Couldn't you just run each side of the NST as a separate 7.5kV source to each SGTC or would the firing of one gap interfere too much with the charging of the second?
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-------- Original message --------From: Matthew Sweeney <msweeney23@xxxxxxxxx> Date: 7/26/18 6:11 PM (GMT-05:00) To: Tesla Coil Mailing List <tesla@xxxxxxxxxx> Subject: Re: [TCML] multiple coils at same time off one NST
That makes sense, I always assume the spark gap In series.
So when the transformer 'shorts' across the gap what happens to current
draw?
That might be a trivial eletrics lesson but I find myself kind of lacking
when it comes to NSTs.
Thanks!
On Wed, Jul 25, 2018, 4:34 PM jimlux <jimlux@xxxxxxxxxxxxx> wrote:
> On 7/25/18 1:59 PM, Matthew Sweeney wrote:
> > How is that possible? With my limited knowledge I would assume this would
> > be quite difficult, what with impedence matching and all that. Wouldn't
> the
> > spark gaps interfere with each other?
> >
> > I would be very interested to know more.
> >
>
> I would assume that basically the NST acts as a constant current source.
>
> In one standard configuration (the one I use for NSTs on a single coil)
> it's
>
> Transformer - spark gap across transformer - series Cpri and Lpri
>
> So when the gap fires, Cpri, Lpri, and SG form a resonant circuit that
> rings down.
>
>
> If you ganged up two coils this way, they'd fire at the same time, but
> the two resonant circuits would only share the spark gap. there's no
> particular reason why the two coils would have the same resonant frequency.
>
> The transformer would be charging both Cpri in parallel, so the charging
> rate is essentially halved (if the Cpri are the same)
>
>
> In the other configuration (more like a DC resonant charging circuit),
> the transformer is across the capacitor, and the spark gap connects
> between Cpri and Lpri.
>
> This one would be harder to analyze - the two coils share the same Cpri,
> and presumably, one gap would fire before the other, and the other would
> never fire, but if it happened to be "lucky", you might get alternate
> firing of the gaps (or you could use a triggered gap?)
>
> If the "ringdown" takes, say, 10 RF cycles at 100kHz, that's 0.1
> milliseconds. That's much shorter than the time to charge the primary
> capacitor (depending on where in the line frequency cycle you are), so
> you could conceivably charge the primary multiple times in a half cycle,
> and fire the gaps more often.
>
> (Assuming you're "smaller than resonant" sized Cpri)
>
>
> >
>
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