Re: [TCML] Considering a new coil build...

[DC Cox <resonance@xxxxxxxxxxxx>]

If you plan on running around 10 kVA, then:

Use energy discharge caps instead of MMC (you would probably exceed the 430
Amp current rating on the MMC).

A 34 x 8.5 toroid (or larger) will work good.  24" is a bit small for high
power.  Dryer tube and alum tape work fine.

Use a 14" dia RSG wheel, 10 electrodes, use pillow block mtg to run around
2400 RPM  (you want approx 400 PPS for huge sparks).
Use 1/2" thick G-10 with 1/2" dia rotor electrodes and 1" dia stationary
electrodes.  I run 2 gaps on each side of my wheel.

At higher power levels, I would go 16" dia on the sonotube.

This will handle up to 16 kVA at which point you will be firing out 15 ft
long sparks.

If you contact me off-list I can give you the complete design.  I have it in
JAVATC with all critical dimensions already determined.

Dr. Resonance







On Tue, Mar 24, 2009 at 12:29 PM, Travis Tabbal <travis@xxxxxxxxxx> wrote:

> It's been a while, but I miss Tesla coiling. :)
>
> I had purchased a number of useful parts before stopping years back, so
> here's what I have and what I'm thinking. I'd love some thoughts from you
> guys.
>
> Power source: 10KVA Pig 14.4KV
>
> Control: 3 giant variacs (I forget the rating). I planned to use 2 to
> control voltage and modify one for inductive current control. They are
> currently stacked with a motor drive for the brushes. I planed to remove
> the
> motor and one of the variacs. The other 2 will remain ganged up and I'll
> move the shaft by hand with a big plastic wheel or something. There may be
> better ways to handle this bit. I might be able to obtain an old arc welder
> for the ballast.
>
> Cap: MMC. To be determined. Ideas welcome.
>
> Secondary: 8" diameter ~30" long. What do people use as a form for these
> big
> coils? I was thinking of drying some Sonotube or other cardboard tube and
> coating with laminating epoxy or even just polyurathane. Or I could get
> ambitious and try to make a fiberglass tube by adding a release agent to
> the
> sonotube so I can slip the fiberglass off after curing. Considering AWG20
> magnet wire. Works out to about 1000 turns. Need a source for that much
> wire
> in one spool. The 11lb spools on EBay and such are too small. I need about
> 15lb if I'm figuring right.
>
> Primary: Copper tube spiral. Probably .25". Need to run the calcs to get
> the
> number of turns.
>
> Gap: Async RSG. I'm thinking to try to build one with .25" G-10 and
> tungsten
> electrodes. About 8" diameter. Construction tips welcome. Particularly
> holding the flying electrodes in place. I'd like to have it be speed
> controled, so I can vary break rate around a bit. Even if it's not realtime
> adjustable.
>
> Topload: I bought 2 8"x24" spun toroids in a group buy years ago. Still in
> the box. It's a shame not to use them. They are so pretty. :)
>
> I also have some RFI filters for the pig I think I bought on the list.
>
> Note that I don't have a machine shop, though I do have a decent tool
> collection both power and hand types. So I can't do fancy stuff like
> machining electrode holders from bar stock. :) I can drill and tap it with
> some acuracy, but nothing too special. No lathe or mill. :)
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