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

[Brandon Hendershot]

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 at earthlink.net> 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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