Primary/sec'y spacing for my big coil. (fwd)

To: tesla-at-pupman-dot-com
Subject: Primary/sec'y spacing for my big coil. (fwd)
From: Tesla List <mod1-at-pupman-dot-com>
Date: Sun, 2 Aug 1998 22:07:18 -0600 (MDT)
Approved: mod1-at-pupman-dot-com



---------- Forwarded message ----------
Date: Sun, 2 Aug 1998 17:11:59 -0500 (CDT)
From: Larry Bud Melman <gasman-at-althea.a-line-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Primary/sec'y spacing for my big coil.

	Hi all...

	Finally got my coilform for my coil - using a 16 inch sonotube,
sealed with urethane varnish, and going to reinforce with fiberglass cloth 
and resin, since I suspect 3500 ft of 14 gauge wire is *pretty heavy*...

	Thinking about overall design, and when I was planning the primary,
I realized that I wasn't sure how large I should make the space between primary
and secondary.  Don't wanna make it too small, but obviously will get more
spark from coil if I can minimize it... (I was planning a flat, archimedes 
spiral - sound good??)

	I'm thinking about 2 inches space.  Whaddya all think??

	Tentative specs of coil:  using 10 kVA PP, 23 kV (27 if using 280v
input)

	--height of windings 54 inches (800 turns) - sec'y inductance 73.01 mH

	--Approx resonant freq 110.8 kHz

	--Tank cap: 50 kV 0.05 uF ($375 at SurplusSales-dot-com - OUCH!!!!)
				  (geez - only gave $250 for my reconditioned
				   pig with non-PCB oil)

	--Primary: using 1/2" (12.7 mm) copper tubing, 8 turns, should tune
between 5 and 6.

	--Sparkgap:  I'm blazing the trail with a Terry Fritz gap on this
relatively high-power coil, planning 5 thousandths gaps times 50 or 60.
I will do most anything to avoid the dreaded and feared RSG.

	--Topload: beats the hell outta me.  I figure this thing will take a 
toroid in the 48-inch range.  I have no idea where to get one.  Try some
muffler shops maybe - I remember that thread.  They'd be awful skinny though.
Need a bigger X-section.  Probably end up with heating duct.

	I'll be mighty disappointed if I can't get 10 - 15 foot sparks from
this one...time to start wining and dining the neighbors...


						Clay   8-}