RE: 15/60 performance

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

Original poster: "Luke" <Bluu-at-cox-dot-net> 


I guess this opened up another question then.
How much for an arc length difference is there between a static gap and
a SRSG assuming everything else stays the same?

After I think about it guess you cant really look at it that way.  You
would need to change the cap size and that would affect a few things.

So if the same top load and secondary were used and all that was changed
was the cap size and the primary was tuned to meet the change.  How big
of a difference is there supposed to be?

Here is the formula I was using:
Rotary    L=1.7 * sqrt (P * 0.9)
Static    L=1.7 * sqrt (P * 0.5)

So for the rotary I could expect 48" for the 900 watts
And for the static I could expect 36"

According to this, and I know it is only a guestimated approximation,
the static is 75% of the rotary length in this case.

Is the multiplying by 0.5 for a static gap not very accurate?  12"
seemed like a significant gain.  The static gap would be a lot simpler.

But something in me still wants to try the SRSG but if I caneasily
expect 40"+ arcs with a static maybe ill go that way and save the SRSG
for later (as someone wrote to me "there's always tomorrow").

I will be using a 15/60 NST
the cap size was going to be .027 mfd
if I go to static it would of course be smaller.

I have decided on the secondary spec.
Radius             6.0365 (PVC drain pipe)
Coil length        26"
Wire gauge         26  .018" dia.
Turns			1444
Feet of wire       2385
All this will of course change a bit when I wind it which should happen
this weekend.  Maybe :)

Haven't decided on a top load size and maybe that is good.  If I change
to a static gap I might want a different size top load.

Any input on this would be appreciated.

Luke Galyan
Bluu-at-cox-dot-net

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Monday, January 19, 2004 10:04 AM
To: tesla-at-pupman-dot-com
Subject: 15/60 performance

Original poster: Brett Miller <brmtesla2-at-yahoo-dot-com>

Luke,

I think you'll easily hit that range with a 15/60.  I used a 12/60 on my

six inch system (full specs and some calculated/measured values are on
my
hot-streamer site) and I get
45" arcs....and that's with a *static gap*.  I could thoretically break
4
feet with an SRSG and LTR cap, especially with a geek MMC.  I'm using an

old school Terry Panasonic/Digikey MMC which works awesome, it's even
survived two scary catastrophic arc overs as well as a few incidents
where
I decided to open up a spark gap to the sizzling point with an OBIT and
an
NST.  One time (a couple years ago) it decided to ground itself out by
blowing a hole through the linoleum floor of my lab and into the
concrete
where it apparently made contact with the iron rebar.  The leads on the
underside of the MMC where this happened were carbonized from the
burning
linoleum, but the cap tested flawlessly after this incident.  Actually
one
such occurance was just
a week ago.  I set up the 6 inch disruptive system outside and fired on
the
porch with a friend's 15/30 nst.  To do this I jumpered only one string
of
my MMC.  Afte! r the coil ran a few seconds the running bank decided to
start arcing over (about 1cm distance) loudly to the other bank.  It was
so
spectacular I actually let this happen for about 20 seconds.  After
turning
down the variac and cutting the mains I examined the bank and it looked
unaffected.  We isolated the strings using a strip of HDPE, and powered
up
the coil.  Flawless performance.

My goodness, this has turned into another commercial for the MMC.  I do
think it is worthy to note, for posterity that I have had the same Terry

cap for about 5 years and it's working perfectly, plus I commonly open
up
my gap to an obscene width.  I have a Maxwell LTR sized cap, plus two
generic resonant size pulse caps as well.  But it is the Terry cap that
gave me the longest arcs (of course that's the resonant size if you
check
my spec sheet).  When I make a new pancake primary for my 6" system I
will
make sure it has enough turns to tune with a larger toroid and an LTR
cap.  So if you end up looking at my site, just try to remember that
some
of the things are out of date (like my primary style) and were done
several
years ago.  I would rather do science than web authoring, so it's the
last
thing that usually gets done on my list.

Anyway, you may find the 15/60 performance to be better than you think.
Course........you can always unpot it and mod it!

-Brett
hot-streamer-dot-com/brett

Tesla list <tesla-at-pupman-dot-com> wrote:

Original poster: "Luke"

I am wanting to get 36" - 40" arcs from my coil.
I will be using one NST 15KV at 60MA
I know I could go to a static gap and just bump up to 2 NST's.