[Fwd: Re: [TCML] DC base driven coil]

[Bert Hickman]

This is a Re-send. Apparently the first time didn't go through...

Bert

-------- Original Message --------
Subject: Re: [TCML] DC base driven coil
Date: Wed, 12 Mar 2008 17:16:23 -0500
From: Bert Hickman <bert.hickman at aquila.net>
Organization: Stoneridge Engineering
To: Tesla Coil Mailing List <tesla at pupman.com>
References: <bfe.31d3b77e.3509a64f at aol.com>

FIFTYGUY at aol.com wrote:
>  
>  
> In a message dated 3/12/08 8:55:33 A.M. Eastern Standard Time,  
> pterren at iinet.net.au writes:
> 
>> Lou Balint.
> 
>> http://www.pupman.com/listarchives/2003/September/msg00163.html
> 
> 
>     Can somebody post a schematic of Lou's (or a  similar) setup? From the 
> Bert Hickman's post in the archives I can't fathom how  to hook up a cap to the 
> base of the secondary in a way that it doesn't interfere  with the resonance 
> of the system, yet discharges through the secondary. Is there  a separate 
> charging supply involved as well?
>  
> -Phil LaBudde
> 
> Center for the Advanced Study of Ballistic  Improbabilities
> 
> 
> 
> **************It's Tax Time! Get tips, forms, and advice on AOL Money & 
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> 

Hi Phil,

If you use a comparatively large DC energy storage capacitor (comparable
to the tank cap or larger), there should be virtually no effect on the
RF characteristics of the secondary. The HV capacitor is simply
connected between the base of the secondary and your RF ground. As you
suspected, you will need to have a separate (and fairly robustly
designed) HVDC supply to initially charge up the base capacitor. I think
Lou used a couple of Maxwell pulse capacitors and a voltage doubler or
tripler circuit.

Warning: This configuration is extremely dangerous, not only because of
the added energy in the streamers (especially during snappy ground
strikes), but also because of the retained charge on the base capacitor
and secondary AFTER the coil is shut down. Your primary circuit should
be well protected from any secondary strikes by using a strike rail
connected to the RF ground. An accidental primary strike may otherwise
take out your main HV supply and/or your tank cap. And, obviously, make
sure that streamers cannot jump to anything they shouldn't...
_especially_ anything connected to mains ground, such as conduit, zip
cords, fluorescent lamps/fixtures, etc. A strike to these can take out
the electronic equipment in your home. Even strikes to the concrete and
rebar can be a problem due to differences in ground potential during
high current discharges. I'd suggest making a counterpoise that covers
the potential ground strike region. Connect one end of the base
capacitor to the counterpoise (AND RF ground) so that YOU can control
the current paths taken by high energy discharges.

This configuration is NOT for the inexperienced, the faint of heart, or
folks with a small or basement lab...  =<:^O

Bert
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-- 
***  /\  ******************************************************
__  _\/_  __  We specialize in UNIQUE items! Coins shrunk using
\_\/_/\_\/_/  intense magnetic fields, Lichtenberg Figures (our
   /\_\/_/\    "Captured Lightning"), and technical Books. Visit
  _\/_/\_\/_   Stoneridge Engineering http://www.teslamania.com
/_/\_\/_/\_\     *     *     *     *     *     *     *     *
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