Re: Practical limit to number of turns on primary ? ? ?

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

Original poster: "Barton B. Anderson by way of Terry Fritz <teslalist-at-qwest-dot-net>" <classictesla-at-netzero-dot-com>

Marc buddy!,

2kva at 120"! All I can say is WOW!!  I knew this coil was running 90" at 
one time, but never would I have expected spark lengths at 120"! Is this a 
record of sorts? This is typically a 75" to 80" spark length on a good 
running coil. You know, your coil has some unique characteristics as Paul 
as modeled with available data (mm3p). There are quite a few differences 
your coil exhibits beyond the norm. I truly like the way you've gone out 
there with this coil.

You know, I still have yet to open up ba0 to see what it can throw out (as 
it's a rather high turn coil and low Fres for it's size). I've been firing 
it up all week and it's running sweet right now. The only thing I've 
changed since those models is pounding an 8 ft rf-rod in the middle of the 
garage directly below the coil (drilled through cement, pounded, sealed), 
but everything else is unchanged. As soon as the weather dry's up, I'll 
roll it out in the backyard and let it go (think I saw a minute or two of 
sun today).

The "myths" as stated have to be used in context. For example, your firing 
voltage is up around 34kV and near 30j bang energy, very high top volts, 
low freq (38.4kHz), and many other values that are outside the typical 
coil. I think too often, turns and their performance are stated without 
stating the other parameters for what makes those statements true, and it 
then quickly becomes a global thought based on many coils that really 
aren't that different. Obviously, one can go outside the "norm" and do 
better. Great job with this coil. A true pioneering development of which 
I'm very happy Paul has been able to get measurements and models on from 
time to time.

Take care,
Bart

Tesla list wrote:

>Original poster: "marc metlicka by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <mystuffs-at-orwell-dot-net>
>
>
>
>Tesla list wrote:
> >
> > Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
> <FutureT-at-aol-dot-com>
> >
> > In a message dated 1/27/03 1:34:26 AM Eastern Standard Time,
> > tesla-at-pupman-dot-com writes:
> >
> > Steve, all,
> >
> > I've found the best efficiency when using a rather large number
> > of primary turns on a small coil.  For example my old research
> > coil used about 18 to 22 turns, and gave 42" sparks from a normal
> > 12/30 NST.  By using a lot of primary turns, the surge impedance
> > is raised, and the gap losses are reduced as a result.  Also, coils
> > with a lot of primary turns probably also have a lot of secondary
> > turns, and this tends to result in a coil which operates at a low
> > frequency.  There is evidence that a lower frequency is effective
> > in producing longer sparks also.  Using a lot of turns may be less
> > important in larger coils which tend to have high surge impedances,
> > and lower frequencies even when using fewer turns, but this seems
> > to be unknown at this time.  Of course if too many turns are used
> > on any coil, it will increase the wire losses due to the high resistance
> > of the thin wire, and the losses will increase too much.  I discuss
> > these issues at my website
> > at:
> > 
> <http://hometown.aol-dot-com/futuret/page3.html>http://hometown.aol-dot-com/futuret/page3.html 
>
> > click on the link for "efficiency theory".
>
>
>  I'm not sure this is the case here? when i built the 3000 turn coil it
>uses 24 turns of 1/8" inch primary, the 3' wide primary form assures
>coupling to the top of the 42" coil. I'm very impressed with the 2kva
>120" discharges compared with the 4' discharges of a 4"-1300 turn coil
>placed on the same psu. Also with using many turns of wire will
>distribute sharp voltage grandaunt lows over a much broader area, thus
>cutting down on mid coil breakout.
>  The whole myth of the 1200-1800 turns being optimal only show that not
>many coilers are willing to try more!
>  With a 6000 turn secondary combined with, a proper primary
>construction, could very well surpass my ten footers at 2kva.
>
>By the way, i have never felt secondary heating along the coils.
>
>http://members.fortunecity-dot-com/marcmet/index.htm
>
>Marc M.
> >
>
>
>