[Prev][Next][Index][Thread]
Re: Power in a TC System
Hi Terry,
Tesla List wrote:
> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>
> Hi Gavin,
>
> At 11:17 PM 05/19/2000 +0100, you wrote:
> >Hi John,
> >I know a bit about coiling, but tend to get lost with definitions (I only
> >learnt
> >the other day what an MMC was, but had been using them for the last few
> >years!).
> >
>
> Really! The first use of today's modern MMCs with high current
> polypropylene caps has been credited to Reinhard in the summer of 1998, so
> far... We are kind of wondering who was the first to use them? Not that
> there is any great pot of gold for being the "first" but if you have used
> them before all of us you should get some kind of honorable mention...
> Other mini caps have been used for a decade plus but only the modern poly
> caps have really worked well.
>
Hmmm, not sure now you said that, I'll tell you what I did, when I did it and
leave it to your better judgment.
I connected five 2.5nF/30kV capacitor sub-banks in parallel to give me a
12.5nF/30kV capacitor bank. Each sub-bank was made up from four 10nF/7.5kV
cylindrical (1 inch diam. by 2.5 inches long) capacitors, don't know what the
gunk (dielectric) inside was. So does this constitute an MMC? This was all done
in probably late 1998.....I think, Reinhard can keep the glory, I have
something
else, but no web site to stick it on. The use of an MMC (if I've got the
definition right) was not some stroke of genius, more an act of laziness.
Winding
a secondary was bad enough, but rolling my own capacitor was too much like hard
work.
> >A matched primary capacitor? Is this when the capacitors impedance matches
> >the NST
> >secondary's at the line frequency, i.e. forms a resonant circuit?
>
> This is referred to as a "resonant matched primary capacitor value". The
> impedance of the cap at 60Hz cancels the output impedance of the NST.
>
> >
> >What is LTR? Is this when the impedance of the primary capacitor loads the
> >NST to
> >it's maximum power capacity:-
> >
> >Xc = Vout / Imax
>
> LTR is really any value above the resonant capacitor size. You can charge
> capacitors larger than the resonant value to the full NST rated voltage
> easily. This gives you greater stored energy (but perhaps a lower BPS).
> This is around 1.5 times the resonant value. With a rotary sync gap, you
> can go further still. My 15/60 NST uses 28nF and my 9/30 NST uses 24nF.
> Far above the 10.6nF and 8.8nF resonant values. With a static gap, my
> 15/60 NST used 17nF.
>
O.K. they say mathematics is the universal language, could you post a
formula for
an LTR and a resonant matched primary capacitor, I'm guessing the following:
Resonance Matched = 1 / ( ( ( 2 pi f ) ^ 2 ) * Lt) Farads
where Lt is the inductance of the secondary of the NST and f is the line
frequency 50Hz/60Hz
LTR ~ It / (2 pi f Vt) Farads
Where It is the maximum current that can be drawn from the NST, Vt is the
output
(rms) voltage of the NST and f is again line frequency 60Hz/50Hz.
Both being the ideal case.
> >
> >Sorry for these elementary questions, but I have got to know some time!
>
> Sure!
>
> Cheers,
>
> Terry
>
>
This may eventually sink in! Please be patient, thanks again.
Kind regards
Gavin, U.K.