Wyniki 1-10 spośród 12 dla zapytania: authorDesc:"Viacheslav PRUS"

Use of neuronets in problems of forecasting the reliability of electric machines with a high degree of mean time between failures DOI:10.15199/48.2016.01.32

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It was investigated the possibility to implement neuronets in reliability models of electric machines with constructive faults. It was grounded the tasks for neuronets during forecasting the failure of main structural units and electric machines in general. The choice of neuronet structure was done as result of analysis of most promising models on the example of evaluation the bearing unit faults. Streszczenie. Przebadano możliwość implementacji sieci neuronowej w modelach niezawodnościowych maszyn elektrycznych z uszkodzeniami konstrukcyjnymi. Postawiono ugruntowane zadania dla sieci neuronowych podczas prognozowania uszkodzeń głównych jednostek konstrukcyjnych. Wyboru struktury sieci neuronowej dokonano w wyniku analizy najbardziej obiecujących modeli na przykładzie oceny uszkodzeń łożyska. (Wykorzystanie sieci neuronowych w prognozowaniu niezawodności maszyn elektrycznych z dużym średnim czasem między uszkodzeniami) Key words: neuronet, reliability model, bearing unit. Słowa kluczowe: sieć neuronowa, model niezawodnościowy, łożysko Introduction Absence of reliable information as to estimated residual life is a particular feature of operation of electric machines (EM) used in industrial production. First of all, it can be explained by the fact that replacement of EMs that exhausted their limit resource is more typical for critical mechanisms. In other cases (up to 85 % of the determined number) EMs are just subjected to more thorough technical maintenance and various types of repairs aiming at restoration of their factual operating capacity. In this case the fact that such EMs operate at the last section of life-cycle curve and are characterized by a high degree of mean time between failures (MTBF) is not practically taken into consideration. They are characterized by accelerated aging and physical wear of the main structural elements and units [1-2], which, in fact, does not provide the possibility to use existing reliability mo[...]

The determination of the current state and the reliability indices of synchronous motors with long time between failures DOI:10.15199/48.2019.05.17

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One of the basic problems of electric machines (EM) operation consists in the impossibility of accurate determination of their current technical state (TS) limiting the possible conditions and modes of operation as a part of technological equipment [1]. Basically, it is explained by the fact that for the identification of EM TS it is necessary to know both electromagnetic parameters that later determine all the main indices of EM control quality and structural and operational deviations from the regulated operation characteristics (excess of the windings temperature, increased vibrations level, etc.), directly determining the ultimate operation life [2]. While it is possible to determine the required parameters of most low- and medium-power EMs during the control-diagnostic tests, practically, there is no such possibility for high-power EMs because of the absence of relevant testing equipment and load. The range of these EMs, first, includes synchronous motors (SM). They are widely applied in the drives of mills, pumps, compressors, smoke exhausters and superchargers. Due to their big mass and other technological features, their repair, as a rule, is performed at the place of their installation, which additionally reduces the possibilities for the account of their TS. As SMs are often parts of responsible mechanisms providing either direct basic technological process or the support of the necessary technological conditions, the problem of the TS prediction is important from the point of view of minimization of production losses. Thus, the purpose of the paper consisted in the solution of the problems of the determination and prediction of SM TS under the conditions of absent of incomplete information about the alteration of their basic parameters and characteristics. Theory The peculiar features of high-power SM include the individual approach to their design. First, it means that every EM of this type is unique as to [...]

The ways for the improvement of the information value of the methods for the assessment of the quality of electric energy as a part of its technical accounting systems DOI:10.15199/48.2019.05.18

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The irreversible growth of energy consumption and the increase of the index of the nonlinearity of the typical load of electrical networks at industrial enterprises, municipal service objects and household consumers, existing during the recent decades, make topical the problems of the assessment of the electric energy quality and the identification of consumers introducing various distortions into the networks [1]. The existing normative acts providing penalties regulate only the distortion of voltage. It does not give practically any idea of the real character of the energy exchange processes in electric circuits. Besides, the application of these acts in practice is opposed by the impossibility to part both the separate consumers influence on each other and their individual and (or) joint action on the mains supply. The above said is the main cause of the violation of electromagnetic compatibility manifested in the increase of energy consumption, the levels of reactive energy interchange, the distortion of electric networks currents and voltages, the disoperation of relay protection and automation devices. The principles of electric network designs in Ukraine often do not enable quick and reliable determination and localization of the sources of such distortions, which results in periodic occurrence of particular engineering problems as well as conflict situations in the relationship of the consumers and energy supplying organizations. Thus, the solution to the problem of the improvement of the information value of the method and the means of the assessment of the quality of electric energy for different types of load and operation modes of the consumers is an important research and technical task. The present paper deals with the solution to this problem. Theory The main consumers with a nonlinear character of the load include, first of all, arc steel-smelting furnaces, frequency converters and other semiconductor conv[...]

Features of certification of electric machines with defects of main structural assemblies during repair and long-term operation DOI:10.12915/pe.2014.12.44

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The methods and algorithms of defects diagnostic and parameters and characteristics of electric machines estimation have been substantiated. The structure of certification system of induction motors during repair and long-term operation taking into account a condition of the main constructive elements has been proved. Streszczenie. W artykule zweyfikowano metody I algorytmy stosowane w diagnostyce defektów I oszacowniu parametrów I charakterystyk maszyn elektrycznych. Struktura systemów certyfikujących dla silników indukcyjnych podczas naprawy i działania długotrwałego przy wzięciu pod uwagę warunków pracy głównych elementów konstrukcyjnych została potwierdzona. (Właściwości certyfikacji maszyn elektrycznych z uszkodzeniami głównego obiektu konstrukcyjnego podczas naprawy i działania długookresowego) Key words: induction motor, videoidentification, stator core properties, certification system. Słowa kluczowe: silnik indukcyjny, identyfikacja video, właściwości rdzenia statora, system certyfikujący doi:10.12915/pe.2014.12.44 Introduction One of basic tasks of electric machines (EM) operation is to provide the required level of their reliability at as high power indices as possible. It can be fully solved only taking into account physical processes taking place in radial-flux or axial-flux [1, 2] EM under static and dynamic operating conditions. Complexity of forecasting EM reliability indices is caused by a wide spectrum of defects and damages conditioned by faults of their production technology, operation and repair [3]. Taking into account variation of properties of basic materials and design changes in EM makes it possible to develop recommendations for to their change and restoration. Besides, estimation of the amount of expenditure and making a final decision about EM further operability are possible. If real EM indices significantly differ from the nominal ones, there appears a necessity of determination of new published da[...]

Ways of efficiency improvement of local diagnostic of the cores of induction motor stators DOI:10.15199/48.2015.01.50

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Methods for improvement of technical and economic characteristics of the systems of local diagnostics of electric machines laminated cores are considered. Operating conditions of power supplies and diagnostics terms providing its best validity are substantiated. The efficiency of application of the considered method and system of diagnostics for obtaining spatial local distribution of electric and magnetic properties of cores of induction motor stators is confirmed. Streszczenie. W artykule rozpatrzono metody poprawy technicznych i ekonomicznych charakterystyk systemów lokalnej diagnostyki rdzeni maszyn elektrycznych. Wykazano, że najlepszą walidację osiąga się poprzez warunki działania układów zasilających i parametry diagnostyczne. Potwierdzono sprawność rozpatrywanych metod i systemu diagnostycznego dla otrzymania przestrzennego lokalnego rozkładu właściwości elektrycznych i magnetycznych rdzeni stojanów maszyn elektrycznych. (Sposoby poprawy efektywności lokalnej diagnostyki rdzeni stojanów silników indukcyjnych) Key words: stator core, local diagnostics, validity, induction motor Słowa kluczowe: rdzeń stojana, lokalna diagnostyka, walidacja, silnik indukcyjny Introduction During long-term operation and repairs of induction motors (IM) the properties of inter-lamina insulation of stator laminated cores change [1]. It is the cause of occurrence of local shorted circuits distributed along the length and in the volume of the cores at random. In this case the properties of the teeth zone change more significantly and irregularly than the properties of the yoke, especially, it concerns the upper part of the teeth. It results in redistribution of the temperature of the stator winding and appearance of local zones of overheats. In contrast to the IM with laminated stator this problem does not arise in the case of electric machines with ironless stator [2, 3]. Also, due to occurrence of spatial magnetic asymmetry, IM vibration parameter[...]

Models for electric machine reliability prediction at variation of the condition of basic structural units DOI:10.15199/48.2017.01.28

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Prospects of working out intelligent models of reliability of electric machines (EM) with long mean time between failures are substantiated and a method for their realization is presented. Limit conditions of basic structural units of low- and medium-power induction motors (IM) and their primary reliability models are determined. The obtained results enable a more accurate prediction of reliability indices and during subsequent improvement and manufacturing application make it possible to pass to maintaining and repair of EM in accordance with its factual condition. Streszczenie. Perspektywy opracowania inteligentnych modeli sprawności maszyn elektrycznych z długim średnim czasem pomiędzy uszkodzeniami są uzasadnione i metoda ich realizacji została zaprezentowana. Warunki graniczne dla podstawowych parametrów konstrukcyjnych silników indukcyjnych o małej i średniej mocy i ich modeli sprawnościowych zostały wyznaczone. Otrzymane wyniki pozwalają na dokładniejszą predykcję wskaźników sprawnościowych a poprzez kolejne usprawnienia dają możliwość utrzymania i naprawy maszyny elektrycznej zgodnie z jej stanem faktycznym. (Modele predykcji sprawności maszyn elektrycznych przy zmiennych podstawowych parametrów konstrukcyjnych) Key words: reliability, model, neural network, fuzzy logic, expert system, experiment planning. Słowa kluczowe: sprawność, model, sieć neuronowa, logika rozproszona, system ekspercki, planowanie eksperymentu Introduction Existing methods of prediction of electric machines (EM) reliability indices differ depending on the solved problems and special features of the used software [1]. Models on their basis are mainly the result of generalization of the available statistic data on failures of EMs of different type, power or version. The use of such models is based on analytical prediction that implies existence of interrelation between EM current and predicted state. It can be described through variation of numerous diagnos[...]

Calculation of electromagnetic component vibration of brushed direct current machines with structural units defects DOI:10.15199/48.2017.12.48

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The state of electric machines (EM) with long meantime- between failures (LMTBF) significantly influences their reliability indices and energy efficiency during operation [1, 2]. Trustworthy and timely detection of this state and its variation due to occurrence and development of different types of structural defects directly determines the energy saving potential with regard to EM with LMTBF [3, 4]. In this respect, the determination of magnetic field parameters in EM air gap and their further analysis is the most promising trend. It provides the possibility to assess the state of the researched EM from the point of view of variation of both the general level of vibration of electromagnetic nature and its separate components. The purpose of this paper consists in creation of a mathematical model on the basis of modern methods of field calculation. This model enables the assessment of the degree of the most common defect type influence on the value and spectral composition of vibration electromagnetic component. Theory On the whole, vibration in EM can be divided into four basic types as to its nature: electromagnetic vibration, mechanical vibration, aerodynamic vibration and vibration caused by operation of commutation equipment [5]. It is the research of vibration electromagnetic component that enables assessment of most defects due to their influence on the machine magnetic symmetry Statistical data of EM failures demonstrate that a great number of them are caused by the influence of variation of the properties and parameters of the basic structural units such as electrical steel core, units of commutation and current pickup, winding, etc. This influence is manifested in the deterioration of EM reliability and accumulation of negative factors increasing the possibility of their failure [1]. This problem is especially topical for brushed direct current machines due to availability of a sliding contact characterized by [...]

The assessment of the processes of aging of the electric machines with structural unit defects using the genetic approach DOI:10.15199/48.2019.01.37

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Flexibility is one of the main features of contemporary production. First of all, it means a capability to quickly readjust to the issue of a new product. In this case, it is necessary to meet a number of basic requirements to the technological equipment foremost determining its efficiency and reliability indices. As a rule, the most part of this equipment is partially or completely automated. This, along with the use of control facilities, implies the presence of controlled devices, first of all, various electric machines (EM). They chiefly determine energy consumption and partially - the reliability of the whole equipment. Having comparatively long mean-timebetween failures, most often, such EMs are not subject to change during the modernization of the equipment [1]. However, everybody knows that their parameters and characteristics deteriorate during long-term operation and repairs due to their aging [2]. Nowadays universal approaches to the analysis of aging processes in technical systems, including EMs, are practically absent. The idea of EM aging did not widely spread in the technical and research literature because of the impossibility of its exact description and mathematical representation. However in this case we can consider it as partial loss of the properties and characteristics by the basic structural materials, elements and whole EMs under the influence of external factors occurring in the process of operation and repairs with the course of time. As the final stage of this process is of little practical interest, one can consider the moment of time when EM does not provide the required technological conditions or when the expenditure on their operation essentially influences the cost of the issued product to be the limit of aging. Thus, the substantiation of the principles of taking into account the processes of EM aging is an important scientific-research problem. In the future, it will enable forecasting[...]

The ways for the improvement of the information value of the thermal image control of electric machines with long mean time between fa DOI:10.15199/48.2019.05.16

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To provide the reliable operation of electric machines (EM) it is necessary to have trustworthy information about their current state [1]. Its presence will enable both the assessment of their operation conditions and the forecast of the residual life for their timely withdrawal to repair or maintenance. In this case, the main problem consists in the impossibility to use many of the most accurate and advanced methods of diagnostics, as the current monitoring of EM condition is performed in most cases with operating equipment with limited access to EMs and their basic structural units [2]. The above said substantiates the use of such methods of measuring, control and diagnostics that minimize the possible preparatory procedures and even eliminate their influence on operating EM, including various distant methods [3]. According to the existing statistic data, most EM failures result from the winding or bearing units breakage preceded by the growth of their temperature. Thus, the diagnostic methods allowing additional assessment of the thermal condition of both separate units and EM on the whole are sufficiently informative [4, 5]. Their application is especially topical in the determination of the deviation of the temperature of the basic structural elements in complex dynamic operation modes and in the assessment of EM condition in the course of aging. The posed problem can be solved with the use of the methods and means of thermal image control (TC), along with the following digital processing of the obtained images. However, the problems of the accurate interpretation of separate sources of heating and the assessment of the intensity remain unsolved. The present paper settles these problems. Theory The direct application of TC to EM is a rather complicated and ambiguous problem nowadays. First, it is explained by the impossibility of the direct assessment of the state of the internal structural units as windings, cor[...]

Determination of power indices for a three-phase induction motor with a phase-wound rotor through particular losses components

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A method of determination of power indices for a three-phase induction motor with a phase-wound rotor through particular losses components in the function of their integral and instantaneous values is developed. The adequacy of the method is confirmed. The prospect of its use is grounded for the situation when the state of structural assemblies and motor elements changes in the process of long-term operation and after repair. Streszczenie. Przedstawiona została metoda określenia wskaźników trójfazowego silnika indukcyjnego z wirnikiem uzwojonym poprzez poszczególne składniki strat w funkcji ich integralnych i chwilowych wartości. Odpowiedniość metody została potwierdzona. Perspektywa stosowania tej metody oparta jest ukierunkowana na sytuacje kiedy konstrukcyjny montaż i elementy silnika zmieniły się w procesie długotrwałego działania oraz po remoncie. (Określenie wskaźników mocy dla trójfazowego silnika indukcyjnego z uzwojonym wirnikiem poprzez poszczególne składniki strat). Key words: induction motor, phase-wound rotor, losses components, power indices. Słowa kluczowe: silnik indukcyjny, wirnik uzwojony, składniki strat, wskaźniki mocy. Introduction In a competitive market, which is especially acute during crisis years, the industrial production aims at considerable decrease of various kinds of expenditure influencing the prime cost of manufactured goods. For most enterprises of metallurgic, chemical and other adjacent industries electric power costs, coming to 30-35 % in the total cost, are considerable. This poses the problem of optimization of power costs in control of various technological objects and processes at an enterprise. It is possible to optimize power consumption in an electric drive by means of control systems estimating real power conditions of electric machines operation and their efficiency. The prospect of the use of such systems is determined by availability of reliable methods of finding power and moment on[...]

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