| 摘要 |
PURPOSE:To detect the overheated state quickly, by contacting the end parts of transmitting and receiving optical fiber cables, which guide the light from a light emitting element, holding the cables, providing a light receiving element at the other end of the receiving optical cable, and imparting heat contracting property to at least one of both optical fiber cables. CONSTITUTION:When the temperature of a high pressure bus conductor 1 is increased and overheat temperature exceeding a specified temperature is reached, the temperature of transmitting and receiving optical fiber cables 4 and 5 is increased through a case 2. Then optical fiber strands 4' and 5' in the case 2 are quickly contracted and the light emitting surface and the light receiving surface are separated. The amount of contraction of the optical fiber strands 4' and 5' (a) with respect to the temperature (b) and the amount of the received light on the light receiving surface from the light emitting surface are shown in the graph. At a receiving element 9, the amount of the received light is extremely lowered by the contraction of the optical fiber strands 4' and 5' at the time of overhead. Thus the overheated state of the bus conductor 1 is detected. Alarm is outputted based on the signal from the light receiving element 9 and current conduction to the bus conductor 1 is stopped. Thus the fault is prevented beforehand. |
