Solid state current limiting circuit interrupter
AssigneeGeneral Electric Company
InventorEdward K. Howell
Life of this patent
Estimating the term…
Abstract
A solid state current limiting circuit interrupter for the arcless interruption of current through a protected circuit includes a pair of mechanically switched contacts electrically connected in series between the power source and the protected load. A solid state switch becomes electrically connected in parallel across the contacts when the contacts are opened to transfer the current to the solid state switch in a first state of voltage drop lower than arc voltage, and then in a second state of voltage drop higher than power source voltage in which stored energy is dissipated and current is forced to drop to zero to interrupt the circuit.
Claims4
An arrangement for rapidly interrupting load current flow with minimal arcing, comprising:
- (a) electromechanical switching means having fixed and movable contacts for connection between a source of electric power and a load and constructed to permit extremely rapid separation of said contacts for interrupting load current flow through said contacts;
- (b) semiconductor switching means comprising first and second primary electrodes and a control electrode;
- (c) first means for switching on said semiconductor switching means and transferring load current away from said contacts, through said semiconductor switching means substantially instantly upon initial separation of said contacts and for thereafter maintaining said semiconductor switching means fully conductive for an interval sufficient to provide for de-ionization of any arc between said contacts and for sufficiently cooling and separating said contacts to permit reapplication of a voltage across said contacts which is greater than the voltage of the source of electric power, said interval being in the order or approximately 100 microseconds;
- (d) said first means comprising:
- (1) saturable transformer means having a primary winding, a secondary winding and a saturable core;
- (2) said primary winding being coupled in series circuit with said first and second primary electrodes across said contacts;
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- (3) said secondary winding being coupled between said control electrode and one of said first and second primary electrodes for turning on said solid state switching means responsive to the voltage created across said contacts upon their initial separation and for turning off said solid state switching means upon saturation of said saturable core;
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- (e) voltage responsive means connected in circuit across said contacts for transferring load current subsequent to turn off of said solid state switching means and subsequent to the voltage across said voltage responsive means exceeding the voltage of said source of electric power.
Dependencies are inferred from the claim text.