<b>Method for Estimating Molten Volume of Current Collecting Materials at Contact Loss Point using <i>ϕ</i>-<i>θ</i> Theory</b>

In order to control electric wear of current collecting materials such as contact wires and contact strips in electric railways, it is necessary to understand the relationship between current and the molten volume at a contact loss point. In this paper, we propose a method for estimating the molten volume of the contact wire whose film resistance is taken into account, on the basis of the ϕ-θ theory. To verify the proposed method, we carried out wear tests under varying current conditions to measure the molten depth, molten radius, and molten volume. The wear test results showed that the experimental values of the molten volume of the contact wire are spread in the range where normalized potential at the contact boundary at which α was estimated to be 0.90 to 0.94.