Re: Leakage reactance

From: 	FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
Sent: 	Friday, August 29, 1997 3:32 AM
To: 	73374.1547-at-compuserve-dot-com
Cc: 	tesla-at-pupman-dot-com
Subject: 	Re: Leakage reactance

In a message dated 97-08-28 23:40:43 EDT, you write:

> I'm very intrigued at the prospect of getting a 42 in arc from a single
> 12 kv 30 ma neon. >snip>    I can't quite picture which circuit
> properties you mean but you've clearly found something we all should 
> know.
> To complete the picture, what kind of main spark gap and what size
> toroid do you have?

Hi Felix, All,

The leakage reactance of neon transformers is the cause of their
current limiting feature.  The cores are designed so that as the
current tries to increase, more magnetic flux bypasses the 
secondary of the transformer.  If we select a tank (main) capacitor
that neutralizes the leakage reactance of the transformer...then
we will have defeated the current limiting feature of a neon trans,
and the trans will draw more current than its rating.  The PFC
cap is not involved here.  The method will work equally well
with or without the PFC cap.  The variac also is not involved.
Main cap resonates with the leakage reactance of the trannie.

I did not discover this technique...it is well known on the Tesla

For a spark gap, I used an 8 gap, series quenching synchronous
rotary, but a regular vacuum quench static gap can do quite well,
and probably give a 36" spark or so.  My toroid is 5" x 20", but
a 4" x 17" one will work almost as well.

For a 12kV, 30ma trannie, use a .006uF to .007uF main cap.
For a 15kV, 60ma trannie, use a .012uF to .014uF main cap.

There's a formula to determine cap size, but I don't have it handy.

I sent this to the list also for the benefit of new coilers.

Safe coiling to ya!

John Freau