Re: Coil pictures - please take a look

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Bob,

Excellent coil and photo's of your setup! I was very impressed. I am
especially impressed with the
use of a static gap in this arrangement and your success with it. I
couldn't make sense from the
photo's of the static gap configuration. Could you elaborate a little on
it? Looks like your cooking
about 3500 watts with your spark lengths. I was a little perplexedabout
your toroid sizes and their
lumped capacitances. Because of your tune at 12 turns, it appears you
are seeing more capacitance on
top when toroids are stacked than I would expect. I've measured toroids
stacked and found their
capacitance is approximately 50% of the lumped value. Something that
does make a little sense to me
is that although your toroids are stacked, they are also a good distance
above the secondary top
winding. When I tested stacked toroids, I never did check how the 50%
value would be affected if the
lower toroid was raised further and further above the secondary winding.
I think you have sparked
another measurement for me to look at.

Great job with your coil. Thanks for sharing with the list. Also, I love
the use of pvc supports.
This year I changed to a pvc secondary and primary support apparatus.
Our supports are nearly
identical to each others. With my own, I made the secondary capable of
raising or lowering in 1/2"
steps using the pvc and capable of a full 12" change (mostly for
measuring purposes).

Take care,
Bart Anderson

Tesla list wrote:

> Original poster: "Bob Thaden by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<robert.thaden-at-amd-dot-com>
>
> I've posted some pictures of my coil, Glamdring  05/27/01
> Please take a look:
>
> www.ycreek-dot-com/bob/glamdring
>
> Specs:
>
> sparks: ~8 feet measured, ~10 feet guess..
>
> second:  8.5" dia, 32" length, 22guage ~37turns/inch
> caps: .055 uf, ~60kv, 'equidrive'  CP and Maxwell (2x .11uf in series)
> Prim: tapped at ~12 turns, 3/8" dia, 1/4" space
> Toroid: 24"x6"(Landergren group purchase) + 32x8" dryer duct
> Supply: <30Amps at 220v, 5kva 14.4kv pig, >200Amp welder ballast
> Gap: 2-gap static, air blown with shop vac
> Controller: large Powerstat, 300Amp mercury relay controlled by latching
>             relay (fire/kill switches).
>
> exposures:  .5-2 seconds, 200ASA Kodacolor, 50mm 1.4  Nikon F3
>             full auto and some are 1 stop minus compensation
>
> -bobt  Austin, TX