Re: SAM BARROS TWIN COIL SYS

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

Original poster: "Powerlabs by way of Terry Fritz <twftesla-at-uswest-dot-net>" <list-at-powerlabs-dot-org>

----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, April 11, 2001 9:19 PM
Subject: SAM BARROS TWIN COIL SYS


> Original poster: "will dork by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<vcdmasta-at-hotmail-dot-com>
>
> I was wondering if anyone could explain to me how sam barros used
>
> 1 nst
> 1 spark gap
> 2 cap banks
> 2 secondaries
> 2 primaries
>
> To power to seperate tesla coils at once, thus forming the twin coil
system. I
> am very intersted in this arrangment. Thanks
>
> Thanks
> Will McManus

 Will,
 Wouldn't it be easier to just ask the person who designed and built the
coils in the first place?
 Yes guys, I do still follow the Tesla Lists (both Pupman and Tesla-2). Just
haven't had the time to be posting here; my own experiments, webpage and
message board (everyone is invited to join!) have kept me far too busy for
that. I do read all the topics though, and I follow all the threads that
interest me.
 So, how did I wire my Twin Tesla Coils? There are pictures on the page that
will help you understand it, so you might want to look at those while you
read the post. My webpage URL, for those of you who do not know (I've posted
it here twice before) is http://www.powerlabs-dot-org/. It deals with a lot more
than just Tesla Coils (its a general "Science in action" site describing
most of my experiments with high voltage and such), but the page you are
looking for (the Twin Tesla Coil page) is at
http://www.powerlabs-dot-org/coil2.htm .
 You may want to look particularly at the 3rd last picture, which shows the
coil arrangement running on top of my dinner table. You might also want to
download the high quality video of the coils in action by clicking on it ;)
 Anyways, here is how it is done:
 The 12kV 30mA NST is fed through a Variac, which has in parallel with its
input two line filters wired in antiparallel and a power factor correction
(PFC) capacitor. The transformer has a 10 segment vacuum quenched spark gap
right across its output, so as to switch the capacitor discharge on the
primary coil while at the same time shorting the transformer output, which
protects it from damaging high voltage surges from the primary second. In
series to the spark gap is the capacitor bank; my beloved and recently
discussed on the list Barium Titanate Doorknob Capacitors... These are 50kV
1,7nF each, produced by TDK. RMS current is 12A, peak current is 1,2kA for
high frequency work, with no decrease in life time (3x10^6 discharges), and
maximum peak voltage is 60kV. I have personally run them for 40 minutes
continuous, and neither the capacitors nor the spark gap overheated. This is
a low power coil though, so I don't count it as a great achievement. I don't
see any reason why the coil could not be run continuously, aside from
perhaps the gap electrodes eventually eroding away. The doorknobs have
safety gaps right across their copper bussbars, set for 30kV (they never
fire).
 Now the coils: There are two primaries and two secondaries; the secondary
grounds are connected by a common ground, which does not actually have to be
grounded, since at any given time the coils have alternating polarities and
thus the sparks attract each other and the coils ground each other out. The
primaries are wired much as in any Tesla Coil, except there are two of them
and they are in antiparallel: One capacitor lead goes to the first turn of
the first primary coil, and the tap of the second primary coil. The other
lead from the spark gap goes to the first turn of the second coil, and the
tap of the first coil. That way they are always outputting opposing
polarities no matter what.
 The equi drive (2 capacitor banks) system is a bit more tricky. The idea is
that you substitute the wire going from the spark gap to the coils for
another capacitor bank, and thus double your energy storage. So far this has
not worked for me though. If anyone has schematics showing how they got it
to work I would be very interested. I still have to try some configurations
out by those capacitors are currently in use for another project of mine; a
400kV high repetition rate Marx generator :)
 I like to think I do a pretty good job at explaining the projects on my
page, but if anything thinks something is not clear or inaccurate please let
me know so I can clarity it. What I really need right now is a tool for
drawing schematics. What do the other webmasters out there use?

Sam Barros,
sambarros-at-yahoo-dot-com
ICQ#:15156975
!!! Check my homepage at http://www.powerlabs-dot-org/ !!!
 "If At First You Don't Succeed, Increase The Amperage"