| 摘要 |
PROBLEM TO BE SOLVED: To provide a breaker monitoring device reduced in size while providing the same count function as that of a prior art and suitable for reducing the work amount of service personnel. SOLUTION: A main circuit current I is detected constantly by a current detector 4. When it is larger than a protective operation set value 7, an over- current detection comparator 8 outputs to output pulses from a one-shot circuit 9 so as to operate a breaking operation circuit 11 through an output amplifier 10 in order to open the main contact 4a of a high speed breaker for cutting off the main circuit current I. When the main contact 4a is open, the auxiliary contact 4b thereof is closed to output a signal from an AND gate 12, and the signal is counted by an IC counter 13b, and the counted value is compared with a count judgment value 14 by a digital comparator 15. The cut off operation is repeated and, when the number of cumulative counts exceeds the count judgment value 14, the digital comparator 15 outputs a signal to light up a light emitting diode 16. Elements including the IC counter and light emitting diode are installed on a printed circuit board. |
