Re: [TCML] SRSG "sputter"

[Gary Lau <glau1024@xxxxxxxxx>]

Awww - where's your sense of adventure ;-) ?

But seriously, component values in Tesla coils are anything but written in
stone.  The only thing that's inflexible is that the primary resonance must
match the secondary resonance.  Beyond that, most things are negotiable.

For a 15/60 NST at 60Hz mains and a 120BPS SRSG, the cap value recommended
in "the book" is .028uF.  But I performed a set of experiments in 2004 (see
http://www.pupman.com/listarchives/2004/April/msg01087.html) to determine
which cap value would give me the highest power throughput when I powered my
NST with a Variac'ed up ~144VAC boost.  Using the halogen bulb dummy load, I
measured the bang voltage at the best SRSG settings, and calculated the
power throughput for each of cap values .02, .03, .04, and .05uF.  The value
.04uF gave the highest power throughput, so that's what I use in my coil.
The characteristics of my NST at the elevated voltage may not work for other
NST's, but it is what it is, and I'm grateful for it.

If the standoff voltage rating of the SRSG is being exceeded, using a higher
cap value would reduce the maximum voltage, so that may be something worth
trying.  Whether it will improve or degrade the power throughput can't be
predicted without measurement.  But since arcing between the primary circuit
and motor could be damaging to the motor (and quite possibly everything in
the house connected to the same power mains as the motor), I would fix the
gap geometry so it can't arc to the motor.

Regards, Gary Lau
MA, USA

On Thu, Jul 8, 2010 at 6:47 PM, Brandon Garretson
<garretsontech@xxxxxxxxx>wrote:

> I would think it best to keep the capacitance within +/- 10% of whatever
> TeslaMap or JavaTC recommend for your power supply and gap type.
> That should give you optimal use of your input power and make tuning
> easier.
>
> On Thu, Jul 8, 2010 at 5:42 PM, Joe Mastroianni <joe@xxxxxxxxxxxxxx>
> wrote:
>
> > ""I have run the gap on the NST alone and there's no issue then. But not
> > with only part of the primary circuit.
> >
> > I am now thinking to try Johns theories about the back ring arcing. *I am
> > also wondering if I should try to increase my mmc capacitance.""*
> >
> >  **
>
>
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