| 摘要 |
<p>PURPOSE:To obtain the monitoring device having a high reliability using small number of parts by a method wherein the pulse width of a command signal is measured, and a device which monitors the state of operation of a circuit breaker is composed of a closing coil, a trip coil, a signal detecting circuit to be converted to said two coils, and a signal processing circuit. CONSTITUTION:A closing coil 14 and a trip coil 2 are connected to the first and the second primary windings 50 and 52 of the current transformer 40 located in a signal detecting circuit 26 respectively, and both terminals 42 and 44 of a secondary winding 54 are connected to the LED elements 12 and 24 which are connected in reverse characteristics respectively. The current monitoring device is constituted as above and when a pulse current which is a breaking signal in the direction as shown by the arrow A in the diagram runs on the coil 2, a magnetic flux in the direction of the arrow B is generated, an electromotive force having the terminal 44 as positive is generated on the secondary winding 54, and the element 12 is turned-ON in the period of time exceeding the threshold voltage. Also, when the current in the direction shown by the arrow C runs on the coil 14, the magnetic flux in the direction shown by the arrow D is generated on the magnetic core 42, and an element 24 is turned-ON in the same manner as above. Subsequently, the light emitted by the above-mentioned element is made incident on the photo diodes 30 and 32 of a processing device 28 through the intermediaries of optical fibers 70 and 72, and whether their operation is normal or abnormal is decided.</p> |
