| Author |
Message
|
| Rambo |
 Posted: 05/14/2006 3:49 AM Post subject: Rail gun |
 |
|
Colonel
Joined: 15 Jan 2006
Posts: 509
775.50 Spud Bux
|
Yesterday I tried to make a rail gun with my 650000mf capacitor(my BFG ignitor).The projectile was a piese of aluminium foil.At 12v when I push the botton it only makes a tiny spark between the projectile end the rail The capacitor remains fully chrged.I think the only think I can do is to rise the voltage.What voltage do you think should be enough, and what is the voltage for the camera flash ignition?
| Description: |
|
| Filesize: |
123.41 KB |
| Viewed: |
59 Time(s) |
|
|
|
| Back to top |
|
 |
|
|
|
| Benny |
| Posted: 05/14/2006 3:55 AM Post subject: |
|
|
Brigadier General
Joined: 19 Apr 2006
Posts: 845
144.97 Spud Bux
|
| use a camera flash to charge the capacitor, what material did you use for the rails? by the way, most camera flashes are around 330 volts.
|
|
| Back to top |
|
|
| Rambo |
| Posted: 05/14/2006 4:53 AM Post subject: |
|
|
Colonel
Joined: 15 Jan 2006
Posts: 509
775.50 Spud Bux
|
The rails are just an ordinery iron.I can't charge 6,5v capacitor with 330v.
I shold try the gun with 400-1000v and more copacitors.
|
|
| Back to top |
|
|
| rna_duelers |
| Posted: 05/14/2006 4:55 AM Post subject: |
|
|
Major General
Joined: 26 Sep 2005
Posts: 1641
3118.23 Spud Bux
|
| The projectile needs to be moving before the charge is ran through the rails it needs it direction of motion and.I found this cool web site and he has a small table top one maybe have a look and see how it works i remember seeing pics of it on here.
|
|
| Back to top |
|
|
| Rambo |
| Posted: 05/15/2006 0:06 AM Post subject: |
|
|
Colonel
Joined: 15 Jan 2006
Posts: 509
775.50 Spud Bux
|
| Another question.What trigger should I use.At low voltage it's easy, but at 1000v and a lot of amps.It can be a very expencive tiristor.
|
|
| Back to top |
|
|
| rna_duelers |
| Posted: 05/15/2006 0:19 AM Post subject: |
|
|
Major General
Joined: 26 Sep 2005
Posts: 1641
3118.23 Spud Bux
|
| Go ghetto,make one that is very simple such as two connections that when you touch together the circuit is complete,it will work and wont cost much at all.
|
|
| Back to top |
|
|
| Rambo |
| Posted: 05/15/2006 0:58 AM Post subject: |
|
|
Colonel
Joined: 15 Jan 2006
Posts: 509
775.50 Spud Bux
|
The problem is that for this gun I will use more then 500v>there will be too much loses in the swich.May be if I sqash the two contact plates with a hummer 
| Description: |
|
| Filesize: |
12.25 KB |
| Viewed: |
519 Time(s) |
|
|
|
| Back to top |
|
|
| FiveseveN |
| Posted: 05/15/2006 8:10 AM Post subject: |
|
|
Captain
Joined: 14 Oct 2005
Posts: 340
766.01 Spud Bux
|
| Go for triggered spark gap . After SCRs, spark gaps are preferred for this aplication. I have an idea for a simple trigered spark gap; will be posting soon. If you use mechanical switching not only will the two plates be welded shut, but you'll lose most of the energy from resistive heating.
|
|
| Back to top |
|
|
| Rambo |
| Posted: 05/17/2006 10:01 AM Post subject: |
|
|
Colonel
Joined: 15 Jan 2006
Posts: 509
775.50 Spud Bux
|
I just made my naw rail gun.It uses 8 110V 2200mf capacitors.It fires small balls from aluninium foil.But it can't do any damage  Because I have no botton I tuch the wire from the gun to the capacitor.The spark is so huge that I cant remember the spark in the gun.
| Description: |
|
| Filesize: |
121.36 KB |
| Viewed: |
61 Time(s) |
|
| Description: |
|
| Filesize: |
124.94 KB |
| Viewed: |
63 Time(s) |
|
| Description: |
|
| Filesize: |
103.05 KB |
| Viewed: |
49 Time(s) |
|
|
|
| Back to top |
|
|
| FiveseveN |
| Posted: 05/17/2006 11:39 AM Post subject: |
|
|
Captain
Joined: 14 Oct 2005
Posts: 340
766.01 Spud Bux
|
Man, if I had as many toys as you do when I was your age
I said I'll draw a triggered spark gap, I'll do it tonight. It should solve your trigger problem.
But why have you wired your caps in series? Do you use a high voltage source to charge them?
8 X 2200mf @ 110V in series = 2200mf @ 8800V
8 X 2200mf @ 110V in parallel = 17600mf @ 110V
And I don't see a charging resistor. Careful there 
|
|
| Back to top |
|
|
| Rambo |
| Posted: 05/17/2006 11:58 AM Post subject: |
|
|
Colonel
Joined: 15 Jan 2006
Posts: 509
775.50 Spud Bux
|
| I don't think it's going to work with less then 300v.I charge the capacitors two by two with 220v.
|
|
| Back to top |
|
|
| FiveseveN |
| Posted: 05/17/2006 13:51 PM Post subject: |
|
|
Captain
Joined: 14 Oct 2005
Posts: 340
766.01 Spud Bux
|
Here's a good description of the trigatron: http://www.angelfire.com/80s/sixmhz/trigatron.html
You should use large screws, sharpened at the end, for the main electrodes and a smaller screw, even sharper, for the trigger electrode.
For 220V, the distance between the main electrodes should be about 0.7 mm, but I could be wrong.
You feed the trigger electrode from a high voltage source - the higher voltage, the better. You could start with the sparker you've been using on combustions. If it doesn't work, make the gap smaller or try a different HV source. An air ionizer would be perfect.
Connect only the negative output of your HV source. If it still doesn't work, add another trigger electrode opposite to the negative one (you will connect this to the positive output), so the main electrodes and the trigger electrodes are at a 90 degree angle.
The triggers should be close enough to eachother to create a spark, but far enough from the main electrodes to prevent arc-over and discharge through the HV source. That would hurt
|
|
| Back to top |
|
|
|
|
