How Coil Guns Work

PLEASE READ VIDEO DESCRIPTION FOR SPECIFICATIONS AND HELP LINKS!!

This video is FINALLY now in HD! I finally have a more powerful computer to edit in HD.

This is my first coil gun I have built. This is capable of shooting through multiple soda cans. I have plans to build a second one in the near future.

Download Simplified Schematics of my coil gun project here:
http://dl.dropbox.com/u/19583353/Do%20Not%20Delete%21/Coil%20Gun%20Schematics...

Old comments on this video with my old YouTube Channels (This is useful for FAQs) can be downloaded here:
http://dl.dropbox.com/u/19583353/Do%20Not%20Delete%21/Old%20YouTube%20Comment...

Disposable flash camera schematics I found on the internet:
http://dl.dropbox.com/u/19583353/Do%20Not%20Delete%21/Disposable%20Camera%20F...

http://dl.dropbox.com/u/19583353/Do%20Not%20Delete%21/Full%20Camera%20Flash%2...

Other Helpful Internet Links:

(Capacitors in Series and Parallel)
http://www.allaboutcircuits.com/vol_1/chpt_13/4.html

Sorry for not including any background music. I do not want any copyright infringements on me.


Some technical information on my coil gun:
U=1/2*C*V^2

U= Potential Energy (Joules)
C= Capacitance in Farads
V= Voltage

My coil gun's energy is:
V = 670Volts
C = 761uF
U= 1/2 x 0.000761Farads x 670V^2 = 170.81 Joules

KE = 1/2*m*v^2
m = mass (kg)
v = velocity (m/s)
KE = Kinetic Energy (Joules)

My coil gun's speed and kinetic energy of projectile:
m = 8g (.008kg)
v = roughly 30m/s

KE = 1/2 x .008kg x 30m/s^2 = 3.6 Joules


Other Notes:
I used 2 diodes to protect the transformers and capacitors from emf feedback created by the coils after firing. The diodes also help reduce the rate of voltage from dropping down when the capacitors are charged at its max.
The diodes have a value of 1000V Max
The diodes sort of limit the maximum performance of the coil gun (could go a few extra m/s faster), but it is better to protect yourself and all the hard work put into it.

The transformer bank should be adequately cooled to protect the transistors from overheating.


**Firing the coil gun over a long period tends to make the coils warm up. The coils need to cool down, otherwise maximum velocity will not be achieved since heat reduces the strength of the magnetic field.

To achieve a high velocity, you need high currents (magnetic field is depended on electrical current) which in turn requires a high voltage so that circuit impedance (resistance) can be overcome and the required current can be achieved. Source: http://www.powerlabs.org/railgun.htm

Thanks for reading and watching.

Need any help on building, please feel free to drop me a message or comment and I'll get back to you soon.

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[Someone7089]

Do you think that only 1 charging circuit from a disposable camera is not nearly enough for charging a few 450V capacitors I have? Because I'm having trouble getting a few of the same disposable camera circuits that take the same voltage.

[JPMediaProductions]

@Someone7089

The use of the multiple charging circuits in this coil gun video was to spread the load across multiple charging units. That's why they are wired in parallel.

Another thing to try is use lithium batteries or freshly charged batteries in the charging circuit. I put the batteries in parallel to boost capacity and output current since one battery cannot do that by itself.

Does this answer your question?

[JPMediaProductions]

@Someone7089

Personally to check if the capacitor is full, you need to use a voltmeter and check the voltage across the capacitor terminals like I did in the video. Notice how the lights on the transformer bank turned on even though the capacitors were not fully charged. Lastly, make sure your voltmeter supports measuring of high voltages.

Hope that is helpful,

JP

[JPMediaProductions]

Greetings YouTubers!,

If any of you noticed that the download links in the video description were not working, that was because I reinstalled Windows 7 to optimized it for performance. Now that my system is back online, the links should be working again. Sorry for the inconvenience.

[Someone7089]

@JPMediaProductions I was afraid that doing that would fully discharge the capacitor. I'm going to try that.

[Someone7089]

@JPMediaProductions Well, I used the one charging circuit to charge up one 450 volt capacitor and the charging light was full in about 15 seconds. I don't know if the capacitor is actually charged as much as the light said it was. Once I add the other capacitor, I am going to take your advice and add more batteries in parallel and another charging circuit if I can get one.

[lokeycmos]

that is awesome!!

[mahela1993]

I appreciate the fact that you didn't include any gaudy background music. The silence is actually much better.

[JPMediaProductions]

@Lukasvasiljevas

Not exactly. You could wind less turns since the wire is thicker (hence the coil diameter would be the same diameter with fewer winds compared to a higher gauge wire)