Re: first post (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Wed, 15 Aug 2007 18:41:30 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: first post (fwd)

Hi Garry,

I understand the transformer hookup but I don't understand your target 
capacitance. You mentioned 0.066uF. This is the "resonant" capacitance 
value that will cause the transformer to operate in a 100% resonant 
charging mode. Are you sure you want to do this? Can be a very bad thing 
for your transformers. Even giant pole pig coils usually run smaller 
than resonant by some margin. And NST's typically run larger than 
resonant by some margin. The idea is to stay away from the resonant cap 
value unless you design your components to take advantage of resonant 
charging. That means large safety margins in the voltage category of the 
cap chosen and the windings voltage standoff capability of the transformer.

I was kind of surprised no one else had mentioned this issue. Your cap 
would do just fine in the 0.02 to 0.04 uF range. Good for MMC with 
regards to the number of caps vs. voltage and current ratings.

Examples:
2 strings of 14 caps per string (CD 0.15uF type) [28 caps)
= 0.0214uF total capacitance at 28KV rating (rms derating of 3.1)

3 strings of 10 caps per string (CD 0.15uF type) [30 caps]
= 0.045uF total capacitance at 20KV rating (rms derating of 2.2)

Where:
4 strings of 10 caps per string (CD 0.15uF type) [40 caps]
= 0.06uF total capacitance at 20KV rating (rms derating of 2.2)

Just food for thought. The 0.06uF value is unnecessary, problematic, 
component dangerous, and expensive.

Take care,
Bart




Tesla list wrote:

>---------- Forwarded message ----------
>Date: Wed, 15 Aug 2007 07:34:54 -0500
>From: Terri Neeley <neeley_111@xxxxxxx>
>To: tesla@xxxxxxxxxx
>Subject: first post
>
>Hey guys im new to coiling but I am building my second coil and I need some
>help.  I don't want to make the same costly mistakes as I did on the first
>coil.  I will have 2 ge 5021g10 wired for 9000v 225ma for a spark gap coil.  My
>question is:  What capacitors should i go with?  I need .06microfarad so I
>thought about the maxwell you see floating around ebay?  2 in parallel of the
>35k .03mF would work but would it survive?  Any suggestions would be great Thx
>in advance.
>Garry Neeley
>
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