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WO2006063367A1 - Reduction du bruit sur une cloture electrique - Google Patents

Reduction du bruit sur une cloture electrique Download PDF

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Publication number
WO2006063367A1
WO2006063367A1 PCT/ZA2005/000179 ZA2005000179W WO2006063367A1 WO 2006063367 A1 WO2006063367 A1 WO 2006063367A1 ZA 2005000179 W ZA2005000179 W ZA 2005000179W WO 2006063367 A1 WO2006063367 A1 WO 2006063367A1
Authority
WO
WIPO (PCT)
Prior art keywords
pulses
pulse
energiser
conductor
polarity
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.)
Ceased
Application number
PCT/ZA2005/000179
Other languages
English (en)
Inventor
Leslie Sean Hurly
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of WO2006063367A1 publication Critical patent/WO2006063367A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B15/00—Suppression or limitation of noise or interference
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05C—ELECTRIC CIRCUITS OR APPARATUS SPECIALLY DESIGNED FOR USE IN EQUIPMENT FOR KILLING, STUNNING, OR GUIDING LIVING BEINGS
    • H05C1/00—Circuits or apparatus for generating electric shock effects
    • H05C1/04—Circuits or apparatus for generating electric shock effects providing pulse voltages

Definitions

  • This invention relates generally to electric fences, used for example for security purposes or for game or animal containment, and more particularly is concerned with electromagnetic interference generated by such fencing.
  • An electric fence typically includes one or more conductive wires which extend along a defined boundary and which are connected to an energiser which applies a succession of relatively sharp and high voltage pulses, of controlled energy, to the conductor.
  • an energiser of the aforementioned type resembles a low frequency radio transmitter which is coupled to a long aerial (the conductor).
  • a possible disadvantage of the type of arrangement is that some of the energy
  • EMI electromagnetic interference
  • RFID radio frequency interference
  • An energiser can have a low frequency component due to the prescribed pulse repetition rate, typically 1 pulse per second, and can also have many high frequency components because of the rapid discharge of energy storage devices used in the energiser.
  • an energiser can be used.
  • an output terminal of an energiser is connected to earth while a second terminal is connected to a live wire or conductor which is used as a deterrent.
  • the condition of the live wire, or of an earth wire which is connected to the earth terminal may be monitored for security purposes or for energiser control.
  • the magnitude of a shock which is experienced by an animal or person touching a live strand is typically determined by the energiser characteristics and the resistance of the earth. Installers are reluctant to use one or more additional earth wires on the brackets because of the cost and perceived waste.
  • the invention provides, in the first instance, an energiser which includes an apparatus for generating a pulse train which includes a plurality of pairs of pulses at predetermined time intervals, each pair of pulses including a first pulse of a first amplitude and a first polarity and a second pulse, which is produced substantially simultaneously with the first pulse, and which is of a second amplitude which is substantially equal to the first amplitude and a second polarity which is opposite to the first polarity.
  • the energiser may be of any suitable form.
  • a desired pulse train can be obtained by synchronising similar energisers which run at the same frequency and by combining their outputs.
  • the energiser includes a transformer with a primary winding and a secondary winding which includes first and second output terminals and a centre output terminal, the first pulses being produced across the first output terminal and centre output terminal and the second pulse being produced across the centre output terminal and the second output terminal.
  • the invention extends, in addition, to an electric fence installation which includes at least first and second elongate conductors and an energiser of the aforementioned kind connected to the conductors so that the first pulses are applied to the first conductor and the second pulses are applied to the second conductor.
  • the installation may be such that the first and second conductors are substantially parallel to each other and are fairly close to each other. Preferably the spacing between the conductors is less than 6 inches (150mm). [0014] In the installation the centre output terminal (with the second type of energiser referred to) may be connected to ground.
  • the invention further extends to a method of reducing electromagnetic noise in an electric fence which includes at least first and second elongate electrical conductors, the method including the step of applying a first series of first pulses to the first conductor and a second series of second pulses to the second conductor wherein each first pulse has a first amplitude and is of a first polarity and each second pulse is produced substantially simultaneously with a respective first pulse and is of a second amplitude which is substantially equal to the first amplitude and which is of a second polarity which is opposite to the first polarity.
  • FIG 1 schematically illustrates an electric fence installation according to the invention.
  • Figures 2 and 3 are graphs of electromagnetic noise generated, respectively, in a conventional electric fence installation and in a fence installation in accordance with the invention.
  • Figure 1 of the accompanying drawings illustrates an electric fence installation 10 according to the invention which includes a fence 12 and an energiser
  • the components illustrated in Figure 1 are used to explain the concept of the invention. It will be understood by those skilled in the art that additional mechanical and electrical components would be required for a complete electric fence installation. Such components are however known and therefore are not further described herein.
  • the fence 12 includes a plurality of standards or posts 16 which are erected in the ground 18 at regularly spaced intervals.
  • Conventional wire netting 20 may be attached to straining wires, not shown, supported by the posts.
  • Elongate electrical conductors 22, which are used for electrifying the fence, are directly mounted to the posts or to stand-off brackets, not shown, so that they are spaced from the wire netting 20.
  • the conductors 22 are installed in closely spaced pairs of conductors designated 22A and 22B respectively.
  • Figure 1 only one pair of conductors is shown but it is to be understood that this is merely for ease of illustration and that the principles described herein have equal applicability to a plurality of pairs of conductors all of which can be energised using the energiser 14 or one or more other energisers.
  • the conductors 22A and 22B run along a predetermined length of the fence 12 and are then returned, at different heights from the output paths of the conductors, to a location which is near the energiser 14. Use may be made of a termination resistor 24 at this location.
  • the e ⁇ ergiser .14 includes a transformer 30 with suitable control circuitry 32. The manner in which this type of transformer is controlled is also known in the art and thus the control circuit 32 is not described in detail. The function of the control circuit is inter alia to control the operation of the transformer 30 and to monitor the condition of the conductors and to provide information which can be used for security and other applications.
  • the transformer 30 includes a primary winding 34 which is connected to a suitable electrical source, not shown.
  • the transformer further includes a secondary winding 36 which has a first output terminal 38, and a second output terminal 40.
  • the secondary winding has a centre-tap output terminal 42.
  • the arrangement is such that, as is known to those skilled in the art, the number of windings between the terminals 38 and 42 is the same as the number of windings between the terminals 42 and 40.
  • the terminal 42 is connected to ground 46.
  • the first terminal 38 is connected to the conductor 22A and the second terminal 40 is connected to the conductor 22B.
  • the operation of the transformer 30, controlled by the circuit 32 is such that pairs of pulses are simultaneously and continuously generated by the secondary winding 36 as the power supply to the transformer is switched.
  • the full output voltage of the secondary winding appears across the terminals 38 and 40.
  • the terminal 42 is connected to ground the voltage at the terminal 38 is of opposite polarity to the voltage at the terminal 40.
  • the voltage pulses appearing across the terminals 38 and 42 on the one hand and 42 and 40 on the other hand have the same magnitude.
  • the voltage pulses are complementary with respect to the terminal 42 and if care is taken in the design and operation of the transformer 30 the same impedance characteristics appear across the terminal pairs.
  • a practical result of operating the energiser 14 in the manner described is that the conductors 22A and 22B are energised simultaneously with pulses of equal magnitude but of opposing polarity. Electromagnetic fields which are set up in each conductor are, as is known, dependent on the magnitude of the current and the direction of the current flowing through the conductor. There is therefore a natural tendency for the electromagnetic noise which is generated by one conductor to be cancelled by the electromagnetic noise which is generated by the other conductor.
  • Figures 2 and 3 contain curves which illustrate the degree of noise reduction achieved by the arrangement of the invention.
  • an energiser of the type shown in Figure 1 was used but the centre terminal 42 was
  • the terminal 38 was instead connected to earth and the terminal 40 was connected to a live wire of the fence.
  • the live wires of the fence were all connected in series.
  • the upper and lower curves respectively depict peak and average values of the resulting electric field strength measured at about 2m from the fence.
  • Another aspect of the invention is that a shock is provided to an animal or person contacting the electric fence, irrespective of the earth resistance. If a single live wire only is contacted then the shock will be at a reduced level and will be a function of the earth resistance. However if two of the wires are simultaneously touched then the shock will be at a greater level. This is achieved without the use of a dedicated earth wire and there is no perceived material wastage.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Insects & Arthropods (AREA)
  • Fencing (AREA)

Abstract

La présente invention concerne un dispositif d'excitation incluant un appareil conçu pour générer un train d'impulsions comportant une pluralité de paires d'impulsions à des intervalles de temps prédéterminés, chaque paire d'impulsions incluant une première impulsion ayant une première amplitude et une première polarité et une seconde impulsion, qui est produite sensiblement simultanément à la première impulsion et qui possède une seconde amplitude sensiblement égale à la première amplitude et une seconde polarité opposée à ladite première polarité.
PCT/ZA2005/000179 2004-12-07 2005-12-06 Reduction du bruit sur une cloture electrique Ceased WO2006063367A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ZA2004/9910 2004-12-07
ZA200409910 2004-12-07

Publications (1)

Publication Number Publication Date
WO2006063367A1 true WO2006063367A1 (fr) 2006-06-15

Family

ID=35976753

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/ZA2005/000179 Ceased WO2006063367A1 (fr) 2004-12-07 2005-12-06 Reduction du bruit sur une cloture electrique

Country Status (2)

Country Link
WO (1) WO2006063367A1 (fr)
ZA (1) ZA200705865B (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1483005A (en) * 1921-07-23 1924-02-05 Mcnair Albert Duy Electric fence
US2928012A (en) * 1954-12-15 1960-03-08 Internat Electric Fence Co Inc Electric fence interference eliminator
US3270276A (en) * 1965-04-13 1966-08-30 J D Cavaness Geophysical apparatus for indicating strata beneath the earth's surface including means for preventing transients from reaching the indicating means
US5158039A (en) * 1992-03-18 1992-10-27 Clark Brian L Electrically chargeable garment
US6371054B1 (en) * 2000-03-21 2002-04-16 Jack Celata System and method for inhibiting creatures from entering defined regions

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1483005A (en) * 1921-07-23 1924-02-05 Mcnair Albert Duy Electric fence
US2928012A (en) * 1954-12-15 1960-03-08 Internat Electric Fence Co Inc Electric fence interference eliminator
US3270276A (en) * 1965-04-13 1966-08-30 J D Cavaness Geophysical apparatus for indicating strata beneath the earth's surface including means for preventing transients from reaching the indicating means
US5158039A (en) * 1992-03-18 1992-10-27 Clark Brian L Electrically chargeable garment
US6371054B1 (en) * 2000-03-21 2002-04-16 Jack Celata System and method for inhibiting creatures from entering defined regions

Also Published As

Publication number Publication date
ZA200705865B (en) 2008-08-27

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