Re: Thoughts on spark length and the "Freau Equation"

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Mark,

Yep, a slight advantage. They can charge a cap to a higher voltage (same cap
value). The frequency is slower, but also, the syncronous motor speed is
1500 rpm
as compared to an 1800 rpm here. Once all is taken into account, a 50Hz
system has
a little better charging cycle. But, it is only a slight advantage. Not a big
deal. Where you notice the change is with higher Cp in comparison to bps.

For example;
A 12/60 xfmr, 120 bps, 60Hz, 40nF Cp = Vp of 10.9kV, 2.29J.
A 12/60 xfmr, 100 bps, 50 Hz, 40nF Cp = Vp of 11.8kV, 2.78J.
Note, the above Cp reflects about a 1 time constant value.

If we assume a 5 time constant value or full charge (small Cp);
A 12/60 xfmr, 120 bps, 60 Hz, 8nF Cp = Vp of 16.9kV, 1.15J.
A 12/60 xfmr, 100 bps, 50 Hz, 8nF Cp = Vp of 16.9kV, 1.15J.

Take care,
Bart Anderson



Bart Anderson

Tesla list wrote:

> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <A123X-at-aol-dot-com>
>
> I was kinda wondering if people running coils in the UK have a bit of an
> advantage over coilers in the U.S. since each charging cycle is longer and
> therefore allows for a bigger bang each time. Actually I'm pretty sure now
> that they do, but how much better is what I'm wondering now.
>
> Mark
>
> In a message dated 6/10/01 8:16:28 PM Eastern Daylight Time, tesla-at-pupman-dot-com
> writes:
>
> >
> > Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <
> > jimlux-at-earthlink-dot-net>
> >
> > I would assume that the equation proposed by John Freau for predicting max
> > spark length  (=1.7 *sqrt(VA)) is based on 120 pulses per second.  That is,
> > it's really more of  (length in inches)= 1.7 * sqrt(120 * energy per
bang) =
> > 18.6*sqrt(energy per bang in Joules).
> >
> > Obviously, there are breakrate effects on spark length, but, for rates in
> > the 100-200 bps range....
> >
> > Comments?
> >
> >