Re: first post (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Wed, 15 Aug 2007 11:50:43 -0700
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>, tesla@xxxxxxxxxx
Subject: Re: first post (fwd)

At 10:59 AM 8/15/2007, Tesla list wrote:

>---------- Forwarded message ----------
>Date: Wed, 15 Aug 2007 13:00:10 -0500
>From: Crispy <crispy@xxxxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: Re: first post (fwd)
>
>Hmm, by my calculations, you'd only need 7 per string.  The caps are
>rated at 150nF, 2kV each, if I recall.  9000Vrms is about 12730V peak.
>Divided by 2000V per cap and rounded up comes to 7 caps per string.
>This alone is more than the 15nF you want.  If you want exactly 15nF,
>you can use one string of 10, and have a healthy voltage margin as well.
>On ebay, the ebay store TeslaStuff sells lots of 12 of these caps for
>under $50.


One thing to watch out for is that you also need to consider the RF 
current through the strings.  With a NST, you're never going to have 
problems, but get up into the hundreds of mA range from your 
transformer, and the RF current might get quite hgh.  I think some of 
the MMC calculators out there take this into account.  You might need 
parallel strings just to handle the current, and that's a rapidly 
escalating cost situation, because to double the current, you need 4x 
the capacitors, just to keep the capacitance reasonable.  (Or, you 
buy 0.05 uF caps instead of 0.15 or 0.10 uF caps... a better plan anyway)


Jim Lux