Resettable circuit breaker for use in ground fault circuit interrupters and the like

Claim 1

Switching apparatus for selectively completing or interrupting an electrical connection between an input and an output conductor comprising: a armature movable between first and second positions, an electromagnet adapted, when energized, to move said armature from the first position to the second position, said armature being unresponsive to said electromagnet when in said second position, an input contact connected to said input conductor, an output contact connected to said output conductor, rocking means rotatable in response to movement of said armature, one of said contacts being mounted on said rocking means and rotatable therewith into engagement with the other of said input and output contacts when said armature is moved from said second position to said first position and out of engagement with said other of said input and output contacts when said armature is moved from said first position to said second position, a pressure sensitive member connected to said armature for moving said armature to said first position from said second position when operability is desired, said armature being inoperable in response to teasing pressure when in said first position, a differential transformer for generating a voltage pulse in response to a current imbalance, a circuit operatively connected to said differential transformer for integrating said voltage pulse, said circuit including a silicon controlled rectifier electrically connected to said electromagnet, said silicon controlled rectifier being caused to conduct current in response to a given magnitude and duration of the integrated voltage pulse thereby energizing said electromagnet to cause said armature to open said one contact for interrupting said electrical connection between said input and output conductors.