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[Re: Just a brush]




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TO: Chris Taylor

Pretend you are a TV repair technician and you get paid by the number of TV
sets per hour your can repair.  The fastest way to resolve your problem is
substitution.  

Try to borrow a good cap from another experimenter and repeat your tuning
experiments.  This would isolate and possibly eliminate the cap as a source
of trouble.  You may have some leakage problems that is killing your system
performance.

A 30 ma transformer is quite possibly being overloaded by a .008 cap.  Try
using a value of .004 or .005 with a 30 ma transformer.  Another quick test
would be to keep your .008 cap and try driving it with a borrowed 60 ma
transformer to provide more current to charge the larger cap.

I presume you have tried the other tap locations on your primary -- you
mentioned a five turn optimal tap on the primary.  Try other locations with
a cap you know has good performance.

On a small coil a good place to start is by elevating the secondary
inductor such that the lowest turn on the secondary inductor is 1 1/2 to 2
inches above the primary inductor.  In many cases it will end up being 3-5
inches above the sec. inductor for best operation with the system running.

Tune for minimum smoke!

DR.RESONANCE-at-next-wave-dot-net



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> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-poodle.pupman-dot-com
> Subject: Just a brush
> Date: Thursday,March 06,1997 7:27 AM
> 
> Taylor, Chris CC wrote:
> > 
> > I have just recently completed building my first coil and fired it up
> > last night. To my utter disappointment all I got was a big racket from
> > the spark gap and little else.
> > 
> > I have a 15/30 neon with a six element spark gap and a plate poly
> > capacitor, (20 plates 10x8" with an 80 mil poly dielectric, theoretical
> > C=0.0085 uF). I haven't got around to placing the cap in an oil bath
yet
> > and it doesn't arc unless the gap separation is very large, the cap
then
> > arcs around the edges and I shut down and reduce the gap separation.
> > Would the cap be providing 0.0085 uF without the oil bath, I can't see
> > why not, it is my understanding that the oil is only used to provide a
> > better insulator than air around the cap.
> > 
> > The coil also has a 1/4" copper tubing primary with 15 turns spaced at
> > 1/4" in a saucer configuration, (30 degree). The secondary is 22 ga
> > transformer wire on a 2.8" PVC pipe with 840 turns, (22.5" long).
> > 
> > All I seem to be able to get from this baby is a small brush discharge
> > from the tip of the secondary wire, (primary optimally tapped at turn
> > 5). I have also built an 11 x 3.5" toroid which when attached does not
> > produce any discharge.
> > 
> > My questions to the lads are;
> > 
> > What sort of diagnostics can I perform to point me in the right
> > direction for larger discharges.
> > 
> > Have I missed anything, I have used a number of the circulating
formulas
> > to roughly size various components.
> > 
> > The coil is working but just doesn't seem the be very efficient. The
> > lowest turn on the secondary is in line with the inner turn of the
> > primary, do I need to lower the primary to get better coupling.
> > 
> > Is my secondary too long for efficient coupling, (H/W ~ 8.5) I have
read
> > this may be a bit large.
> > 
> > The addition of the torus increases the resonant frequency, do I
> > increase or decrease my tank capacitance as the secondary frequency
> > increases and how do I adjust the primary tap as the secondary resonant
> > frequency increases.
> > 
> > Any help would be greatly appreciated and will speed me on my way to
> > coilers nirvana.
> > 
> > Chris Taylor
> > Perth, AUSTRALIA

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