A long conduction-time, 2-ma commutating switch

An array of eight parallel opening switches is designed to commutate the 2-MA current of an energy storage inductor into a low-inductance, low-resistance load for electromagnetic launcher research. Switch opening is achieved by interruption of the current path with a small explosive charge which, in this particular switch, is totally surrounded by the conductor. This switch, in its normally closed state, carries current during the 5-s interval required for the inductor to be energized by the Air Force Armament Laboratory (AFATL) battery power supply. Conductor cross section is determined experimentally so that Joule heating of the conductor does not cause overheating and improper detonation of the explosive. Prototypes of the switch modules were tested at AFATL with 168-kA, 5-s current pulses.