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450J Coil Gun

     Coil gun is the weapon of the future. No gunpowder, cartridges or mechanical trigger. Iron projectile is accelerated by a strong magnetic field coils. The huge current in the coil is ensured by capacitor bank. The current is switched using button via a large thyristor (SCR). Switching mechanically such current is impossible - switch would be destroyed, you will be deaf, and most of the energy would consume the explosion of contacts and not the acceleration of the projectile :).
     My coil gun uses a capacitor bank with a total capacity 11600uF rated to 350V. Maximum power is about 700J. I charge it only to 280V, which is 450J. It is charged using 1:1 isolation transformer 230/230V 50Hz 300VA. You can also use smaller, but charging will be slower. Charging is activated through a button TL1, button TL2 is a trigger. Capacitors have a protective diode, which protects against negative voltage generated in the coil. For switching I use a big thyristor made by CKD, which can withstand pulse approx 5000A ... Thanks to David :). Shot coil has 34 turns and is wound using three wires with a diameter of 1.1 mm. The cross section is therefore about 2.8 mm2. The projectile has a 5 mm (0.2'') diameter and 5 mm (1.38'') length. After switching the thyristor the projectile is pulled by the electromagnetic force to the center of the coil. Pulse must be very short and strong. When the projectile reaches the middle of the coil, the capacitor must be almost discharged, otherwise the magnetic field will start to slow down the projectile instead of accelerating it. The coil must therefore have a relatively small number of turns. The formula to calculate the energy in a capacitor:
Energy in Joules, the capacity in Farads and voltage in volts.

     Warning! Coilgun can cause serious injuries or damage to property. The projectile may reflect or change direction unexpectedly. The capacitors store large energy, and when they are discharged, a very high current can flow. Wires and components can explode. Capacitors are deadly even after switching the coil gun off. Everything you do at your own risk. For any personal injury or property damage I do not take responsibility.

Coil gun cut.

450J (700J max) coil gun schematic

Video - Coil gun shoots holes in the spray and metal cap.

Video - shooting into a glass, polystyrene, spray, CD, ...

RLC circuit simulation - Java aplet

Metal lid with holes.

Can with holes

Large thyristor, which I use a smaller double thyristor (both CKD).

Voltmeter (charging to the 300V, so far the highest voltage)

Capacitor bank. If you were not on Czech site, ther would be something like "... very cheap on ebay, only 200 USD ..." , but my capacitor bank is made ‚Äč‚Äčtypically Czech (and for free). Most of the capacitors is TESLA, some are from the USSR (CCCP).

Different projectiles (best results with the second from the bottom)

Various experimental coils

location of the projectile in the coil (shoots left)

Iron sheet looking as a colander.