The Trolley Wire that supplies power for the operation of the urban railway train is pulled in the running direction of the train by friction with the pantograph that transmits the electricity of the train. Besides Trolly Wire vibrates up and down by the push-up force of pantograph, the Trolly Wire is broken due to accumulated fatigue cracks. As a result, the operation of the urban railway is eventually interrupted, and safety accidents may also occur while a passenger on the urban railway evacuates.
Currently, Inspection of the urban railway Trolly Wire is difficult to secure the reliability of inspection. This is because an worker who is in charge of the inspection boards the maintenance work vehicle moving along the path of the train and depends only on visual inspection. So it is a fact that in urban railway management agencies, the Trolly Wire which have been aged more than 25 years are batch replaced at once.
In this study, in order to improve the efficiency of urban railway management and prevent suspension of operation of the train, I attempted to develop a technique for detecting the defect of a Trolly Wire by Eddy current based on the law of Faraday electromagnetic induction.
First, based on Faraday ''s law of electromagnetic induction, the theory of Trolly Wire defect detection by eddy current is described.
Secondly, we developed an eddy current checker and an ECT probe of drive pick up type. And I tested by setting inspection target values of hole type defects due to salt damaged and crack type defects due to fatigue cracks, by processing artificial defects on the same copper rod material as the material of the Trolly Wire. As a result, it was confirmed that the shape of the Lissajous graph due to salt damaged and the Lissajous graph due to cracks are clearly different from those of ordinary test pieces.
Thirdly, it was confirmed that the defect signal of the specimen can be detected up to the target value (0.63 mm hole and 0.1 mm crack) by the Lissajous graph.
From the above results, it is proved that the test for detecting the defect of the Trolly Wire applying the Faraday electromagnetic induction law proposed in this study is valid.