15/60 performance

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

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of the things are out of date (like my primary style) and were done several 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.