Heavy-Duty Explosively Operated Pulsed Opening and Closing Switches: Reducing Cost and Turnaround Time

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Peterson, D. R.
Price, J. H.
Upshaw, J. L.
Weldon, W. F.
Zowarka Jr, R. C.
Gully, J. H.
Spann, M. L.

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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


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D.R. Peterson, J. H. Price, J. L. Upshaw, W. F. Weldon, R. C. Zowarka, Jr, J. H. Gully, M. L. Spann, “Heavy-duty explosively operated pulsed opening and closing switches: reducing cost and turnaround time,” IEEE Transactions on Magnetics, vol. 27, no. 1, January 1991, pp. 369-373.