New pistol coilgun
dingo27, Sun Jul 15 2007, 12:13PMHi, I wanna make my second CG because my first was (maybe) damaged...
I have these capacitors -
9x 470uF/200V
2x 680uF/200V
2x 100uF/200V
1x 330uF/400V
1x 150uF/400V (maybe i´ll get another one)
What can you reccomend me ? All capacitors are electrolytics, from PC PSU, and AC/DC changers
Build simple 1 stage or 2 stage CG? Which thyristhor will be suitable for it ? i have some photogates ready (two) so... it can be also 3 stage CG :) First coil is 3 or 4 layers and about 30 winds, 0,8mm wire
photos on my website -
Re: New pistol coilgun
Ronnie, Sun Jul 15 2007, 10:08PM
Find out the internal resistance of the capacitor bank you are using, reasonable numbers can be looked up for each capacitor online if you don't have this information. Then using V=IR, and the minimum possible resistance for the entire circuit, find out the current rating for your switch. Choose a voltage rating which is slightly higher than the voltage you aim to charge your capacitors to, just to be safe. Get a single stage working perfectly, before you start designing the second stage. Once the first stage is as good as you can get it, then do not change it while optimising the second stage. This would be much easier than attempting to improve every stage at once. If you have decided on the first coil, then you can only change the capacitors, and the voltage they are charged to. Also experiment with different projectiles. Look at Barry's coilgun site, it has a large amount of theory on improving coilgun efficiency.
Ronnie, Sun Jul 15 2007, 10:08PM
Find out the internal resistance of the capacitor bank you are using, reasonable numbers can be looked up for each capacitor online if you don't have this information. Then using V=IR, and the minimum possible resistance for the entire circuit, find out the current rating for your switch. Choose a voltage rating which is slightly higher than the voltage you aim to charge your capacitors to, just to be safe. Get a single stage working perfectly, before you start designing the second stage. Once the first stage is as good as you can get it, then do not change it while optimising the second stage. This would be much easier than attempting to improve every stage at once. If you have decided on the first coil, then you can only change the capacitors, and the voltage they are charged to. Also experiment with different projectiles. Look at Barry's coilgun site, it has a large amount of theory on improving coilgun efficiency.
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