Re: Vacuum Tube Tesla Coil Design (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Tue, 25 Sep 2007 18:06:24 EDT
From: FutureT@xxxxxxx
To: tesla@xxxxxxxxxx
Subject: Re: Vacuum Tube Tesla Coil Design (fwd)

 
In a message dated 9/25/2007 3:58:30 P.M. US Eastern Standard Time,  
tesla@xxxxxxxxxx writes:
 
Brad,
 
There's not really much information available.  You may want to copy  an 
existing
design that works well.  There are designs such as Steve Ward's,  Cameron
Prince's which is based on Steve's I think, and others.  I show  some VTTC
work I did at my website at:
 
  _http://hometown.aol.com/futuret/page3.html_ 
(http://hometown.aol.com/futuret/page3.html) 
 
Click on tube coils or VTTC's.
 
For VTTC's, it's not enough to have the primary tuned to the  secondary.
The ratio of tank inductance to capacitance is also important because
it affects the matching of the tube to the tank and affects  efficiency.
It's not super-critical as to the exact ratio, but should be within a
suitable range.  Power transformers for VTTC's should have no  current
limiting.  MOT's have some current limiting shunts but work OK  anyway in a 
VTTC.
Removing the shunts will increase the spark length.  The current  draw
in a VTTC is controlled by the circuit parameters.  I usually put  the
vacuum tubes in parallel rather than bother with push-pull.  The  more
tubes are put in parallel, the lower the primary inductance can be.  
There are some rules of thumb and formulas at Steve's site which are  
helpful.  
 
VTTC's are especially dangerous because of the non-shunted
transformers.  Follow all safety rules.  VTTC's are power  hungry.
Spark length relates to power input according to :
 
 spark length (inches) = 0.5*sqrt input power (watts)
 
The formula is approximate.  The use of Staccato (pulsed)
operation will increase the "efficiency" greatly of course.
 
John
 

Hello  everyone,

I posted a while back about a batch of 4-400  tubes I was gifted. I also 
have a stack of MOT's in good working order. I  would like to design a VTTC. 
I've found many sites and a few programs that  help with the design of 
standard spark gap type coils, but none really  mention VTTC's directly. 

I realize that a lot of the  calculations will remain the same. However, are 
there any formulae that I  should know about specifically for designing a 
VTTC? 

Are there any sites about the design of VTTC's?

Thank  you,
Brad







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