[TCML] Climbing Arcs

[Sfxneon at aol.com]

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)