Re:

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Chris the great" <downnessisgoingup-at-hotmail-dot-com> 

The main reason for the cap size is the output current on the transformer.
The number of primary turns will be around 4, meaning I may have problems 
with primary arcing.
However, I am not sure if 200nF is a good idea, ss I could experience alot 
of secondary arcing at that power level.
I am new at this, and 200nF DOES seem to be on the large (huge) size for my 
coil, however, would it work?  Or would my coil destroy itself?
Should I keep cap size to perhaps 50-100nF at the very maximum?

Chris



>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Re: Date: Sun, 16 Nov 2003 11:36:31 -0700
>
>Original poster: Bart Anderson <classi6-at-classictesla-dot-com>
>
>Hi Chris,
>
>Are you sure you want to run a 200nF cap size? That's on the huge side for 
>a 4.5" coil. Have you looked at the number of turns required on the 
>primary when using a cap of this size? Also, the cap energy is going to be 
>way up there for a coil this size. I run between 20nF and 80nF on my 10KVA 
>pig. David Rieben runs 85nF on his. These are just a couple higher powered 
>coils for reference. BTW, these are roughly 13" diameter coils. What made 
>you consider a 200nF cap? Was it the transformer output current?
>
>Take care,
>Bart
>
>> > Original poster: "Chris the great" <downnessisgoingup-at-hotmail-dot-com>
>> >
>> > I have done some work on my coil since I have last posted, and I have
>>found
>> > my problem.  I think my tank cap is WAY to small for my MOT power source,
>> > which will soon be a 4 MOT stack.  I have calculated (from
>> > http://home.earthlink-dot-net/~electronxlc/tccalc.html) that my tank capacitor
>> > should be 200nF at 8kV, 650mA, not 13nF.
>> > I would like to make sure that this is indeed a good tank cap size, so I
>> > don't go and make a huge poly capacitor for nothing (actually 3 in
>> > parallel).  Or would another type of capacitor be easier to
>>transport/make,
>> > or cheaper, or better?
>> >
>> > Needless to say I will need a very large topload, I was thinking about a
>>40
>> > inch toroid on top of a 24 inch toroid, for a total secondary capacitance
>> > of 77.6pF, with an inductance of 19.6mH.
>> > My primary inductance will be very small, however I have found that a
>>lower
>> > primary inductance produces brighter sparks that are slighly longer.  I
>> > will have 2 series static sucker gaps, until I can get a rotary gap.
>>More
>> > on my coil here
>> > http://hot-streamer-dot-com/chris/4inchcoil.html
>> >
>> > Are these good values for my 4.5 inch coil?  I expect a major increase in
>> > performace over my 12 inches of spark so far, but will they be around
>> > optimum values?
>> >
>> > Thanks!
>> > Chris
>> >
>> >