Analysis of bistable electromagnetic relays design features

This paper pays attention to a classification of bistable electromagnetic relays. The following signs of the classification of mentioned relays are emphasized, such as: design, type of contact fixation, relay contact diagram, type of current and value of the control voltage of the coil, the number of coils, nature of the load switched by the relay; the power consumed by the coil, and others. The undertaken classification systematizes information on the design, technical and functional features and parameters of such relays and demonstrates the current level of technical development of relays that are mentioned above. A conclusion is made concerning tendencies and directions of bistable electromagnetic relays capabilities developing in the future by the authors.

Construction of computer multiphysics models of electromagnetic relays for predicting their operational reliability

Рассмотрено построение компьютерной мультифизической модели электромагнита в составе электромагнитных реле. Благодаря моделированию, а также методу натурно-модельного эксперимента, производится сбор данных для анализа эксплуатационных характеристик электромагнита и прогнозирования его эксплуатационной надежности. На основе этих данных строится регрессионная математическая модель, включающая перевод данных в меньшую размерность методом главных компонент. Полученная регрессионная модель предназначена для подбора составных частей электромагнита с целью улучшения эксплуатационных характеристик готового изделия, уменьшения брака и увеличения срока эксплуатации.

IoT Based Home Automation using PIR Motion Sensor and Node MCU

This paper depicts a unique home automation system where its efficiency and accuracy can be improved by integrating the PIR motion sensor and google voice assistant. It comprises of Node MCU (esp8266) which is a Wi-Fi module used to transmit data over internet, electromagnetic relays, and the PIR sensor. This developed system works when there is any motion within the defined sensor range and it can also be controlled through the mobile application. Blynk application has been configured with the system so that it works flawlessly on both iOS and android devices. The developed microcontroller has been configured with the Blynk server which makes the home appliances work remotely and eliminates the need for a dedicated PC server. The final prototype is also configured with google assistant so that the relays can be triggered with the voice too and this system has been successfully developed, and the working prototype has been tested with various test cases.

Relay-semiconductor circuit switching in safe interface units based on electromagnetic relays

The paper considers methods of realization of relaysemiconductor circuit switching in systems of railway automatics with the use of promising elemental base. It also gives recommendations on selection of semiconductor switching elements for various spheres of application of relay interface units.

Innovative simulators for automation and telemechanics systems

The article deals with the issues of training in educational institutions and enterprises of railway transport using simulators built on the basis of real actual equipment of railway automation and telemechanics, and virtual simulators that simulate the operation of real equipment by analog or digital modeling. Advantages and disadvantages of real and virtual simulators are considered. The directions for their further improvement are indicated. One of the directions is the development of innovative simulators that combine real equipment and its virtual environment in one laboratory layout. The first innovative simulator at the Department of “Automation, telemechanics and communication on railway transport” is the automated workplace of the train dispatcher. Further improvement of innovative simulators is the development and implementation in the laboratory of station systems of automation and telemechanics of the department of the set of remote fault assignment with an automated workplace of the teacher. The article describes the structural flowcharts of the remote fault assignment set and its main blocks. Innovative simulators also include a simulator of the train passing through the control section KTSM-02, which allows to simulate the operation of floor sensors in the same sequence as when passing a real train. The article describes a virtual simulator, which includes a laboratory model for the study of neutral electromagnetic relays in 3D. Advantages of integrating innovative simulators with virtual educational environment of the University are indicated.

ОСОБЛИВОСТІ ПОБУДОВИ СИСТЕМ ЕЛЕКТРОЖИВЛЕННЯ ІНВЕРСНОЇ МАГНЕТРОННОЇ РОЗПОРОШУВАЛЬНОЇ СИСТЕМИ ДЛЯ ФОРМУВАННЯ БАГАТОКОМПОНЕНТНИХ ПОКРИТТІВ (ПРАКТИЧНІ АСПЕКТИ РОЗРОБКИ РЕЗИСТИВНИХ ЛАНЦЮЖКІВ У СКЛАДІ ГЕНЕРАТОРА ПЛАЗМИ)

The consideration of the features of constructing the power supply system of a pilot industrial-technological installation for applying multicomponent coatings by the ion-plasma method is continued. The main attention is paid to the practical aspects of developing controlled resistive circuits connected to various elements of the power supply circuit of a technological plasma generator. It is noted that the control of the operation mode of the technological installation is provided by changing the resistance of these chains by the corresponding automated system. A mathematical expression is proposed in the form of a polynomial for the resistance of chains, which meets the requirements for a research installation and the condition for minimizing the number of resistors in a separate chain. The structure of the chain is considered as a combination of the required number of cells. Each of them differs from the others not only in the connection scheme of the resistors but also in their resistance. An algorithm is proposed for determining the nominal resistance, heat loss power, the number of resistors and the circuitry for their connection. For example, a diagram and the main technical characteristics of a chain connected to a group of target cathodes from tungsten are given. Such cathodes are used in the formation of nanostructured and multifunctional coatings of tungsten carbide on the surface of metal parts. Particular attention is paid to the control elements in the individual cells of the technological plasma generator. The analysis of requirements for control elements such as semiconductor switches and electromagnetic relays is carried out. It is noted that these requirements are met by conventional (not high-voltage) electromagnetic relays of domestic production, provided that their contacts are connected in series with each other. Attention is drawn to the need to prevent the formation of an electric arc when the relay contacts open, can be achieved by including a resistor and a capacitor in series with the control element. It is also important to use means of forced air cooling of the resistive chain block.

Electrodynamic Contact Bounce Induced by Fault Current in Low-Voltage Relays

Due to fault currents occurring in electrical installations, high electromagnetic force values may be induced in current paths of low-voltage electromagnetic relays. This force may lead to an electromagnetic bounce that will further result in an electric arc ignition between contacts, and under some circumstances, it will result in contact welding. For the proper exploitation of relays, the threshold value of the maximum current, and thus the electrodynamic force, should be known. This force depends on several factors, including: contact materials, dimensions of relay current paths, relay electromagnetic coil, etc. This paper presents the results of calculations and an experiment on electromagnetic forces, which cover these factors. A static closing force, acting on the contacts, and the fault current were measured. As a result, values of the force and current threshold were obtained, which inform when an electrodynamic bounce may occur. The obtained result may be used in designing contact rivets and relay current paths together with the selection of adequate fault protection devices.