Design and Construction of an Expandable Series Trans-Augmented Electromagnetic Railgun [open pdf - 3MB]
From the thesis abstract: "Long range maritime land attack can be accomplished with today's chemically propelled munitions only by sacrificing responsiveness. Projectiles launched with electromagnetic forces can achieve velocities above 2-3 kilometers per second. The technical challenges to be overcome before electromagnetic launch can be considered practical for maritime land attack include development of high density pulsed power supplies, high current power switching and a long life launcher. To investigate electromagnetic launch technology a 1.2 meter railgun was constructed. It was designed to allow augmentation and various bore configurations. The railgun power unit consists of two 11 kV, 830 microfarads capacitors discharging through a 7 micro-H inductor coil. A crowbar circuit provides capacitor protection. Operational testing of the firing circuit, instrumentation, power unit, and launcher structure was satisfactory. The 7 micro-H coil induced currents within the power unit, which adversely effected triggering circuitry. The molybdenum projectiles initially tested proved disappointing due to their tendency to meld with the copper rails. An extended current pulse resulting from such a meld caused failure of the crowbar circuit, which curtailed further testing. The induction coil could safely be discarded, and a revised crowbar circuit will prevent further failure. Future operational testing will focus on alternative armature materials and designs and on operational methods."
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