I have to agree with John - a change in the cap size requires a change in
the SRSG phase. And not only that, but a change in the Variac setting to
the NST also requires a change in the SRSG phase for peak performance.
John's SRSG phase controller is IMHO an absolutely necessary component of
an SRSG system, he really should be getting royalties for each one used
;-) If one attempts to set the SRSG presentation timing to coincide with
the peak mains voltage peak, you are deluding yourself and shortchanging
the performance. The charging behavior of the primary cap in a TC vs. the
mains voltage, particularly using an LTR cap, is far from intuitive. The
peak cap voltage does NOT coincide with the peak mains voltage, it's much
more complex, and this is borne out by circuit simulations and
measurements. Just twiddle the knob for maximum performance.
Regards, Gary Lau
MA, USA
On Fri, Sep 11, 2020 at 8:54 PM jimlux <jimlux@xxxxxxxxxxxxx> wrote:
> On 9/11/20 4:58 PM, shaun wrote:
> > How in the world can the cap keep charging higher after peak sine wave
> and
> > on the down side of the sine wave, there is only one peak. Peak is at
> 4.16
> > ms anything after that is lower voltage. Unless you are saying:
> >
> > Say my cap is only charged to 70% at peak mains, so what you are saying
> is,
> > after peak use roughly another 2 or so ms of time on the other side of
> the
> > sine wave to continue charging won't be as high, but higher than 70%.
> >
> >
>
>
> Don't forget that your charging source (NST) has a big inductance. It's
> easy to set up situations where you're getting a resonance with the
> primary cap, and ring up to higher voltages.
>
> Back 10-15 years or so, plenty of people killing NSTs with async gaps
> that happened to fire at just the wrong time.
>
> This is why we talk about STR (smaller than resonant) and LTR (Larger
> than resonant) Primary caps - it's resonance with the L of the source,
> not the TC primary.
>
> The big advantage of LTR is that it's hard to kill it with a rotary gap,
> no matter the phase (and potentially bigger bangs, from the larger
> stored energy). The downside is that it's more expensive.
>
>
> >
> >
> >
> > -----Original Message-----
> > From: Tesla [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of Yurtle
> Turtle via
> > Tesla
> > Sent: September 11, 2020 4:30 PM
> > To: 'Tesla Coil Mailing List'
> > Subject: Re: [TCML] Old post, Sync. rotary phase effect
> >
> > Not necessarily. If your current limited NST can't fully charge the
> cap by
> > the time your mains hit their peak, the cap can keep charging up to the
> > point where its "charge" = NST output, which can occur after mains peak.
> >
> > On Friday, September 11, 2020, 2:57:22 PM EDT, shaun
> > <snoggle@xxxxxxxxxxxxxx> wrote:
> >
> > I adj my sync gap using a scope, when the sine wave is at its peak is
> when
> > my gap is aligned and fires. The peak of the ac sine wave is when I want
> the
> > cap to discharge. So I set the gap to fire at precisely peak of the
> charging
> > sign wave. I want my tank cap in all cases to fully charge and that is at
> > the peak of the sign wave. So no matter what size tank cap I have, I
> want it
> > fully charged and that will always be at the peak of the sign. If it
> fired
> > any other place it would not be full charge. The peak ac don't change.
> >
> >
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