Re: tesla virgin no more ! but need help

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

Original poster: Mark Broker <mbroker-at-thegeekgroup-dot-org> 

Congrats on first light!

.025uF is *way* too much cap for a 15/30!  You want more like .008uF for a 
static gap and a 15/30.  Did you retun when you removed capacitors?  Are 
you using a Safety Spark Gap?  Did you set it properly before 
operation?  What type of MMC cap are you using?  Brand and model will be 
great, or just type of dielectric will suffice.  Where on the caps are the 
holes/failures located?

My first MMC used 11 caps per string of 1600VDC caps.  No problems there 
despite shorting the MOVs in a "Terry Filter...."

So I, too, think that your MMC is probably suspect.  Answers to these 
questions will help us determine what's going on.

Cheers,

Mark Broker
Chief Engineer, The Geek Group


On Wed, 04 Feb 2004 18:07:59 -0700, Tesla list <tesla-at-pupman-dot-com> wrote:

>Original poster: "steven hyman" <steve502-at-bellsouth-dot-net> I have been 
>building my first coil (Researched this lists archives for over a month 
>,along with all the websites Thanks), and had first sparks
>on Saturday  WOW!!!, about  15 inches, but having some problems, I cannot 
>figure out, and need some expert advise
>
>     Spark gap , static type with 6 ,1" diameter x2" long copper pipes 
> laid out flat, gap spacing about 1mm  with fan
>.  MMC with 2 strings 12 each string(24total of 1600kv .15uf poly's.Total 
>value .025 uf ??? ( can someone check this)
>      I am presently powering this coil with 15/30 NST
>
>first light was great, ran the coil 10-15 short runs 12-24 inch 
>sparks.   Then the  spark gap would only fire for about a second and stop, 
>after inspecting the MMC realized I had burned 2 caps up ( big holes in 
>two caps together in series), I replaced these caps, and added 3 more per 
>string( now qty 15- .15uf 1600kv each per string x 2 strings)) but same 
>problem, after some evals, my present  situation remains the same , if I 
>remove the parallel connection between the 2 strings of 15 caps, and use 
>each string alone, the gap fires ( but no sparks from top load( I can get 
>spark from topload with breakout), but if I reconnect the 2 strings of 
>caps , same problem, gap only fires for about a second or two, and 
>nothing, I have tried the coil using a smaller NST (9/30 )   and the coil 
>works well all components working with about 15" sparks.
>
>4" secondary 1050 turns ,24awg, 21.5 " coil length
>12 turn primary 1/4 od, 1/4 spacing( tuned at about 7 turns)
>
>I suspect the MMC  configuration, but cannot figure this out !! I thought 
>15 x1600kv caps would suffice for a 15/30 nst (15 x 1600=24kv
>any help would be greatly appreciated
>
>Steve
>
>