[TCML] Climbing Arcs

Tue May 27 21:58:00 MDT 2008

I have a 20's vintage X ray transformer, oil filled and weighs about 
300 pounds. It has a built in reactance coil. It runs on 220V
On 110, I could produce a very HOT Jacob's ladder with the peak being 
about 10" apart and the inverted V or the arc was over 8" tall.
I used coat hanger rods and it made a beautiful display.
I tried some larger dia tubing and the arc would not travel the full 
length. A lot of times it would stop part way up and the arc would 
remain stationary. I had to fan it with some paper to get the arc moving again.

Conduit is not a good choice for another reason, it is usually 
galvanized and the arc will burn the coating releasing zinc fumes 
which are quite toxic.
Frank

At 08:40 AM 5/27/2008 -0700, you wrote:
>Tony:
>
>Do NOT use the 3/4 inch conduit tubing.  Use 1/8th inch stainless
>steel rods.  The smaller dia rods strike easier and do not conduct the
>heat away as fast as the 3/4 inch conduit.  Result is a better
>climbing arc the performs well without re-striking all the time.
>
>Dr. Resonance
>
>
>
>On 5/27/08, Bert Hickman <bert.hickman at aquila.net> wrote:
> > Hi Tony,
> >
> > Some suggestions:
> >
> > 1. Use a wide "V" to more rapidly spread the arc. The higher the current
> > the wider the end gap should be
> > 2. Use inductive ballasting for best performance
> > 3. Use smooth rails to avoid incandescent "hot spots" that will cause
> > the arc roots to temporarily hang in one spot. I'd recommend using 3/4"
> > hard copper pipe or non-magnetic stainless steel tubing. Periodically
> > remove any oxide buildup. I suspect the oxidation of the galvanizing may
> > a major part of the problem you're seeing.
> > 4. Enclose on 4 sides to reduce disruption by air currents. Leave top
> > AND bottom portion open to permit vertical air flow. Be sure to leave
> > plenty of clearance on either side of the gap, especially for a higher
> > current ladder.
> > 5. For grins, try connecting a small (500 - 1000 pF) HV doorknob cap
> > across the gap to make for "snappier" performance at start and at long
> > arc lengths.
> >
> > Good luck,
> >
> > Bert
> >
> > Sfxneon at aol.com wrote:
> >> Hi Ken,
> >>
> >> You're right, the arc climbs because it's hotter and less dense than the
> >> surrounding air. I've had no problem making the small NST powered ones
> >> work, but
> >> at higher currents the middle of the arc tends to rise faster than the
> >> ends.
> >> It  grows in length but hardly ever makes it to the top of the rails, even
> >>
> >> when set  close. It seems to get stuck along the way and doesn't want to
> >> climb
> >> smoothly.
> >>
> >> Does anyone know if the smoothness of the rail's surface or the zinc
> >> coating
> >> would have anything to do with it?
> >>
> >> Thanks,
> >>
> >> Tony G
> >>
> >> In a message dated 5/27/2008 8:47:52 A.M. Central Daylight  Time,
> >> kwillison2 at cox.net writes:
> >>
> >> I never built a really large one. I have however observed that any  air
> >> movement across the ladder will disrupt the arc. Conducted some
> >> experiments
> >> tilting the electrodes from vertical it would not work beyond 30  degrees.
> >> The curve of the arc remained vertical while the electrodes were  tilted.
> >> I
> >> surmised that heat causes the arc to rise and heat raises  vertically so
> >> won't work when it passes about 30  degrees.
> >> Ken
> >>
> >> -----Original Message-----
> >> From:  tesla-bounces at pupman.com [mailto:tesla-bounces at pupman.com] On
> >> Behalf
> >> Of  Sfxneon at aol.com
> >> Sent: Tuesday, May 27, 2008 12:10 AM
> >> To:  tesla at pupman.com
> >> Subject: [TCML] Climbing Arcs
> >>
> >> Hi All,
> >>
> >> I have a  spare 12.5 kVA/20 kV bombarding transformer and sliding choke
> >> with
> >>
> >> which I'm building a large Jacob's ladder using 3/4" x 10' EMT  conduit.
> >> It
> >> works reasonably well, but the arc tends to rise up the  rails too slowly
> >> and
> >> the
> >> middle of the arc outruns the ends, resulting in  a restart before it
> >> reaches
> >> the  top. I've adjusted the angle of the  rails from near parallel to
> >> about
> >> 18" apart  at the top, without much  success.
> >>
> >> Does anyone know how to tweak the performance of a big climbing  arc so
> >> that
> >>
> >> it will climb to the top of the rails more often? I'm  guessing that
> >> increasing
> >> the air convection around the arc would help it  to climb, so will
> >> inclosing
> >> it in a tall clear tube or box make a  difference? Does the material  that
> >> the
> >> rails are made of have any  effect? How about the ballasting  of the
> >> transformer, as far as  inductive or resistive, etc?
> >>
> >> Thanks,
> >>
> >> Tony Greer
> >>
> >>
> >>
> >>
> >> **************Get trade secrets for amazing burgers. Watch "Cooking with
> >> Tyler Florence" on AOL Food.
> >> (http://food.aol.com/tyler-florence?video=4&?NCID=aolfod00030000000002)
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> >
> >
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