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Re: Pipe scraps

>>From Benson_Barry%PAX5-at-mr.nawcad.navy.milMon Oct  7 21:40:08 1996
>Date: Mon, 07 Oct 1996 07:03:00 -0400 (EDT)
>From: Benson_Barry%PAX5-at-mr.nawcad.navy.mil
>To: tesla-at-poodle.pupman-dot-com
>Subject: Re: Pipe scraps

>Robert,
>Experienced indeed!  Such efficiency.  52" with 900 watts!  Way!
>Awsome!  What are the specs on your micas (series, parallel, individual 
>value?)
>I heard that you use really big chokes on your neon to protect it.  How is 
>it
>holding up?  How long have you run it?  What brand of neon do you have.
>Is it new or used.  Primary, flat spiral or dish or?
>
>I used two 5kv photocopier transformers with a grounded center arrangement
>which use about 2400 watts (using the 20 ampere breaker test).  I don't
>know the number of turns but it has 5 lbs of #18 heavy formvar magnet
>wire on it with .065uF polyproplene capacitor with a rotary gap.  I think
>that the dent may be a detriment.
>Barry


Barry,

This 52 inch distance claim is for the very occasional streamer that actually 
does make it this far out to a flat grounded metal sheet.  Most of my 
streamers will strike such a target much more frequently at 42 
inches.  Still, I am impressed with even this for a system that stores 
less than 1.6 peak  Joules in the primary circuit.  With 15 KV RMS divided 
by the capacitive reactance of the 0.007 mfd system cap my charging 
current is actually only _ 594 watts_!

My micas are 30 pieces of 0.002 mfd -at- 12400 Volts peak, in three 
parallel banks of ten in series, yielding 0.0067 mfd -at- 37,200 V peak. 
I had two of these go intermittent recently causing the coil to work 
less well, then well, then less well.  I actually had to build a 
small tesla coil that would run on a single one of these 0.002 caps 
and use it to test, one at a time, all thirty after disconnecting 
them by removing all the copper bus strapping..  They all passed the test the
first time around.  I raised the voltage and tried them all over again.  
Two failed to dead short mode almost instantly.  I replaced them with 
spares that also passed the more extreme test, put the bank back together 
and now no more trouble.  Took me over four hours to find and fix 
this though.  Someone posted a great information post about different 
capacitors a while back (I think Richard Hull?).  Said micas were 
lossy but their redeeming social value was that they could withstand 
the great heat that their loss generated, and that mica has a good 
high dielectric constant.  This bank of micas certainly works very 
well in this particular coil.  I only went to this much trouble 
because caps are hard to find and I found this great lot of micas for 
$5.00 each, which still put me in fair shape compared to the cost of 
a single made to order commercial tesla cap.

My primary falls under 'other'.  It is a two layer short solenoid 
with about 1.5 inches between layers.  Total 24 turns, 12 per layer.
My system tunes at about 16 turns.  It's wound with #8 AWG PVC 
covered stranded wire. 

Yes, it's true what they say.  This kid uses large value air core 
chokes.  This coil has a 320 mH choke in each leg of the Jefferson 
neon.  Run times are as long as 2 minutes per run.  I've accumulated 
maybe 1/2 hour total run time on this system without transformer failure so far.
I also run a blunt needle point safety gap across the transformer output 
gapped at 1.125 inches, it fires every several seconds or so.

Toroid is a  3 X 24 inch commercial, smooth aluminum Hydro corona hold 
off ring.

You can see a single photo of this small system in picture stc01rws.jpg in my
file at ftp://nic.funet.fi/pub/sci/electrical/tesla/pictures/rws.
The donut topload in this photo is a smaller 3 X 18 incher.

Sounds like you are using the same photocopier transformers that Jeff 
Parisse <jparisse-at-ddlabs-dot-com>  is experimenting with.  You might want to
touch base with him.  As a matter of fact, I just sent Jeff a pair of 
my Mega-Henry brand RF chokes for his coil.
 
regards,

rwstephens