Re: Fast ground rod

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Rick W by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rickwilliams404-at-earthlink-dot-net>

Well hey list,

Rick here. Yes, I have a 12.5 inch secondary, 47" coil length. The project
is still under construction. Projected tank cap is 80nF (might go 100nF) ,
primary about 16 turns of 1/4" tubing spaced 1/4" apart, 29" outside
diameter. (Couple of extra turns for tuning) Resonant freq is just a little
under 50K (1/4 wave). Going for 5 NSTs, 15Kv 30ma each. But I'm going DC
with this project. Shooting for about 100 BPS as an arbitrary starting
point. The filter cap for the supply is 12 times the value of the tank cap.
Also the DC filtered output is 1.414 times the AC input, 15Kv times 1.414 =
21KvDC.

During initial design a limiting resistor was employed to soften the shock
of charging the tank cap through the SPDT RSG. The was calculated to allow
the tank cap to be charged after 5 time constants, about 1 millisec. After
charging there would be very little demand, if any at all, of current from
the filter cap.

So, 100 BPS figures out to 1 pulse per 10 millsecs leaving 9 milliseconds
for the filter cap to recoup the energy expended. There will be a voltage to
which the filter cap will settle out to as per the input current. That
voltage should be well over 15Kv anyway (there will be ripple
*understatement*). Once the tank cap charges the energy stored there is the
energy that's pumped into the system, the supply current is then out of the
picture and can then be used to begin recharging the filter cap. At 80 nF
(maybe 100nF) charged to over 15Kv there should be plenty of energy to power
the coil.

The beauty of DC is I'll be able to vary BPS a lot with no concern about
crossover and sync problems.

But now there may be new light on the DC coil horizon concern how the SPDT
RSG is connected in the circuit. In the meantime I'll continue construction
of the DC supply. Hope to have the supply finished at the end of next week.

Rick Williams
Salt Lake City


----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, July 25, 2001 9:10 PM
Subject: RE: Fast ground rod


> Original poster: "Loudner, Godfrey by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <gloudner-at-SINTE.EDU>
>
> Hi all
>
> Well I guess I should have wrote that it was my dictum. I would hate to
> search the archives for the listings which led me to form this dictum. It
> was simply a series of listings which seemed to be saying that big coils
> needed big power supplies. I was certainly a believer. After getting a 10
> inch diameter secondary form Marc Metlicka and seeing the huge size of the
> form, my impression was complete. I decided that I would need my
14.4kV/5kVA
> pole pig for the power supply. I am far from completing my pig system, but
I
> am thinking about Marc's suggestion of using a triggered gap. My adult
> experience with tesla coils is limited to diameters not exceeding four
> inches. A was aware of Terry's big research coil using a 15kV/60mA NST,
but
> I just assumed that he did not want long streamers because they would get
in
> the way of making measurements. So I was very surprised when I saw Terry's
> big coil in action.
>
> If you look at John's formula for streamer length, it says that streamer
> length is only a function of wallplug watts. Yes sir,
> that's what it says. When someone off the list (now on the list) told me
> that he had a 12 inch diameter secondary, I told him that he had to load
up
> on NSTs or get a pig. Rick got five 15kV/30mA NSTs, but he did say that he
> wanted to start off with over 100mA. Well I always have said, "how could
you
> be so wrong about something that you thought was so right."
>
> Godfrey Loudner
>
> > -----Original Message-----
> > From: Tesla list [SMTP:tesla-at-pupman-dot-com]
> > Sent: Wednesday, July 25, 2001 4:13 PM
> > To: tesla-at-pupman-dot-com
> > Subject: Re: Fast ground rod
> >
> > Original poster: "Malcolm Watts by way of Terry Fritz
> > <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
> >
> > Hi all,
> >
> > On 25 Jul 01, at 11:28, Tesla list wrote:
> >
> > > Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> > <FutureT-at-aol-dot-com>
> > >
> > > In a message dated 7/25/01 9:43:29 AM Eastern Daylight Time,
> > tesla-at-pupman-dot-com
> > > writes:
> > >
> > > > Original poster: "Loudner, Godfrey by way of Terry Fritz
> > > <twftesla-at-qwest-dot-net>"
> > > >  <gloudner-at-SINTE.EDU>
> > > >
> > > >  Hello Terry
> > > >
> > > >  When someone comes on the list stating that they are going to use a
> > > >  15kV/60mA NST as a power supply for a tesla coil having a diameter
of
> > about
> > > >  10 inches, the usual advice is to get a pig or equivalent because
you
> > won't
> > > >  have enough power to even cause the toroid to breakout.
> > >
> > > Godfrey, all,
> > >
> > > I wonder how that view developed?  I often use a 6" x 24" secondary
> > > with a 12/30 NST with excellent results, so a 10" dia coil for a 15/60
> > > would seem very reasonable to me.
> > >
> > > John Freau
> > > --
> > >
> > > Your coil is
> > > >  certainly a counterexample to such a dictum. Can you say something
> > about
> > > why
> > > >  your large diameter coil is working so well with a small power
> > supply.
> > > >
> > > >  Godfrey Loudner
> >
> > I too wonder where that idea came from. As Bert Pool can attest, the
> > transformer I use for my 10" coil is smaller than most NSTs of any
> > rating. It was photographed last year throwing sparks over 5' in
> > length with an oblate topload measuring 10" thick with a 19"
> > diameter. The bottom line is: ability to breakout is dependent on
> > primary energy and rep rate takes over from there. The capacitive
> > loading for the transformer defeats the faceplate ratings so you can
> > basically suck what you like from it within the limitations its
> > leakage/ballast inductance will allow for the capacitor being used.
> >
> > Malcolm
> >
> >
> >
> >
> >
> >
> >
> >
>
>
>