| Summary: | In order to suppress electric wear of current collecting materials such as a contact wire and a contact strip in an electric railway, it is necessary to estimate the relationship between current and melting volume at a contact loss point. In this paper, we focused on a molten bridge which is considered as the main factor of electric wear at the contact loss point. And we proposed the estimation method of melting volume of contact wire and contact strip; in which film resistance is considered by using the relationship between the electric potential and the temperature at the contact spot. From estimation results, it is found that the melting volume increases as current increases, and that it increases as a contact boundary factor decreases. In addition, the authors carried out wear tests and measure a melting depth, a melting radius, and a melting volume under two conditions of current. From wear test results, experimental values of melting volume of the contact wire were in the range where contact boundary factor α was estimated from 0.90 to 0.94.
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