Re: [Phys-l] Chimp unsuccessfully hangs from high voltage line

["Matt Coia" <matt.coia@gmail.com>]

I seem to recall using long grass blades to "test" to see if a fence was
on.  By using the grass as an insulating buffer between your hand and the
fence, you can minimize the jolt to a light tingle in a live wire.  Of
course, I've had my share of full jolts, too! :)

Matt


On 8/26/06, Brian Whatcott <betwys1@sbcglobal.net> wrote:
> At 07:45 AM 8/26/2006, Joe,  you wrote:
> >Some years ago, I had a crazyish uncle who had a small resort in the
> >Catskills, and decided it would be fun to have a chimp to entertain
> >the guests.  While as it happened, one day the chimp got away.  Now
> >this "resort" was in the middle of cow pasture country, a very lovely
> >setting with pastures separated by electric fences...a single wire
> >with some high voltage on it.  There was enough internal resistance
> >in the power supply so that animals got shocked by not killed.
> ///
> >Joseph J. Bellina, Jr. Ph.D.
>
>
> I have lately developed a personal interest in electric fences.
> During a hot Summer, when grass easily burns out, horses are tempted
> to reach through wire to the greener grass on the other side.
> If that wire is barbed, they cut ears, shoulders, legs etc., in reaching
> through.  Unlike cattle, they are said to be slow to learn from their
> cuts.
>
> Horse owners like to place an offset electric wire, to keep them back.
> The ordinary sort of fence charger resembles an induction coil, which
> pulses the fence wire with a high voltage pulse.
> (Some are apparently configured like a transformer, instead)
>
>     The source impedance is high enough to avoid permanent injury to
> animals.   But this leads to a problem.    The grass that is no longer
> nibbled, grows to touch the wire, and this can easily emasculate
> the pulse.
>
> A recent approach to fence charging takes a different tack: a high
> voltage pulse is still generated, but now, its output is lower impedance.
> Instead, its duration is limited in   order to avoid injuring the
> quadrupeds. These are billed as "Low impedance" in that they are
> not disabled by moderate grass/weed loading.
> Chargers are also rated by pulse energy:
> 0.1 J to 1.5 J are to be seen in the feed store.
>
>
>
> Brian Whatcott    Altus OK    Eureka!
>
>
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