Armature Structure Research of a Synchronous Induction Coil Launcher
Armature is very important for a synchronous induction coil launcher which can transform the electric energy to kinetic energy and push the load forward. The structure of the armature will influence the kinetic energy conversion efficiency directly. This paper analyzes the armature structure of a capacitor-driven synchronous induction coil launcher. Length and thickness of the armature are analyzed that how these parameters influence the maximum velocity and system efficiency of the launcher. Current filaments model is used to calculate the motion characteristics of a tubular linear induction motors, which is verified by an experiment and finite-element code. Genetic algorithm optimizer is used to calculate the best trigger times of the coils and the maximum velocity under the conditions of different length and thickness of the armature. It is shown that when the armature mass is fixed, length and thickness of the armature will greatly increase the velocity of the armature. The best length of the armature should be almost 2–2.5 times the length of the coil. The best thickness of the armature could be estimated by skin depth.
Investigation of Synchronous Induction Coilgun With Stepped Coil Launcher and Stepped Armature
Synchronous induction coilgun (SICG) typically includes an array of drive coils and a conductive armature. The structure of the drive coil and armature can greatly affect the launching performance of SICG. The traditional drive coils and armatures have a cylinder-shaped structure for simplicity and ease of fabrication. In this article, a novel structural SICG with stepped drive coil and stepped armature (SA) is proposed and investigated. As a comparison, four structural SICGs are researched by static and transient simulations. The static simulation results show that the stepped drive coil makes the magnetic field larger and the center of the magnetic field moves backward toward the tail end. The transient simulation results indicate that the SA improves the eddy current distribution and the positive propulsion force and weakens the reverse electromagnetic force and the armature capture effect at the same time. As a result of integrating the above characteristics, the new structural SICG with stepped drive coil and SA makes the optimal trigger position of armature move backward by 7 mm and improves the muzzle velocity by 4.79% and the launch efficiency by 9.82%.
Results from Sandia National Laboratories / Lockheed Martin Electromagnetic Missile Launcher (EMML)
Sandia national laboratories (SNL) and lockheed martin MS2 are designing an electromagnetic missile launcher (EMML) for naval applications. Lhe EMML uses an induction coilgun topology with the requirement of launching a 3600 lb. missile up to a velocity of 40 m/s. Lo demonstrate the feasibility of the electromagnetic propulsion design, a demonstrator launcher was built that consists of approximately 10% of the propulsion coils needed for a tactical design. Lhe demonstrator verified the design by launching a 1430 lb weighted sled to a height of 24 ft in mid-December 2004 (Figure 1). Lhis paper provides the general launcher design, specific pulsed power system component details, system operation, and demonstration results.