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small coil ground question
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From: Bert Hickman [SMTP:bert.hickman-at-aquila-dot-com]
Sent: Friday, March 20, 1998 6:40 AM
To: Tesla List
Subject: Re: small coil ground question
Tesla List wrote:
>
> ----------
> From: Mad Coiler [SMTP:tesla_coiler-at-hotmail-dot-com]
> Sent: Thursday, March 19, 1998 9:30 PM
> To: tesla-at-pupman-dot-com
> Subject: small coil ground question
>
> Coilers,
>
> I am considering for an IEEE project here at college to build a small
> coil that can be demonstrated in the labs or classrooms. I would like
> some advice on wether or not a small coil can use the third terminal
> ground on an outlet for its ground source. By small I am saying probably
> 2 feet long arcs or less. I have done this with my current coil that is
> producing about 2 foot arcs and drawing about 8amps out of 120V outlet,
> nothing seemed affected. I cannot think of any other possible earth
> grounds seeing how pounding a rod into the ground is out of the
> question.
>
> Tristan Stewart
>
Tristan,
While the 3rd-wire ground could be used, you risk creating some
interference and possible damage to nearby sensitive equipment. A small
coil can be run with a piece of sheetmetal or conductive screening
that's at least 1-2' below the primary (to reduce eddy curren losses),
and at least 3-4' in diameter or on a side/square to form a
counterpoise. The actual shape isn't really very important. Connect the
metal plate to the base of your secondary so that it forms the other
"plate" of the capacitor with your toroid and yo'll be in business.
Another option is to make a small "twin" coil, using a pair of small
identical coils with the smaller primaries connected in series and in
phase opposition. By connecting the bases together, you may be able to
get by with NO ground needed for your secondaries.
Safe coilin' to you!
-- Bert --