Arc flash

Is this for welding or do you just want some cool looking electrical arcs?

>>1122806
Mostly just cool arcs. Maybe make a mini potato cannon that runs on just electricity and lack of self-preservation instincts.

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>>1122802
jacobs ladder my friend

just get yourself a neon sign transformer and some coat hangers. spark gap is about 1 inch per 10,000 volts.

the only downside is ozone generation. you know its time to shut it off when you get a sore throat, and you will eventually get a sore throat.

Just buy an old disposable camera and use the xenon tube.

>>1122812
I don't want just an arc. That's too plain and simple.

I want to dump amps into that arc. Enough amps for the result to be describable as an arc flash.

>>1122838
So you basically want to build a lightning machine?

Go google how to build a lightning machine, the secondary stages of these will be what you're after.

>>1122839
Not finding anything. Just tesla coils, flybacks, voltage multipliers and show equipment.

>>1122802
>>1122806
>>1122838
>>1122844
>>1122844

Please stare into the arc deeply so that you go blind and no one ever has to ready any dumb ass shit you type ever again.

>>1122844
..right, and it is up to you to evaluate those displays and work out how thy did their thing.

You're not here just to be spoonfed, are you? I mean, The last thing I would be taking advice on from 4chan would be HV systems, especially if I was incapable of doing my own research to make sure what I was being told was not going to kill me..

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>>1122812
Not OP but Jacobs Ladder looks good. It could even work as a wide-band RF jammer.
>1 inch per 10,000 volts
That would be about 400V/mm. Normal dielectric strength of air is around 3kV/mm.

>>1122860
They just generate high voltage to produce arcs at minimal current. Which I already know how to.

What I want is to exploit the conductivity of the ignited arc to dump some decent energy into that arc from some capacitors.

That's pretty simple, OP.
An arc is ionized air, air that has become conductive. Once it's ionized, you don't need a high voltage to sustain it.
All you need to do is use a low-current, high-voltage supply in series with a higher current supply, such as a spark coil and 220v mains. Once the initial spark starts the arc, the high current will flow and sustain it.
https://www.youtube.com/watch?v=euBpVr_XhuU
In this video, some russians use a stun gun in electric sockets. The high voltage from the stun gun makes an arc wherever the wires come close together uninsulated, then the full current of the mains is dumped through the arc. I think that's exactly what you want.

>>1122967
In parallel, I mean to write, they should be in parallel. Essentially to sum the currents through the arc.

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>>1122967
That is exactly what I want. But my concern is that the high voltage source will fry the low voltage part.

Pic related would be the first and simplest approach, but doubt there's a semiconductor diode that would survive both the reverse voltage and the high forward current.

>>1122802
>For an potato gun.
Google ye "piezoelectric bbq igniter"

Things that create arcs like that can kill OP.

Though if you wish, google ye also "voltage multiplier"

>>1122996
>piezoelectric
I don't want to create a spark to ignite a fuel aerosol. What I want would be best described as an electric explosion.

Very unlikely to kill unless you grab it with both hands. Quite likely to do some serious damage to the skin/tissues though.

>>1122992
In series works too, look up auto strike boxes for arc welders, exactly what you're trying to do.

>>1123043
It is a lot like an arc welder. But I fail to find any schematics for "auto strike" ones.

Do you mean the spark gap and capacitor bank in series? Don't see how that would work out as there would be an inductive element in series as well, negating the whole point of dumping a lot of energy into the arc.

I'd still require a way to switch from much higher voltage (because fixed gap size) to much higher current (because pulse operation) than welders.
And for various reasons I'd very much prefer it not being reliant on mains.

>>1122811
Find an old crt and rip out the transformer. 15kV with enough amperes behind it should do the trick.

>>1123070
My issue isn't in lighting an arc, but in how to switch in a much lower voltage but high current capacity source (capacitor bank) to exploit the lit arc.

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>>1122802
Go buy an cheap welding machine. Arcs will flash.

>>1122802

An arc through air won't be "low" resistance simply because the air is plasma.

To sustain anything more than a tiny arc you need high voltages, or something other than normal pressure air.

>>1123126
I mean relatively low resistance. Though I should probably look up a graph on that.

>>1123132

It's current dependent, the arc will "choke" itself.

Try looking up carbon arc furnaces. I saw one in a book full of fun, dangerous experiments. It uses two carbon rods from D batteries. Direct line will burn your retinas. Intended to be used to melt metal. It ran from mains. Can't do Calc atm, but I'm confident capacitors will be prohibitive. Simply too many joules.

OK since I'm in a broken bus on the side of the road I'll try. E.g. 1500 watts is 1500 joules per second.

To run 10 seconds is 15000 joules. Capacitor energy is 0.5 * c * v^2.

Assume v is 240 from an AC doubler circuit, then 0.5 c = 15000 / 57600.

So c is about one half farad? And voltage needed is 240V. That's a tall order but maybe doable. Maybe I'll check digikey and get back since it looks like we're stuck in 10th gear and have to wait for another bus.

>>1123148
OK yeah looks like about $1000 dollars in caps. Best deal I can see is about 16x 35v caps. This math isn't perfect due to the voltage doubler, if I don't freeze to death I'll do more detailed math later.

>>1123148
>>1123153
Sucks about the bus. What's the weather there?

Arc furnaces need a sustained arc and power. I only want a high power pulse, <1s. I'm considering capacitors, because they can be a high voltage, high current supply for pulsed applications and wouldn't require a massive transformer or mains.

My issue is with connecting them in a way that would protect them from the high arc strike voltages but allow them to discharge through the lit arc.

>>1122967
Those guys are crazy!

You can buy cheap hv converters on AliExpress. Just look for 400kv converter

>>1122802
Op look into spark chamber particle detectors. They have electronics that funnel high voltage at the exact moment a photomultiplier tube gives the signal. You just have to adapt them to take a different signal. Essentially they take advantage of the tiny amount of ionized air a high energy particle produces to ignite an arc between plates. Kind of like what you're trying to do

>>1122955
I'm pretty sure it's /cm

>>1122992
Well, the reason why the stun gun worked for those crazy russians is because of the frequency at which it oscillates.
It's a very high frequency, so it can't make it back through the mains transformer to the line. Nor can it be shorted by the transformer secondary, for the same reason.
You could exploit the same principle. Use a resonant transformer to make your HV, and supply your LV through a transformer with a high impedance to the HF HV.

You can buy 3v to 400kv bosters on ebay since you just want a pretty arc

http://s.aliexpress.com/26JvI363
Get some of these

Google ZVS flyback

>>1123059
He means a high frequency starter, search up arc pig

>>1122844
Look up hf start for welders and marx generators with trigger coil ie http://www.electricstuff.co.uk/marxgen.htm

Its also what goes on in those disposable camera circuits, hv pulse ignites the flash tube whilst the 300v capacitor is what makes it bright.

>>1124761
Welder HF starter seems a lot more like what I'm looking for. Though having an inductor in series is probably going to prevent a fast discharge.

>>1125162
Flash tubes have a third electrode on the outside of the tube to trigger the ionization. Also pressurized.

>>1125184
Believe me, crank that sucker up though a cheap 300 amp ac welder and you will have wicked sparks

You will want a very well timed battery isolator controlled by isolated audrino, or through relays
>isolation is key, don't fry your shit
>don't fry you

>>1122812
I made one of these from an old neon light sign. It's kinda cool but gets boring after a few minutes. Btw I've always wanted to touch it would I get electrocuted?

>>1125262
>welder
Way too large and relies on mains. I want something far more portable.

>>1125296
Isolation is the exact issue I want help with.

>arduino
Certainly not needed.

https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.instructables.com/id/Build-A-Plasma-Speaker/&ved=0ahUKEwih2LGh3fTRAhXIYyYKHU6tASwQFggmMAI&usg=AFQjCNGYen-jguSR7brwyyjBpaz3RcBrIA&sig2=Pp4HgP9b7Pcj2wK2i0--lA