| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve a failure detection ratio by providing a voltage monitoring circuit directly coupled to each wire of a three-phase generator and having two closed circuits including a light emitting element and a signal processing circuit including a light receiving element corresponding to the light emitting element for outputting two signals. SOLUTION: When respective wires of a three-phase generator are normal, current flows to closed circuits 4a, 4c of a voltage monitoring circuit 1, is converted into light by photo diodes 3a, 3c, and is transmitted to photo Darlington transistors (light receiving elements) 5d, 5e. In a signal processing circuit 2, the light receiving elements 5d, 5e react with light of the photo diodes 3a, 3c to have current flowing, thereby signals at terminals (d), (e) exhibit 0V. On the other hand, when a wire connected to a terminal (a) is broken, no current flows to the light receiving element 5d, so that a signal at the terminal (d) exhibits a certain value. Similarly when the terminal (c) or the terminal (b) is broken, a signal at the terminal (e) or both signals at the terminals (d), (e) exhibit a certain value. Thus with monitored signals at the terminals (d), (e), it can be easily detected which wire has been broken.</p> |
