Arc-fault detecting circuit breaker system

An arc-fault detecting circuit-breaker system operable with a direct current protected electrical circuit having a protected-circuit input that receives a direct current electrical signal, the arc-fault detecting circuit-breaker system comprising:

• a normally closed line circuit breaker having an electrical input and an electrical output;
• an electrical line connecting the electrical output of the normally closed line circuit breaker to the protected-element input;
• a detector of the rate of change with time of a current flow in the electrical line;
• an activating element alternating current voltage source having an activating element alternating current output at an activating element alternating current output frequency;
• and
• a circuit-breaker activating element operable responsive to the detector, wherein the circuit-breaker activating element is electrically connected between the electrical line and the alternating current output, and wherein the circuit breaker activating element is a normally open switch that closes to establish a connection between the electrical line and the alternating current output in the event that the detector detects a rate of change of current with time in excess of a permitted maximum rate-of-change value.

An arc-fault detecting circuit-breaker system operable with a protected electrical circuit having a protected circuit input that receives an alternating current electrical signal at a protected circuit frequency, the arc-fault detecting circuit-breaker system comprising:

• a normally closed line circuit breaker having an electrical input and an electrical output;
• an electrical line connecting the electrical output of the normally closed line circuit breaker to the protected-element input;
• a detector of the rate of change with time of a current flow in the electrical line;
• an activating element alternating current voltage source having an activating element alternating current output at an activating element alternating current output frequency at least twice that of the protected-circuit frequency;
• and
• a circuit-breaker activating element operable responsive to the detector, wherein the circuit-breaker activating element is electrically connected between the electrical line and the alternating current output, and wherein the circuit breaker activating element is a normally open switch that closes to establish a connection between the electrical line and the alternating current output in the event that the detector detects a rate of change of current with time in excess of a permitted maximum rate-of-change value.