RE: [TCML] My terry filter capacitors blew up!!

["Lau, Gary" <Gary.Lau@xxxxxx>]

I think the string Amir was talking about was the Terry filter cap, not his main tank cap.  The necessary voltage rating of these strings is only half that of tank cap and should be fine, unless his system goes into resonant meltdown.  It does seem hard to believe that one could smoke a 19.2kV-rated string in a Terry filter, as the total string would be rated at 38.4kV.  I wonder if there was a wiring error that caused an incorrect cap string configuration?

Gary Lau
MA, USA



> You never want to run a MMC cap bank with a resonant match value for the
> NST --- as you discovered, it will definitely blow up.  When resonance
> between the power supply and cap bank occurs, the potentials can
> definitely rise to high levels which can blow cap banks and even push
> Terry filters to their limit.
>
> You should use approx 1.3 to 1.5 x resonant value for the capacitance.
>
> Also, you have way to few MMC caps in the series string.
>
> You need to run 2.5 x Erms value, ie, with your 15 kV xmfr, then 15 x 2.5
> = 37.5 kV DC rating on the MMC for each series string.
>
> 37.5 kV DC / 1.6 kV = 23.4, ie, use 25 caps per series string.
>
> Dr. Resonance
>
>
>
>
> > Hello all,
> >
> > Recently I built an MMC for my medium sized 4.5 inch diameter Tesla coil,
> > and the total value for it is .0053uf at around 35,000 volts. This is
> > resonant
> > for my Magnetek 15kv 30ma NST.
> >
> > I had a Terry filter on the NST, (i bought the kit off ebay) and when  I
> > ran
> > the coil, the capacitors on the Terry filter blew up and caught fire. I
> > was
> > wondering why this is, and also I need to know how I can replace the
> > caps.
> >
> > Do they need to be the exact same kind of capacitors? The  ones that blew
> > were .0033uf at 1600v each. There were 12 capacitors in series.
> >
> > I was wondering if I could use these other caps I had which are  0.015uf
> > each
> > at 1600v. I have around 20 of those.
> >
> > Would the extra capacitance make a difference? How does the capacitance
> > affect the Filter and in general the whole Tesla Coil?
> >
> > Sorry if I seem naive to this, but I'm only 14 years old.
> >
> > I really appreciate this a lot!!!!
> >
> > Thanks,
> > Amir M.
> >
> >
> >
> > **************Biggest Grammy Award surprises of all time on AOL Music.
> > (http://music.aol.com/grammys/pictures/never-won-a-
> grammy?NCID=aolcmp003000000025
> > 48)
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>
>
> Dr. Resonance
>
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