Re: [TCML] frailty of NSTs

["DC Cox" <resonance@xxxxxxxxxxxx>]

Your best bet with nsts is to remove the tar and then drop them into a
plastic tank of oil.  Better insulation and heat is removed.  You can also
remove a few shunts to increase your coil's performance.  Caps love current
--- the more the better.

Most failures, are, as Ted says, related to HV insulation failure.

Dr. Resonance



On Mon, Mar 24, 2008 at 6:19 PM, Vinnie <teslatech@xxxxxxxxxxx> wrote:

> Hello
>
>  I have some questions about NST failures. I haven't had one yet but was
> wondering what characterists they
> have when they do fail. Do they just suddenly stop working or do they
> become
> intermittent? Is there a way
> to determine NST health after years of operation in a tesla coil?
>
> Thanks for your time.
>
> Vinnie
>
> ----- Original Message -----
> From: "tesla" <tesla@xxxxxxxxxxxxxxx>
> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
> Sent: Sunday, March 23, 2008 12:22 PM
> Subject: Re: [TCML] frailty of NSTs
>
>
> > .
> >>
> >> What is it about NSTs that makes them so fragile?  I suspect it is the
> >> current through a secondary wound with
> >> inadequate wire size.
> >>
> >>
> > Hi
> >
> > These beasts are frail for two main reasons
> >
> > 1) In normal operation the HV is "shorted" by the gas discharge tube
> when
> > it strikes so that the terminal  voltage is at HV for a few fractions of
> a
> > second. The internal insulation is thus not designed to cope with
> extended
> > periods of HV
> >
> > 2) They are made with a magnetic shunt which produces large series O/P
> > inductance to limit the current. In Tesla service this inductance can
> > resonate with the Tesla primary cap and this series resonant cct
> exhibits
> > resonanat rise. This could produce hundreds of kv but naturally the
> > insulation fails prior to that
> >
> > 3) RF from the Tesla may contribute to the failure of the insulation due
> > dielectiric heating I suspect
> >
> > Best
> > Ted L in NZ
> > _______________________________________________
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> > Tesla@xxxxxxxxxxxxxx
> > http://www.pupman.com/mailman/listinfo/tesla
>
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