Re: tube coils

["Tesla list" <tesla-at-pupman-dot-com>]

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

In a message dated 10/10/01 10:44:12 AM Eastern Daylight Time, tesla-at-pupman-dot-com
writes: 



>
> Hello all, 
>
> Recently, I have been working late at uni and have therefore had the 
> chance to explore the piles of junk laying around. Last night I came 
> across a box full of literally HUNDREDS of vacuum tubes. Most of these 
> appear to be spares for our old x-ray diffractometer. Some of the tubes 
> are quite large (over 8" tall) and are rated at 150kV DC. Now, I have 
> no idea how tubes work or how to make a tube coil. What kind of tube is 
> required for tesla coil use. Will any tube do? I am allowed to have all 
> of these if I want them. I'm also allowed to have the old (from the 
> 50's or 60's) x-ray machine itself! I also found an old Hewlett Packard 
> computer tape drive cabinet from the late 80's. It will make a perfect 
> housing for the control circuitry for my pole pig. 
>
> Cheers, 
>
> Greg Peters 
> Department of Earth Sciences, 
> University of Queensland, Australia 
> Phone: 0402 841 677 
> http://www.geocities-dot-com/gregjpeters 



Hi Greg, 

Most of the big tubes found in Xray equipment of that vintage are rectifiers
rather than oscillator/amplifier type tubes. You could make a massive DC power
supply, but would still need the oscillator to produce the HF pulses. The only
other tube is usually the Xray tube itself, good for irradiating yourself and
loved ones, but not particularly good for TC work. 
If you really want to understand how it works, I would recommend "Fundamentals
of Xray and Radium Physics"  4th ed. 1967 by Joseph Selman, MD; pub. Charles C.
Thomas Springfield, IL, USA. It has lots of basic diagrams of how and why
tube-based XRay machines work. Another good source of information on machines
of  a little earlier vintage, but still useful is "Roentgenographic Technique" 
by Darmon A. Rhinehart, AM, MD, FACR; pub. Lea  & Ferbiger Phila. PA USA, 
1943. Both books were available on eBay and other www sources last year. If you
can't find the book(s) I can email some diagrams off-list. 
Hope this Helps, 
Matt D.