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Weird Phenomenon from Jacob's Ladder last night.

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MikeT1982

Sun Jul 10 2011, 01:50AM

Registered Member #621 Joined: Sun Apr 01 2007, 12:37AM
Location:
Posts: 119

Hey guys, i haven't been on here for quite some time but last night i was bored and decided to fire up my jacobs ladder i have in the garage. It consists of an old GE 9kV 60mA NST with a home made coat hanger V that terminates with a 3.5" or so gap and a small Garbriel's starter elctrode that i have sitting ontop of the transformer and consists of a finnishing nail in a small block of wood with a very high ohm resistor attached. So the ladder will start it's own arc every time the previous arc finnishes. I think the inductance kickback of the main arc breaking is what triggers the garbriels to arc again. Depending on the humidity, i have to slide the gabriels closer or further to get a nice arc per 2 seconds or whatnot.

Alrighty so anyways, i foudn a small 12 inch long fluorescent tube and decided i wanted to hook it to the NST to see what would happen. I grabbed a set of very crapy test leads that consisted of 18 gauge speaker wire with aligator clips on the ends (perfect for 9kv right!) LoL. I was expecting arc over and all kinds of cool stuff, but that's just part of the fun.

So i connected one lead to each side of the NST but left my ladder inplace. I then left the leads hanging to see how they woudl handle the high voltage. I plugged in the old NST and i the ladder was VIOLENT! Like much hotter arcs and actually so much so that the gabriels electrode arced through the wood block. and started burning! SO i pulled the power and was left wondering what the hell just happened. I didn't even conect the fluorescent tube or allow the alligators to arc, however i could hear the 3 foot long run of speaker cable sizzling while it was energized.

Did i just experience capacitance or inductance or something, the wire was pretty straight, not coiled or anything. If this is happening at 9kv, how the heck do power transmission lines deal with this, and does this pehenomenon, whatever it was, have anything to do with the banks of capacitors i see every so often on telecphone poles randomly through the neighborhod....i see some sort of connection and i:m kind of guessing but can someone explain what was happening? Thanks a ton!

Mike

Chip Fixes

Sun Jul 10 2011, 03:53AM

Registered Member #3781 Joined: Sat Mar 26 2011, 02:25AM
Location:
Posts: 701

I don't know enough to answer your question haha but if you wouldn't mind posting a picture of your "arc starter" that would be great! It seems like a really neat idea and I wouldn't mind seeing a picture

Dr. Dark Current

Sun Jul 10 2011, 10:13AM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

Might be capacitance to ground, which could give a more "buzzy" sound to the arc especially before it breaks on top. Could also explain the melted starting electrode as the capacitance can make it harder for the arc to start.

MikeT1982

Sun Jul 10 2011, 11:11PM

Registered Member #621 Joined: Sun Apr 01 2007, 12:37AM
Location:
Posts: 119

Oh neat @capacitance to ground. Yeah i was amazed at a very noticeable increase in the loudness and brightness of the arc. I am really suprised at how well this bare bones setup work. i measured the top of my coat hanger arc last night and it is exactly 4". The arc almost always makes it up there, where i bent an even further rounded flair and then the little started electode fires a sim spark to the opposite ladder's arm (the NST is the kind with a pair of big insulators, one on the right and one on the left and i have the coat hangers bolted right onto them. I have no base even for the transformer which must weigh 30lbs. It is old, ugly, and rusted. I have a cut off vaccuum cleaner cord without ground running to the 120v input which is also an open insulator/bolt ceramic block. So anyways, i used a single coat hanger and clipped off with a wire clipper, the part where it is twisted and becomes the hanging arch leaving me with all available wire. I then cut it exactly in half at the bottom so i had two pieces and then bent each one to form the ladder whcih starts at 1/4 inch at the bottom and expands to 4" over a distance of probably 9". It wills it there and hum when plugged in, so i would start each arc climb by placing a scredriver breifly and removing it inbetween the two coat hangers to create a kickback and the arc would climb very nicely! But i would nto start itself. So i read somewhere on a site about the "Gabriels starter electrode" which this fella nicknamed it. So i took a 1/4" thick peice of wood that measures 2" by 6" and partly drove a baby 1" 22 gauge finnishing nail into it. then i stripped the insulation off of about 3 foot of 22 gauge wire and wrapped a coil around a sharpie to act as just a flexible wire, yet hold itself off of the metal transformer's case (why i coile dit) but i suppose it has become an inductor too as it jumps each time the arc starts adding a cool motion effect! So i then dug through my junk box and found a big ceramic 10 watt 15k ohm resistor. Now 9kv at 60mA is around 540 watts i think! The resistor gets hot, but it only sparks the gabriels once every 3 or 4 seconds so it has survived kind of continuos duty (i only run for a miniute or so at a time when i need a power fix LOL!) The resistor is wrapped around the right bolt on the NST just like the right jacob's leg. It hangs under its own support, and to it's other end is wrapped the end of the 18 gauge wire coil (the coil si about 4 inches long with about 4 inches of straight wire that is stapled to the block of wood to hold it and then wrapped around the finnishing nail. I started by sitting the block with the gabriel's ontop of the transformer and plugging in the NST and having it hum but do nothing, and then i used a well insulated screwdriver to slowly push it closer to the middle of the 1/4" gap at the bottom of the ladder when finally at about 1/8" away (not directly between the bottom of the ladder, it jumped to the left leg and started the arc. The Garbeil's arc immediately goes out when the main arc starts and when the main arc gets tot he top and breaks it starts the whole cycle over again with the gabriels arcing and extinguishing and the main arc starting! Once in a while there is a lag time after the main arc breaks. If it is too slow or not working i just slide the gabriels over closer. It seems to work just as well if i put it over next to the left jacobs arm rather than in the middle. Either way it only arcs to the left arm. I would highly reccomend leaving the garbiels free to slide around..this thing is not consistant LoL...as some nights i'll fire it up and it will arc way to fast and the main arcs wont make it tot he top. I suppose it is the humidity that makes it vary so much! The arc is intense enough with just 9kV and 60mA that i can get a strong whiff of ozone. When i hooked the speaker wire leads to the 9kV bolts the other night the ozone smell went through the roof when i was experiencing the capacitance effect or whatnot. OHH!! Something else, i took a screwdriver and jumped over the resistor to bypass it and see if it is really needed to slow the current flow to the gabriels and it sure as heck is! What happened was everytime i bypassed the 15kOhm 10 watt ceramic resistor was a very hot arc would jump fromt he gabriels to the left fabriel leg coat hanger and sit there and just arc untill the nail and spot on the gabriels turned red hot. The main arc would never even start when the current limiting resistor to the starter nail is taken out. So yes the current limiting is necessary to make a weak starter arc and then i think the 60HZ swing in the NST secondary gets an inductive kick up from the gabriels arcing and then gives enough boost to arc over the lef tto right jacobs leg and then once the current sees that low resistance hot arc it says to hell with the Gabriels and starts riding up the hot air all the way to the 4" break point! It will not make it further than 4" i tried and that was max and makes me very happy.

Soooo...i have no camera now, as soon as i do i'll find this post and update it with a picture and video if this site allows it! Very simple fun machine! I got the NST for free, actually all parts were free!

Adam Munich

Mon Jul 11 2011, 04:17PM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Holy wall of text! <br/>
<br/>
Use line breaks man!

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