Re: LTR vs. STR for pigs was Re: PFC Question

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Steve Ward <steve.ward@xxxxxxxxx>

Hi Dmitry


> first - as far as i remember Greg Leyh said something like "the
> longest streamers with my coil  were achieved at bps around 300".

Right, perhaps he got super streamers at 300bps, but was it more
efficient (spark length vs input power) at say 100bps?  Im guessing so
(at least all of my DRSSTC work is most efficient at about
100-120bps).


> well - just everything has its limits - when decreasing the bps lower
> than 70, the efficiency also falls visibly - even at enormous energy.
>

Yes, definately.  It seems that with bigger coils you might be able to
operate efficiently below 70bps.  This is something ive been wanting
to experiment with, but you need a BIG coil to really see the effect i
think.  But you can see the difference even when comparing my
miniature TC which needs maybe 90bps to form good streamers, to my
medium TCs which do ok at say 60-70bps before the streamers "fall
apart".  But these numbers are just from memory... i need to validate
them accurately sometime.

>  > My 400bps coils get about 1.3 to 1.4.
>
> how about "other" Steve?
> "Steve from other side" - halloo %-)

Generally, with my DRSSTC work i find a "sweet spot" at about 180bps.
That is, i get my LONGEST sparks possible at that BPS, but at a great
increase in input power!  The extra spark length achieved does NOT
account for the extra input power (that is, my "Freau number" falls at
higher break rates).  I suspect this might be the same case with
Greg's coils.  Longer sparks are to be had at higher break rates, but
in general it seems to produce a less efficient system as far as spark
length is concerned.

But... something people dont often consider is spark intensity and
just overall "performance" of a system.  When i operate at 100bps, its
not nearly as awesome as when running it up to say 200-400bps.  The
sparks are usually a little hotter, and you get a much more terrifying
display!

I have also attempted to cut my bang energy by some amount (say
35-50%) and increase the break rate to again get the same Freau
number.  It just doesnt work for me.  100-120BPS seems to do the trick
if spark length vs power is your goal!

>
> p.s.
>
> as for the "freau number" - reading the archives i found the
> absolutely champion of all times - of  course it`s Malcolm Watts:
>
> http://www.pupman.com/listarchives/1996/may/msg00090.html
>
> "The coil I fire at work has been putting out 4+ footers with a PRF of
> 100 (1/mains half cycle) on just 1.25 Joules per pulse (about a third
> of what I had previously thought)."
>
> 4.29+
> yeah, you don`t need any mega-joules - you just have to be a
> mega-coiler :-D
> so you guys all suck again :-)))

WOW!  Malcolm... how about a little bit of info on that coil?  Do you
have the specs/parameters still on hand?  I suppose a good description
of the spark gap would be useful.  Looks like DRSSTCs still have a
long way to come if 4.29 is the number to beat! :-)

Steve Ward

>
> -----
> The solution to no primary hits lay in getting rid of the primary!
> This is no joke either.
> 20-06-96 (c) Richard Hull, TCBOR
>
>
>