Re: spark gap spacing

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jeremiah by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jmeizis-at-kc.rr-dot-com>


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, June 09, 2001 2:09 PM
Subject: RE: spark gap spacing


> Original poster: "Pete Komen by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<pkomen-at-zianet-dot-com>
>
> Hello Jeremiah,
>
> It would help to know more about your setup.  What is the HV transformer?
> Is the 11.5 KV AC or peak?  Are the 10 caps in one string all that you
have?
> That would be 6.8nF at 12.5 KV.  If the 11.5 KV is AC then the peak
voltage
> is 1.414 * 11.5 KV = 16.26 KV or well over the limit for your caps.  I
don't
> know the breakdown voltage of air but for my 12/60 NST, the spark gap is
set
> about 1/4 to 1/3 of an inch.  With sharp edges I can get more than 1/2
inch,
> but a 1 inch gap is much too large.  I would worry about resonant voltage
> build up with a gap so large.
>
> I set the gap as follows:  with the NST connected to the protection
circuit,
> connect the spark gap to the output (after the protection circuit).  Set
the
> gap so that it always arcs across but if opened farther, it doesn't arc.
> Leave it there.
>
> Regards,
>
> Pete Komen
>
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Saturday, June 09, 2001 10:29 AM
> To: tesla-at-pupman-dot-com
> Subject: spark gap spacing
>
> Original poster: "Jeremiah by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <jmeizis-at-kc.rr-dot-com>
>
> Hi,
> I was wanting to know how far you should set your gap?  Today i was doing
> some
> testing and i set my gap real close together and it was a very poor
> performance.  I noticed the more i opened up the gap the better the
> performance.  When i opened it up all the way, and i was turning up the
> variac
> it finally started arcing at 11.5 KV then one of the capacitors on my MMC
> blew
> up.  It didn't actually explode but part of the insulation popped off, it
> was
> kind of weird.  Why did that happen in the first place?  The caps i'm
using
> are
> 10 .068uF 1.25 KV and the gap is an inch wide at full open.
> Thanks
> Jeremiah
>
>
>
>

The transformer is a 12/30 NST controlled through a variac and i have only
set it at 115 on the variac.  I didn't know how to calculate the peak
voltage.  Is 1.414 a constant or an independent variable in an equation?
Now should i set gap so that it arcs dependably and then add the caps in
their?  If i set the gap this way is that going to be the peak voltage at
that voltage setting?
Thanks
Jeremiah