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Coil Gun Project

ferrex7

Nov 13, 2010
3
Joined
Nov 13, 2010
Messages
3
First off, I am a new member here. Just wanted to say hello!

I am currently building a Coil Gun. I will be using two 450V 1800uF Capacitors (approx. 364 joules) My original plans called for ten 120uF 330V capacitors from disposable cameras-i wanted something a bit more powerful so I decided to go with the two big capacitors. Originally, I was to use the charging circuit from one disposable camera, however, i am curious as to if the charging circuit could handle the now beefier capacitor bank
Also, a 10A rated switch was to be used in place of the clicker plate on the charge. circuit, will a 10A still be ok for the increased power? (also was using 10A switch for firing)

Thanks!
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
How are you triggering it? The current will probably exceed 10A by at least an order of magnitude.

The camera charger will "handle" any size bank of capacitors, it will just charge them proportionately slower.

I really hope you're not connecting a switch to the capacitors to discharge them across a coil. If you are then you may have a death wish. Try to find some method of remotely triggering the current. Hint: your camera flash unit uses one such method.
 

carebare47

Oct 21, 2010
66
Joined
Oct 21, 2010
Messages
66
First off, I am a new member here. Just wanted to say hello!

I am currently building a Coil Gun. I will be using two 450V 1800uF Capacitors (approx. 364 joules) My original plans called for ten 120uF 330V capacitors from disposable cameras-i wanted something a bit more powerful so I decided to go with the two big capacitors. Originally, I was to use the charging circuit from one disposable camera, however, i am curious as to if the charging circuit could handle the now beefier capacitor bank
Also, a 10A rated switch was to be used in place of the clicker plate on the charge. circuit, will a 10A still be ok for the increased power? (also was using 10A switch for firing)

Thanks!

I strongly recommend a high voltage relay.
 

ferrex7

Nov 13, 2010
3
Joined
Nov 13, 2010
Messages
3
How are you triggering it? The current will probably exceed 10A by at least an order of magnitude.

The camera charger will "handle" any size bank of capacitors, it will just charge them proportionately slower.

I really hope you're not connecting a switch to the capacitors to discharge them across a coil. If you are then you may have a death wish. Try to find some method of remotely triggering the current. Hint: your camera flash unit uses one such method.

The camera flash unit?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
Whilst not ideal, you *could* use a flash tube as a trigger device.

Note that a very low energy pulse is used to trigger the flash tube.

But the thrust of my suggestion is that you shouldn't be getting yourself anywhere near the high energy parts of the circuit.
 

ferrex7

Nov 13, 2010
3
Joined
Nov 13, 2010
Messages
3
Whilst not ideal, you *could* use a flash tube as a trigger device.

Note that a very low energy pulse is used to trigger the flash tube.

But the thrust of my suggestion is that you shouldn't be getting yourself anywhere near the high energy parts of the circuit.

I'd definitely perfer to be at a safe distance ;) How would I go about using the flash tube as a trigger?????
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
I probably wouldn't. The key id to find some way of using a low power (and preferably low voltage) method of switching the high voltage to the coil.

The suggestion above is to use a relay (but consider the contacts and the maximum current).

There are also SCRs that are designed for switching very high current loads.

Here, for example is an SCR that can switch very high currents. You could use an optocoupler to trigger it and be totally isolated.
 
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