450V Coilgun

[Alexander]

Hello,
I love your site! Your projects are just the sort of things I'd like to attempt.
I'm looking for some technical device regarding a coilgun I'm trying to put together. I managed to acquire some 8,800uF capacitors rated for 450V each (w/ up to 550V surge or there abouts) and made a couple bus bars out of a copper pipe. For my coil, I used a 2.5 foot piece of PVC pipe, and wrapped the coil around about a 6 inch length of it (it's a less than pretty amalgamation of carboard, ducktape, and about 240 turns of stranded 14 AWG THHN wire).

My questions are these: how should I determine how long/how many turns my coil should be? I don't mind wrapping a new coil, or using a different gauge of wire, if necessary.

Where can I find: good step-up transformer, bleeder resistors, and high-voltage switch? I have the coil, and the cap bank; need the rest. ^^

How should I determine what values to use for resistors, triggering circuits, etc? I understand the concept well enough and know some basic electronics, but the specifics elude me. I think I am eventually just going to buy a power supply, or make a voltage doubler and connect it to the mains, but I would love to avoid damaging my equipment (and myself XD ) if at all possible.

Any insights or criticisms you, or other forum members, could provide would be more than welcome : ) I'll provide pictures of what I have as soon as I am able.

[245Tommy]

You can try different coils with the simulator on this site http://www.webalice.it/saverio.filip..._frameset.html, for the first stage I'd go with a big mechanical switch and if the coil doesn't have a lot of ringing, you won't need a anti parallel diode (with a mechanical switch).

[StarKannon]

Ebay is your friend I just scored 2 350 volt 4500 mF capacitors for 11.00 including shipping For your switching mechanism I would advise going with a contactor which can be found on ebay easily. If I am not mistaken the most basic formula for your coil specs is B = μNI where B = field in teslas μ = magnetic constant N = number of turns I = amps. For you coil, I would recommend some proper magnetic wire I have no idea what that twisted stuff you used will do, lol. Other than that the math is pretty straightforward electronics math. PM me if you need anything more

For more on contactors
http://en.wikipedia.org/wiki/Relay
For magnet wire
http://www.magnet4less.com/index.php?cPath=8_40