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First Light for me :-)

Hey guys and gals,

I got my first light over the weekend.  Oh what a wonderful sight!  I
don't think I have ever seen something so pretty.  I got arcs to a
ground rod from a surface breakout point of about 5.5"{139.7mm}.  Yea I
know that's nothing but hey for my first coil and first time ever seeing
one actual firing I was real impressed.  The specs are below and yea I
have some problems with the design (gotta start somewhere).

My main problem is the safety gap.  I can't get it to stop firing. At
approx. 40 volts & up of input power it fires about once every two to
three seconds.  I originally had the gap set so it would fire at 130V
coming into the NST alone but not at 120V.  I got agitated with the
safety and started opening it up ( I know this is dumb but at the time I
figured I had NST's to burn).  I am currently at 1/4" (6.35mm) from each
leg to the ground bolt.  This seems like way to much.  Any ideas would
be appreciated on how to get it to stop firing.  I know I need to get a
protection circuit in there but I had to fire it up.  So far the NST's
are OK but I would prefer not to kill them if I can help it.


NST's:          (9KV/30ma Transco units)  -at- in parallel for 9KV/60ma
Variac:           (General Radio W20 20 amp unit)
Capacitors:    (3 Fair Radio Door knob caps. .004 uF caps each in
parallel for .012 uF total) (I have 50 .056uF caps. ordered currently to
make MMC)
Primary:         (1/4" {6.35mm} copper tubing spaced at 1/4" {6.35mm} in
a 15 degree inverted cone.  Inside diameter 5.5" {139.7mm} 14.9 turns
total tapped at 8 turns out.)
Secondary:    (3.31"{84.07mm} diameter cardboard tube with six coats of
spar urethane for sealant then 953 turns of 26 gauge (.019"{.48mm}
wire.  Wound length of 18.05"{458.47mm} then covered with two coats of
slow cure west system 105/206 clear epoxy approx. 1/16"{1.59mm} thick.
Two sealing disks inside made of same epoxy but 3/8" {9.53mm} thick.
Entire secondary wound/cured on self-made lathe turning at 30RPM with
digital readout for total number of turns.  Ratio of 5.45:1 {I know this
is whacked. I calculated something wrong somewhere}
Topload:    (2 stainless steel bowls taped together. {overall
dims:6.75"{171.45mm} diameter/ 4.5"{114.3mm} high)
Static gap with 6 gaps each set to .030"{.762mm} total gap of
.18"{4.57mm}
Secondary is 1/4" {6.35mm} above primary with 2" {50.8mm} space between
top of windings and topload.
Strike rail is 3/8"{9.53mm} copper tubing with same size gap spaced
1.1875"{30.16mm} above last turn of primary.
Safety Gap: polished rounded head bolts with polished rounded ground
bolt in center.
Entire system past safety is ran with 8 gauge wire. except for wire for
the tap point.  Currently it is 15KV GTO wire.
RF Ground system consists of 8'{ 2.43m} long 5/8"{15.88mm} copper coated
steel ground rod driven to with 2"{50mm} of flush with the soil.
Ground to coil connection is an industrial 3 phase power cable with four
10 gauge fine stranded copper wire lines all connected together at ends.
(This was an extra power cord for a saw I had at work so I liberated
it.)


Who long of sparks could I expect from this coil?
How can I fix my Spark Gap Problem?  Will the MMC help or hurt this?
Any ideas on the protection circuit?  My understanding is chokes are now
taboo which is what I was going to use.
Did I forget anything??

Thanks for everything.

Neal
NDWhitaker-at-worldnet.att-dot-net

P.S.  I am still working on all of the NST's I have acquired and as soon
as I figure them all out I will contact the group and all of the folks
who have requested some of them.  I have not forgotten about any of you.