scholarly journals Experimental Analysis of the Influence of the Electrical Arc on the Wear Rate of Contact Strip and Contact Wire in a.c. System

2016 ◽  
pp. 449-456 ◽  
Author(s):  
Giuseppe Bucca ◽  
Andrea Collina ◽  
Ezio Tanzi
Keyword(s):  
Wear Rate ◽  
Experimental Analysis ◽  
Contact Wire ◽  
Electrical Arc ◽  
Contact Strip

scholarly journals Resource evaluation of friction pair “contact wire – contact strip”

2017 ◽  
Vol 44 (4) ◽  
pp. 7-15 ◽  
Author(s):  
Andrii V. Antonov ◽  
Víctor G. Sychenko
Keyword(s):  
Mathematical Model ◽  
Wear Rate ◽  
Friction Pair ◽  
External Factors ◽  
Collection System ◽  
Contact Wire ◽  
Current Collection ◽  
System Parameters ◽  
Contact Strip ◽  
The Impact

Purpose. Investigate the impact of current collection system parameters and external factors on the resource of friction pair “contact wire – contact strip”. Relevance. The level of electrified railways reliability depends on the reliability and durability of the individual objects of power supply system and the locomotive facilities, in turn, the current collection quality depends on design of contact network and pantographs, contact wires materials, contact strips and external influencing factors. The resource system “contact wire – contact strip” is an important technical and economic characteristics, and its average actual resource is much less established. It means that the actual resource does not reach the optimum value from an economic point. Increasing velocity of the electric rolling stock exacerbates the problem of improving the current collection quality, becomes an actual task of increasing the resource friction pair “ contact wire – contact strip” for mainline railways. Scientific novelty. This work determined the influence structural parameters of the friction pair, the current collection system parameters and external factors on the wear rate of the friction pair “contact wire – contact strip”. Proposed to create a predictive mathematical model that uses the dependence of the influencing parameters obtained in this work to assess the wear and resource of contact wire and contact strips. Practical importance. Developed the device for wear researching of friction pairs in laboratory conditions allows assessing the wear rate of the system “contact wire – contact strip” and their residual resource at different combinations of the friction pair and external factors. The obtained results allow us to construct a predictive mathematical model to evaluate wear rate of the elements of the friction pair “contact wire – contact strip” and identify their residual resource.

scholarly journals Influence of Embankments With Parapets on the Cross-Wind Turbulence Intensity at the Contact Wire of Railway Overheads

2010 ◽  
Author(s):  
Sergio Avila-Sanchez ◽  
Oscar Lopez-Garcia ◽  
Jose Meseguer
Keyword(s):  
Wind Tunnel ◽  
Environmental Factor ◽  
Turbulence Intensity ◽  
Experimental Analysis ◽  
System Operation ◽  
Contact Wire ◽  
Aerodynamic Loads ◽  
Essential Parameter ◽  
Railway System ◽  
Undamped Oscillations

Winds as an environmental factor can cause significant difficulties for the railway system operation. The railway overhead has been particularly vulnerable to cross-winds related problems, such as development of undamped oscillations due to galloping phenomenon. The installation of windbreaks to decrease the aerodynamic loads on the train can affect the loads on railway overheads triggering cable galloping. One essential parameter to indicate the influence of the parapet wake on the catenary contact wire is the turbulence intensity. In this paper the results of an experimental analysis of the turbulence intensity due to the presence of parapets carried out in a wind tunnel are reported. Embankments equipped with different parapets have been tested and turbulence intensity has been measured at both contact wire locations, windward and leeward. The relative influence of the parapets is measured through a reduced turbulence intensity, defined as the ratio between the turbulence intensity measured with parapet and the turbulence intensity in the case without any parapet on the embankment. In general the reduced turbulence intensity increases as the height of the parapet increases.

Theoretical and Experimental Analysis of the Influence of Abrasives on Nozzle in Pre-Mixed Abrasive Water Jet

2012 ◽  
Vol 233 ◽  
pp. 425-428
Author(s):  
Yu Ying Jiang ◽  
Lie Hang Gong ◽  
Hai Tao Wang ◽  
Cong Cong Gong ◽  
Xin Lin Xu
Keyword(s):  
Grain Size ◽  
Wear Rate ◽  
Experimental Analysis ◽  
Water Jet ◽  
Abrasive Water Jet ◽  
Material Hardness ◽  
Nozzle Wear ◽  
Abrasive Hardness

This paper introduces the influence of the shape, grain size, density and hardness of abrasives particles on nozzle wear. Different parameters of abrasive hardness are investigated through theoretic and experimental analysis. The results show that the ratio of abrasive hardness to nozzle material hardness governs the wear rate Ca.

scholarly journals Study on Friction and Wear Properties of Pantograph Strip/Copper Contact Wire for High-Speed Train

2014 ◽  
Vol 8 (1) ◽  
pp. 125-128 ◽  
Author(s):  
Tao Ding ◽  
Wenjing Xuan ◽  
Qiudong He ◽  
Hao Wu ◽  
Wei Xiong
Keyword(s):  
Wear Rate ◽  
Electric Current ◽  
High Speed ◽  
Friction And Wear ◽  
Optical Microscope ◽  
Wear Properties ◽  
Contact Wire ◽  
Arc Erosion ◽  
The Coefficient Of Friction ◽  
Friction And Wear Properties

A series of experiments on friction and wear properties of carbon strip rubbing against copper contact wire is performed on high-speed friction and wear tester with electric current. The results show that the friction coefficient is generally maintained between 0.24 and 0.37. In the absence of electric current, the coefficient of friction is higher than that in the presence of electric current. The wear rate of carbon strip materials is generally not more than 0.014g/km. In particular, the wear rate under the electric current of 240 A is 14 times more than that in the absence of electric current. By observing the scar of worn surface with optical microscope, it can be found that there are obvious slip scars and arc erosive pits. The dominated wear mechanisms are abrasive wear and arc erosion in electrical sliding frictional process.

scholarly journals Experimental Analysis of the Effect of Tri-Nano Additives on Wear Rate of Mild Steel during Machining

2019 ◽  
Vol 35 ◽  
pp. 395-400
Author(s):  
Sunday A. Afolalu ◽  
Great E. Efekodha ◽  
Samson O. Ongbali ◽  
Abiodun A. Abioye ◽  
Enesi Y. Salawu ◽  
...  
Keyword(s):  
Wear Rate ◽  
Mild Steel ◽  
Experimental Analysis ◽  
Nano Additives

Dynamic performance of a pantograph–catenary system with consideration of the contact surface

2016 ◽  
Vol 232 (1) ◽  
pp. 262-274 ◽  
Author(s):  
Dongli Song ◽  
Yanan Jiang ◽  
Weihua Zhang
Keyword(s):  
Contact Force ◽  
Wear Surface ◽  
Contact Surface ◽  
High Speed ◽  
Shape Parameter ◽  
Dynamic Performance ◽  
System Dynamic ◽  
Contact Wire ◽  
Catenary System ◽  
Contact Strip

The influence of contact surface upon the dynamic performance of a pantograph–catenary system is a question that has been highlighted by the increasing use of high speed railways. Using the mode-superposition method, we establish a pantograph–catenary-coupled dynamics model with consideration of the contact surface; we analyse the characteristics of the contact surface based on a large amount of measured data; and we determine the characteristic parameters according to their influence upon the system dynamic performance. The results show that the contact wire irregularity contains a periodic component formed by gravity and a random component formed by wear, local assembly errors, hardpoints and the like. Periodic and low-frequency random irregularities mainly lead to the increase in contact force amplitude at peak points with wavelengths submultiple of the tension length, span or dropper spacing. On the contrary, high-frequency random irregularity has a great influence upon the amplitude of all frequencies and is the main factor leading to the deterioration of the system dynamic performance. The contact strip wear surface achieves quadratic function fitting, and we propose two characteristic quantities of this surface, namely, shape parameter A, and wear depth B. The wear surface of contact strip enhances the periodic characteristics of pantograph–catenary system of each span, leading to the amplitude increase of the contact force in frequency with span submultiple wavelength. The bigger the absolute value of the shape parameter, the poorer the dynamic performance. According to the criteria of the contact force eigenvalues, we determine the threshold value of the contact strip shape parameter A, and the contact wire irregularity amplitude of each frequency. The threshold given in this paper can be used in the condition assessment of parts, and make judgements on whether a servicing is needed, which is part of the technologies for informationisation and intelligent high-speed train health management.

Effect of the vibration on friction and wear behavior between the carbon strip and copper contact wire pair

2012 ◽  
Vol 226 (8) ◽  
pp. 722-728 ◽  
Author(s):  
HJ Yang ◽  
GX Chen ◽  
SD Zhang ◽  
WH Zhang
Keyword(s):  
Wear Rate ◽  
Wear Mechanism ◽  
High Speed ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Arc Discharge ◽  
Discharge Energy ◽  
Friction And Wear Behavior ◽  
Contact Wire ◽  
Arc Erosion

This article reports an experimental study on the friction and wear behavior of carbon strip sliding against copper contact wire under strong electric current utilizing a high-speed block-on-ring tester. The dynamic mechanism of electric arc generation was investigated. Scanning electron microscopy was used to observe morphology of worn surfaces of the carbon strips. The results show that arc discharge has a certain correlation with low-frequency vibration of the carbon strip. The arc discharge frequency and the average single arc discharge energy initially decrease and then tend to stable with increasing normal load at different speeds. The wear rate increases first and then decreases and has the minimum when the load is equal to 100 N especially. Moreover, the wear rate steadily increases with increase in arc discharge energy and is almost directly proportional to arc discharge energy. Arc erosion was a dominant wear mechanism occurred in carbon strip sliding against copper contact wire at a low load, accompanying with adhesive wear and material transferring. However, mechanical wear was a main wear mechanism at a high load. Severe arc erosion weakened the conductivity of the carbon strip.

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