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Re: [TCML] Grounding a Tesla Coil (Yes, Again)



Alright,
Sorry for the delayed response,
I didn't get any exact math to calculate the counterpoise size, but the most I can safely get away with is 7.25' x 1.5' or 10.875 sqr/ft. Will this work with a 3.5" x 16" secondary, 1007.7' of 29 AWG wire, topload being 4" x 16"?
Thanks for all your guys's support,
Brandon

On May 5, 2010, at 6:01 AM, jimlux <jimlux@xxxxxxxxxxxxx> wrote:

Brandon Hendershot wrote:
Exactly how big should a counterpoise be in relation to the size of the topload? I only really have about 4' of room available to the coil because I have my drill press and alarm clock on their too. That's 4' including the space used by my NST and variac, which are both safety grounded in the case.

Why not make the counterpoise flexible.. Think of a conductive rug that you can roll out when you're experimenting. It could cover the drill press and clock and whatever..



I imagine it would be problematic having the
counterpoise connected to mains ground...

Why? If you're concerned about RFI, then put a suitable RF choke in the connection. But for safety, the counterpoise should be connected to whatever you might be touching, and that generally means "green wire ground" as well.

Hmm, does the counterpoise
actually need to be wired to the secondary, or is there some sort of coupling going on?

Yes, it definitely needs to be connected to the secondary (i.e. the bottom of the coil).

One more, I think it would really help me understand
how to construct a functioning artificial ground if I knew exactly what an ordinary ground functions as under normal circumstances.

Have you run one of the modeling programs that shows the electric field around the coil?

Your secondary is basically a resonant LC circuit with the L (inductor) being the coil, and the C being the top load (one plate) and the surroundings (the other plate). Like any circuit, current flows through the L and C, so that means that current flows through the surroundings.

What a counterpoise does is give a low impedance path for that current to flow in.

It also serves as sort of a limited faraday cage for things under the counter poise. That is, if a streamer comes out of the topload it will strike the counterpoise rather than what's under the counterpoise.


Thanks, I really appreciate all your guys' help,
Brandon

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