| 摘要 |
PURPOSE:To detect the arc light due to the loose contact between a pantograph and a trolley wire, by providing plural photodetectors, which are arranged so as to divide the visual field of measurement, and a circuit to which pulses due to the received arc light are inputted to add and amplify them. CONSTITUTION:A loose contact measurer 18 is attached onto the roof of a vehicle 17, and an arc light 16 due to the loose contact between a trolley wire 6 and a pantograph base body 12 at the tip of a pantograph 4 is detected. A photodetector group 15 fractionizes a visual field 13 of measurement through a lens 14 to detect lights, and the output is inputted to a summing amplifying circuit 20 through a low frequency eliminating circuit 19. Since the variation of the quantity of natural light is gentle, the output is stopped by the low frequency eliminating circuit 19, and the arc light is not stopped because of pulses and is inputted to the summing amplifying circuit 20. Thus, the arc light is detected without the influence of natural light, and the loose contact is measured with a high reliability. |
