Re: Scroungein' (fwd)

• To: tesla-at-pupman-dot-com
• Subject: Re: Scroungein' (fwd)
• From: Hollmike-at-aol-dot-com (by way of Terry Fritz <twf-at-verinet-dot-com>)
• Date: Sun, 18 Apr 1999 14:08:10 -0600
• Approved: twf-at-verinet-dot-com

> 
>  Project 1
>  Design Goal: To produce 5' discharge from a 120VAC <20Amp input.
>  Secondary size: 25" X 4"
>  Secondary winding: 26 AWG? (any ideas?)
>  Secondary form Schedule 40 PVC 4" pipe with glued on endcaps
>  Winding method: Lathe....BIG lathe.
>  Primary winding: 1/4" soft copper tubing
>  Primary form: Flat helix?
>  Primary size? Number of turns/spacing????? any ideas?
>  Caps: Where can we get some? What size do we need? How long will they 
>  last? We need rock-solid-reliability.
>  NST: 15KVAC -at- 30mA
>  Variac: ? what size do I need 20A?
>  Spark Gap:Static (no shrapnell) possibbly the Quick model
>  Torus: ?? biggest possible?
>  Anything else? What am I forgetting?


Two comments:
1)  A flat, or Archimedes spiral primary and a helical primary are entirely 
different.  Your secondary is helical.  In either case, you should keep about 
.25 inch spacing between turns.  As for the number of turns, that depends on 
your primary cap.  It can be calculated by setting LpCp=PsCs and using the 
Wheeler equation(rearranged) to estimate the required number of turns.  
Always add in a couple of extra turns to be sure that you can tune the system 
or make modifications (like adding a larger toroid).
2)  A 15/30 neon will only draw about 1000 VA, so an 8 amp variac is 
adequate.  You will not likely get 5 foot sparks with this amount of power(if 
you do, tell us how you did it).  I would use the wire gauge necessary to get 
about 1000 turns.  That seems to be what the concesus says is about right, 
although not an absolute.  24g wire also seems to be the popular choice for 
that size secondary.
>  
  <snip>
> There may be a Faraday cage in the HV room for viewing, if this can 
>  be done with ABSOLUTE safety to persons/ cameras inside...any ideas?
>  
>  
It sounds like you have some big plans.  The Faraday cage is not a bad idea,  
just make sure it is well grounded.
IMO, you should first get the small coil built and running well before 
embarking on the bigger projects.  You should have a clear understanding of 
how to build, tune and operate them before getting into such high power 
systems.   
Mike

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