Design and evaluating the driving coil on induction coilgun

The driving coils in the synchronous induction coilgun are stacked end-to-end forming a barrel. During the launching, the pulsed current flows through the driving coil, the magnetic force propel the projectile. The driving coil endures not only the outward radial force because of the magnetic flux compression, but also the axial force. In the process of designing the coil, the mechanical strength and electrical insulation should be both considered. Due to the nonlinear of insulation materials, the theoretical calculation can not reflect the true state for the driving coil. The static-state test method is analyzed and verified through experiments. The experimental results show that this method is effective in certain extent, but it neglects the axial counterforce and does not reflect the true state of launching. An improved method for evaluating the coil strength is proposed based on the analysis of the basic principle. The projectile is accelerated by the former stages, and the test coil accelerates the projectile with the initial speed. This method could test the coil mechanical strength and electrical insulation effectively similar to the practical launching. An equipment for single coil is designed based on the existing multi-stage coilgun and placed in the muzzle of the barrel. The coils is tested, and the experimental result shows that this equipment is convenient to install and detach the coil and could evaluating different types of the coil, it can reflect the true dynamic characteristics for the single coil. The structure of the driving coil could be improved combined with the dynamic-state testing and evaluating, which provide experimental reference for the mutli-stage induction coilgun design.