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Re: 4 inch coil
I've only built a single coil but I'd check your specs.
I used a 4 inch secondary with 22awg at 21.5". Primary is 1/4" copper
tubing spaced 1/4" with a 6.5" inside diameter and a 21.25" outside
diameter, 16 turns total rising at 15 degrees and took about 60 feet of
copper. Copper tubing works great and I believe would be cheaper than 4awg
solid. I built a slightly modifed RQ Spark Gap with 10 1" x 2.5" copper
pipe spaced .025". I have it set at 8 gaps at the moment but will try
different settings later. I put kind of a venturi (?) in the center to
direct the airflow directly to the pipes and I believe it also speeds
airflow. I'm currently using a 3" x 16" toroid (AL tape over AL flex duct.
I got better performance from a 4" x 22" toroid which was destroyed during a
move. I think my toroid size should be somewhere in between the two sizes
and intend to try several sizes. With the smaller toroid the coil seems to
tune over a wide range, 5-7 turns. With the larger toroid, the sweet spot
was much smaller at around 13.5 turns. I started with a single 15kv .030
NST and .0052uf cap. It ran well. I now use 2 15kv .030 NSTs and .012 cap.
I still have a lot of tuning to do but I'm getting sparks over 30". With
the larger toroid I was over 40".
Opinion Only: The inside diameter of your primary seems way too small.
Your caps also seem too small. The rest sounds in the ballpark.
Good Luck,
dj
----- Original Message -----
From: Tesla List <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, April 18, 1999 12:17 PM
Subject: 4 inch coil
> Original Poster: "afa2fg" <afa2fg-at-email.msn-dot-com>
>
> Hi all,
> I am presently putting my first coil together. Actually this is my 2nd.
> secondary. I started to do a 2 1/2 in. secondary but changed my mind and
> have decided to go with a 4 in. I plan to wind it 20 inches tall with 24
ga.
> wire. The primary will be 4 ga. solid copper wire. It will have an 11 inch
> inside diameter with 1/4 in. spacing, and a total outside diameter of
19.14
> inches. The cap for the primary tank circuit will be about .0029 mf. The
> toroid will be 4 in. aluminum flex tubing. Diameter yet to be determined.
I
> will be using a 15 KV-at-30 ma. NST. I am building one of Richard Quicks'
> cylinder spark gaps. Am using 1 in. copper pipe with .028 gap spacing.
there
> will be 13 pipes -at- 4in. long.
> Any comments on whether this thing will work??? Any and all coments
> welcome.
> Thanx
> George Stein
>
>
>