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2x9 secondary



    Hi all,

 Got bored (and in a *very* bad mood) this afternoon, so I set up a
2" secondary on my testbed to relax myself.  Today, I finally set a
mark of achievement for myself, though I don't know if I can repeat
it (I'll certainly try!)

  Using a 9/60 NST, 3 strings of 13 caps, and a 2x9 secondary wound
with 32 gauge wire.  Async gap -at- ~400-500 bps, and a 4" metal
sphere for a topload (smooth polished).  After a little tuning and
fiddling with a 3" sphere on top, I slapped the 4" sphere up there,
moved my tap out 1 turn, and let 'er rip.  I must have hit the
sweet spot dead on, 'cause there was very little flashover, and
great big 20-24" streamers comin' off the thing.  I scared myself
silly, being as I was only about 3-4' away.  Note to myself, be
back a little further.  I moved myself (and the relay and variac
for the DC motor back a bit), and tried it again.  Again, I got the
big strong streamers off of this thing.  At one point, I had 3 good
10" streamers roaming around, and they started to converge at the
top, but I guess a breeze disturbed it and it started wandering
again.  Darn!!!  I ran it a good 4-5 minutes, till I couldn't stand
the noise and figured I'd messed up the TV's bad enough.  The caps
were slightly warm to the touch, but otherwise fine.  But my tank
wiring (10ga PVC 600v wire) was really warm to the touch, and my
primary tap (1/4" fuse holder!), was downright scalding.  The
primary wasn't detectibly warm, nor was the secondary.
   I varied from low bps (~120, saftey gap firing about half the
time), to full wide open (~530 bps).  At high bps, the sparks got
really frantic when moving, but if they settled, or I used a
breakout, they'd visibly grow as I ran the speed up.  Maybe 10%
from 120bps to 500+bps.  I'll re-assemble a sync motor tomorrow and
run it at 240bps if I have time to compare the setup.  But wow
man...I couldn't believe such huge arcs coming off of that thing!!!
It's this teeny little form, a cutesy little 1/4" copper tubing
primary, and a sorta-beefy 9/60 NST.  And a gap that sounds like a
tablesaw eating through steel.  Punctuated by really sharp cracks
as the saftey fires.  And these bright blue-purple arcs wandering
all over.  I got a few hits to the plexi shield over the primary,
and a few strikes the primary tap lead till I tucked it down out of
harm's way.  All the rest of the stuff was down out of the way
(including the DC motor, once I saw how long the arcs were
getting), so nothing got "zapped" tonight.

   I checked the setup before I broke it all down and put it away.
The secondary is set up so it'll be coupled exactly the same next
time I run it.  Maybe I can raise it a tiny bit to cure the little
flashovers I had.  Then again, I should really tune it a bit better
(I didn't touch the tune once with the 4" sphere on it).  A baffle
in the secondary would be a good idea, as I'm running the ground
wire on the outside, and have the sphere sitting in the end of the
open secondary.  I'd hate it to arc over internally and ruin the
form.  BTW, I checked my ground (from the 120v line, and I'm
pulling 118v to my ground (and 118v to the other side of the outlet
:), and only ~10-20 ohm from house neutral to my ground.  I'd
suffice it to say it's a good ground :)  Wonder what my 15/30 would
do on this......Need to string more caps...Hey, I just happen to
have a whole bag and a half of those Panasonic caps here!  Imagine
the good fortune!!! Look!  Solder!  and a soldering iron!  Perf
board!!!  Hmmmm.......all I need is some double-sided copper-clad
board (for mounting the finished strings) and I'm set.  I'll try to
charge the video camera and get some footage tomorrow.

  A thought I just had...I've a nearly-identical secondary, so
maybe I'll try a magnifier setup?  Hmmm....The freq. of both coils
together would drop down really far.  I'd have to tap outwards, but
I'm on the next-to-last turn on my primary.  Add capacitance?  Add
inductance?  Splicing on more primary turns isn't too feasible, as
I'm out of space on the cutting board.  Maybe re-wind a vertical
selenoid for the magnifier setup?  I figure I'll need double the
inductance I have now...probably and then a little... :)  I love
when a plan comes together.   I'm off to do math and assemble PVC
tubes :)  Caio!
                                                            Sundog