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LAN_403

Plasmaniac

Wed Feb 22 2006, 06:09PM

Registered Member #206 Joined: Sat Feb 18 2006, 03:17PM
Location:
Posts: 72

I use a spring-injector:

I dont use it to get higher speeds, the projectile wouldn't even leave the rails if I accelerate it just with my injector. I use the injector because I am a poor student who doesn't have enough money to buy a big scr

I think it would be the best choice for you, if you don't have that much time left.

Quantum Singularity

Thu Feb 23 2006, 01:22AM

Registered Member #158 Joined: Sun Feb 12 2006, 09:53PM
Location: Central Ohio
Posts: 282

I have made some 'poor mans buss bars' before and they seemed to work fine. Didnt know if anyone else might have done something like this? I took copper tubing, like maybe 1" tubbing or so (cant remember exactly) and flattened out about 6" or so at each end and drilled hole for mounting via bolt. I cant remember if I flattened it with my 5" vise or by large hammer, or maybe both.

Something I was wondering, is it important to feed the rails with buss that feeds in fairly straight fromt the back to avoid a magnetic field that might interfere with the field in the rails? I ask because in my crappy prototype my projectile shot straight up out of the rails rather than going down the rails. I thought maybe because my power was comming into the rails from a 45* angle down and back from the rails. But it was a crappy design anyways though, i didnt really expect it to work. But maybe someday I'll start back in on the project

J.Lanum

Thu Feb 23 2006, 02:24AM

Registered Member #161 Joined: Mon Feb 13 2006, 03:15AM
Location:
Posts: 20

So buss bars are an option, but what type of wire do I need if I choose to go that way.

Self Defenestrate

Thu Feb 23 2006, 03:51PM

Registered Member #87 Joined: Thu Feb 09 2006, 01:36PM
Location: San Jose
Posts: 191

Some really big thick wire. Perhaps you could cut off the clamps on a jumper cable, and rip the bits apart. That would suffice.

Jasonr

Thu Feb 23 2006, 05:25PM

Registered Member #167 Joined: Mon Feb 13 2006, 06:41PM
Location: Waterloo, WI
Posts: 54

or copper water pipe put inside some type of clear plastic hose for insualtion will work ok. also you can crush the ends and drill a hole to make connection points.
You can also put extra wire inside the copper pipe (insulation stripped off) to be a better conductor.

Madgyver

Thu Feb 23 2006, 07:14PM

Registered Member #177 Joined: Wed Feb 15 2006, 02:16PM
Location: Munich, Germany
Posts: 214

Jasonr wrote ...

Yes you could do that. However a spring means you need to be right by the rail! I tell you what I have no desire to be with in 25feet of mine. But that is not an apples to apples compare.

Well, you still could use something like a realllllly loooong stick or just a small piece of wood and a 25feet long rope.

J.Lanum

Fri Feb 24 2006, 03:14PM

Registered Member #161 Joined: Mon Feb 13 2006, 03:15AM
Location:
Posts: 20

When the capacitors discharge their energy into the rails, how long does that duration last?

M_Gargantua

Thu Mar 02 2006, 04:50PM

Registered Member #276 Joined: Thu Mar 02 2006, 04:40PM
Location: NY
Posts: 5

only an instant.

Madgyver wrote ...
Well, you still could use something like a realllllly loooong stick or just a small piece of wood and a 25feet long rope.p

or you could use a swinging rubber mallet attacted to a cradle above the rails

J.Lanum

Fri Mar 03 2006, 12:13AM

Registered Member #161 Joined: Mon Feb 13 2006, 03:15AM
Location:
Posts: 20

How should I go about charging my caps? Can I use a standard 110v oulet? I'm pretty sure I can't but I need clarification on what I can and cannot use.

...

Fri Mar 03 2006, 12:24AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

you can't use a normal 110v outlet, however with a few modifications you can.
the first thing you will need is a diode rectifier, almost any diode will work, and you will need 4 of them. This will give you about 170v, but since you are using 450v caps you will not get even half of the energy available.
So you can use a voltage doubler, which will give you 340v, or a tripler which will give you about 500v.
Because the caps will appear as a short circuit to the mains when they first charge you also need to add a ballast resistor to them. To keep power to a reasonable .1a you would need about 5k worth of resistance, and this resistor should be able to dissipate about 25w. (assuming a voltage tripler charger).
You also need to include the simple safety devices, a fuse in series with it, a bleeder resistor on the caps, etc.

If you do go the tripler route, you will need to have a way to stop it charging when the caps get to a high enough voltage. If you have a variac it would be a good way to do it, and it would eliminate the need for a ballast resistor (just raise the voltage slowly). If you don't you can just use a switch to turn of the charger when they get full.

Good luck and be safe!

btw, the caps went out today

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