Physics experiment with coil gun / gauss gun

[el-taco]

Hello everyone

I am looking to do a physics experiment for electromagnetic induction and I think it owuld be interesting to do it on a coil gun / gauss gun.

I have seen many youtube guides and such showing how to build them using disposable cameras, however Im wondering how I can make one using different rated capacitors. I dont know an awful amount about electronics but I know the capacitor is instrumental to getting the large current discharged in a short time.

Would it be as simple as hooking up a capacitor to a power source to a coil/pipe set up, or would more complex circuitry be required?

I only have about a week to actually build the rail gun before i need to experiment, so that is a factor that must be taken into consideration.

Thanks for any potential help!

<3 from me

 

[anselm]

How come you missed this thread, just next to yours?
http://laserpointerforums.com/f57/halo-style-2-stage-coilgun-59647.html
Yeah, it's long and kinda chat-style, but there's alot of info inside.

 

[GBD]

I made my own a long time ago out of a couple of filter capacitors out of a three phase VFD (450VDC 5200uF). Using a boost converter with a simple voltage cutoff (as it was bieng powered from 12VDC). Lost interest since then for other stuff.

Id personally have a switch between your charging circuit and your capacitor, the simplest you can get for firing is a spark gap (where you manual short out a gap, which I will warn you right now, with these capacitors its loud as hell and sends alot of sparks flying from the cap.).

Another method is to get more electronicly involved and use SCRs with a freewheeling diode. while still simple, it is alot quiter and efficient.

Generally I would make it so that your charger can be disconnnected (either manualy or automaticly) from the capacitor bank, and then you can trigger your capacitors to dump thier power into your coil. Again, Id use a big stud/puck SCR (although pucks require compression most of the time, studs can just be mounted regularly.). For a basic system. (thier triggering isn't too complex either, just requires feeding thier required voltage into the gate).

Heres a forum im part of before I joined LPF, a section in particular, all you ever wanted to know about coilguns and the parts needed:

4hv.org: Forums / Electromagnetic Projectile Accelerators

 

[millirad]

Yes, that's a good link for the OP to look at. And just in case it isn't known to anyone considering a powerful coilgun, the HIGH VOLTAGE must be respected. All precautions for building these circuits must be taken. All circuits must be considered live until discharged and checked with a meter. ^^

 

[el-taco]

Thanks for the replies. Ive just gone with a disposable camera set up because its relatively easy to find information on.

Im not very good with electronics, which is a brick wall Id like to get over.

Im down to just the flash circuit on the camera. I have discharged the capacitor (although Im still being very cautious).

Im not sure about some features of the circuit.

This is the whole circuit. Note that on the right is the clip for the battery

This is the flash, which I read that I am supposed to pull out. However, there is a wire (black) attached to a metal plate on top which I dont know what it does. Looking at the camera it came from, the wire wasnt attached to anything.

The black wire:

These two protruding bits of metal were originally headed over to the other parts of the camera assembly. I assume that I am to put a switch here? Im thinking this is a switch to actually fire the flash?

This is the piece (the triangular bit) where you push in on the camera to charge the capacitor. To charge the capacitor for the coil gun do i just have to push this in as well?

The capacitor has 224 written on it. Can anyone elude me to what this means? Thanks

As you can tell Im not the world's greatest expert on circuitry. Any help provided would be very very appreciated.

thanks

 

[EnergyCoherence]

The black wire is ground which can be discarded. Be very careful with that cap, as it's rated for 300 volts, and will yield a pretty good shock. These cam circuits make convenient fluorescent bulb drivers.

 

[Seoul_lasers]

The black wire is ground which can be discarded. Be very careful with that cap, as it's rated for 300 volts, and will yield a pretty good shock. These cam circuits make convenient fluorescent bulb drivers.

In some isolated cases they can yield a fatal shock. When the circuit is charged, treat like you would a loaded gun. Camera flash caps are incredibly dangerous! I have had a few close calls with them.

 

[GBD]

Camera caps are good for starters, Im not too proud to admit, but years ago I had my share of shocks from them.

Its very easy to feel a sence of false invincibility when you get alot of experience thereafter, so always treat them with respect, especailly when you move on to larger screw mount capacitors. (some of which will store 1KJ easly in one capacitor).

The capacitors/banks I have on hand now will no doubt kill you if you touch it. If your lucky to survive it will probably screw you up for the rest of your life.(Ive heard of someone's forearm exploding before from the higher powered ones)