| 摘要 |
PURPOSE:To enable highly sensitive detection for a long time by a method wherein a sound related to abnormal state is detected to be converted into an electrical signal and duration time of a specified frequency component is counted and judged. CONSTITUTION:In a closure type distribution panel CUB, a main circuit conduction section 3A or 3B is provided with an alarm sound generator 1 to store a coil spring. With an overloading, an excessive current flows through conductor parts 3A and 3B and as a connection part thereof reaches an abnormal temperature, a bimetal of the generator 1 deforms to release the retaining of a hammer, so that the manner strikes a bell flange by a stored force of the spring to generate an alarm sound. The sound is received with a microphone 20 to be converted into an electrical signal and inputted into an abnormality judging device 2. The judging device 2 amplifies the electrical signal and extracts a 3-frequency component to rectify. Then, DC voltage are compared with a reference voltage separately and a signal is outputted when it exceeds the reference voltage. The duration time of the signal is counted and when it reaches a specified time, a signal judging abnormal state is outputted. |
