The article analyzes the methods for calculating the actual capacity of leadacid batteries at different temperatures. The performed analysis showed that the assessment of the technical condition of batteries by the methods of rapid diagnostics should be applied with the mandatory consideration of the correction temperature coefficients for capacity, and the use of the considered methods for this purpose is undesirable, since it leads to significant errors at temperatures below 0°C. The article suggests possible ways to solve this problem.Keywords: battery, diagnostics, battery capacity, calculation method, temperature.
The article is devoted to the problem of efficiency power transformers operation in traction power supply system 25 kv AC. Models for calculating thermal depreciation and remaining life time of windings insulation of traction transformers are reviewed in article. The article analysis of the voltage measuring transformers indications. The voltage measuring transformers are connected to the switch gear bus-bars 25 kV and windings of power transformers for calculating thermal depreciation and remaining life time. Voltage measuring transformers indications connected to the windings of power transformers prove an increase in the accuracy of assessing the winding insulation. Extending the service life of the winding with the greatest insulation wear increases the service life of transformers in modern conditions. Determination of the predicted service life of the corresponding transformer based on thermal wear of the winding insulation ensures their monitoring in operation.Keywords: traction power supply system, alternating current traction substations, power transformers, service life, depreciation of winding insulation.
Currently, for the purpose of increasing throughput of railways, electrified with 25 kV AC, there are static VAR generators (SVGs) installed in the catenary section points. Such SVGs have several flaws, such as increased power loss and higher cost price. The purpose of this article is the task of SVG enhancement, such as decreasing power losses in the traction network, as well as reducing its cost price. To achieve this, the power of the adjustable SVG is decreased by a certain value, and instead an unregulated filtering and compensating device is installed of the same power value, with resonance filters for 150 Hz and 250 Hz frequencies, thus forming a complex adjustable compensation and filtration system. The voltage at the substation and the catenary section points are measured, and depending of the voltage loss, several operation modes, such as «voltage stabilization» or «power loss minimization», are possibleKeywords: Railway throughput, VAR compensation, switchable compensation and filtration system.
The force characteristics of the electromechanical magnetorheological damper are analyzed. The magnetic fields and velocity fields of the magnetorheological suspen-sion were calculated. The mutual influence of magnetic and hydrodynamic processes is taken into account. The influence of the form of poles and directions of currents in the control coils of a multipole magnetorheological damper has been studied.Keywords: electromechanical magnetorheological damper, interrelated influence of magnetic and hydrodynamic processes, finite element modeling.
The problem of wireless transmission of electrical energy to moving carriages is relevant for high-speed transport on a magnetic suspension, as well as for recharging on-board batteries of automobile and urban autonomous transport with an electric drive. The best technical and economic indicators are possessed by wireless power transmission systems based on the phenomenon of electromagnetic induction. The article discusses the principles of non-contact inductive power transmission, power transmission systems used to supply power for their own needs of highspeed TRANSRAPID vehicles, and also proposed technical solutions for wireless power transmission to moving vehicles based on linear generators with a direct current source and using permanent magnets.Keywords: noncontact transmission of the electrical energy, high-speed land transport.
Switched reluctance motors differ from traditional types of electric machines in their mathematical descriptions. The article presents the currently used simulation options using lookup tables. In order to reduce the volume of SRM initial data, it is proposed to use the description of phase flux linkage with Fourier series instead of lookup tables.Keywords: switched reluctance motor, simulation, initial information, Fourier series, lookup table.
In order to increase the energy efficiency of resonant semiconductor converters for transport systems, a technique has been developed that allows identifying the presence and investigating the nature of the hysteresis of the output capacitance of MOSFETs when operating at high voltage, as well as evaluating the dynamic losses in the transistor due to the hysteresis of the output capacitance. A test facility was created and experimental studies were carried out demonstrating the presence of hysteresis of the output capacitance of n-channel Mosfet transistors, the results of experiments are presented.Keywords: semi-conductor converter, MOSFET, output capacitance, hysteresis, research methodology, dynamic losses
The paper presents the results of the multifactorial study of the influence of the road situation on the parameters of the error-rate performance of the onboard electrical system of motor cars to the electromagnetic influences during operation.Keywords: motor car, errorrate performance, electromagnetic compatibility, operation.
World trade is not without the proper functioning of international transport. The increased demand for optimization of transport management systems has become a prerequisite for the emergence of multimodal transportation - the process of consecutive transportation of goods performed by several types of vehicles under a single contract. Transport companies carrying out this activity, following the growing trend towards digitalization and automation of logistics processes in order to improve the efficiency, economy, speed, safety and quality of international cargo transportation, are increasingly introducing various solutions in the field of electronics and electrical equipment of transport and transport infrastructure, a review of examples of their application at various stages of multimodal transportation is devoted to the purpose of this studyKeywords: electronics, electrical equipment, multimodal transport, automation, optimization, vehicles, logistics companies.
The kinetic energy of the automotive vehicle during braking is converted into electrical energy using a low-inertia synchronous electric machine in generator mode, driven by the vehicle’s transmission. It is not possible to store this electrical energy with the help of an electrochemical battery for a short braking time, sometimes in seconds. Automotive systems use supercapacitors to conserve energy during braking. On a simulation computer model in the Simulink SimPowerSystems, the simulation of energy recuperation when braking a car using a supercapacitor was carried out. The possibility of energy conservation in a short braking time, which is unavailable for electrochemical batteries, is shown.Keywords: energy recuperation, supercapacitor, transmission, electrochemical battery.