embodiment of the invention, and FIGURE 2 shows various modes of operation of the invention.

The embodiment of the invention shown in Figure 1 comprises a reduction device suitable for use on standard ac mains supplies. In the mode shown in Figure 1 the switch 14 is illustrated in the full power position where the incoming supply (live, neutral and earth) can be connected to the output side (L, N 8 E) without reduction in power. Thus the live rail passes via switch 1 6 and fuse 11 to the output.

The neutral rail passes via switch contacts 14C and 14B to the output (see Figure 2a). When it is desired to operate on half power, switch 14 is moved so as to connect contacts 1 4A and 1 4C in which case the output passes via power diode 12. This diode only allows half the normal alternating cycle to pass to the output, thus providing power to the connected appliance at half normal rate (see Figure 2B).

To provide an intermediate saving in power consumption a thyristor 13 is provided which can be triggered to switch on periodically to allow full cycle conduction (see Figure 2C). To provide suitable triggering the system includes a pulse generator 10 (e.g. integrated circuit chip type 555) with associated components (resistors R1-R3 and capacitors C1, C2). The generator produces pulses at a rate determined by preset resistor R2 and fixed resistor R3 in combination with a capacitor C2. The pulses are provided from pin 3 which is shown connected with load resistor R1.The pulses are received by the gate of thyristor 1 3 via resistor R4 to trigger the thyristor into conducting.

The pulse generator receives its supply (8v dc) from a suitably included standard power supply unit (not shown) with transformer and rectifiers to allow it to operate from the incoming mains supply.

To activate the pulse generator, switch 1 5 is closed which provides connection of the neutral line to the mains input of the power supply unit. Opening of switch 1 5 will cause termination of the generated pulses.

Although a diode 12 and thyristor 13 are shown these could be replaced by a triac to allow only pulsed ac to be provided (see Figure 2d). The pulse rate is determined by R2/R3 and C2 and increasing the pulse rate will increase the average current flow and decreasing the pulse rate will decrease the average current flow.

With additional modification to the power supply for the pulse generator and inclusion of a mechanism to allow the thyristor to be turned off, the system could be used to operate on a dc supply or rectified ac (see Figure 2e).

Expansion of the basic system will allow the device to operate on three phase ac supplies (see Figure 2f).

The system of the invention is particularly suitable for appliances incorporating a heating element such as an electric fire so that even though the power consumed is reduced with a resulting lowering of heat from the appliance, this may only be marginally noticeable to the user yet allowing substantial savings in electricity over a period.

Items such as immersion heaters may also be used with this device.

An exampie of the heat output from a 1 KV 230 volt fire measured by a Digatron Instrument model number 1 75 is given below under various operating conditions.

Full Wave 15 minutes Pulsed 15 minutes Half Wave 15 minutes Probe at 1/16" from 28% saving 50% saving element 486" to 495"C 365'to375"C 492" to 502"C Probe at 1/4" from 28% saving 50% saving element 302" to 311"C 156' to 158"C 310" to 316"C Probe at 1" from 28% saving 50% saving element 201 to208"C 110' to 111"C 210" to 212"C

Claims

1. An electric power consumption reduction device including input means for receiving power from an electricity supply, output means for providing power output to an electrical appliance in use when connected thereto, and cyclically operating control means for reducing power to said output means by periodically terminating the source of supply to said output means.

2. A device as claimed in claim 1, wherein the control means includes a timer for cyclically terminating the source of supply for a predetermined period.

3. A device as claimed in claim 1, wherein the supply is an AC supply and the control means includes a regulator for allowing only a predetermined number of cycles in a given period to be passed to the output means.

4. A device as claimed in claim 3, wherein selector means are provided to adjust the predetermined number of cycles.

5. A device as claimed in claim 3 or 4, wherein the regulator comprises a solid state timer and switching circuit.

6. A device as claimed in claim 5, wherein the switching circuit includes a semiconductor switch triggerable by said timer to be conductive either during or between timing periods.

7. A device as claimed in claim 5 or 6, wherein DC voltage means are provided for deriving a DC supply from the AC mains to power said timer circuit.

8-. A device as claimed in claim 6 or 7, wherein the semiconductor switch comprises a thyristor.

9. A device as claimed in claim 6 or 7, wherein the semiconductor switch comprises a triac.

10. A device as claimed in claim 1, or any one of claims 3 to 9, wherein the supply is an AC supply and the control means includes a blocking component to prevent half of each AC cycle passing to the output means.

1 A device as claimed in claim 10, wherein the blocking component includes a semiconductor diode.

12. An electric power consumption reduction device substantially as described herein and as illustrated in the accompanying drawings.