Heavy-duty explosively operated pulsed opening and closing switches: reducing cost and turnaround time [railgun power supplies]

Improvements to heavy-duty, explosively operated opening and closing switches to reduce component cost, installation cost, and turnaround time without sacrificing reliability are discussed. Heavy-duty opening and closing switches operated by small explosive charges (50 g or less) are essential to operation of the 60 MJ Balcones power supply. The six independent modules can be discharged sequentially. Each delayed inductor must be isolated from the railgun circuit with a heavy-duty closing switch capable of carrying megampere currents of millisecond duration. Similar closing switches are used to crowbar the railgun as the projectile approaches the muzzle. The switches-both opening and closing-are characterized by microhm resistance in the closed state. The opening switches must be structurally and thermally capable of carrying megampere currents for more than 100 ms (~10⁵ C) and develop 10 kV on opening, stay open for 10^-2 s, and safely and reliably dissipate megajoules of inductive energy in the event of a fault, a failure of the switch to operate, or an attempt to commutate into an open circuit. An example of the severe switching requirements is presented