EARTH DETECTOR BUILT-IN DIRECT CURRENT BREAKER

摘要

PROBLEM TO BE SOLVED: To quickly and surely determine which circuit causes an earth fault by miniaturizing an earth current detecting transformer and a control circuit board equivalent to a relay and integrating them with a breaker. SOLUTION: This breaker is arranged in each of a plurality of circuits An [(n) means a positive integer value] branched from a main circuit 2 having a direct current power source 1, while electrical power is supplied to loads Ln, and the breaker detects and informs an earth fault in the case of its occurrence. The breaker is constructed of a breaker CBn interrupting the circuit An if an overcurrent flows through it, a current transformer CTn having a coil mounted on a ring-type iron core and detecting an earth current flowing through the circuit An because of occurrence of an earth fault, and a control processing circuit Cn connected to the current transformer CTn in each circuit An and detecting an earth fault on the basis of an earth current detected by the current transformer CTn for informing it via a lamp, a buzzer and the like. Both of the current transformer CTn and the control processing circuit Cn equivalent to a relay are incorporated into a breaker main body Bn so as to be integrated.