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Re: tesla virgin no more ! but need help
Original poster: "steven hyman" <steve502-at-bellsouth-dot-net>
thanks
based on some of these replies I will rework My MMC today
if best capacitance -at- 50k ohm impedance is .0085uf
and 18/19 1600vt cap per string will meet voltage requirements -at- 15kv x
2.5=37.5kv
then one string 17 caps .15 uf /1600 vt
total capacitance .0088/ total voltage 27.2kv
whether I use 17/18/or19 caps per string
I should only use 1 string to better meet capacitance requirements Right
??????
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, February 06, 2004 10:04 AM
Subject: Re: tesla virgin no more ! but need help
> 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
> > > >
> > > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
>
>