The theory and design of the coilgun, including diagrams and schematics, is now available for viewing and download.

Download the Coilgun Manual PDF - 104kB

Objective and Theory of Device

The objective of this device is to propel a projectile using solely electromagnetic forces. This was accomplished using coil wrapped around the barrel the projectile travels through. A ferromagnetic material must be used for the projectile as only ferromagnetic materials can be magnetized. A large voltage across the coil causes a large current to flow through the coil. This current induces a magnetic field through the barrel where half the barrel is one magnetic pole and the other half is the opposite pole. These poles cause the projectile to be accelerated toward the center of the barrel.

Circuit Diagram

The above circuit is the main circuit for operating the coil gun. A 120V/240V transformer ups the wall voltage to 240V. The charging switch open and closes the RC circuit for initiating the charging of the capacitor. This is a small 120V switch as only a small amount of current will flow through this branch of the circuit. Due to the transformer’s output current being limited to .5A a limiting resistor is required for charging the capacitor. 1.5k ohm restricts the max current to below .5A. The capacitor is rated for 400V which is more than sufficient to support the 340V DC which results from the rectification of 240V. The second switch is used for firing the coil gun. This switch is a three-phase motor contactor relay. A heavy duty switch was required due to the high impulse of current at switching. The coil itself is made from 12 AWG enamel coated wire.