| 摘要 |
PROBLEM TO BE SOLVED: To prevent stop of power supply to an apparatus to be protected, caused by a failure in an SPD, by operating a circuit protector earlier than an input breaker of the apparatus to be protected, irrespective of the situation (resistance value) of the SPD in failure, when the SPD fails owing to deterioration. SOLUTION: A lightning surge current flows to a ground 4-1 through SPD 1-1, 1-2 or 1-3 via an SPD 1-4, and a circuit protector 6 does not cause the interrupting operation of an interrupting section 7. For a circuit in which the SPD 1-4, a separator 2-4 are arranged in parallel to the circuit protector 6, a failure current flowing due to the failure of the SPD 1-1, 1-2 or 1-3 flows in the circuit protector 6 side having a rated current smaller than that of the input breaker 3. Thus, the circuit protector 6 is driven to perform the interrupting operation of the interrupting section 7 before the input breaker 3, thereby disconnecting the SPDs 1-1, 1-2 and 1-3 without having an influence on the power feed to a device 10 to be protected. COPYRIGHT: (C)2010,JPO&INPIT
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