NOVOSIBIRSK STATE TECHNICAL UNIVERSITY Contact Wire Reducing Wear Researcher: graduate student, Faculty of mechatronics and automation, electrotechical units department, Roman Vagaytsev. Research adviser : Cand. Eng. Sc. Associate Prof. , electrotechical units department, Birykov V. V. Novosibirsk 2016
Objectives: 1. Reducing wear of contact wire at stations for extending the life time of contact wire and for reducing the contact loss of pantographs of passing high speed trains; 2. Conduct the experiments. 2
Wear experiment facility and conditions of the experiments (a) Side view (b) Front view Figure 1. Composition of wear experiment facility 3
(a) Disk and pantograph (b) Disk Figure 2. External appearance of wear experiment facility Specifications Items Max. sliding velocity 250 km/h ( 7± 0. 4 km/h in these experiments ) Max. current DC 500 A ( 0 or 100 A in these experiments ) AC 350 A Voltage between disk and pantograph DC 200 V ( in these experiments ) AC 148 V Lateral motion of pantograph ( left and right ) 200 mm each ( cycle is variable, 52. 4 sec. / cycle in these experiments) Table 1. Features of wear experiment facility 4
Items Cu Nominal cross-sectional area ( mm ) Tensile strength ( MPa ) Conductivity ( %IACS* ) *: International Annealed Copper Standard Specific weight ( g / cm 3 ) Hardness Hv ( MPa ) Items Size ( length * width * depth (mm) ) Tensile strength ( MPa ) Conductivity ( % ) Specific weight Hardness HB ( MPa ) Properties Contact wire Cu-Sn Cu-Cr-Zr ( "PHC" ) 110 110 344 364 477 98 70 80 8. 9 120 8. 9 130 Contact strip 270 * 40 * 10 254 4. 1 7. 1 126 8. 9 180 Table 2. Properties of contact wire and contact strip Items Sliding velocity Normal load ( force pressing strip ) Voltage between disk and pantograph Sliding time Lateral motion of pantograph ( left and right ) Current condition Conditions 7± 0. 4 km/h 47. 04 N DC 200 V 370 min 200 mm each 52. 4 second / cycle (1) (2) (3) No current DC 100 A with boundary lubrication Table 3. Experiment conditions 5
Results of the experiments (a) Cu (b) Cu-Sn (c) Cu-Cr-Zr Figure 3. Changes of friction coefficient with time 6
Results of the experiments 7
Results of the experiments 8
Conclusion • In the cases of boundary lubrication, it seems that there is a possibility that the powder cut from contact wire is mixed into the grease. It can be considered that this would contribute to electric conduction and make contact resistance smaller. • It seems effective to mix conductive substances into the grease for boundary lubrication. However, the influence on contact wire and contact strip by the pantographs which pass at high speed needs to be checked. • If the wear of contact wires of stations at the points where pantographs stop can be decreased, speed of passing trains especially at stations without through tracks can be raised. This promotes convenience for customers. 9
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