RAILGUN ARMATURE ARCING VOLTAGE DROP

Controlling the transition of metal armatures to hybrid armatures is e ssential for the design of reliable transitioning armatures and launch packages. The basic physics of transition must be understood to contr ol transition. Railgun tests are inadequate to understand the basic ph enomena of transition. They have many uncontrolled parameters. Bench-t ype experiments where all operating parameters can be controlled are n eeded to understand basic transition phenomena. We designed a pin-on-d isk experiment and measured the contact voltage drop across arcing con tacts. The tests were conducted with current densities similar to rail gun current densities. We also varied the are gap and velocity. We fou nd that arcing contact voltage for an aluminum contactor on a copper d isk is about 40 V and concluded that when the muzzle voltage in a rail gun test with a metal armature is greater than 40 V, one side of the m etal armature must have transitioned to a hybrid. In this paper, we de scribe the experiment, the measurement technique, and present the resu lts of the experiment.