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@xxxxxxxxxx> 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@xxxxxxx 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@xxxxxxx 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@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
>> Behalf
>> Of Sfxneon@xxxxxxx
>> Sent: Tuesday, May 27, 2008 12:10 AM
>> To: tesla@xxxxxxxxxx
>> 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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