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Registered Member #1225
Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253
Gah, nevermind, you already mention Gabriel electrodes
But i will still say, i suggest trying a Gabriel electrode. You have *no* resistors? It does not have to be a big high quality one, just one that won't vaporize if you drop close to 2kv for a short amount of time. A 1w resistor would probably work, the arc from the Gabriel electrodes needs not be high voltage or current.
EDIT: You can't use a voltage doubler for drawing arcs or a jacobs ladder without limiting the current, or the capacitors will discharge all at once, making loud sparks instead of a constant arc. A doubler with a limiting resistor would would, but you would need a big resistor, and you would waste a ton of power. A high voltage inductor may work, im just not sure if the arc would be stable enough. It serves the same purpose but instead of dissipating alot of power like resistance, it just tries to keep current from changing quickly. I have fullwave rectified a MOT and smoothed it with a capacitor, and i used another MOTs secondary in series to keep the capacitors from fully discharging once an arc was ignited.
Registered Member #3922
Joined: Thu Jun 02 2011, 06:24AM
Location:
Posts: 23
ya know what, i just was sorting my electric parts and found i ripped some 10k resistors out of an old crt :D should work, but i left the ladder at school, maybe i can get it tomorrow and work on it though.
if i hooked another mot up in parallel supplying power in parallel (basically stack them on top of each other, but not literally) would that help to keep them cooler? it heats up REALLY fast and i dont want it to burn out. I have 2. -- would that mess anything up?
as for voltage limitation i'm gonna put a dimmer switch on the low voltage side so i can get a range of nice arc types, but other than over heating is there really any reason to limit it? you said you used a secondary as a limiter, what did you really need it for?
oh, and how long can you all run yours before it gets too hot? i'm at about a minute of striking as soon as the last one dies.
Registered Member #2893
Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242
Put one MOT in series with the other and short out the secondary of one. This will ballast the ladder and limit the current. The problem is the transformer is saturating and a lot of the current going in doesn't make it out to the other side and just makes heat. Some more information on MOT ballasts can be found here:
Also remember that a typical TRIAC dimmer switch can only handle up to 600 watts, though if you push it you might get 900 at the risk of reduced reliability.
Registered Member #3766
Joined: Sun Mar 20 2011, 05:39AM
Location:
Posts: 624
If you try that you run the risk of messing with something if the MOT's aren't identical. A small voltage difference could lead to a large current flowing between the two, if you go that way get another 1:1 transformer and use it as a choke to equalize the voltage.
Also, what you propose won't change the voltage, only the current, and you have more than enough of that. Try the ballast, it will protect your MOT's much better. Also, a variac is a much better way to control the voltage, you'll probably fry that dimer before you can say kilowatt.
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My Mot jacobs ladder, improvments?
