Re: [TCML] Primary Coil Simulator for Safe Primary Circuit Experimentation

[Gary Lau <glau1024@xxxxxxxxx>]

I just thought of another use for the halogen lamp dummy load.  When one
begins the design of a coil, after you decide what size NST you'll be using,
the next step is to determine the tank capacitor size.  The standard method
is to just look it up in a table for what size your NST is, using an LTR cap
for a static gap, being some factor 1.3-1.7 times the mains-resonant value.
Personally, I've found better results using ~2 times the mains-resonant
value.

Experimentally trying different cap sizes isn't practical, as each time you
change the cap size, you must also change the secondary to keep things in
tune (which changes multiple things, rather than just one), and you must
also subjectively judge at what point the sparks are better, at widely
distant points in time.

However, if you replace the primary with the dummy load, one can quickly
change the cap size and nothing else, and gauge the amount of power
processed by the brightness of the lamps.  For a more quantitative result,
you can mount a thermocouple on the lamp and see with what capacitor size
causes the lamps to get the hottest.  I believe that this would give a very
accurate determination of the optimum capacitor size.  I'll have to
resurrect my coil and try this!

I've also long suspected that the optimum cap size might differ
significantly depending upon the applied AC voltage to the NST - potentially
very different for 120 vs. 140VAC.  It would be easy to determine if this is
true using a dummy load.

Regards, Gary Lau
MA, USA



On Sat, Jul 24, 2010 at 9:02 PM, Brandon Hendershot <
brandonhendershot@xxxxxxxxx> wrote:

> Hi Gary,
> Thank you! I am quite proud of it...
> No RSG's here. Interesting prospects though, well have to have somebody
> with one make one of these and try that out.
> Brandon
>
> On Jul 24, 2010, at 4:27 PM, Gary Lau <glau1024@xxxxxxxxx> wrote:
>
> > Hi Brandon,
> >
> > Your load rig looks a lot more presentable than mine ever did.  I like
> the
> > way you used screws for the bulb contacts - I wish I had thought of doing
> > that!
> >
> > Are you using it with a sync RSG?  I'd be curious to hear your experience
> as
> > you vary the phase.  Using just the Freau adjuster, you should be able to
> > see the lamps go from almost nothing, to very bright, and suddenly mayhem
> > and safety gaps firing.
> >
> > Regards, Gary Lau
> > MA, USA
> >
> > On Sat, Jul 24, 2010 at 6:35 PM, Brandon Hendershot <
> > brandonhendershot@xxxxxxxxx> wrote:
> >
> >> Hi All,
> >>
> >> Just wanted to share this with you.
> >> http://drop.io/BrandonTCML
> >> It will safely dissipate the energy from the capacitors using three 120V
> >> 500W J Type Halogen Flood Lamps connected in series. Opposed to the
> primary
> >> coil doing this naturally.
> >>
> >> "If the primary is replaced with a short circuit, the cap will charge
> >> normally,
> >> but each time the gap fires, it will directly short out the charged cap,
> >> and
> >> this will be extremely stressful on the cap (HUGE discharge currents) as
> >> well as the gap (all the energy that went into charging the cap will be
> >> dissipated in heat, light, and sound, and the gap will be a fearsome
> >> thing)."
> >>
> >> It was created by Gary Lau, designed and built by myself.
> >>
> >> Brandon
>
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