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Registered Member #2909
Joined: Wed Jun 09 2010, 12:31AM
Location: fort belvoir, Va USA ( south of DC)
Posts: 145
Well when I first built the bank I had all of my caps in series but this made it discharge to slow, before I rearrange them for higher voltages (400 to 1200) I used a thin wire (telephone wire) to shorten the time of the discharge it. I had a flat coil to launch Al platters in the air and I found out it would go higher if I had a wire that would vaporize when it discharged, this would only let alittle of the power of the caps thru but it was much quicker of a pulse. But the problem was it wasn’t vary controllable and there was still around 200v in the caps after the discharge that I had to deal with.
This may be counterproductive for the cooled coil but it could prevent resonance on the caps.
Registered Member #1451
Joined: Wed Apr 23 2008, 03:48AM
Location: Boulder, Co
Posts: 661
All the caps in series made the discharge too slow? If this is true then there must have been something else going on, as if all the caps are the same, with them in series is the way to get the shortest pulse as the capacitance is the least. This is if the coil was the same used in all cases.
Registered Member #2998
Joined: Tue Jul 13 2010, 08:34PM
Location: Swedish forests.
Posts: 26
Vapourizing wire indeed sounds like a good way to cut the pulse short if you are having problems with the projectile getting stuck, but that pulse is going to be difficult to control, and if it's a single stage coilgun it will most likely be too short.
Maybe you could change the duration of the pulse by choosing different thickness wires that takes longer to vapourize... Multiple small strands seems like a good way. Maybe out of topic but sure an interesting approach. And it's kinda against the coilgun philosophy of being silent, clean and ammunition-free save for the projectile.
Using more exotic materials such as superconductors only seems worth it to me if your triggering is solid state so you can optimize pulse width. It's only then you will see the full benefits of zero resistance. I might conjure something up with my two 72 amp IGBT:s...
Registered Member #2909
Joined: Wed Jun 09 2010, 12:31AM
Location: fort belvoir, Va USA ( south of DC)
Posts: 145
Well the wire short was to make quick pulses with my flat coil to fling Al hard drive platters in to the air. as for solid state I have yet to figure those out, I think I will stick to my 800A solenoid switch box with has the option to have a handle for more manual use, simplicity at best (come on who doesn’t like pulling a giant lever, now all I need is Igor….) maybe I will learn to use those IGBTs and other abbreviated solid state things I like to know exactly how they work before I use them so I can expand on there uses.
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super cooled coil guns
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