THE RESULTS OF BENCH TESTS OF THE SLIDING CONTACT OF ELECTRIC TRANSPORT TO DETERMINE THE WEAR OF THE CONTACT WIRE

Purpose. Electric rolling stock of railways receives power from a 25 kV AC or 3 kV DC overhead contact network using a high-current sliding contact that transfers energy to locomotive or electric train, while the current can reach values of 2500 A. Of course, the reliability of this sliding contact determines the operational reliability of the unit. electric transport in general. The pantograph of an electric locomotive or electric train is equipped with a pantograph – a pantograph with contact strip, which should damage and wear it to a minimum when sliding along the contact wire. When introducing new materials for pantograph contact strip, they must pass tests, among which there are bench tests to determine the wear of the contact wire. The purpose of the research is to determine the possibility of using various types of linings on the electric rolling stock of railways, with the determination of the value of the wear of the contact wire and its comparison with the standard. Methodology. The main research method is an experiment on a test bench with control of the main indicators, which include – contact current, clamping force, speed of rotation of the disk of the test bench, temperature in the contact zone. The method of bench tests is standardized, in accordance with DSTU GOST 32680: 2016. Results. During the experiments on the test bench, six types of pantograph contact strips were investigated, and the indicators on the amount of contact wire wear were obtained. Determination of the wear of the contact wire is carried out as the difference between the heights of the contact wire before and after the experiment. The wear values of the contact wire were recorded every 10 thousand passes of the test bench disk. The obtained values of wear are stochastic probabilistic in nature, so they were processed by methods of mathematical statistics to determine the value of the mathematical expectation of the amount of wear of the contact wire. Based on the obtained values, the relationships between the amount of wear of the contact wire and the number of revolutions of the test disk of the stand are constructed. Originality. The scientific novelty of the research lies in the obtained relationships between the number of passes and contact wire wear for different types of samples of pantograph contact strips of electric rolling stock of railways, which allows to determine the contact wire resource when implementing different types of current collector inserts. Practical value. The main purpose of bench tests is to reproduce the conditions of actual operation with certain restrictions. Test specimens in bench tests were in the same conditions, so the obtained values of wear of the contact wire for different types of contact strips allow to estimate the possible service life of the sliding high-current contact in real operating conditions. The obtained values are relative, the first type of inserts is accepted as a base sample, which allows to determine the quantitative indicators of wear of contact strips in comparison with this reference sample. The normative value of contact wire wear is 40 μm per 10 thousand passes of the test bench disk. The tests are considered successful if the wear of the contact wire does not exceed the specified standard value. According to the test results, three samples of contact strips were identified, the use of which will not lead to wear of the contact wire above the normative value. Analytical expressions are obtained for three types of contact strips, with the help of which it is possible to obtain comparative values of resource indicators of sliding high-current contact. Figures 11, tables 2, references 13.