RE: A search for a better primary

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Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>

Hi Gerry,

My 8" 35.5" was one inch above a 15 degree 1/4" primary tapped near 15. Cap
was 1.5 ltr. I was running a RQ heavily blown gap that roared healthily when
it was up to voltage. The top hat was a 32"x8" with a 4"x12" lower dryer
duck siliconed to the big toriod which added much strength and additional
shielding. It was powered by two Transco 15/60 HP with a Terry filter and
safeties all carefully adjusted with HV - tuned with a freq gen, scope, and
freq counter. I always cranked it to 140v+ and the sparks did fly. It would
consistently strike a 6 foot target; and, without a breakout or target
flared chaotically outward, impressive, and very loud.

My point is I used a 2" arc space (12" first turn) clearance and never had a
racing arc yet K was well in good range.

Jim Mora

 P.S.

Not many agree, but I believe the larger primary couples and rings higher
into the secondary coil reducing the very high currents at the base and
eases the quench which most agree on.

In the interim (until the 12" is finished), I'm going to use this coil with
my pig and a 1/2" flat primary with as much arc space I can get and still
have a reasonable k factor. While being aware that I'll be near resonance
charging, as you pointed out - THANKS, I therefore will keep the break rates
>200 to prevent over-volting my new, tedious MMC. Having said that, I have a
couple of construction easing ideas to share latter.



-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Saturday, September 09, 2006 9:58 PM
To: tesla@xxxxxxxxxx
Subject: A search for a better primary

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi All,

I just finished part 3 of this exercise that makes an in depth
comparison between an "existing" primary located 1 inch below the
bottom turn of the secondary that has a 1 inch space from the 8 inch
coil form and a "new" primary design that is located 1 inch above the
bottom secondary turn but with a 3.5 inch clearance from the same
coil form.  The existing primary has demonstrated a tendency for
racing arcs that prompted this search.

Part 2 showed a simulation method that not only seems to predict the
high stress levels needed for racing arcs, but also predicts where
they would breakout.  The prediction agrees with observation.  The
simulation, as shown in part 3, also shows what happens when the TC
is out of tune.

In part 3, it is shown that even though the new primary has a greater
overall coupling,  it also has less stress on the coil reducing the
tendency for racing arcs, and also shows greater tolerance for
mistuning.  If this approach works out, this may be a way to avoid
racing arcs and yet get higher coupling and higher topload
voltage.  This may also be a way to improve the energy rise time at
the top load and facilitate better streamer formation.  The following
are the links to the most recent of each of 3 parts.  Please read the
papers and comment.

<<http://hot-streamer.com/temp/GerryReynolds/In_Search_for_a_Better_Primary1.>http://hot-streamer.com/temp/GerryReynolds/In_Search_for_a_Better_Primary1.
pdf>http://hot-streamer.com/temp/GerryReynolds/In_Search_for_a_Better_Primar
y1.pdf

http://hot-streamer.com/temp/GerryReynolds/A_Search_for_a_Better_Primary2.pd
f

<<http://hot-streamer.com/temp/GerryReynolds/A_Search_for_a_Better_Primary3.p>http://hot-streamer.com/temp/GerryReynolds/A_Search_for_a_Better_Primary3.p
df>http://hot-streamer.com/temp/GerryReynolds/A_Search_for_a_Better_Primary3
.pdf

Gerry R.