Purpose. The article aimed at comprehensive analysis of the processes occurring in the lubricant films of the friction surfaces of the tribosystem «overhead line -current collector contact strip» (OLCCCS) and identification of the features of such systems. Methodology. The systematic analysis was used as the main methodology for studying the physico-technological aspects of work of the lubricant films in the tribosystem «overhead line -current collector contact strip». Findings. The theory of electro-friction interaction is now at such a stage that is characterized by a large amount of accumulated empirical data, hypotheses and models that cannot adequately represent phenomena in a sliding, high-current electrical contact. The sliding electrical contact of the tribosystem «overhead line -current collector contact strip» during the operation is affected by many factors, one of which is the processes in the lubricating layers of the friction pair. The work leads to a new level of understanding of the peculiarities of the processes occurring in the lubricating layers and their effect on the work of a sliding, high-current electrical contact, which can become the guarantee of significant increase in the efficiency of such systems and, as a consequence, substantially increase the reliability and safety of the work of the electric stock. Originality. It is proposed to consider the processes of electro-friction interaction of electrical contacts from the position of synergy using the theory of fractals as the core one for the quantitative description of self-organizing structures. Practical value. Taking into account the empirical experience of operation of the tribosystem «overhead line -current collector contact strip» in combination with theoretical knowledge allows us to propose three possible directions for solving tribological problems in highcurrent sliding electrical contacts. They are: 1) change in contact geometry and surface topography, for example, the use of regular macrorelief of contact surfaces; 2) development of conductive composites which are characterised with self-lubrication, for example the use of composite materials containing solid conductive lubricants; 3) development of effective lubricants for electric high-current sliding contacts, which may require some complication of the component design.

Purpose. The main purpose of our work is to develop a method for assessing the heating temperature of the contact area of contact wire with contact strip of pantograph (the contact wire element – the contact strip element of pantograph, in abbreviated form – CWE – CSEP) for parking conditions when preparing the train for the trip with the determination of the maximum current load on given node. Methodology. We proposed to consider the CWE – CSEP contact from the point of view of the classical theory of electrical contact and heating of a homogeneous body. Findings. The features of thermal state of the current collection unit of CWE – CSEP in the conditions of preparing the electric rolling stock for the trip are considered. Within the framework of the study a methodology for assessing the heating temperature of the zone of power sliding contact in the conditions of train preparation for the trip has been developed. The application of the methodology will help reduce the number of burnings through of the contact wire due to the precise choice of the heating/conditioning time of the train for a certain heating/conditioning current when preparing the electric rolling stock for the trip. Originality. It has been established that the reason for burnings through the contact wire in stalls when preparing the train for the trip is the excess of permissible temperature of the power sliding contact as a result of prolonged action of the heating/conditioning current. In contrast to the standard approach for determining the duration of the train heating, the proposed methodology takes into account additional factors, namely, the wear and condition of the contact wire, condition of contact strip of the pantograph. This methodology is based on the classical theory of electrical contact and the theory of heating a homogeneous body, which allows accurate assessment of the thermal state of a power sliding contact, and is convenient enough for use in operating conditions. Practical value. The results of the work are of practical value, since the technology of preparing a train for a trip can be supplemented by calculating the temperature of the CWE – CSEP contact in accordance with the proposed methodology. This will allow applying a set of measures to prevent burnings through of the contact wire in case of possible temperature exceeding the permissible value for a specific train in specific conditions.

No abstract

The features of the thermal state of the current collection unit «contact wire -contact insert of the current collector» in the conditions of preparation of electric rolling stock for the journey are considered. As part of the study, a methodology has been developed for estimating the heating temperature of the power sliding contact zone in the conditions of train preparation for journey. Application of the method will help to reduce the number of «burnouts» of the contact wire due to the exact selection of the heating/cooling time of the train for a certain heating/conditioning current when preparing the electric rolling stock for the journey.It was established that the cause of the «burns» of the contact wire in the parking lots when preparing the train dispatch is the excess of the permissible temperature of the power sliding contact as a result of the prolonged action of the heating/conditioning current. The standard approach for determining the duration of heating is based on the average values of the loads on the system and therefore does not take into account some factors, for example, the state of the contact wire, the state of the contact insert of the current collector, the number of cars in the train, and so on. The proposed technique is based on the classical theory of electrical contact and the theory of heating a homogeneous body, which makes it possible to accurately assess the thermal state of the power sliding contact and convenient enough for use in operating conditions.The results of the work are of practical value, since the technology of preparing a train for dispatch can be supplemented by calculating the contact temperature «contact wire elementcontact insert element» in accordance with the proposed methodology. This will allow for a specific train in specific conditions to apply a set of measures to prevent «burnout» of the contact wire in the event of a possible temperature exceeding the permissible value.

Purpose. The purpose of this work is the formation of conceptual approaches to the construction of an effective integrated system of simultaneous synchronized control of the movement and suspension of a maglev vehicle – a magnetoplane. Methodology. The paper uses a technique for simultaneous control of the movement and suspension of a maglev vehicle with the mutually coordinated application of both levitation methods, electromagnetic and electrodynamic, through individual control of the energy supply of each track coil. Findings. The conceptual control principles of a traction-levitation system in a hybrid mode of its operation are substantiated. The interaction of a track structure with a vehicle on an electrodynamic suspension with a linear drive is disclosed and the features of the implementation of the power unit are highlighted. Originality. It is shown that a significant improvement in maglev technology can be achieved due to the mutually coordinated combination of electromagnetic and electrodynamic methods of magnetic levitation and the use of a fundamentally different architecture for constructing a MAGLEV track. It is constructed not from long sections with three-phase power windings, but from discrete ones, they are also linear engine traction coils, and a component (load) of a solar track power plant located along the overpass. The power plant includes a photovoltaic module (solar battery) that converts solar energy into electricity, a storage device and an inverter. This construction makes possible independent supply of each travel coil and its autonomous control with the ability to switch to traction or levitation mode. The control concept is that each track coil can participate both in the creation of a static suspension due to the interaction of the magnetic field of the onboard superconducting magnet and the magnetic field of the track coils when a certain amount of direct current is applied to them, as well as the dynamic suspension provided during the train movement as a result of the interaction of the magnetic field of the onboard superconducting magnet and the magnetic fields created in the track coils by currents induced in them when the magnetic fields of the onboard superconducting magnet intersect. Practical value. The results are of practical value, as the use of such complex control system of the suspension and the magnetic plane movement will significantly improve the quality of MAGLEV technology, increase the efficiency and reliability of high-speed land transport based on electrodynamics levitation using superconducting magnets.