High current shorting switch for rapid fire electromagnetic launchers

Claim 2

A switching system for switching large electric currents comprising: a plurality of controllable switching devices electrically connected in parallel with each other; means for turning on said controllable switching devices; a current actuated mechanical switch having a pair of contacts electrically connected in parallel with the parallel connection of said switching devices, said mechanical switch including means for shorting said mechanical contacts in response to current flow through said controllable switching devices, thereby limiting the energy dissipated in said controllable switching devices during each current switching operation; wherein said means for shorting includes a fixed conductor, a movable conductor positioned adjacent to said fixed conductor and electrically connected in series with said fixed conductor, such that current flows in opposite directions in said fixed and movable conductors, and a shorting member attached to said movable conductor; and said fixed and movable conductors lying in parallel planes and being electrically connected in series with the parallel connection of said controllable switching devices such that initial current flow through said controllable switching devices also flows through said fixed and movable conductors resulting in electromagnetic forces between the fixed and movable conductors, which force said shorting member into electrical contact with said pair of contacts.

Claim 3

A switching system as recited in claim 1, wherein said fixed conductor and said movable conductor are each shaped to form a coil.

Claim 4

A switching system as recited in claim 1, further comprising: a plurality of resistors, each of said resistors being electrically connected in series with one of said controllable switching devices to form a plurality of parallel connected branch circuits such that said pair of contacts is electrically connected in parallel with the parallel connection of said branch circuits.

Claim 5

A switching system as recited in claim 1, wherein said controllable switching devices are solid state devices.

Claim 6

An electromagnetic projectile launching system comprising: a pair of generally parallel conductive rails; means for conducting current between said rails and for propelling a projectile along said rails; a pulse current source; a switching system for switching current from said pulse current source to said rails, wherein said switching system includes a plurality of controllable switching devices electrically connected in parallel with each other, means for turning on said controllable switching devices, and a current actuated mechanical switch having a pair of contacts electrically connected in parallel with the parallel connection of said controllable switching devices, said mechanical switch including means for shorting said mechanical contacts in response to current flow through said controllable switching devices, thereby limiting the energy dissipated in said controllable switching devices during each current switching operation; wherein said means for shorting includes a fixed conductor, a movable conductor positioned adjacent to said fixed conductor and electrically connected in series with said fixed conductor, such that current flows in opposite directions in said fixed and movable conductors, and a shorting member attached to said movable conductor; said fixed and movable conductors lying in parallel planes and being electrically connected in series with the parallel connection of said controllable switching devices such that initial current flow through said controllable switching devices also flows through said fixed and movable conductors resulting in electromagnetic forces, between the fixed and movable conductors, which force said shorting member into electrical contact with said pair of contacts; and wherein said rails include an insulating portion positioned such that as said means for conducting current passes adjacent to said insulating portion, an arc is formed, with said arc being extinguished at a subsequent current zero.

Claim 7

An electromagnetic projectile launching system comprising: a pair of generally parallel conductive rails; means for conducting current between said rails and for propelling a projectile along said rails; a pulse current source; a switching system for switching current from said pulse current source to said rails, wherein said switching system includes a plurality of controllable switching devices electrically connected in parallel with each other, means for turning on said controllable switching devices, and a current actuated mechanical switch having a pair of contacts electrically connected in parallel with the parallel connection of said controllable switching devices, said mechanical switch including means for shorting said mechanical contacts in response to current flow through said controllable switching devices, thereby limiting the energy dissipated in said controllable switching devices during each current switching operation; wherein said means for shorting includes a fixed conductor, a movable conductor positioned adjacent to said fixed conductor and electrically connected in series with said fixed conductor, such that current flows in opposite directions in said fixed and movable conductors, and a shorting member attached to said movable conductor; said fixed and movable conductors lying in parallel planes and being electrically connected in series with the parallel connection of said controllable switching devices such that initial current flow through said controllable switching devices also flows through said fixed and movable conductors resulting in electromagnetic forces, between the fixed and movable conductors, which force said shorting member into electrical contact with said pair of contacts; and wherein said rails include an insulating portion positioned such that as said means for conducting current passes adjacent to said insulating portion, an arc is formed, with said arc being extinguished at a subsequent current zero.

Claim 8

An electromagnetic projectile launching system as recited in claim 5, wherein said fixed conductor and said movable conductor are each shaped to form a coil.

Claim 9

An electromagnetic projectile launching system as recited in claim 5, further comprising: a plurality of resistors, each of said resistors being electrically connected in series with one of said controllable switching devices to form a plurality of parallel connected branch circuits such that said pair of contacts is electrically connected in parallel with the parallel connection of said branch circuits.

Claim 10

An electromagnetic projectile launching system as recited in claim 5, wherein said rails include a resistive portion positioned such that when said means for conducting current makes electrical contact with said resistive rail portion, resistance is added to the circuit to reduce the current magnitude.

Claim 11

An electromagnetic projectile launching system as recited in claim 5, wherein said controllable switching devices are solid state devices.

Claim 14

The method of claim 10, wherein said step of shorting of said controllable switching devices through said mechanical contacts allows the use of a smaller number of parallel controllable switching devices than would be required in the absence of said mechanical contacts for each switching operation.

Claim 15

The method of claim 10, wherein said step of shorting of said controllable switching devices through said mechanical contacts reduces the length of time during which current is conducted through said controllable switching devices for each switching operation.