Re: [TCML] Variac Amps for a VTTC?

[carsten <cgz365@xxxxxxxxx>]

Thanks for the advice Shannon.  I'm well aware of the potential for serious injury and/or death with working with high voltage.  While not having any direst experience with working with TCs, I have many hobbies that do involve occasionally dealing with high amounts of current.  Home theater, night club DJ, IT professional, home owner... ;-)   That being said I do realize that a good bit of extra caution should be exercised and I do appreciate and respect the concern.


On the technical and practical end, I do have a few reasons for going the VTTC route.  First and foremost, I have been wanting to build a TC since I was a kid browsing my dad's pop-sci mags.  Now that I'm in my early 30's I have the time/money to make it a reality.  Secondly I am into the steam-punk movement and am rather tickled by the idea of a the retro cool wtf factor of a VTTC.  If and when i get it all tuned I would like to modulate it into a plasma speaker and possibly DJ off of it, but that's a topic for another thread.   I consider my self a rather smart individual, with a general thrust for knowledge and a slew of rather technical hobbies already.  Computer science, amateur astronomy, home brewing, home theater, and hot-roding just to name a few!  I'm no stranger to late nights on a work bench or copious research for sure.

That ebing said, im probably crazy as well, but im sure that goes for half the people on here!




________________________________
From: Weinhold Shannon L <Shannon.L.Weinhold@xxxxxxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Wednesday, May 11, 2011 3:05 PM
Subject: RE: [TCML] Variac Amps for a VTTC? 

My advice would be to start with a smallish spark gap coil and to work with that until you have a through understanding of general coiling theory and optimization and most importantly - safety,  before you jump in on a vacuum tube project. Not knowing what your experience is with high voltage, I can't really guess what you know of the safety habits that you must develop when working with it. I only know that when I made my only mistake with high voltage, I was happy that it had occurred with a small current limited NST with the variac at very low voltage, because if it had happened with a MOT it probably would have killed me. And until you have such an experience its hard to appreciate the care you must take at absolutely every moment when you are dealing with the primary circuit of a coil. A MOT absolutely has the potential to be a life taking apparatus, even at a low voltage input, and especially when combined with a tank capacitor. And if you
 make such a mistake your death will likely be very painful and very messy. 
Not to scare you off from coiling, but vacuum coils are quite complex, and they are inherently much more difficult/dangerous to build & tune than a spark gap coil built with a current limited nst. And really spark gap coils perform much better in terms of streamer length with much less input. 
They are more of a specialty type coil, unique for their sword like streamers and high frequency, and in my opinion should be reserved for more advanced coil builders. 
If all of this is redundant and you're some high voltage technician/engineer/electrician, please excuse this post. 
Otherwise I highly recommend starting out with a spark gap coil. There is a lot of weird physics involved in coiling, most quite counter-intuitive, and I know that if I would have started out with a vacuum tube coil I most likely would have abandoned coiling all together because of the
 combination of the lack of basic knowledge that naturally comes about with your first coils and the added complication of tube coiling. 

Whatever you choose to do, be safe and best of luck on your coiling adventure. 

Shannon Weinhold




-----Original Message-----
From: carsten [mailto:cgz365@xxxxxxxxx] 
Sent: Wednesday, May 11, 2011 10:19 AM
To: tesla@xxxxxxxxxx
Subject: [TCML] Variac Amps for a VTTC?

I'm working on my first coil and plan to use 1-2x MOTs in series with 1-2 GU-81m tubes.  How big if a variac do I need @120vac?  I'm guessing a minimum of 10A, but probably 20A to be on the safe side.  What woudl be the requirement for 1 MOT vs 2?

Thanks!

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