Triggered spark gap type of surge arrestor

Claim 1

IN A D.-C. CIRCUIT COMPRISING A PAIR OF CONDUCTORS OF OPPOSITE POLARITY, A SURGE ARRESTOR COMPRISING: (A) A PAIR OF SPACED APART MAIN ELECTRODES, (B) MEANS ADAPTED TO ELECTRICALLY CONNECT SAID MAIN ELECTRODES ACROSS SAID CONDUCTORS, (C) EACH OF SAID MAIN ELECTRODES COMPRISING AN ARCINITIATION PORTION AND AN ARC-RUNNING PORTION ADJACENT SAID ARC-INITIATION PORTION, (D) HIGH-FREQUENCY-RESPONSIVE TRIGGERING MEANS COMPRISING A FIRST TRIGGER ELECTRODE LOCATED ADJACENT THE ARC-INITIATION PORTION OF ONE OF SAID MAIN ELECTRODES FOR CAUSING AN ARC TO BE ESTABLISHED BETWEEN THE ARC-INITIATION PORTION OF SAID MAIN ELECTRODES WHEN SAID HIGH-FREQUENCY-RESPONSIVE TRIGGERING MEANS IN ENERGIZED BY A VOLTAGE SURGE ON SAID D.-C. CIRCUIT OF A PREDETERMINED MINIMUM MAGNITUDE HAVING A HIGH RATE OF CHANGE, (E) LOW-FREQUENCY-RESPONSIVE TRIGGERING MEANS FOR CAUSING AN ARC TO BE ESTABLISHED BETWEEN THE ARCINITIATION PORTIONS OF SAID MAIN ELECTRODES WHEN SAID LOW-FREQUENCY-RESPONSIVE TRIGGERING MEANS IS ENERGIZED BY A VOLTAGE SURVE ON SAID D.-C. CIRCUIT OF A PREDETERMINED MINIMUM MAGNITUDE HAVING A RELATIVELY LOW RATE OF CHANGE, SAID LOW-FREQUENCY-RESPONSIVE TRIGGERING MEANS COMPRISING A TRANSFORMER AND A SECOND TRIGGER ELECTRODE IS CIRCUIT WITH SAID TRANSFORMER AND ELECTRICALLY INSULATED FROM SAID FIRST TRIGGER ELECTRODE, SAID SECOND TRIGGER ELECTRODE BEING LOCATED ADJACENT THE ARC-INITIATION PORTION OF SAID ONE MAIN ELECTRODE AND INSULATED THEREFROM, (F) THE ESTABLISHMENT AND INSULATED THEREFROM, ELECTRODES COMPLETING A BY-PASS CIRCUIT BETWEEN SAID D.-C. CONDUCTORS AROUND SAID TRANSFORMER THE PROTECTS SAID TRANSFORMER FROM SAID HIGH RATE OF CHANGE VOLTAGE SURGES, (G) AND MEANS OPERABLE WHEN AN ARC IS ESTABLISHED BETWEEN SAID MAIN ELECTRODES FOR DEVELOPING AN INCREASING ARC VOLTAGE FOR DRIVING THE ARC CURRENT TOWARD ZERO, COMPRISING MEANS FOR PROPELLING SAID ARC ALONG THE ARC-RUNNING PORTIONS OF THE MAIN ELECTRODES.