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Re: T-coil discharge


From: 	Tesla List[SMTP:tesla-at-stic-dot-net]
Sent: 	Monday, November 17, 1997 1:26 AM
To: 	'Tesla List'
Subject: 	Re: T-coil discharge

Steve Roys[SMTP:sroys-at-umabnet.ab.umd.edu]

From: 	Gomez[SMTP:gomez-at-netherworld-dot-com]
Reply To: 	gomez-at-netherworld-dot-com
Sent: 	Sunday, November 16, 1997 6:40 PM
To: 	Tesla List
Subject: 	Re: T-coil discharge

Tesla List wrote:

>>  I read with interest, your description of the discharge from your coil
>>  sometimes forming a long slowly moving single tendril.  I once built
 
> I have not seen this on either of my coils when using a toroid for the
> discharge terminal.  I have set a 6" dia aluminum foil covered styrofoam ball
> on the center of the toroid on the small 3.5" dia coil.  It sits up about 3"
> on a metal support right in the center of the toroid.  When first powered up,
> the discharges will wander around on the ball but after maybe 10 to 15
> seconds will finally start going straight up for maybe 16 to 18 inches with
> only short branches at the top.  It is interesting to watch.  I think the
> rising heat and no air movement (running in the basement) has something to do
> with it.  I would like to see this on my large coil - something that can put
> out 5 to 6 foot discharges, but I can only run that coil outside and have not
> tried it.

I saw this for the first time running my (previous model) of big coil at 
our haunted house last year.  We had the Encore Channel in there filming 
for their Vincent Price marathon trailer, and I ran it for one of the longest 
times I'd ever dared up to that point.  (because I felt that my spark gaps at 
the time was a bit anemic for this size coil, nevertheless, it came through  
with flying colors)

The "tree trunk" discharge showed up after about thirty seconds of 
operation. It was a thick, white, _hot_ (I found snail trails afterward on 
my toroid) streamer that hardly moved, and it extended longer and longer 
until it was about 4 feet long.  The brushes stayed about the same distance, 
so what I was seeing was the brush area getting smaller and smaller as the 
"trunk" lengthened.  I wanted to run it for quite a bit longer to see where it 
would stabilize or what would happen, but the director yelled "cut" 
(twice- I was enthralled with what was happening with my coil), and I had 
to shut it down.

I was amazed that the coil didn't destroy the RF remote control widget on 
their Steadicam- the camera contractor was pretty nervous about that.

If anybody saw this trailer last Hallowe'en season, it looked very nice on 
TV, almost like "fake" imagery because of the bluish halation around the 
arcs. (caused by using excessively long shutter times and very fast film 
for the very low light levels in the haunted house.)

OBTW, the coil was inside the HH, which was in an old K-Mart building 
with 14' ceilings (just barely high enough- it hits the suspended ceiling 
grid on a regular basis), so air currents were non-existent, which is nice.
I'd kinda hope we'd stay in there, because there was a back warehouse area 
with steel-reinforced concrete walls on four sides, steel roof, and 22' 
ceilings. *sigh*

-Gomez

-- 
Gomez: certifiable mad scientist, extreme fetishist, fiction dabbler, 
pyrophiliac, technomage, goth, faan, lighting designer, dominant 
pervert, and juggler of labels... http://www-dot-netherworld-dot-com/~gomez