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HV school project

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I wonder if it needs 50mA like in the Jacob's Ladder project using a neon sign transformer. It would take a miracle to get 1200W from a little 9V battery.
 
yeh, thats about right, 2.4 was about the maximum gap I could get, but i reduced it down to 1.5cm to have a reliable spark.

It's such a high voltage, the crappy "heavy duty" 2 core wire, couldnt handle it, and you hear the sparking going through the insulator and into the other wire.
 
i have had a better, safer idea. i have 150vdc from it so i have buit a coil gun. using a 680uf cap rated a 200v
 
no, but getting some. my total capacitance will be 60,000uf i have used very thick wire so they will discharge fully. even with 3A at 6 volts the nail that is heavy goes up about a foot.
 
You dont need all that tick wire becose its an very short pulse.

I found two paralel 1 mm magnet wire up to the job.It gets a bit warm afer a few fireings.

You also need an SCR to fire your coilgun.

Also you need an way of charging up the caps.In my case i need "only" 100V and i get that by conecting an voltage dubler to an 50V mains transformer.The transfomrer is capable of 20A peak so it charges the caps in les than a second.

What voltage caps are you geting?
 
i want to be able to fire twice from one charge, it has more han one stage.
il post a circuit diagram when i go back home from bournmouth.
 
Someone Electro said:
You dont need all that thick wire becose its an very short pulse.
Wrong! Time has nothing to do with it.
Thicker wire can pass more current with less loss.

I found two paralel 1 mm magnet wire up to the job.It gets a bit warm afer a few fireings.
The temperature rise shows that power is wasted by heating the resistance of the wire.
 
But then agen using very very thick wire will make the distance from the projetile biger and also makes loss.
 
hmm, i think audioguru is right (not taking sides) i think this because less resistance = higher current and higher voltage i = v*r. but, a thin wire can carry a high voltage but not as much current and still be close to the projectile. i don't know much about making a electromagnetic field stronger i.e what is more inportant current or voltage. i would personaly have thick wire.

here is my schematic for the setup i have at the moment.

PS: the switch is just two wires.
 

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just tryed the coilgun i charged the caps to 200v there limit and put a small screw in and fire! it went so fast it hit my door 2 metres away as soon as a fired it :!:
 
does anyone have a schematic for a simple dc-dc converter up to 140v from 24v
 
danielsmusic said:
does anyone have a schematic for a simple dc-dc converter up to 140v from 24v
I guess the amount of current doesn't matter to you. Rub your dry hands together and you'll have plenty of voltage!
First make your schematics look like positives instead of looking like negatives. They make my eyes hurt, you too?
 

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i think the black background is easyer to read, but maby im wrong. so here is a white background.

a dc-dc converter would be usefull but everywhere i look on the internet it is low voltage ones it it posible to achive 150v without ac? what about a capacitor pump or is this a dc-dc converter? i have looked eveywhere i can think of. my coil gun worked untill the transformer melted. and it works good. i don't want to use transformers.

ps: thanks for all the help on the topic.
 

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danielsmusic said:
I think the black background is easier to read, but maybe I'm wrong. So here is a white background.
Thanks, it is easier to see. :lol:

A dc-dc converter would be useful but everywhere I look on the internet they are low voltage ones. Is it posible to achive 150v without ac? What about a capacitor pump or is this a dc-dc converter? i have looked eveywhere I can think of. My coil gun worked until the transformer melted, and it worked well. I don't want to use transformers.
You need a high voltage with power in it. Power equals the current times the voltage. A capacitor charge pump can't supply much current and when you use a step-up transformer then the primary current is high.

Make an AC stepup-the-voltage circuit with enough power to do the job.
If you need 150V at 10A then it is 1.5kW!
1.5kW from a 12V battery uses 125A plus more for losses!
If your transformer doesn't melt then your wiring and battery will. :lol:
 
I like to use black background,becose its much easyer on the eyes.

To charge my caps i use an mains transformer.It can output 60V at 20A peak.So it charges the caps up in less than a second.(Also no melting trafromers)This dosent go for you since you need higher voltages.

How about making an flyback trasformer around an ferite core.I built it and works good.But i have it a big secundary that made about 3000V and was very shoching to toch.(It also gave you an RF burn if you got close to only one contact)
You may give it an les thurn secundary to get your 200V.
 
does it mater if it just a pencil for the core? i too have a transformer that can output 60v at 20a
 
A pencil as a transformer core will be very ineffective. The core usually has to be iron of some kind, and needs to be either a complete circal (toroid type) or a more ordinary box type one. Some transformers can use air cores though, I think a tesla coil does essentially, but its not suitable for higher current. I'd buy a large ferrite ring and a lot of magnet wire, 2 thicknesses are good. You'll also need a bucketful of time and patience :lol: . I'm pretty sure there will be a suitable transformer around if you look hard enough though, mabye ebay would have that kind of thing :?:
 
Ware you thinking of making your own mains transformer around an pencil?

I know i do a lot of stupid things but even im not that insane.

If you want to still live dont ever do that.
 
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