| 摘要 |
PROBLEM TO BE SOLVED: To shut down power supply completely if a large earthquake occurs by providing a relay connected on the way of a relay energizing circuit, an operation holding circuit which is connected to an earthquake sensing switch in parallel, and a relay contact which is connected on the way of the operation holding circuit and closes the operation holding circuit by the operation of the relay. SOLUTION: If an earthquake larger than a prescribed one occurs, an earthquake sensing switch 32 turns on, and very small current restricted by a limiting resistor 34 runs through the passage of a dummy leakage circuit 31 which bypasses a leakage breaker 10. At this time, current is guided to a coil 17, and is amplified to be inputted into a switching circuit 19, however, the current going from power supply side to load side and the current going from load side to power supply side are not equal to each other, which is caused by the very small current which bypasses a leakage breaker 10 mentioned above. As a result, the switching circuit 19 closes a switch 14, and a relay 15 is operated, so that relay contacts 20A, 20B, 20C are opened to stop power supply. |
