Re: Remove tar from NST

To: tesla-at-pupman-dot-com
Subject: Re: Remove tar from NST
From: Ed Phillips <evp-at-pacbell-dot-net> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Fri, 25 Sep 1998 22:57:34 -0600
Approved: terryf-at-verinet-dot-com

Tesla List wrote:
> 
> Original Poster: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
> 
> Hi Daniel,
> 
> > Original Poster: Daniel Hess <dhess1-at-us.ibm-dot-com>
> >
> > Malcolm, All;
> >
> > Well doggonnit! Now I'm going to have to dig out my "Neon Sign Techniques"
> > manual and get to the bottom of this open/shorted secondary thing. As I
> > recall,
> > the fastest way to burn up a nst was to run it under loaded, something
> you'ld
> > want to avoid in the neon sign business. And an open secondary was
> considered
> > the ultimate underload albeit something desirable for the purpose of
> depotting
> > the core.
> 
> Probably because running with the secondary o/c exposes the insulation
> to full peak voltages. You still need secondary current to heat the
> winding.
> 
> ?
> Malcolm
> 
> 
> > I'll dig it out this weekend and post the results of my research and who
> > knows;
> > Maybe I'll get to eat some crow while I'm at it...
> >
> > Daniel
> >
> >
> >

	When an NST is operated open circuit the voltage across the windings is
just the name plate voltage, which it should withstand for thousands of
hours.  The easiest way to blooie one is to use a "matched" capacitor
(gives series resonance and a probable voltage rise to at least twice
the rated voltage or more if operate without load) and open up the spark
gap too far in the quest for bigger and bigger sparks.  Been there, done
that!  (Several times, before I finally wised up.)

Ed