Determination Method of Optimal Trigger Position for Induction Coil Launcher Based on the Reverse Point of Electromagnetic Force on Armature

The optimal trigger position of the induction coil launcher is difficult to determine, which can affect the design efficiency of the induction coil launcher. Accordingly, the characteristics of the induction current and the reverse point of electromagnetic force for an armature are analyzed based on the electromagnetic force equation and the electromagnetic induction law. Then, the relative position of the electromagnetic force and the discharge current curves are analyzed, and the intrinsic characteristic of the optimal trigger position is obtained. After that, the determination method for the optimal trigger position and the calculation equation are given based on the reverse point of the electromagnetic force. At last, taking the armature whose initial velocity is 200 m/s, for instance, the validity of the determination method for the optimal trigger position is verified by calculation instance and numerical simulations. Meanwhile, the determination method is also verified by experimental results. One can draw the conclusion that the essence of the optimal trigger position is to make the peak zone of the discharge current located just in the acceleration zone of the electromagnetic force, which can improve the launching efficiency of the coil launcher. Furthermore, the optimal trigger position of the driving coil can be determined rapidly when the curve of the electromagnetic force for the armature at a certain initial velocity is obtained. Thus, it is unnecessary to obtain the optimal trigger position by a large number of simulations and experiments, which can improve the efficiency of the simulation and the experiment for the coil launcher.