US2315757A - Electrical fence charging apparatus - Google Patents

Description

April 6, 1943. F. E. WENGER 2,315,757

ELECTRICAL FENCE CHARGING APPARATUS Filed Sept. 20, 1939 Jm F'zovn E. Wruam,

Patented Apr. 6, 1943 2,315,751 ELECTRICAL FENCE CHARGING APPARATUS Floyd Wcnger, Bhrflton, 0E0, assignmto Ray L. Triple, mum,

- Application September on, racasenai 1v. 295,199

electricity which The present invention relates to electrical interrupters and more particularly to a stock fence using electricity to preventanimalsfrom rubbing against the fence and breaking it.

One type of electric fence now in use employs a relatively strong current with a. thermally operated circuit breaker which will automatically disconnect the current for a sufllcienttime to enable the animal to free itself. This type of electric fence has been found to gives the animal too severe a shock when the current is flowing and time to break the fence when the current is disconnected.

A second type of electric fence employs an induction coil. or spark coil. The ordinary spark coil employed has an interrupter which vibrates rapidly and draws a. constant heavy current of also gives the animal too severe a shock.

Still a third type of electric fence employs a transformer, the primary winding of which is connected through a condenser and a chargecontrolling resistor to a source of direct current. A gaseous discharge deviceis connected across the condenser so that when the latter becomes fully charged and assuming that the discharge potent al is higher than the ionization potential of the gas within the tube, the current from the condenser will pass through the tube and cause an impulse to be transmitted across the transformer. While a circuit of this character operates quite satisfactorily when the load is constituted of an electric fence, it is open to the objection that the gas tube is always connected through a closed circuit, i. e. the primary of the transformer, and therefore there is continually passing through the tube at intervals determined by the charging rate of the condenser impulses of current to offset the leakage losses of the transformer. It is apparent that under these conditions. the gaseous discharge device cannot have an extremely long life. Moreover, in view of the fact that the gaseous tube operates continuously regardless of whether or not aloud is being drawn at thetransformer secondary, it is impossible to determin. by observation oi the tube, 1. e. by its glow, whether or not conditions at the output terminals as represented by the electric fence are normal.

The primary object of the present invention is to prov de an improved circuit of the general type describ d in connection with the third class immed ah y above-hut in which the gaseous discharge device is connected in a normally open circuit and is not called upon to pass impulses be unsatisfactory as it oi current until that circuit has been closed by physical contact with the fence. Another object is to provide a circuit of this character in which a visual inspection of the gaseous discharge device will show whether the electric fence is in operating condition or is inoperative as, for example, when the fence is permanently grounded or otherwise short circuited These objects are attamed, in brief, by connecting. the gaseous discharge device in the secondary .circuit of the transformer and arranging connections to the device in series with the terminals of the electric fence.

when these terminals are closed as by having an animal strike the fence, a circuit is established through the gas tube to produce shock impulses at the fence. Since a gaseous discharge device operates with a visible glow and inasmuch as this glow is present in the improved system only when the output terminals, as represented by the electric fence, are shorted, a casual inspection of the tube would at once indicate whether the terminals are temporarily or permanently being short circuited. Other features and objects will be apparent as the following specification is erused in connection with the accompanying drawing which shows a circuit diagram connected to an exemplary form of electric fence, all embodying my improved system.

Referring to the drawing, the numeral 1 designates a transformer having a primary winding 2 and a secondary winding 3. The primary winding is adapted to be connected to any suitable source of alternating current. The secondary winding is connected through a half-wave rectiner l to a pair of parallel circuits which extend from the points 5, 6. One of the circuits of this pair'may consist of a filter element represented by a condenser I connected directly between the points 5, B. The other circuit of the said pair may include a condenser 8 and an equipotentiai conductor 9 which is connected through a resistor it to the point 6.

The rectifier 4 is preferably of the gaseous discharge type in order to pass considerable currents and is represented by an envelope containing a filamentary cathode H and a cold anode II. An inert gas at a suitable pressure is contained in the envelope. The filament H may be conveniently heated by the battery l3.

From a. position between the point 5 and the left-hand plate of the condenser B a conductor ii is taken which is connected to one of the electrodes ll! of a gaseous discharge device it. The device l8 may constitute any suitabl and well-known tube of this character and In addition to the cold plate electrodes I5 contains an Inert gas at a pressure and of such character as preferably to exhibit a high ionization or break down potential. Tubes of this type are readily procurable on the market. The other electrode I5 is connected through a wire I! to an ammeter I8, and a conductor I9 is taken to one side of the electric fence.

This fence may be of any standard form and is exemplified by a couple of strands of barbed wire which are supported at equidistant positions throughout a field enclosure by a number of metallic uprights 2i driven into the ground as indicated at 22. The wires 20 are insulated from the uprights, in cas the latter are of metal. by being threaded through a pair of cylindrical insulators 23 secured in any suitable manner to the uprights 2i. The latter are completely grounded by a wire 24 in order to assure minimum resistance between the lower end of each upright and ground. A terminal 25 is connected to the upper portion of one of the uprights M. The barbed wires 20 are electrically connected together in any suitable manner, for example, by means of an upright metal bar 26 which is rigidly secured to the wire at 21 and carries at its upper end a terminal 28. The conductor I9 leading from the ammeter I8 is connected to the last mentioned terminal and therefore is connected to the wires 20. A conductor 29 is connected between the grounded terminal 25 and a point 30 which is positioned between the right-hand end of the resistor and th righthand plate of the condenser 8.

Operation of the circuit Assume that a voltage of standard periodicity is applied to the primary 2. These impulses are transmitted across the transformer I by induction and are rectified by the tube 4 to produce impulses of a unidirectional character across the points 5, 6. The condenser I is preferably of a small size, for example, .5 microfarad and its purpose is to by-pass small alternating current components which find their way through the rectifier and thus necessitate filtering out. It is apparent that any suitable form oi filter may be substituted for the condenser I.

The unidirectional impulses available at the points 5, 6 then serve to charge up the condenser I at a rate depending on the magnitude of the resistor Iii. The condenser 8 is preferably of a size such that when fully charged, the potential across the plates is somewhat greater than the ionization potential of the gas contained in the tube I6. If it were assumed that the circuit which contains the tube I6 were closed, the .potential ofpthelcharged condenser ll-would be free to discharge itself through the tube It causing a blue glow therein which is readily visible from the exterior. Thus the tube I6 depends for conduction on cumulative ionization of the gas contained therein. The ammeter I8 which is connected in thetube'circuit would indicate the amount of current flowing through the tube. However, it willbe noted that the circuit containing'the tube I6 is normally open assuming that the barbed wires 20 are not grounded so that the condenser B is unable to discharge itself through the tube but instead is maintained in a charged condition as long as the tube circuit is open.

If an animal were to touch either one oi the wires 20, the latter is immediately iii grounded through the animal's body which in effect closes the tube circuit across the terminals 25, 2B and a strong impulse 01' current is passed from the condenser 8 through the tube IB into the electric fence. This impulse is followed by other impulses at a rate determined by the size of the charge-controlling resistor Ill and will continue as long as the barbed wires are grounded. It is apparent that the voltage of these impulses is dependent, not entirely on the charged potential of the condenser 8 but also on the ionization potential of the gas contained within the tube iii. The fact that the latter tube contains electrodes of the cold i. c. nonfilamentary type, which are subject to relatively low current saturation limits. the current passing through the tube and hence through the animal at the fence is not dangerously large.

In view of the fact that the tube I 5 passes current only when the wires 20 are grounded, the condenser E retains its charge during all other periods of time so that during this time,

it is necessary for the rectifier 4 to provide charging currents only to make up for leakage losses at the condenser. This means that during the idleperiods of the fence which obviously is by far the greatest proportion of the protecting life of the fence since only momentary contacts are made by animals, the power consumption 01' the circuit as a whole is reduced to the minimum of the ordinary circuit losses occasioned in the transformer I and the condensers 1 and 8. Over a course of many years which is the normal life of an electric fence, this saving in power consumption is considerable.

Moreover when the barbed wire circuit is open and no current is passing through the tube I6, the electrodes within the tube are called upon to do no work and hence are not deleteriously affected during the long idle periods. Thus the operating life of the tube approximates its ordinary shelf life. A tube of this character might be quite expensive depending on the character of the contained gas and electrodes. In this connection, I have satisfactorily employed a tube which has an approximate breakdown potential of 500 volts. Such a tube is procurabie from tube manufacturers but is expensive. Consequently an increase in its operating life is decidedly advantageous.

the conductors I9, 29 by the condenser B is of a correspondingly high value. 7 Another advantage of arranging th tube gl 5 in a circuit which is normally kept open is thatwhen the circuit becomes inoperative as, for example.

electric fence. This visual indication is available at all times and is not dependent on the presence of the ammeter I8 which is provided solely to determine the amount oi current passing through the conductors I9 and 29.

While I have shown and described my improveed circuit for electric fences in connection with the use of a rectifier 4 and a filter I, it will be imimpulses transmitted to the fence which periodicity is independent of the alternations at the primary source of energy. The rate at which the voltage impulses are applied to the conductors I9 and 29 is important in the operation of electric fences because a sufficient time should elapse between impulses to enable the animal to free itself from the fence. The higher the periodicity the greater is the tendency for the animal to freeze to the wires 20.

It will be evident from the foregoing that my improved circuit is not limited to an electric fence load, although, it offers unusual advantages in this particular connection. For example, the impulse generating circuit shown to the right of the transformer i might be employed in connection with any kind of load which requires an interrupted current, such as a vibrator or a flasher sign and the like, to take the place of mechanically operated or electrically magnetized coil devices. There are no contacts or moving parts in the improved system. The advantages of having the tube ii draw no idle current and also of giving a visual indication of abnormal conditions at the load are available regardless of the character of the load.

It will be understood that I desire to comprehend within my invention such modifications as come within the scope of the claims and the inventlon.

Having thus fully described by invention, what I claim as new and desire to secure by Letters Patent is:

1. An electric fence protective system comprising a transformer having primary and secondary windings, said primary winding being adapted to be connected to a source of alternating current, a circuit including a. rectifier solely of the single wave type connected across said secondary winding, a condenser in series with said rectifier, and means for controlling the rate of charging said condenser by the unidirectional current output of said rectifier, a cumulative ionization device and an electric fence connected in series acrosssaid condenser, said ionization device being connected directly in series with the fence load except i or a current-measuring device.

2. An electric fence protective system comprising a transformer having primary and secondary windings, said primary winding being adapted to be connected to a source of alternating current. a circuit including a rectifier solely of the single wave type connected across said secondary winding, a condenser in series with said rectifier to receive unidirectional current impulses from said rectifier, an electric fence, and means for causing the periodic unidirectional discharge of said condenser into said fence. said means including a gaseous discharge device having a breakdown potential less than the full charge potential of the condenser and connected directly in series with the fence load except for a current measuring device.

3. An electric fence protective system comprising a transformer having primary and secondary windings, said primary winding being adapted to be'connected to a source of alternating current, a. circuit including a rectifier and condenser connected across the secondary winding, and a pair of circuits connected in parallel across said condenser. one of said pair of circuits comprising a condenser and a resistor, and the other of said pair of circuits comprising a gaseous cumulative ionization tube and a pair of terminals connected respectively to an electric fence and ground, said tube being connected directly in series with the fence load except for a current-measuring device.

4. An electric fence protective system comprising a transformer having primary and secondary windings, said primary winding being adapted to be connected to a source of alternating current, a. circuit including a gaseous rectifier and an alternating current filter connected across the secondary winding and a pair of circuits connected in parallel across said filter, one of said pair of circuits comprising a condenser and a resistor, and the other of said/pair of circuits comprising a gaseous glow discharge tubeand a pair of terminals connected respectively to an electric fence and ground, said tube series with the fence measuring'device.

5. An electric fence protective system comprisa. transformer "having primary and secondary windings, said primary winding being adapted to beconnected to a source of alternating current, a circuit including a geaseous rectifier and an alternating current filter connected across the secondary winding and a pair of circuits con nected in parallel across said filter, one of said pair of circuits comprising a. condenser and a resistor, and the other of said pair of circuits comprising a gaseous glow discharge tube and a pair of terminals connected respectively to an electric fence and ground, said gaseous discharge tube being open circuited until the physical contact is established at the fence, said tube being connected directly in series with the fence load except for a current-measuring device.

6. An electrical system comprising a transformer having primary and secondary windings, said primary winding being adapted to be conload except for a currentnected to a source of alternating current, a load connected to the secondary winding, means including a tube rectifier interposed between the load and the secondary winding for translating the alternating current impulses of the primary winding into uni-directional impulses at the load, and a filter connected in series across the secondary winding, a condenser and a resistor connected in series across said filter, and a gaseous glow discharge device connected at one side to a point between said filter and condenser and at the other side directly to said lead except for a current-measuring device whereby said discharge device is in series with the load, said rectifier being also in series with the load whereby when the load circuit is opened the gaseous discharge dev ce and the rectifier are both rendered inoperative.

FLOYD E. WENGER.

being connected directly in

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