RE: Static Gap Break Rates

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>



-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Tuesday, March 14, 2006 8:36 PM
To: tesla@xxxxxxxxxx
Subject: Re: Static Gap Break Rates

Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Curt,

Excellent question. If we assume 120 bps is a properly set gap where
the gap width sets the arc voltage, then the tank capacitance,
charging voltage, and charging current will determine how fast the
arc voltage will be reached to achieve 120 BPS during the time domain
of the charging frequency. If the current is large enough, the cap
can attain the arc voltage many times during the first 1/2 cycle.

**** I can conceive that ok***

In the same respect, the current can also be so small that it may take
several cycles to reach the arc voltage

*** we are talking peak to peak now, please help me understand how the
primary cap is not forced to except a polarity reversal regardless what its
level of charge is, based on the charge rate****.

The arc voltage time "IS"
the BPS determinant.

In the real world, there are other factors that are not accounted for
which affect the charging voltage and time domain. One factor is
resonant charging. This is something that Gerry and I have been
mulling over the past few weeks (how to account for it with some
degree of accuracy). For now, it is not fully accounted (although, Rs
and Rp measurement inputs help impedance accuracy. There may be
resonant charging occurring depending on transformer and actual cap
size. Bps is affected by this. It may be that the NST coupling may be
needed as an input. This would obviously be one of those optional
inputs. I can envision a help file for "how to measure transformer
coupling" for those who wish to attain higher accuracy (should
coupling be needed). Let's face it, there is information that
requires measurement if we want to attain higher accuracy in our
predictions.

On this same topic, I recently posted NST coupling inquiries and
data. The reason I asked how to and then measured was to simulate
resonance situations with different cap sizes, but while simulating,
I found the NST coupling was critical in the model which stopped me
in my tracks (because I first used a typical NST coupling value).
After measuring and inserting the measured NST k value, the model now
predicts resonance where it should be. One "cannot" assume a typical
NST coupling value in this type of simulation (in other simulations,
it may be of no consequence), but for this study, it is important.
For example, a difference of 0.95 and 0.93 can easily mean a 30%
error (no kidding!). There is a lot of study and "figuring out" to be
done before this gets into Javatc.

Take care,
Bart

Tesla list wrote:

>Original poster: "C. Sibley" <a37chevy@xxxxxxxxx>
>
>In a discussion today I realized that I can't explain
>some assumptions I've accepted regarding static spark
>gaps.
>
>I've run a lot of designs through JAVATC and have
>accepted that the break rate increases as current
>increases (assuming all other things remain same).
>Depending on the current available the capacitor
>charges quicker and the break rate goes up.  What I
>can't come to terms with is break rates in excess of
>120Hz.  Wouldn't the 60Hz input limit the break rate
>to 120Hz for a properly set gap?  Based upon
>experience I realizes there must be more going on than
>just a simple RC circuit charging a capacitor. Am I
>missing the point?
>
>Thanks,
>
>Curt.
>
>