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Re: Refining 10kv -at- 23ma

Subject:  Re: Refining 10kv -at- 23ma
  Date:   Fri, 23 May 1997 19:35:49 Eastern Daylight Time
  From:   "Mad Coile{" <ts5815-at-devrycols.edu>
    To:   Tesla List <tesla-at-pupman-dot-com>


>Subject:   Re: Refining 10kv -at- 23ma
>  Date:    Thu, 22 May 1997 11:46:20 -0400 (EDT)
>  From:   FutureT-at-aol-dot-com
>    To:   tesla-at-pupman-dot-com
>
>
>>snip>
>> What I would appreciate any input on would be;
>> Is this level of output good, average or paltry? I know I can get more
>> if I simply start adding neons (thanks Chip :) but I am really
>> interested in maximizing EFFICIENCY, what is the absolute most I can get
>> out of a two coil system without simply throwing more power at it. Is it
>> time for a rotary? (I am of course, looking for an excuse to build one) 
>> Also, can anyone reccomend a reasonable Safety Gap width for this power
>>level? I rather like my tough little OBIT, and I dont want to cook it.
> 
>> Thanks
>  >>
>
>Chris,
>
>You're getting good results from this coil.   I have built 
>a similar coil and have obtained an absolute max output 
>of 13" to a ground wire.   You definitely don't need a rotary
>at these power levels, if fact oil burner and neon transformers
>tend not to work well using nonsynchronous rotary gaps.  
>They work well using synchronous gaps, but a rotary is just 
>not needed at this power level.  Some people do use non-sync
>rotary gaps with multiple neons.  I would set the safety gap
>so that it fires occasionally.  BTW, I only get the 13" spark 
>when I connect the transformer to a 140 volt "step-up" type 
>variac, without this higher input voltage I get shorter sparks, 
>but I haven't measured the output at a normal 120 volts input. 
>Unfortunately, if you want max spark output from these
>transformers you have to abuse them a little ( higher input 
>voltages, and wide spark gaps).  This can lead to a short
>transformer life.
>
>I am also very interested in trying to obtain max efficiency 
>from my coils, and most of the work I'm doing lately is towards 
>that end.
>
>Here are the specs for my coil in case you are interested or
>want to compare:  trans--10kV, 23 ma, oil burner type. 
>secondary is 3" by 12" polystryrene form, #28 formvar wire.
>Primary is 21 turns of 8281 video coax cable at 40 degree 
>angle.  Capacitor is 0.0015uF mica.  Spark gap is a simple
>4 gap static gap with 1" silver faces, no air.  The set-up was
>somewhat cobbled together with clip leads, etc.  The 5" x 1.5" 
>toroid was made from the bottom of two 1 liter coke bottles 
>taped together and covered with aluminum foil.  Adding the
>toroid, if I remember correctly, gave me about 1" extra spark
>on this coil.  
>
>I have a couple of questions for you;  do you use a toroid, 
>and do you use a 140 volt input variac?    Hope some of this 
>is helpful, and I'd be interested to hear how your project 
>comes along.
>
>John Freau
>
>
>
>

John, sorry to jump into your conversation but I was wondering. How did
you
calculate your capacitance, my resources say you should be using several
times that capacitance for your oil-burner trans. I say this because I
also
am using oil burner trans for my small coil, and wonder if I am off to
much
in my figures. One OBIT = about .006uF in my calcs and two OBIT's (what
I
use) need about .012uF although I have found that with two OBIT's, I
have
some really weird effects happening when I switch from .006 and .012 -
but
both discharge about the same after retuning.

T Stewart