Alternative power sources for a coilgun?

I was wondering if there was any other method to power the firing coil of a single stage coilgun without using capacitors.  My main reasoning is to try to reduce recharge time, and to also avoid making massive groups of capacitors and finding a place to put them.

It needs to be able to be powered by some form of battery, meaning I could connect voltage to this circuit (1.2 volts up to 12 volts.  I'm not picky) and shouldn't consist of hard to find components.

I'm not looking for the greatest efficiency in the world, just making a step (okay, maybe a stomp) toward building a 'capless coilgun'.

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frollard6 years ago
Thing is with a coil gun (or any other high-impulse short period device) is there is no other suitable alternative -- you *could* use the output from a power plant to get the thousands of volts you need at ridiculous amperage.

It's like the cheap, good, fast analogy -- but with power its voltage, amperage, and time (power, in a sense). A coil gun is putting a HUGE impulse on an object for a very short (less than milliseconds) period of time. Batteries have lots of power but not 'quickly available' power. Capacitors don't have much comparatively, but they do put it out almost instantly.

Recharge time is 'slow' because you're not putting power into the capacitor quickly enough, not because the cap charges slow. Within reason, your problem can be solved with a bigger power supply.

Lastly, lots of people take for granted how much actual energy is stored in gasoline or gunpowder...even sugar has HUGE power compared to 'capacitors'.
Madrias357 (author)  frollard6 years ago
Well, would I be able to use a flyback transformer to fire the coilgun? I have a CRT monitor that my friend took the tube (and thereby the cap) out of, but I got the flyback transformer from it.
Again, voltage is NOT power. Watts is power. Watts is Volts x Amps. A transformer transforms volts and amps back and forth, but never increases the watts. Thus, put 50 watts in, get (ideally, never real-worldly) 50 watts back out.

The flyback would take 'average' voltage and high current and turn it into low current high voltage.
Capacitors would take that flyback voltage (high voltage, low amperage) and store it up for a while, so it has a high overall energy (high voltage high power). THAT capacitor energy can be released in a fraction of a second (while the object is still in the barrel). THAT will make a good coil gun.
If you tried to fire with just the transformer, you'd get enough voltage, but not enough current.

so, I If attach a high voltage capacitor to the flyback transformer, will it work.

I have a flyback 2n3055 driver ready.

Madrias357 (author)  frollard6 years ago
Ah. So what I'd need is something that can generate a lot of amperage with a fair amount of voltage. I guess it's somewhat time to go break something for a few capacitors and figure out a way to charge them up.
You could always use the mini-board from one of them electric flyswatter units, only takes 2 AA batteries and can charge capacitors fairly quick. I'm working with a similar set-up but want to up it to a flyback trans. and perhaps a microwave capacitor.. I've tried it but dont think I have it set up right.. I get a massive spark when I dump the power into the coil.

using a flyback by itself would probably not work particularly well.

keep in mind that the amount of energy a coil gun can store is calculated as:

(c*v^2)/2 were c is capacitance in farads (1 farad= 100000 microfarads) and v is voltage.

i do not think (correct me if i'm wrong) that a flyback has any capacitance of its own. whoever, if you were to connect a relatively low value capacitor with a very high voltage rating(5-100kv, depending on the transformer you are using) would help solve this. Googling 'bottle capacitors' should set you on the right track. also remember that to achieve a high voltage output on a flyback you will need to construct a driver circuit for it. further more, i would suggest that you start small, building a coilgun like this (http://www.dangerouslymad.com/sample-chapter) until you properly grasp the theory behind a dangerous high voltage project.

i hope this has been of assistance.

Good luck and be very careful around high voltage power supplies!!!

I think the big guys are using homopolar generators to run coil guns.