scholarly journals THERMAL MODEL OF THE "INDUCTION GENERATOR–INDUCTION MOTOR" SYSTEM WITH NON–SYMMETRY IN THE STATOR WINDINGS

2021 ◽  
Vol 2 (53) ◽  
pp. 47-55
Author(s):  
V. Chenchevoi ◽  
◽  
Iu. Zachepa ◽  
O. Chornyi ◽  
R. Yatsiuk ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Thermal State ◽  
Asynchronous Motor ◽  
Operating Conditions ◽  
Factors Affecting ◽  
Thermal Transients ◽  
Operating Modes ◽  
Stator Windings ◽  
Asynchronous Generator

Purpose. Development of the IG model for estimation of influence of variations of parameters of the generator on quality of process of self–excitation at definition of the basic and boundary operating modes and system of initial excitation at invariable parameters of the generator. Result. The article presents studies of the system "asynchronous generator-asynchronous motor" with parametric asymmetry to determine the quality of generated electricity in load modes of operation on a mathematical model. The assessment of the thermal state in steady-state conditions was carried out using an equivalent thermal equivalent circuit. Thermal transients were investigated when starting an asynchronous electric motor from an autonomous power source based on an asynchronous generator. On a thermal mathematical model, a study of the influence of the asymmetry of the output voltage and its deviation from the nominal value on the heating of the connected asynchronous motor was carried out. A regression model has been developed for studying the operating conditions of electricity consumers when powered by an asynchronous generator with an asymmetry of the stator windings. Practical value. The use of the obtained equations will make it possible to determine the most rational combination of factors affecting the heating of the stator windings of asynchronous machines, at which they will not overheat in excess of the maximum permissible temperature values of the corresponding insulation classes. Figures 9, tables 2, references 23.

scholarly journals Development of mathematical models of energy conversion processes in an induction motor supplied from an autonomous induction generator with parametric non-symmetry

2021 ◽  
Vol 4 (8(112)) ◽  
pp. 67-82
Author(s):  
Volodymyr Chenchevoi ◽  
Valeriy Kuznetsov ◽  
Vitaliy Kuznetsov ◽  
Olga Chencheva ◽  
Iurii Zachepa ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Induction Motor ◽  
Output Voltage ◽  
Thermal State ◽  
Operating Conditions ◽  
Induction Generator ◽  
Thermal Transients ◽  
Operating Modes ◽  
Stator Windings

The paper presents studies of the system "induction generator-induction motor" with parametric asymmetry on a mathematical model to determine the quality of generated electricity in load operating modes. A mathematical model of the "induction generator-induction motor" system has been developed taking into account losses in steel and parametric asymmetry. The analysis of the transient characteristics of an induction generator when a motor load is connected in symmetrical and asymmetrical modes of operation is carried out. The results of changes in the main characteristics of an induction motor at various degrees of parametric asymmetry in the generator are presented. The quality of the generated electricity was analyzed based on the calculations of the unbalance coefficients for each of the operating modes. The assessment of the thermal state in steady-state conditions was carried out using an equivalent thermal equivalent circuit. Thermal transients were investigated when starting an induction motor from an autonomous energy source based on an induction generator. On a thermal mathematical model, the study of the effect of the output voltage asymmetry on the heating of the connected induction motor was carried out. It is shown that the asymmetry of the output voltage of an induction generator reaches 3–10 % and causes overheating of the windings in excess of the permissible values. A regression model has been developed for studying the operating conditions of an induction motor when powered by an induction generator with an asymmetry of the stator windings. The use of the obtained equations will make it possible to determine the most rational combination of factors affecting the heating of the stator windings of induction machines, in which they will not overheat above the maximum permissible temperature values of the corresponding insulation classes

scholarly journals Computer-based model of asynchronous electric propulsion drive with three stator windings

2021 ◽  
Vol 1 (395) ◽  
pp. 132-140
Author(s):  
I. Kalinin ◽  
Keyword(s):  
Mathematical Model ◽  
Electric Power ◽  
Electric Propulsion ◽  
Frequency Converter ◽  
Asynchronous Motor ◽  
Electric Power System ◽  
Propulsion System ◽  
Stator Windings ◽  
Phase Coordinates ◽  
Computer Based

Object and purpose of research. This paper discusses electric propulsion system of leader icebreaker. Its purpose was to develop mathematical and computer-based model of electric propulsion drive powered by asynchronous motor with three stator windings for further investigation of steady, transitional, asymmetric and emergency operation scenarios of electric power and propulsion system for the leader icebreaker. Materials and methods. Hardware and methods for computer-based simulation of complex engineering structures. Main results. Development of the mathematical model representing asynchronous motor with three windings in phase coordinates. Computational studies on direct startup of 15 MW propulsion motor, as well as on steady and transitional operational conditions of ship electric power system consisting of 36 MW synchronous genset, two-winding transformers and electric propulsion drive with 15 MW asynchronous motor in phase coordinates with three stator windings and three-level frequency converter. Calculation of voltage non-sinusoidality ratio for MSB buses with operation of 15 MW propulsion motor driven by 36 MW synchronous genset. Conclusion. Mathematical model of asynchronous motor suggested in this paper could be used to calculate steady and transitional operation scenarios of marine power systems with frequency-controlled three-winding asynchronous motor, as well as to calculate electromechanical and electromagnetic processes and refine frequency control algorithms. This is especially relevant because each of the asynchronous electric machines used in the electromechanical assemblies of leader icebreaker propulsion motors has three stator windings, and this icebreaker is the first experience of applying a 15 MW marine electric drive.

scholarly journals Optimization of Parameters and Operating Modes of Disc Sowing Device According to Seeding Uniformity Criterion

2018 ◽  
Vol 28 (3) ◽  
pp. 379-388
Author(s):  
Vladimir A. Ovchinnikov ◽  
Mikhail N. Chatkin ◽  
Alena V. Ovchinnikova
Keyword(s):  
Experimental Studies ◽  
Operating Conditions ◽  
Design Parameters ◽  
Optimal Parameters ◽  
Plant Growth And Development ◽  
Important Condition ◽  
Operating Modes ◽  
Favorable Conditions ◽  
Uniformity Criterion

Introduction. When cultivating agricultural crops, it is necessary to take into account the plants’ need for moisture, nutrients, location by area of nutrition, determining illumination, etc. Taking into account the biological characteristics of crops, various methods of sowing are used to create favorable conditions for plant growth and development. An important condition for sowing is the uniform arrangement of seeds along the sulcus, especially in the cultivation of testes of small-seeded cultures. A key role in the uniformity of seeding is provided by the design parameters and kinematic operating conditions of the sowing device. Materials and Methods. To determine the optimal parameters and operating modes of the disk sowing device, methods of factor experiment and multi-criteria optimization were used. Results. Mathematical models of the technological process of sowing seeds were obtained based of experimental studies. Conclusions. To ensure the improvement of the seeding quality of small seeds, the design parameters of the experimental seeder: х4 – is the diameter of the cell; х5 – the number of cells on the disk, will tend to the maximum values. The optimum circumferential speed of the sowing disk should be in the range from 0.127 to 0.192 m/s, and the speed of the machine’s movement is no more than 2 m/s.

scholarly journals MEASURING TEMPERATURE OF THE MEDIUM OF SHIP COMPRESSOR PIPING USING TEMPERATURE OF THE OUTER WALL

2018 ◽  
pp. 81-86
Author(s):  
Alexander Evgenyevich Semenov ◽  
Sergey Anatolyevich Putilin
Keyword(s):  
Heat Transfer ◽  
Theoretical Data ◽  
Outer Wall ◽  
Operating Conditions ◽  
Measured Temperature ◽  
Medium Temperature ◽  
Factors Affecting ◽  
Operating Modes ◽  
Piping Systems ◽  
Pipeline Wall

To determine the temperature of the medium in the ship's piping systems there are used readings of contact thermometers, pyrometers and thermal scans which measure the temperature of the pipeline rather accurately. Aside from corrections for accuracy of the measurement of the wall temperature, it is necessary to move towards measuring temperature of the medium. Readings of the temperature of the pipeline wall differ from the readings of the medium temperature inside the pipeline, so it is necessary to calculate and find the temperature of the medium in the pipeline. After solving a system of equations describing the phenomenon of heat transfer through the cylindrical surface, there has been worked out the technique of measuring temperature of the pipeline medium, according to the measured temperature of the pipe wall. The conditions of heat transfer can vary for different pipelines and media. The paper gives calculated temperature corrections for different operating conditions of the pipeline. To carry out calculations, a computer program has been written in the Mathcad mathematical package. Temperature corrections have been calculated to determine the medium temperature inside the pipeline using the temperature value of the outer wall of the pipeline. There has been carried out analysis of various factors affecting temperature changes: heat transfer to the air, heat transfer of medium inside the pipeline, wall thickness and contamination. Verification of theoretical data has been made on a ship of the compressor unit. The experiment confirmed the possibility of measuring temperature of the medium inside the pipeline, according to the temperature of pipeline surface using the developed corrections. Devices measuring the temperature of the pipeline walls can be used as additional measurement to enhance informativeness of testing results, analysis of operating modes, and improve the operation reliability of ship piping systems

Optimization of the Blast Furnace Operating Modes for Identification of the Areas of Unimprovable Solutions

2017 ◽  
Vol 743 ◽  
pp. 363-368 ◽  
Author(s):  
Lev Kazarinov ◽  
Dmitry Shnayder ◽  
Tatyana Barbasova
Keyword(s):  
Blast Furnace ◽  
Coke Consumption ◽  
Thermal State ◽  
Real Life ◽  
Operating Mode ◽  
Optimal Choice ◽  
Operating Modes ◽  
Consumption Reduction ◽  
Reasonable Choice

This work reviews the issues of modeling of the operating modes for a blast furnace and identification of areas of unimprovable solutions on a set of indicators of cast iron output, coke consumption, and thermal state. These areas define the boundaries of potential opportunities for achieving high values of quality of the blast-furnace processes on a set of real-life operating modes of a blast furnace. They also indicate the reserves of coke consumption reduction and output enhancement, which might be implemented by optimal choice of a blast furnace operating mode and which enable the reasonable choice of the operating mode of a blast furnace based on the potential opportunities for increasing the output, minimizing coke consumption for the specified coke quality and the specified requirements to the furnace thermal state.

The Concept of Mechanical Part of the Model Micro-Energy Sources for Electrical Laboratories

2016 ◽  
Vol 835 ◽  
pp. 810-815 ◽  
Author(s):  
René Drtina ◽  
Jaroslav Lokvenc ◽  
Josef Šedivý ◽  
Jan Škoda
Keyword(s):  
Renewable Energy ◽  
Alternative Energy ◽  
Electrical Engineering ◽  
Renewable Energy Sources ◽  
Operating Conditions ◽  
Energy Sources ◽  
Operating Modes ◽  
Alternative Energy Sources ◽  
Asynchronous Generator ◽  
The Subject

The use of renewable (alternative) energy sources of energy is still a hot topic. In the electrical engineering laboratories of the Department of technical subjects created a model of micro energy sources that can be operated in various operating modes to simulate in various operating conditions. The machine set is dedicated for laboratory of electric engeneering. Goal is to show students in the subject Renewable energy sources and their application, practical use and parameters an the asynchronous generator. The article deals with the mechanical concept and mechanical construction of laboratory machine set.

scholarly journals OPTIMAL CONTROL OF THE TRACTOR MOVEMENT

2020 ◽  
Author(s):  
E. Kalinin ◽  
◽  
M. Myasushka
Keyword(s):  
Optimal Control ◽  
Travel Speed ◽  
Gear Ratio ◽  
Operating Conditions ◽  
Design Parameters ◽  
Logic Device ◽  
Factors Affecting ◽  
Operating Modes ◽  
Methods Analytical ◽  
The Right

Goal of the study. Assessment of the possibility of optimizing tractor control by methods of automatic search for the optimum point. To achieve this goal, you must complete the following tasks: – to analyze the operating conditions of the tractor unit with the determination of the force factors affecting its operating conditions; – to develop a scheme and algorithm for the operation of the extreme regulator and analyze its functioning. Research methods. Analytical studies are based on methods of optimization of power factors acting on a tractor. The results of the study. An automatic regulator is considered, which provides an optimal ratio of the engine speed and the transmission gear ratio for each speed. The logic device generates a signal to change the power train ratio. The required travel speed of the tractor unit is set by the operator using the speed regulator. Changing the gear ratio changes the speed of the tractor. The signal of the deviation of the speed of movement, after amplification, provides an effect on the fuel supply and, by changing the revolutions of the crankshaft of the engine, brings the actual speed of the tractor to the set one. In the control system, the measurement of the amount of fuel consumed by the engine is carried out by a flow meter, and the measurement is carried out at certain intervals, and the current value is compared with the previous one. Reducing fuel consumption means that the influence on the change in gear ratio has been chosen in the right direction. Conclusions. The paper proposes a self-adjusting system. In a theoretical study of the possibility of optimal control of the tractor movement, equations are determined that are easily solved by the graphical analytical method. The graphical plotting determines the time the system reaches the optimal mode. The considered example of regulation of the power drive and the tractor engine does not exhaust the scope of application of self-adjusting systems. The operating modes of a number of units, as well as some interrelationships of design parameters, have static characteristics that ensure widespread use of these systems.

scholarly journals Influence of transition modes of blast-furnace smelting to change the temperature of the cooling-system plates

2018 ◽  
pp. 3-9
Author(s):  
V.V. Horupakha ◽  
Yu.S. Semenov ◽  
E.I. Schumelchyk ◽  
S.V. Vashchenko ◽  
E.D. Vyshinskaya
Keyword(s):  
Blast Furnace ◽  
Natural Gas ◽  
Thermal State ◽  
Cooling System ◽  
Furnace Operation ◽  
Operating Conditions ◽  
The Body ◽  
Blast Furnace Smelting ◽  
Operating Modes ◽  
Furnace Smelting

Purpose. Estimation of the influence of non-stationary blast-furnace smelting on the thermal state of the cooling system. Methodology. Analysis of changes in the meanings of thermocouples installed in the body of the cooling system plates, under different operating conditions of the blast furnace. Results. The study of the influence of transitional modes of blast-furnace smelting on the temperature change of the cooling-system plates at the joint use of natural gas and coal-pulverized fuel, under conditions of a low-intensity blast furnace operation and using pulverized coal with a consumption of more than 110 kg/ton of pig iron. Findings. The peculiarities of the influence of transitional modes of blast-furnace smelting on the thermal state of the cooling system are established: incl. with various fuel additives for blasting and with the operation of the furnace with reduced intensity. Practical value. The results presented in the article can be used in the design of the cooling system, as well as in the selection of rational operating modes of the blast furnace. Keywords. blast furnace, PCI technology, natural gas, cooling-system plates, thermocouple.

The Analysis and Operation Control for the Gypsum’s Low Purity of Wet FGD

2013 ◽  
Vol 726-731 ◽  
pp. 225-229 ◽  
Author(s):  
Xiao Xiang Zhou ◽  
Xue Ying Zhang ◽  
Xue Feng Dong
Keyword(s):  
Main Product ◽  
Operating Conditions ◽  
Factors Affecting ◽  
Comprehensive Utilization ◽  
Actual Operating ◽  
Operation Control

Gypsum is the main product of wet desulfurization, combined with the actual operating conditions of desulfurization unit, the factors affecting the purity of gypsum is analyzed. Combining with the comprehensive utilization of gypsum requirements, from every aspect of characteristics of coal, limestone’s quality and operation control, improve the gypsum’s quality of wet desulfurization in coal-fired plant.

Fuzzy Cognitive Maps in Reliability Modeling

2021 ◽  
pp. 1-19
Author(s):  
Alexander Rotshtein ◽  
Ludmila Pustylnik ◽  
Denys Katielnikov
Keyword(s):  
Storage Conditions ◽  
Spare Parts ◽  
Operating Conditions ◽  
Fuzzy Cognitive Maps ◽  
Fuzzy Cognitive Map ◽  
Design Quality ◽  
Reliability Modeling ◽  
Factors Affecting ◽  
Importance Index

The fuzzy cognitive map is considered as a tool for the ranking of factors affecting reliability. The rank of a factor is defined as an equivalent of the Birnbaum importance index in the classical reliability theory. Models and algorithms are proposed for calculation of the importance indexes of single factors and their joint effects on the reliability. The method is exemplified by the reliability and safety of an automobile in the “driver-automobile-road” system subject to the driver's qualification, traffic situation, unit costs of operation, operating conditions, maintenance scheduling, quality of maintenance and repair, quality of automobile design, quality of operational materials and spare parts, as well as storage conditions. The advantages of the method include 1) use of available expert information with no collection and processing statistical data and 2) capability to take into account any quantitative and qualitative factors associated with people, technology, software, quality of service, operating conditions, etc.

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