Re: Safety Considerations

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Sundog <sundog@xxxxxxxxxxxx>

Hi Chris, All,

The 813 is a good tough tube to run a VTTC on.  Some advice,

Bring it up with a variac.  Makes it easier to tune without blowing 
anything up :)
A dedicated RF ground is a good thing to have.  I've run small VTTC's 
using the third wire to ground the secondary, but never on a powerful coil.
VTTC's can put off a goodly amount of RF trash.  Don't run it next to 
any solid state devices you care about.  I'd take the watch off while 
playing with the coil.
As an aside, I'd remove all rings and earrings too.  I accidentally 
induction-heated my 3 earrings (stainless hoops with steel balls that 
clip in, looked like a shorted turn) while adjusting the filament 
voltage on a running 2kW VTTC.  No bad burns, but *very* uncomfortable.

Don't touch the sparks!  You can't feel the high frequency, but it's 
doing damage. RF burns follow the nerves and blood vessels.  Takes 
forever to heal and can get infected at the drop of a hat.   The 
output can easily set stuff on fire.

If running the coil in your garage, unplug the garage door opener, 
and tuck the antenna wire up into it.  Wrap it up in tinfoil 
(grounded) for good measure.  Never had to replace one myself, and I 
hope never to need to.

I'm currently working on a solid state device to drive the grid of a 
VTTC.  Still in the experimental/testing stage, but it looks very 
promising.  Does away with the grid leak network, and allows the tube 
to run in pulsed mode.  Lowers the duty cycle so you can abuse the 
tube even more than staccato allows :)

Got any pictures of your setup?

Shad H

At 08:45 PM 8/1/2005, you wrote:
> Original poster: "Chris Fanjoy" <zappyman@xxxxxxxxxxx>
>
>   After months of work, my VTTC is almost ready to power. But 
> before I prepare to bring it to life, there are a couple of 
> important safety issues I'd like some info on.
>   First of all, some specs: the coil uses two 813 tubes, powered by 
> a (massive) MOT and voltage doubler. Frequency is 157KHz, and the 
> expected spark length is anywhere from 1-2 feet. It will be run by 
> a staccato controller, rather than continuous wave. Currently I do 
> not have a topload on the secondary, save for a long bolt to which 
> a toroid could be attached.
>   Question 1: what precautions should I take to protect nearby 
> solid-state devices? (TV's, VCRs, my wristwatch, etc). Is it enough 
> simply to keep them a good distance away, or are other precautions needed?
>   Question 2: how hazardous is the output of the secondary itself? 
> I know very well that the primary side carries lethal current and 
> must be avoided at all times. But I've seen pictures of people 
> touching the sparks from their coils, and this looks very 
> fascinating to say the least. I actually tried it with a small, 
> crudely-rigged VTTC a few months ago. It used a single 6146 tube 
> powered by a 400VDC power supply. The spark was only about 1/2" 
> long, but was run continuous-wave since I didn't yet have a 
> staccato controller. Curiousity got the better of me and I just 
> *had* to touch it and see what happened. It was a new, and exciting 
> experience, to touch a high-voltage arc and NOT receive a painful 
> shock! However, because of the CW operation, it would quickly start 
> to burn my fingers if I held them in place too long.
>   So before I go touching the sparks on this thing, I'd like to 
> advice on safety first. And I'd also like to know how to keep my 
> other gadgets from getting fried as well.
>   Thanks for any advice.