Re: Bang size and break-rate
Tesla List skrev:
> Original Poster: FutureT-at-aol-dot-com
> Just a clarification:
> I've spoken a lot about the benefits of a low break rate with a larger
> cap size. Other times I've mentioned the benefits of a large bang
> size. I should mention that it doesn't matter how the large bang is
> created, i.e. either by using a large cap, or a higher input voltage,
> the main thing is the large bang size and low break rate. The higher
> voltage might even be a little more efficient due to lower gap and
> other tank losses. The corona onset point is of course the limiting
> factor for using higher input voltages.
> John Freau
I get a strong sence of "katharsis" reading this, since I am running
MMC`s from a 20 kV RMS pig, and have not forgotten the initial responce
that I got to this homemade pig, where it was pointed out to me, that I
should have gone for lower voltages, and saved the high voltage for the
But what I have in mind specially now, is a discussion about how we
build coils today.
800-not much more than 1000 turns secondarys.
preferably more than 10 turns primarys.
topload 2-3 times bigger than sec. self-C
a cap that matches sec. system res. freq.
power: untill it burns up. :-)
I have seen, how my sparklength increases, if I apply the available
power through a wide sparkgap, thus high voltage, and low breakrate, as
opposed to a narrower gap, with lower voltages and a higher breakrate.
This is a highly resonant charging system, with a static gap, where only
my nerves, and ultimately the cap, sets the voltage limit.
If we assume that the secondary system is optimized, with a high Ctop,
and we want to increase the bang size, keeping the voltage, and
breakrate fixed, the cap must be increased in size for more bang. This
in turn requires the primary to be tapped in at fewer turns.
It is my impression, from my own experience, and from looking at
numerous sites, that the first coil that a person builds is made to meet
the "many primary turns" criteria, the next, and bigger coil is
frequently not. Many of the big coils have 4-5 turns primarys, Bill
Wysoc`s model 14 has only 2. (ok!, it`s a maggie, but still...)
So, is there some mechanism inherent in really big coils that allow for
these low primary turns counts, or are the newcomers making a lot of
primary turns in vain, for the sake of a (perhaps) outdated tradition.
If not, I would feel tempted to push for 30 kV in my next design, for
low C, high L, even though I alresdy have experienced some of the
problems of insulating to 20 kV in my present tank circuit.