| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electronic breaker that trips a main contact using an electronic overcurrent tripping device instead of using a mechanical overcurrent trapping device when a short circuit occurs in a high-impedance circuit. <P>SOLUTION: A diode 15 rectifies an AC voltage taken out from an electric path 4 and a capacitor 16 smoothes the rectified voltage. A power circuit 8 steps down a DC voltage from the capacitor 16 and supplies the voltage to a CPU 7 as an operating voltage. When an electric path voltage falls because a modest amount of short-circuit current flowed via a distribution line or load device impedance, the CPU 7 operates on a discharge voltage of the capacitor 16 and checks the short-circuit current that flows to the electric path 4. When the short-circuit current exceeds a reference value set smaller than an operating current value of a mechanical overcurrent tripping device 3, the CPU 7 outputs a trip command to an electronic overcurrent tripping device 2 and trips a main contact 5 with a trip coil 9. <P>COPYRIGHT: (C)2012,JPO&INPIT |
