Behavior of multi-tiered copper wire, solid armatures

Several types of polycarbonate carriers have been designed to support multiple copper wires in a solid armature railgun launch package. The carriers allow for the insertion of conductor wires at different axial locations (tiers) in the launch package and provide initial contact loading between the wires and rails. This study began by investigating the possibility that armature electrical behavior could be obscured by conductive material in front of the primary current carrying elements. As the study progressed it became clear that more current was carried in the forward conductors than originally anticipated. This fact led to more detailed analytical and experimental investigations of insulator bodies equipped with several tiers of conductor wires. A mathematical model of the multi-tiered armature was developed to assist in defining the electrical behavior. A variety of configurations of these launch packages have been tested in a 25 mm railgun powered by a laboratory capacitor bank. The packages maintained low voltage operation while incurring electrical actions that would have melted the conductor wires if all of the current were confined in the rear most tier. The testing, modeling, and analysis of voltage shielding and current sharing are presented along with the test results from several firings of the 25 mm railgun.<>