The article discusses the design and principle of operation of a universal converter with a pulse width modulator. The device operates in three modes: conversion of DC voltage 12V from the battery to AC 220V, conversion of AC voltage to DC with output characteristics necessary for arc welding and conversion of AC voltage 220V to DC 12V. The general structural and control scheme is described, as well as preliminary calculations are performed. The device is implemented on a modern element base, using compact transformers on ferrite cores, and IGBT, MOSFET transistors
Keywords: universal converter, battery, pulse width modulator, Push-pull circuit, transistor keyThe article considers the system of electric drives of a conveyor. Functional and structural diagrams are compiled. The analysis of the operation of single- and double-drum electric drives is carried out. Structural diagrams of the mechanical part of the conveyor are obtained. A mathematical description, structure and model of an elastic link are compiled taking into account friction forces. A mathematical model of the electrical complex is compiled. The main variables of the conveyor coordinates are identified
Keywords: conveyor, elasticity, model, identification, distributed parameters, damping, drive drumThe article discusses the features of the operation of car batteries in various climatic and operational conditions. The influence of extreme temperatures, vibrations and prolonged downtime on the condition of batteries is discussed, as well as the importance of maintaining optimal charge parameters to extend their service life. Graphs of the dependence of the voltage and density of the electrolyte on the storage time are shown, which illustrate the process of self-discharge of batteries
Keywords: car, battery, self-discharge, electrolyte density, battery voltage, climatic conditions, rechargingIn this work, the synthesis of moment and rotation speed coordinate calculators for two-channel control of anwound rotor induction motor is carried out. Experimental results are presented and formulas for calculating the required coordinates are determined. The error of the coordinate calculators was found. The synthesis of the circuit of speed meters has been performed
Keywords: induction motor, coordinate calculator, two-channel control, error, stator, rotor, speed, torqueAdditive manufacturing (AM) has been rapidly developing in recent years. AM is recognized as a key technology providing a wide range of applications, including medical, aerospace and automotive industries. The use of AM opens up new opportunities for design solutions that are difficult or impossible to implement using traditional manufacturing methods. No or low waste, high flexibility are the distinctive characteristics of modern AM. The purpose of this review article is to provide an overview of existing examples of AM use in the manufacture of electrical machines. The article discusses research and development work related to the additive manufacturing of electrical machine components. These include active parts such as windings, electrical insulation, stator and rotor magnetic core packs, permanent magnets
Keywords: additive technologies, electric machine, rotor, stator, permanent magnetsOne of the leading problems limiting the efficiency of field-effect transistors made on the basis of gallium nitride (GaN) is the phenomenon of self-heating, which leads to irregular power distribution and a decrease in the basic electrical characteristics of the devices. This work is aimed at the development of a field-effect transistor with an improved cooling system, as well as at the study of thermal processes occurring in such devices using numerical modeling methods. In the course of the study, transistors made on a sapphire substrate are considered, in which a graphene element is integrated, designed for efficient heat dissipation. In addition, the design provides heat-conducting materials placed in the grooves of the passivation layer, which should help improve the heat-dissipation properties of the device. Both the electrical and thermal characteristics of these structures are evaluated. The results of numerical simulation confirm the effectiveness of the proposed cooling system, which, in turn, significantly reduces the effect of the self-heating effect and improves the operational characteristics of field-effect transistors. The new concept integrates the cooling system with an element responsible for heat absorption, which effectively removes excess heat from the maximum temperature area through a high-quality heat-conducting groove in the passivation layer. The data obtained as a result of the study can be used to optimize the design of power electronics based on gallium nitride and can be used in the Russian electronics industry, contributing to the development of more efficient and reliable field-effect transistors
Keywords: field effect transistors, gallium nitride (gan), self-heating, efficiency, electronics, thermal processes, numerical modelingIn recent decades, the on-board electrical complex (OEC) of vehicles (TS) has been saturated with new electrical components operating as part of systems aimed at increasing comfort, safety and operational efficiency [1, 2], and a significant part of the introduced electrical components are based on electromechanical energy converters presented in the form of DC electric motors [3]. As a result, the mass production of DC electric motors for transport engineering is steadily increasing. Statistically, it can be assumed that an increase in the production volume of DC electric transport machines will lead to an increase in the number of such types of defects as structural, technological and operational
Keywords: transport; electromechanical energy converters; fault tolerance of DC machinesThe wear of the contacting surfaces of assemblies and parts is an urgent problem for almost all sectors of the national economy. Railway scientists pay special attention to the issues of wear of components and parts of wagons, including wear of wheelset ridges, contacting surfaces of the center plate unit, friction dampers of bogies, as well as centering beams. The wear processes of assemblies and parts are considered taking into account the tribological characteristics of the interaction of friction pairs. An actual case of a wagon derailment due to wear of the contacting surfaces of the center plate unit and friction dampers of bogies is presented. The requirements for owners of railway rolling stock for their technical condition in the Russian Federation, the Republic of Belarus and the Republic of Kazakhstan are summarized and analyzed. Various measures are proposed and justified that will eliminate (minimize) cases of rolling stock derailment due to wear of the center plate unit and the damping unit of long-wheelbase flatcars. The conclusions of the research conducted in the article are based on the analysis of the operation of long-wheelbase flatcars, which ensures the establishment of the production-science cycle
Keywords: train safety, carriage facilities, wear, coefficient of friction, tribology, center plate unit, friction wedge, centering beam, derailment of wagons, rules of technical operation of railwaysThe article deals with the actual problem of environmental pollution by thermal power plants, presents an analysis of factors that negatively affect the ecosystem. The main ways of increasing the effective reduction of the negative environmental impact of energy facilities are described. The methods for reducing toxic substances in emissions through the introduction of the best available technologies and optimization of the use of natural resources in the production of thermal and electric energy in order to harmonize the environmental legislation of Russia with the functioning of electric power facilities are considered
Keywords: electric power industry, thermal power plant, environment, ecology, the best available technologies, ash collection, ash and slag waste, emissions, electrofilters