Improved Energy Utilization of Linear Induction Launchers by Considering Each Section as an Individual Sub-Launcher

Abstract

In the linear induction launcher (LIL), the barrel is divided into sections, and either a discharging capacitor bank or a flywheel motor/generator set energizes the sections sequentially with polyphase currents. Within the sections, the drive coils of the LIL can be connected either in series or in parallel. In previous publications, two different parallel-connected configurations of the drive coils were described. One has a single flywheel generator per section supplying all the phases, and all the drive coils per-phase are parallel connected. However, the generators get larger and larger the nearer one gets to the muzzle. The second configuration has one pair of shaft-coupled flywheel generators for each N-S pole-pair, but has all of the generator-pairs (in a given section) shaft-coupled together to form a cascaded array. This arrangement permits one to supply the increasingly larger energy needs by dividing the energy among many generators of nearly equal output. Since all the generators in one section are shaft-coupled together, forming a cascade array, they produce the same voltages and frequencies. This paper deals with the effect of running the generators/section at incrementally increasing frequency and voltage, rather than at a constant level. In effect, it means that each section of the whole launcher would be operated as an individual sub-launcher. By doing this, the acceleration of the projectile becomes smoother. Moreover, it would be possible to disconnect generators in a section from their drive coils once the projectile has passed them by; this would help to improve the system efficiency. This paper describes the new pulse-generator configuration, explains the improvement on the system efficiency, and provides graphs to compare the new results with those obtained previously with the cascade array configuration.