Re: tesla virgin no more ! but need help

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

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


The math goes:

A 15 kV, 30 mA NST has an effective impedance of 50K Ohms.

Capacitor value for resonant match = .0053 uF, ie, 5.3 nF

With stationary sparkgap, best capacitance = 1.6 * Cres = 1.6 * 5.3 nF =
8.48 nF = .0085 uF

For synchro RSG, best capacitance = 3.2 x Cres = 17 nF = .017 uF  (this is
absolute max value)
2.8 to 3.2 is good range for synchro RSG's.


Voltage rating using MMC type caps:

Erms = 15 kV     15 kV x 2.5 = 37.5 kV (total DC rating for each string)
this requires 18-19 caps per series string

with synchro RSG and cheating a bit on the voltage rating:

.15 uF / 17 caps per string = .0088 uF per string x 2 strings = .0176 uF =
17.6 nF bank total capacitance


Your .02 uF rating would be extreme even for a synchro RSG type sparkgap and
way to large for a stationary sparkgap.


Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913
 >
 > My caps are Cornell 942C16P15k   rated -at-.15uf 1600VDC . I figured on a
total
 > capacitance
 > of around .02 uf , why am i way off here?
 > I have a safety gap set a hair over firing gap space about .28". What I
 > don't understand is if ..02uf is way overkill for a 15/30 with a static
gap
 > why does the coil operate with my 9/30,
 > I would like to properly match MMC size and Gap size for this 4" coil
based
 > on  some recommendations
 >
 > I have not blown any other caps since then
 > when I apply power to the coil  with  a 15/30
 > the gap fires briefly the coil functions for 1-5 seconds and then stops.
 >
 > Steve
 >
 > Steve
 >
 >
 > Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Thursday, February 05, 2004 10:12 AM
 > Subject: Re: tesla virgin no more ! but need help
 >
 >
 >  > 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
 >  > >
 >  > >
 >  >
 >  >
 >  >
 >  >
 >  >
 >
 >
 >