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J.Lanum

Sat Mar 04 2006, 12:32AM

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

I'm having a hard time comprehending parrellel. From what I understand is that every cap needs to be seperately wired to the rails right? However I look at a lot of cap bands and the bussbar runs straight through the caps. Can someone link me to a pic and/or diagram?

...

Sat Mar 04 2006, 01:13AM

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

You just use a single piece of copper connected to the caps, which you connect to the rails using some heavy duty wire/pipe/busbar...

Steve Conner

Sat Mar 04 2006, 01:20AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Parallel simply means that you connect all the + terminals of your caps together with one busbar, and all the - terminals together with another. So you have effectively a single daddy-o capacitor with one + and one - terminal. You connect these terminals to the rails of your gun at the breech end, either directly for a projectile switched launcher, or via a high current switching device like a SCR or ignitron.

Having a switching device is neat because it allows you to load the projectile into the rails by hand, charge your capacitor up, and then close the switch to launch your projectile from a standstill using only EM energy. Leaving the switch out saves a lot of money and hassle, but the projectile has to be fired into the rails at high speed by an injector mechanism, so it's not nearly so cool, since you don't get a clear demo of a projectile being launched by electricity.

One thing that sometimes catches people is that the busbars and wiring of the launcher feel much the same magnetic pressure that the projectile does. So they need to be mechanically strong and firmly fixed in place if you're planning to use high energy.

J.Lanum

Sat Mar 04 2006, 02:14AM

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

That exlplains it perfectly thanks guys. Now where can I find a 4k resistor and a voltage doubler?

Hazmatt_(The Underdog)

Sat Mar 04 2006, 04:49AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

This is what I would do:

1. Single high current pulse coil at the tail just like my ring tosser causes Vi to be about 22 f.p.s. AND you already have a charging source! So you have 3 extra small caps, who cares!
Okay, that thing is SCR pulsed, the projectile flys down the barrel into the conducting bars and BANG gets accelerated a second time!

All electrical. AND YOU KNOW WHAT! If you increase Vi by increasing your 1st stage repulsive accelerator, you could theoretically get more Vf.

>>>waits for applause<<<

...

Sat Mar 04 2006, 06:22AM

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

um, are you sure you put that in the right thread?

In any case, JL check your pm's I just sent an offer for a 4k resistor and a doubler

Steve Conner

Sat Mar 04 2006, 03:00PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

I think hazmatt is suggesting using a coilgun as the injector stage for your railgun. That might be tricky, since a good railgun projectile (a piece of teflon with thick wads of copper strands shoved through holes in it) is not at all the same thing as a good coilgun projectile (a piece of iron)

You could make it work- one sensible idea might be to use an induction coilgun and an aluminium projectile, since an aluminium block makes an OK railgun slug- but suddenly the swinging rubber mallet injector proposed by a previous poster seems attractive

J.Lanum

Mon Mar 06 2006, 03:18PM

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

I already asked about usinga coilgun as an injector in a previous post but was told that ferrous materials doesn't work well w/ the railgun.

Are there any good Electricity books you guys have read. I need one for basic electricity.

Hazmatt_(The Underdog)

Mon Mar 06 2006, 11:37PM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

What's the problem with it being non-ferrous if its in a railgun?
Accelerating Al magnetically in the first injector stage is not a problem, then after that, blasting down the high current rails doesn't really necesitate being ferrous either.

I see the problem in a coilgun yes, but not railgun. And I thought discussion was allowed since I saw a picture of a railgun. Sorry if I got confused.

Steve Conner

Tue Mar 07 2006, 12:33AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Non-ferrous is fine in a railgun. The problem is with non-ferrous in a coilgun, or ferrous in a railgun. Hazmatt's ring tosser only works well because the projectile is in the shape of a ring and gets very high coupling to the launching coil. A railgun projectile needs to be more of a slug shape that makes it hard to launch by induction. A ferrous metal projectile in a reluctance coilgun would work better, but then ferrous metal doesn't play well in the rails.

If you really wanted to do it, I guess the best route would be a toaster-bored railgun (with its slice-of-bread-shaped projectile) and an induction launcher that pops the projectile sideways like a toaster, such as Chris's "Lateral disc cannon" from the old board.

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