RE: [TCML] pole pig question

["Jim Mora" <jmora@xxxxxxxxxxx>]

(120) 120v 100 watt light bulbs in series are as practical...:-)
Jim Mora
-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Lau, Gary
Sent: Thursday, January 17, 2008 5:48 PM
To: 'Tesla Coil Mailing List'
Subject: RE: [TCML] pole pig question

Perhaps I missed something, but why is a 1 KOhm value being discussed?  If
it's to be used as a dummy load for a distribution transformer, such a low
resistance value would, *if it could*, draw over 14 Amps.  While I doubt
that the high side of a distribution transformer could source 14 Amps, it is
not a current limited transformer, and even if it managed to eek out more
than 1 Amp, it would exceed the power rating of the 1kW resistor, and smoke
it.  Whether the smoke is due to over current or over voltage is difficult
to predict and academic.

I guess more to the point, why is a dummy load for a distribution
transformer even being considered?  I would guess that it's rare that the
transformer is faulty, and a lashed-up Jacobs's ladder should be adequate
evidence of its functionality.  A proper full-power dummy load resistor for
a distribution transformer would be HUGE.

Regards, Gary Lau
MA, USA

> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of G Hunter
> Sent: Thursday, January 17, 2008 6:38 PM
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] pole pig question
>
>
> --- BunnyKiller <bunnikillr@xxxxxxx> wrote:
>
> > Hey Jim,
> > test the piggie using a hi current hi voltage
> > resistor 1KW @ 1KOhm (
> > wire wound dont work to well they simply arc over to
> > the next winding)
> >
> > Scot D
>
> I disagree.  An ordinary wirewound power resistor is
> as good as any in this application.  A 1kohm power
> resistor will feel no more than a few hundred volts
> potential across the whole body of the resistor, even
> if it is connected across the pig HV terminals.  The
> reason is as simple as Ohm's law.  If a 1kohm resistor
> passes 500mA of current, then it will have a potential
> of 500volts across it--hardly sufficient to cause
> turn-to-turn arcing on a big (100W or larger) one.
> The pig simply cannot develop it's full HV potential
> across such a low resistance.  Besides, wirewounds
> have been used for decades in vacuum tube equipment,
> where they routinely handle 100's of volts of plate,
> grid, and screen bias without failure.
>
> Greg

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