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Re: Refining 10kv -at- 23ma

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