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Re: safety gap and primary cap question



Hi Justin,

At 04:10 AM 12/30/1999 -0500, you wrote:
>  I had read that the safety gap on a coil should be "Just far enough that 
>the NST does not arc over during normal operation."  Since my last coil was 
>battery operated, I haven't had any experience with safety gaps, so I was 
>wondering if anyone could elaborate on this.  Does that mean an initial spark 
>across, or a sustained arc after a spark is initiated?

With an NST, once the arc is started, it will sustain since the current is
avaialable 120 times per second.  The air in the gap is heated and the
breakdown voltage will go down so that the arc will continue.  You want to
set the gaps so that they just do not fire when just the bare NST with
nothing else connected is put across it at full voltage.  You don't have to
be super precise about it.  As long as it is close.

>
>  Also, my previous coil used capacitors of aluminum foil and pvc plastic for 
>a capacitor, but it was rather large and cumbersome all laid flat.  Where can 
>I get some info on rolled capacitors, or if you want to write it in a reply, 
>that'd be fine too.

Use the web serch engines at:

http://members.xoom-dot-com/_XOOM/GrandSearch/tesla.html

or 

http://www.pupman-dot-com/htsearch.html

They will lead you to rolled caps, plans etc.

I wrote back on another post today "capacitors" that also has info.  Be
sure to consider MMCs!

Cheers,

	Terry


>
>      Justin D.
>