Circuit interrupter control responsive to wave form

Claim 1

A CONTROL FOR A CIRCUIT INTERRUPTER HAVING A PREDETERMINED DELAY BETWEEN RECEIVING A TRIPPING SIGNAL AND SEPARATING ITS CONTACTS, COMPRISING, MEANS CONNECTED TO RECEIVE A MEASURE OF A CURRENT WAVE FORM OF THE ELECTRICAL SYSTEM IN WHICH THE CIRCUIT INTERRUPTER IS CONNECTED AND RESPONSIVE TO A FIRST POINT OF PREDETERMINED MAGNITUDE ON THE WAVE FORM TO PRODUCE AND MAINTAIN A SIGNAL INDICATING THAT A FAULT HAS OCCURRED IN THE ELECTRICAL SYSTEM, DERIVATIVE MEANS RESPONSIVE TO SAID FAULT INDICATING SIGNAL AND RESPONSIVE TO SAID WAVE FORM IN A REGION BETWEEN SECOND AND THIRD POINTS OF PREDETERMINED MAGNITUDE ON THE WAVE FORM TO PRODUCE A SIGNAL VALUE THAT IS A FUNCTION OF THE SLOPE OF THE WAVE FORM IN SAID REGION, DELAY MEANS INCLUDING A CAPACITOR CONNECTED TO RECEIVE SAID SIGNAL VALUE TO CHARGE SAID CAPACITOR TO A LEVEL DETERMINED BY THE MAGNITUDE OF SAID SIGNAL PRODUCED BY SAID DERIVATIVE MEANS, AND MEANS FOR DISCHARGING SAID CAPACITOR AT A PREDETERMINED RATE, AND MEANS RESPONSIVE TO THE DISCHARGE OF SAID CAPACITOR TO PRODUCE A TRIP SIGNAL DELAYED FROM SAID THIRD POINT BY A TIME THAT IS A FUNCTION OF SAID SIGNAL BEFORE SIGNAL DERIVATIVE, THE MAGNITUDE OF SAID THIRD POINT, AND THE CIRCUIT INTERRUPTER DELAY TO SEPARATE THE CONTACTS AT A PREDICTED POINT OF PREDETERMINED MAGNITUDE IN THE WAVE FORM.