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Re: Primary/sec'y spacing for my big coil. (fwd)
---------- Forwarded message ----------
Date: Mon, 3 Aug 1998 17:14:19 -0600
From: "D.C. Cox" <DR.RESONANCE-at-next-wave-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Primary/sec'y spacing for my big coil. (fwd)
to: Larry Bu aka Clay
We use an 18 inch dia. tube (close to your 16 in size) and run the lowest
turn of the sec coil 2 1/2 inches above the primary coil and 1 3/4 inches
primary to secondary spacing. This will give you the approx proper
coupling for fire-up. 3500 Ft. is good --- match it with a 0.1 MFD
capacitor on the primary and a good 34 x 8 1/2 inch dia toroid for a nice
12-14 ft. spark output at 15 kva input.
DR.RESONANCE-at-next-wave-dot-net
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Primary/sec'y spacing for my big coil. (fwd)
> Date: Sunday, August 02, 1998 10:07 PM
>
>
>
> ---------- 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-}