Re: Transformer Questions


Tesla List wrote:

> Original Poster: Chris Tominkson <internetinbox-at-yahoo-dot-com>
> I am really new at this tesla coil business and I have a few
> questions/ideas about transformers, here they are:
> What would be better, a 9KV-120mA NST, or a 15KV-72mA NST. So what is
> more important, Amps or Volts?

They will both work for a nice TC. But, I personally would recommend the
9kv-120mA as this will provide 1.08kw of power which is a couple hundred
over the other and because your cap breakover voltage would be lower (note
that some may disagree with my personal preference).

> Has anyone heard of or used an air capacitor? It is a bunch of sheet
> metal squares stacked on top of each other, insulated from each other,
> and then every other one is wired to in/out, +/-. Like this, 2-4-6-8
> would be wired to live, 1-3-5-7 would be nuetral. All sheets are
> spaced apart .75".

Sure we've heard of it. But the plates are so far apart the capacitance
would be too low for TC use and the corona which would develop would lead
to arc over. This is basically a plate cap design. However, usually a
dielectric (polyethylene, etc..) is used between the plates and the cap is
tight together and submerged under oil.

> What would happen if you did not use a capacitor, while using a rotary
> spark gap and the usual config.

Nothing (literally). There are many reasons one of which would be the
capacitance missing in the primary LC circuit. The cap stores the charge
which is dumped across the spark gap. If your thinking about the output of
the transformer performing this function, forget it, it won't, and you
will definately need an LC circuit both in the primary and secondary tuned
to the same frequency of each other. The tank cap and the primary coil
make up the primary LC. The secondary coil and it's self capacitance make
up the basic secondary LC. When a top terminal is placed on top, the
capacitance of the top terminal adds to the secondary self capacitance of
the coil.

> Would I be able to wind a choke with some uninsulated 16 gauge wire?
> Do I just have to keep it space apart, is there a equation for these?

I don't use them, so I'll let someone else answer that one.

> Well thats all, thanks to anybody who replys/ responds!
> Chris.