GB2215536A - Three-phase electrical power control system for multiple loads - Google Patents
Three-phase electrical power control system for multiple loads Download PDFInfo
- Publication number
- GB2215536A GB2215536A GB8806071A GB8806071A GB2215536A GB 2215536 A GB2215536 A GB 2215536A GB 8806071 A GB8806071 A GB 8806071A GB 8806071 A GB8806071 A GB 8806071A GB 2215536 A GB2215536 A GB 2215536A
- Authority
- GB
- United Kingdom
- Prior art keywords
- loads
- switch
- control
- phase
- diodes
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/26—Arrangements for eliminating or reducing asymmetry in polyphase networks
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
- G05D23/1906—Control of temperature characterised by the use of electric means using an analogue comparing device
- G05D23/1912—Control of temperature characterised by the use of electric means using an analogue comparing device whose output amplitude can take more than two discrete values
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
- G05D23/275—Control of temperature characterised by the use of electric means with sensing element expanding, contracting, or fusing in response to changes of temperature
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Power Engineering (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
A three phase supply, control and distribution apparatus has two control units 10, 11 arranged to switch between full-power and half-power energisation of two sets of loads, particularly radiant heater, without altering the phase load balance. The half-power setting is achieved by diodes 12, 22 connected in parallel with switch contacts 14, 24 which are opened in unison when either a switch 34 or a thermostat, or a fuse 42 (supplying contactor solenoid 11, 21 and fans) open, the diodes 12, 22 being poled so that one set of loads receives positive half waves and the other set receives negative half waves. Each load set may be formed by three groups of three radiant heater star connected between the three phase output lines 13 or 23 and neutral 32. <IMAGE>
Description
ELECTRICAL POWER CONTROL SYSTEM FOR
MULTIPLE LOADS
This invention concerns control apparatus for controlling and distributing three phase electrical power to multiple unit loads, and electrical apparatus incorporating such control apparatus.
Such apparatus is usually complex, expensive and can give rise to operational problems for the user, and an object of the invention is to provide relatively efficient, simple and less expensive apparatus.
According to the present invention there is provided control apparatus comprising a ganged input isolator in three live phase input lines and a neutral line; and two control units connected electrically in parallel with the input lines, each control unit providing three live phase output lines and power setting means to control the level of power to each output line; wherein the power setting means comprises diodes or like partially conductive devices in parallel with level switches which are controlled to operate in unison and are arranged so that each switch can close to shunt out a respective one of the diodes; and wherein the diodes or like devices are arranged so that from each input line one half wave or portion thereof of the phase supply is conducted to the respective output line of one unit, and the other half wave or portion thereof of the phase is conducted to the respective output line of the other unit.
The present invention further provides electrical apparatus comprising the control apparatus and at least twelve individual loads arranged in two sections of six or more; wherein each section is supplied by a respective one of the control units; and wherein in each section the loads are arranged in three sets of at least two loads connected in parallel.
The loads are thus operable at full power or halfpower (or less) according to the common state of the level switches without altering the phase load balance.
The apparatus preferably comprises switch actuating means to switch on cooling means and/or to open the level switches if an excessive condition, e.g. overheating arises.
The invention is particularly applicable to heating installations in which the loads are radiant heating elements and the cooling means comprises fans.
The power supplies for the cooling and switch actuating means are preferably taken from one or more of the input lines between the isolator switch and the control units.
The sets are preferably in star connection between the neutral line and the live phases.
The invention will be described further, by way of example, with reference to the accompanyiny diagrammatic drawings wherein FIGURES 1 and 2 are circuit diagram showing respectively control apparatus and supply connections for one of two sections of loads of electrical apparatus of the invention.
Referring to FIGURE 1, the control apparatus includes two control units 10 and 20, each comprising a normally open three contact relay 11 or 21, the contacts 14 or 24 of which provide a respective level switch in parallel with a respective one of three diodes 12 or 22.
Three live phase lines 30 connect the two units in parallel to an input isolator switch 33 in three live phase input lines 31 and in a neutral line 32. The diodes 12 are arranged in opposite polarity to the diodes 22 so that the live phase output lines 13 of the unit 10 are fed, when the contacts 14 are open, with half-waves of one polarity whilst the half-waves of opposite polarity are supplied to the output lines 23 of the unit 20. The relay solenoids are connected in parallel in a control circuit including a power level switch 34, and optionally a thermostat (not shown), so as to permit energisation to close the level switches in unison to shunt the diodes and apply full power to the output lines. The thermostat, if provided, is arranged to break the control circuit to de-energise the relays irrespective of the state of the switch 34.Two switches 36 and 37 are reciprocally linked to the relays to operate power level indicator lamps 38 and 39 to show the power output level.
Each output line has an individual fuse 40.
The control apparatus also provides a fan circuit 43, including a fan "on" indicator diode 41, arranged to supply power continuously to fan units (not shown) when the switch 33 is closed. The control and fan circuits have a common supply fuse 42 so that in the event of the fuse blowing the power to the output lines is automatically halved whilst the fans are off, and so that a fan failure indicator lamp 45 is illuminated.
The electrical apparatus includes the control apparatus and multiple loads arranged electrically (and preferably also physically) in two sections of approximately equal power rating, each of which sections is connected to a respective one of the control units 10 and 20 by the output lines 13 or 23, and to the neutral line 32 and an earth line 51. The distribution interconnections are the same for each section.
In FIGURE 2 there are shown the distribution interconnections of one section for an embodiment in which each section comprises nine loads in the form of radiant heating elements 50.
In each section the loads are arranged in three sets. Each set is connected between a respective one of the three phase output lines 13 (or 23) and the neutral line 32. In each set, three elements are connected in parallel. Each section, together with respective fans and optionally a thermostat is mounted in a housing, preferably earthed, to form a heating unit, but many other physical arrangements of the loads are possible to suit installation requirements.
Where other numbers of loads and loads of unequal power rating are involved, the distribution interconnections are preferably arranged so that the total power ratings of the loads in the sets are as similar as possible, and so that each set includes a plurality of loads.
The invention is not confined to details of the foregoing example and many variations are possible within the scope of the invention. The latter includes any novel feature or part or combination thereof disclosed herein or in the drawings, and mechanical, electrical and
functional equivalents thereof.
Claims (8)
1. Control apparatus comprising a ganged input isolator in three live phase input lines and a neutral line; and two control units connected electrically in parallel with the input lines, each control unit providing three live phase output lines and power setting means to control the level of power to each output line; wherein the power setting means comprises diodes or like partially conductive devices in parallel with level switches which are controlled to operate in unison and are arranged so that each switch can close to shunt out a respective one of the diodes; and wherein the diodes or like devices are arranged so that from each input line one half wave or portion thereof of the phase supply is conducted to the respective output line of one unit, and the other half wave or portion thereof of the phase is conducted to the respective output line of the other unit.
2. Electrical apparatus comprising control apparatus as claimed in Claim 1 and at least twelve individual loads arranged in two sections of six or more; wherein each section is supplied by a respective one of the control units; and wherein in each section the loads are arranged in three sets of at least two loads connected in parallel.
3. Apparatus as claimed in Claim 1 or 2 further comprising switch actuating means to switch on cooling means and/or to open the level switches if an excessive condition arises.
4. Apparatus as claimed in Claim 3 wherein the loads are radiant heating elements and the cooling means comprises fans.
5. Apparatus as claimed in Claim 3 or 4 wherein power supplies for the cooling and switch actuating means are taken from one or more of the input lines between the isolator switch and the control units.
6. Apparatus as claimed in any preceding claim wherein the sets are in star connection between the neutral line and the live phases.
7. Control apparatus substantially as hereinbefore described with reference to FIGURE 1 of the accompanying drawings.
8. Heating apparatus substantially as hereinbefore described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8806071A GB2215536A (en) | 1988-03-15 | 1988-03-15 | Three-phase electrical power control system for multiple loads |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8806071A GB2215536A (en) | 1988-03-15 | 1988-03-15 | Three-phase electrical power control system for multiple loads |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8806071D0 GB8806071D0 (en) | 1988-04-13 |
| GB2215536A true GB2215536A (en) | 1989-09-20 |
Family
ID=10633426
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8806071A Withdrawn GB2215536A (en) | 1988-03-15 | 1988-03-15 | Three-phase electrical power control system for multiple loads |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2215536A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5229908A (en) * | 1991-04-24 | 1993-07-20 | U.S. Products, Inc. | Multiple circuit overload protection device |
| EP2190268A1 (en) | 2008-11-21 | 2010-05-26 | Hendrikus Johannes Kraakman | Device and method for controlling a power of several lights |
| CN105449700A (en) * | 2015-12-30 | 2016-03-30 | 北京四方继保自动化股份有限公司 | Balance control system and method of three-phase active unbalanced loads of isolated grid generator |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108834233A (en) * | 2018-04-16 | 2018-11-16 | 上思县东岽电子科技有限责任公司 | A kind of constant temperature energy-saving automatic control device of electric oven |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB301814A (en) * | 1927-09-03 | 1928-12-03 | Birmingham Electr Furnaces Ltd | Improvements relating to the control of the load factor in electrical current-supplysystems to factory and similar installations including electrical resistance furnaces |
| GB400219A (en) * | 1932-04-11 | 1933-10-11 | George Ralph Baker | Improvements in and relating to electrical heating devices for baking or other ovens |
| GB1089273A (en) * | 1964-07-21 | 1967-11-01 | Cressall Mfg Company Ltd | Improvements relating to heating resistor assemblies and associated control means therefor |
| GB2148678A (en) * | 1983-10-18 | 1985-05-30 | Thorn Emi Domestic Appliances | Heating apparatus |
| EP0174774A1 (en) * | 1984-09-11 | 1986-03-19 | THORN EMI Patents Limited | Heating apparatus |
| GB2178914A (en) * | 1985-07-26 | 1987-02-18 | Bosch Siemens Hausgeraete | Electric heating means |
-
1988
- 1988-03-15 GB GB8806071A patent/GB2215536A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB301814A (en) * | 1927-09-03 | 1928-12-03 | Birmingham Electr Furnaces Ltd | Improvements relating to the control of the load factor in electrical current-supplysystems to factory and similar installations including electrical resistance furnaces |
| GB400219A (en) * | 1932-04-11 | 1933-10-11 | George Ralph Baker | Improvements in and relating to electrical heating devices for baking or other ovens |
| GB1089273A (en) * | 1964-07-21 | 1967-11-01 | Cressall Mfg Company Ltd | Improvements relating to heating resistor assemblies and associated control means therefor |
| GB2148678A (en) * | 1983-10-18 | 1985-05-30 | Thorn Emi Domestic Appliances | Heating apparatus |
| EP0174774A1 (en) * | 1984-09-11 | 1986-03-19 | THORN EMI Patents Limited | Heating apparatus |
| GB2178914A (en) * | 1985-07-26 | 1987-02-18 | Bosch Siemens Hausgeraete | Electric heating means |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5229908A (en) * | 1991-04-24 | 1993-07-20 | U.S. Products, Inc. | Multiple circuit overload protection device |
| EP2190268A1 (en) | 2008-11-21 | 2010-05-26 | Hendrikus Johannes Kraakman | Device and method for controlling a power of several lights |
| NL2002234C2 (en) * | 2008-11-21 | 2010-05-27 | Hendrikus Johannes Kraakman | Device and method for controlling a power of several lights. |
| CN105449700A (en) * | 2015-12-30 | 2016-03-30 | 北京四方继保自动化股份有限公司 | Balance control system and method of three-phase active unbalanced loads of isolated grid generator |
| CN105449700B (en) * | 2015-12-30 | 2018-05-25 | 北京四方继保自动化股份有限公司 | The active out-of-balance load balance control system of island network generator three-phase and control method |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8806071D0 (en) | 1988-04-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |