FR2640845A1 - ELECTRICAL FENCE WITH CONTROLLER INCORPORATED - Google Patents

Abstract

Power supply device for electric fences, intended for penning livestock or for avoiding human intrusions into an enclosure, consisting of a box connected to a main power supply source generating high-voltage pulses of more than one second spacing comprising an indicator of isolation of the electric fence line, characterised in that the box contains a system for digitising a characteristic electrical quantity and an isolation indicator consisting of a digital or bar-graph display which displays the degree of isolation on each pulse, the assembly consuming only energy provided directly or indirectly by the said main power supply, and not by an auxiliary power supply source.

Description

ELECTRICAL FENCE WITH CONTROLLER INCORPORATED

  Electrical fences are known to send high voltage pulses at regular intervals over a wire surrounding or dividing a field where animals graze. It is also known that such electric fences can be used to prevent the intrusion of people into an enclosure. The effectiveness of an electric fence decreases when grass touches the wire; these herbs short the impulses that must normally pass through the animal or

  the person coming into contact with the wire.

  Users are looking for means of control to check the condition of the fence, ie its isolation from the ground, and thus be reassured about

the effectiveness of the fence.

  A rudimentary method is to put a hand to the ground and touch the wire at

  medium of a long grass that dampens the electric shock.

  More elaborate means exist, consisting of a resistive voltage divider

  associated with a detector. One of the ends of the resistor bridge is grounded by a small ground stake, the other end being placed on the electrified wire. The detector associated with the resistor bridge (ignition threshold lamps or digital voltmeter powered by a battery) allows then to evaluate the remaining voltage

on the fence wire.

  The present invention describes an energizer having an insulation measurement system integrated into the enclosure of the electric fence and having no source

auxiliary energy.

  The energizer described is of the "capacitor discharge" type, but it can be

  also of the type "alternating injection network".

  A diagram for better describing the principle of the invention is represented by

Figure 1.

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  The capacitor C is charged by a power supply A connected to the source

  of energy: the sector, a battery or a battery. Capacitor C is discharged at inter-

  regular valleys, greater than one second, by means of switch I in the

  main transformer T. The role of the transformer T is to raise the voltage of the pulse and to ensure, particularly

  especially in the case of mains power supply, the indiscriminate isolation

  thinkable between the energy source and the fence circuit.

  A voltage divider R1-R2 consists of several resistors placed in series to prevent breakdowns due to high voltage. The output voltage of the pulse, associated with a certain notion of duration of the pulse, determines the energy remaining on the line to give a painful discharge to the animal or to the man touching the wire. This energy decreases when the isolation of the fence wire from the earth is

  degraded by plants touching the wire or by defective insulators.

  The impulse, divided by the resistance bridge, is sent to a control system.

  sure M whose role is: -to integrate the pulse with a constant time sufficient to eliminate voltage peaks whose duration is too short to be significant in terms of the pain felt by the animal touching the wire ; -b- to detect the peak value of the voltage thus integrated and to digitize it; -c- to attack a digital dial which displays at each pulse a value

  proportional to the peak voltage detected.

  The displayed value can range from 0 to 99 (or 99.9) and then indicates a sort of

  centage of the isolation of the fence.

  The display can also be done using a bar-graph, or a system a ai-

  mobile guille; reading is then more intuitive.

  The measurement module M is powered by a system of rectifiers D, of conden-

  C1, C2 ... and resistors R3, R4 ..., all of these components being connected according to a well-known voltage rectifier / voltage stabilizer scheme; The ensemble then forms a circuit which is connected on the one hand to the "earth" exit of the fence, and on the other hand to

  a point K where an alternating or pulsed or continuous voltage is generated.

  For energizers powered by a battery or battery, the "earth" output of the enclosure

  It can be connected to one of the battery or battery terminals, and point K to the other terminal of the battery or battery.

  For energizers supplied by the network, galvanic isolation is essential.

  only the "earth" + "fence" circuit of the primary circuit of the main transformer which is itself connected to the grid. The point K can not therefore be directly connected to

the main power supply.

  Isolation can be obtained in two different ways: -a- The point K is fed by a transformer T2 as shown in Figure 2. The transformer primary T2 is connected to the AC network; The secondary

  is connected between the output "earth" and the point K. The isolation between the primary and the

  T2 should be particularly cautious in order to guarantee a complete sepa-

  ration between the network and the "earth" + "fence" circuit, the latter being subject to

  high voltage pulses up to 10,000 volts.

  The point K is connected to a special output of the secondary of the main transformer T according to the wiring diagram of FIG. 1. The circuit M working at low voltage (a few volts), only a few turns are selected between the output "earth "T and the special output o is connected K. These few turns allow to

  recharge the capacitors C1 and C2 with each electric discharge, without

  sea a lot of energy. A second advantage of this method of supplying the module M is to require only one very highly isolated transformer: the main transformer T. Figure 3 and Figure 4 relate to a variant of the present invention where

  the degree of isolation of the fence by a measure made in the connecting part

  primary transformer primary.

  Between the outputs P and Q of the primary of the transformer, is connected a divider bridge

  voltage, consisting of resistors or possibly capacitors. A tendency

  proportional voltage to the voltage between P and Q appears between the points R and Q. This proportional voltage can also be obtained on an intermediate output provided for this purpose during the winding of the primary of the transformer, or by an additional winding on the transformer T completely separated from primary and secondary. The Zener diode Z and the load resistance Rz of Z make it possible to obtain, between

  point S and Q, a voltage Vm = [h (Vp - Vq) - Vz], where Vp and Vq are the voltages

  at the primary boundary, h the proportionality ratio of the voltage divider

  chosen voltage, and Vz the voltage of the zener diode.

  The solid line curve of FIG. 4 represents the voltage h (Vp - Vq) when the electric fence wire is well insulated. The dashed curve of the same figure 4 represents the

  voltage h (Vp - Vq) when the fence wire is poorly insulated. These two curves are

  by the dashed line of the voltage of the zener diode Vz. It is found that the duration of the first alternation during which h (Vp Vq) exceeds Vz very largely depends on the degree of isolation of the electric fence wire: tl is much smaller than t2. The measurement and the afficiage of this duration are thus a means of informing

  the user on the state of his electric fence.

  The measurement of the times t1 or t2 can be done advantageously by opening an electronic gate when Vm = [h (Vp - Vq) - Vz] becomes positive and closing the door when Vm returns to zero; then keep the door closed for a while

  on the order of 0.3 to 0.5 seconds so as not to take into account any rebounds

  of the signal. The measurement and display of the opening time of the door are then

  an indication of the degree of insulation of the electric fence wire.

  The advantage of this measurement made in the primary circuit of the transformer, is that the measurement block and the display, which are completely separated from the secondary circuit by the insulating barrier existing between the primary and secondary

  of the transformer T, can be powered by a conventional diode circuit,

  sistances and capacitors, itself connected live on the alternative power supply

network.

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  It is also possible to use a transformer that can be in low isolation.

  Another method of estimating the isolation of the electric fence is to

  to measure the peak current passing through the primary of the transformer T during the pulse; this peak current can be analyzed either by measuring the voltage it generates at the terminals of a resistor Rs, of low value, connected in series with the primary of T (Figure 5), or by measuring the voltage appearing at the terminals of the secondary of a small annex transformer T3 whose primary, low self inductance, is crossed by the current of the main discharge (Figure 6). Identical to the variant of the invention described above (FIGS. 3 and 4), the measurement and display part of the signal characteristic of the isolation of the fence wire is fed by a circuit connected to the terminals of the AC network without Security

be called into question.

Claims (8)

  A device for feeding electric fences, intended to park livestock or to avoid human intrusions into an enclosure, consisting of a housing generating high voltage pulses spaced apart for more than one second, the housing being powered by the power supply network. sector or by an accumulator or a dry cell,   characterized in that it comprises an incorporated measurement system displaying on a readout   digital meter or on a bar-graph or on a moving-needle dial, the degree of isolation of the fence; 2- Device according to claim 1 characterized in that the measuring system consumes only energy supplied directly or indirectly by the single main power, and not by an auxiliary power source; 3- device according to claim 1, characterized in that the measuring system of the isolation of the fence in fact measures the voltage in the closing circuit by means of a voltage divider which is galvanically connected to the fence circuit;   4- Device according to claims 1 and 3 characterized in that the measured voltage   is slightly integrated over time in order to eliminate the voltage peaks whose too short duration makes them insignificant;   - Device according to any one of claims 1 to 4 and characterized in that   the power supply of the electronic measuring and display system can be powered   part of the secondary winding which recovers a small part of the pulses   and send it to a rectifier / stabilizer supply circuit decoupled   vanically primary primary transformer;   6. Device according to any one of claims 1 to 4 and characterized in that   the system of the measuring and display circuit can be powered for electri-   connected to the AC distribution network, by a transforma-   voltage-reducing device having a very strong isolation between the primary and the secondary;   7- Device according to any one of claims 1 to 4 characterized in that the   measuring and display circuit system can be powered, for electri- 7 2640845   connected to a battery or accumulator, directly to the main source of energy; 8- Device according to claim 1 characterized in that the evaluation of the isolation of the fence wire is done by measuring the duration during which the voltage across the primary of the output transformer remains greater than a certain value ;   9- Device according to claim 8, characterized in that the measurement of the time   the voltage across the transformer primary is only   the first alternation of the discharge;   10- Device according to any one of claims 8 or 9, characterized in that   that the voltage across the primary of the transformer is measured by means of a divider bridge composed of resistors and / or capacitors, or by means of an additional winding on the main transformer, or by means of an output special on the main transformer primary; 11- Device according to claim 1, characterized in that the evaluation of   the insulation of the closing wire is made by measuring the peak current of the current of de-   load passing through the main transformer primary;   12- Device according to claim 11 characterized in that the peak current passes through   the primary is measured by the voltage across a low resistance   their connected in series with the main transformer primary; Apparatus according to Claim 11, characterized in that the current measurement   crest crossing the primary is made by measuring the voltage at the terminals of the se-   Conductor of a measuring transformer whose primary, of low inductance, is connected in series with the primary of the main transformer;   14- Device according to any one of claims 8 to 13, characterized in that   the system comprising the measuring and display circuit is fed directly   by the main source of energy by means of galvanic connections or   low isolation transformers.