RE: Capasitor match

To: tesla-at-pupman-dot-com
Subject: RE: Capasitor match
From: "Bryan Miller" <ftbll-at-MailAndNews-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Thu, 17 Feb 2000 08:07:11 -0700
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Terry,
    Sorry for not providing the specifics.  I am using a 12kV 30mA NST.  I am 
planning on using a rolled capacitor rated for about 54,000 dc and  .01uF.  My 
primary is 15 turns of 1/4" copper tubing spaced 1/4" in a 15 degree angle.  
My secondary has a diameter of 4.5" pvc and is wound with 985 turns of #22 
enamel covered magnetic wire.  I know my capacitor match would be .0066, but 
would the .01 capacitor do fine, or would I need to arrange a few of them in 
parallel to get an exact match?  Thanks again!


Bryan

>On Mon, 14 Feb 2000 21:31:55 -0700 Tesla List <tesla-at-pupman-dot-com> writes:
>> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>>
>> Hi Bryan,
>>
>> 	There are three basic capacitor sizes:
>>
>> 1	Resonant.  This is the size that will resonant with the
>> transformer at
>> 60Hz allowing fairly high power transfer.  You will get more that
>> 120
>> breaks per second.  Safety gaps are an absolute must because if
>> anything
>> goes wrong the voltage can jump up to like 50,000 volts and blow
>> everything
>> up.  These are very popular but they have left many dead NSTs in
>> their wake.
>>
>> 2	"Big"(I just made that up)  This cap size is about 50%
>> large than a
>> resonant cap and has fewer BPS but the larger cap makes up for it.
>> It is
>> far less likely to destroy anything if something goes wrong.  I
>> would
>> recommend this.  Many would consider this as an "LTR" type but I
>> like to
>> reserve that for the really optimized coils.
>>
>> 3 	"LTR" Larger Than Resonant.  The cap size is the maximum
>> that can be
>> charged at the line frequency.  This usually takes advantage of the
>> timing
>> of a rotary sync gap to work.  Very safe and has very good power but
>> fairly
>> complex to figure out and build.
>>
>> These are all for NST systems that have current limited
>> transformers.
>> Other transformers have other considerations.  Let us know what kind
>> of
>> transformer you have and a little detail on your coil and we can be
>> more
>> specific.
>>
>> Cheers,
>>
>> 	Terry
>>
>>
>> At 07:23 PM 02/14/2000 -0500, you wrote:
>> >Hello everyone,
>> >      I am building my first capasitor.  I know you want to try to
>> match the
>> >capacitance of the capacitor with the transformer, but is it okay
>> to go
>> over.
>> >Is there any advantages/disadvantages to haveing a larger
>> capacitor?  Thanks
>> >for any help.
>> >
>> >
>> >
>> >Bryan Miller
>> >
>>