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Re: my mini coil that doesn't work



Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 11/24/01 12:22:13 AM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:

> I've been working on my mini coil for a while now and i just can't seem 
>  to get much performance out of it. the best I can do right now is 5" 
>  arcs to ground with 15/30 input. here are the specs.

Robert,

Everything looks fine pretty much except that it's probably better
not to connect the secondary to the bottom turn of the primary
because this puts 60Hz AC on the secondary which is a safety
hazard when a midpoint grounded NST is used.  The use of the
small value cap will limit the spark some, yet I've obtained 13"
sparks with a 0.0015uF cap with a 230W OBIT.  (You do mean
0.0015uF, not 0.015uF?)   Since you're tapped at 5 turns, this
makes me suspect you're using a 0.015uF cap ??  How does
the coil sound; steady, smooth, and hissy?  Or does it sound
clattering, and unsteady?

The TCBOR gap should be fine.  I assume you've tried using
various numbers of series gaps, and various spacings.  The
gap pipes must be kept clean or the output will shrink.  The
1000 turns of 30awg wire and the primary both seem fine.  I've
never tried a small secondary like that, so it's hard for me to
judge what it's capable of.  I would think you should be able to
get at least a 13" to 15" spark, if the cap value is 0.0015uF.
A larger cap value can give longer sparks.

I assume you've arced both sides of the NST separately to
ground to verify the NST is good?  (Danger, use proper
safety methods for this.)

If you're getting a lot of small streamers from various places
on the toroid, then a smoother toroid may be of some benefit.
Can I assume the sparks break out without being drawn off
the toroid using a ground rod?

Cheers,
John

>  
>  capacitor: .0015 geek mmc bank
>  
>  gap: tcbor gap cooled with 120 cfm fan hooked up to variac. (the fan 
>  improves performance a little, but not much.)
>  
>  topload: small dryer duct bent into a torroid and covered in aluminum tape.
>