The determination of induction motor losses in steel taking into account its saturation

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mykhaylo Zagirnyak ◽  
Vita Ogar ◽  
Volodymyr Chenchevoi ◽  
Rostyslav Yatsiuk
Keyword(s):  
Induction Motor ◽  
Electromotive Force ◽  
Induction Machine ◽  
Content Type ◽  
Operating Modes ◽  
Machine Steel ◽  
Harmonic Components ◽  
First Time ◽  
Analytical Expressions

Purpose This paper aims to work out a method for calculating losses in induction motor steel taking into account its saturation. Design/methodology/approach The theory of electric machines is applied during the analysis of induction motor equivalent circuits. The theory of Fourier series is used to determine the harmonic components of voltage, current and power. Instantaneous power theory and trigonometric transformations are used to solve algebraic and differential equations and their systems. The methods of approximation and interpolation are applied to obtain analytical expressions from the experimental data. Experimental research was carried out to verify the reliability of theoretical provisions and research results. Findings A method for assessing an induction machine steel as a function of the generalized electromotive force has been proposed. It allows taking into account higher harmonics of the current, which are caused by the presence of nonlinearity of an induction motor magnetic circuit. Practical implications The obtained results can be used in calculating the energy characteristics and operating modes of an induction motor, as well as in the construction of control systems. Originality/value A method for determining the losses in the stator steel of an induction motor, using a generalized electromotive force, has been proposed for the first time. It enables taking into account the currents flowing both in the stator circuit and in the rotor circuit.

scholarly journals Improving the energy efficiency of electric drives for auxiliary units of traction rolling stock

2021 ◽  
Vol 2131 (4) ◽  
pp. 042085
Author(s):  
T S Titova ◽  
A M Evstaf’ev ◽  
A A Pugachev
Keyword(s):  
Energy Efficiency ◽  
Control Systems ◽  
Induction Motor ◽  
Induction Machine ◽  
Rolling Stock ◽  
Electric Drives ◽  
Operating Modes ◽  
Stator Current ◽  
Power Loss Reduction ◽  
Rotor Winding

Abstract The review of technical solutions and schematic characteristics of auxiliary drives for traction vehicles has shown that the most rational variant is an electric drive with an induction machine. Given the operating modes of the auxiliary drives and the share of their power consumption in the total locomotive power, the task of using scalar control systems for induction machines becomes relevant. Based on a mathematical model describing the dynamic energy conversion processes in the T-shape substitution circuit of an induction motor, taking into account stator steel losses and current displacement effects in the rotor winding and saturation along the main magnetic path, possibilities for reducing stator current have been investigated. In order to improve the energy efficiency of electric drives two variants of control system have been proposed. One based on search method of self-tuning to the stator current minimum and the other - on maintaining the power factor of induction motor at the level that ensures equality of active and reactive components of stator current. The hardware and software requirements for implementing control systems have been analysed. Modelling using Matlab has shown that both control systems work - power loss reduction can be as low as 50% and as high as 60% in certain modes.

scholarly journals THE ANALYSIS OF THE THREE-PHASE INDUCTION MOTOR WITH DEEP ROTOR BARS THROUGH NUMERICAL SIMULATIONS UTILIZING A MODIFIED MATHEMATICAL MODEL

2021 ◽  
Vol 2020 (1) ◽  
pp. 1-11
Author(s):  
Mihai IORDACHE ◽  
Sorin DELEANU ◽  
Neculai GALAN
Keyword(s):  
Mathematical Model ◽  
Numerical Simulations ◽  
Induction Motor ◽  
Skin Effect ◽  
Induction Machine ◽  
Rotor Resistance ◽  
Three Phase ◽  
Space Phasor ◽  
Analytical Expressions ◽  
Circuit Resistance

The three-phase induction machine mathematical model presented in the paper, is adequate for applying to the deep rotor bars case. The rotor resistance R’r(r), respectively its leakage inductivity L’r(r), depend upon the rotor currents’ frequency fr because of the skin effect. Following the previous considerations, one developed slip dependent analytical expressions of the rotor circuit resistance R’r(s), respectively rotor circuit leakage reactance L’r (s). A modified space phasor based mathematical model of the deep bar induction motor is tested through simulations to assess the motor’s characteristics. The results are in accordance with the literature.

Numerical simulation of the fractional Lienard’s equation

2019 ◽  
Vol 30 (3) ◽  
pp. 1223-1232 ◽  
Author(s):  
Razan Alchikh ◽  
Suheil Khuri
Keyword(s):  
Decomposition Method ◽  
Design Methodology ◽  
Nonlinear Term ◽  
Initial Conditions ◽  
Recursive Algorithm ◽  
Content Type ◽  
Fractional Differential ◽  
Laplace Decomposition Method ◽  
First Time

Purpose The purpose of this paper is to apply an efficient semi-analytical method for the approximate solution of Lienard’s equation of fractional order. Design/methodology/approach A Laplace decomposition method (LDM) is implemented for the nonlinear fractional Lienard’s equation that is complemented with initial conditions. The nonlinear term is decomposed and then a recursive algorithm is constructed for the determination of the proposed infinite series solution. Findings A number of examples are tested to explicate the efficiency of the proposed technique. The results confirm that this approach is convergent and highly accurate by using only few iterations of the proposed scheme. Originality/value The approach is original and is of value because it is the first time that this approach is used successfully to tackle fractional differential equations, which are of great interest for authors in the recent years.

Analysis of Higher Harmonic Components Influence on the Electric Circuit at Induction Motor Functioning Equipped with Adjustable-Frequency Electric Drive

2014 ◽  
Vol 698 ◽  
pp. 173-177 ◽  
Author(s):  
Tatyana Vladimirovna Myateg
Keyword(s):  
Induction Motor ◽  
Frequency Converter ◽  
Electric Circuit ◽  
Rotation Velocity ◽  
Higher Harmonics ◽  
Motor Functioning ◽  
Current Harmonics ◽  
Operating Modes ◽  
Advantages And Disadvantages ◽  
Harmonic Components

This paper deals with analyzing the operating modes peculiarities of induction motor equipped with ACS 550 frequency converter. Great attention is given to the study of higher current harmonics behavior at changing rotation velocity and momentum of the induction motor. Advantages and disadvantages of frequency converter application are discussed in detail. Wetry to define the main trends in higher harmonics behaviorand give general recommendations to quench such higher harmonics.

Direct Parametric Analysis of Resonance Regimes for Nonlinear Vibrations of Bladed Discs

2006 ◽  
Author(s):  
E. P. Petrov
Keyword(s):  
Large Scale ◽  
Contact Stiffness ◽  
Design Parameters ◽  
Strongly Nonlinear ◽  
Resonance Frequencies ◽  
Interface Parameters ◽  
First Time ◽  
Analytical Expressions ◽  
Contact Stiffness Coefficients

A method has been developed to calculate directly resonance frequencies and resonance amplitudes as functions of design parameters or as a function of excitation levels. The method provides, for a first time, this capability for analysis of strongly nonlinear periodic vibrations of bladed discs and other structures with nonlinear interaction at contact interfaces. A criterion for determination of major, sub- and superharmonic resonance peaks has been formulated. Analytical expressions have been derived for accurate evaluation of the criterion and for tracing resonance regimes as function of such contact interface parameters as gap and interference values, friction and contact stiffness coefficients, normal stresses. High accuracy and efficiency of the new method have been demonstrated on numerical examples including large-scale nonlinear bladed disc model and major types of contact interfaces including friction contact interfaces, gaps and cubic nonlinearities.

Profitability factors and efficiency of Greek banks

2012 ◽  
Vol 7 (2) ◽  
pp. 185-200 ◽  
Author(s):  
Nikos Ioanni Schiniotakis
Keyword(s):  
Economic Crisis ◽  
Banking Sector ◽  
Banking System ◽  
Economic Recession ◽  
Content Type ◽  
Cooperative Banks ◽  
Greek Banks ◽  
First Time ◽  
Published Research

PurposeThis paper aims to search for the factors that influence the profitability of Greek commercial and cooperative banks by examining other variables that have never been used before. It also seeks to examine bank performance before and during the economic crisis in Greece. The survey is based on previous similar research.Design/methodology/approachA multiple regression analysis has been used for the determination of the factors which influence the profitability of the Greek banking sector as well as the multicriteria method PROMETHEE for the examination of the Greek banking sector performance before (2007) and during the economic recession (2008‐2009).FindingsThe paper finds that: type of bank plays an important role in profitability; the indicator ROA is associated only with well‐capitalized banks with sufficient liquidity and cost efficiency; and cooperative banks in general at the beginning of the crisis were less influenced by the economic crisis than commercial banks.Originality/valueThis is the first time that the entire Greek banking system has been examined for the particular period regarding the factors that influence bank profitability. Up to now there has been no published research examining whether the type of the bank influences profitability or which of banks remained efficient and “durable” before and during the first two years of the economic crisis in Greece.

scholarly journals Determination of digital technologies preferences of educational researchers

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mehmet Fırat ◽  
Hakan Altınpulluk ◽  
Hakan Kılınç
Keyword(s):  
Mixed Method ◽  
Human Factor ◽  
Scientific Research ◽  
Digital Technologies ◽  
Mixed Method Research ◽  
Content Type ◽  
Advanced Technologies ◽  
Sequential Explanatory Mixed Method ◽  
First Time

PurposeThis study aims to investigate the preferences of 96 educational researchers on the use of digital technologies in scientific research.Design/methodology/approachThe study was designed as a quantitative-dominant sequential explanatory mixed-method research.FindingsDespite the spreading use of advanced technologies of big data and data mining, the most preferred digital technologies were found to be data analysis programs, databases and questionnaires. The primary reasons of using digital technology in scientific research were to collect data easily and quickly, to reduce research costs and to reach a higher number of participants.Originality/valueThe use of digital technologies in scientific research is considered a revolutionary action, which creates innovative opportunities. Through digitalized life, probably for the first time in history, the educational researchers have analytical information, which we can benefit from more than the individual's own statements in research involving human factor. However, there are a few studies that investigated the preferences of educational researchers who use digital technologies in their scientific research.

scholarly journals HARMONIC DISTORTION ASSESSMENT BY AREA BASED APPROACH AT SINGLE PHASING OF AN INDUCTION MOTOR

2013 ◽  
Vol 14 (2) ◽  
Author(s):  
Surajit Chattopadhyay ◽  
Samarjit Sengupta
Keyword(s):  
Power System ◽  
Induction Motor ◽  
Reference Signal ◽  
Induction Machine ◽  
Harmonic Distortion ◽  
Specific Reference ◽  
Real Power ◽  
Reference Signals ◽  
System Data ◽  
Harmonic Components

ABSTRACT: This paper presents harmonic distortion assessment by area based approach at single phasing of an induction motor. This has been achieved by assessing voltage and current signals using area based approach. Some specific reference signals have been defined, after which, real power system data are plotted with this reference signal and areas thus formed by the real power system data with the reference signal have been calculated wherefrom contributions of fundamental waveform and harmonic components in real and reactive powers have been assessed separately. Single phasing is done on induction machine and total harmonic distortion factors have then been calculated. Significant change is observed in harmonic distortion due to single phasing. ABSTRAK: Kertas kerja ini membentangkan penilaian herotan harmonik menggunakan kaedah keluasan kawasan pada pemfasaan tunggal motor aruhan. Menggunakan kaedah keluasan kawasan, penilaian terhasil dengan memantau isyarat arus dan voltan. Sesetengah isyarat rujukan tertentu dikenal pasti, di mana, data sistem kuasa sebenar diplotkan berdasarkan isyarat rujukan ini. Kawasan kemudiannya dibentuk dengan adanya data sistem kuasa sebenar dengan menggunakan pengiraan isyarat rujukan. Pengiraan ini memberikan bentuk gelombang asas dan komponen harmonik sebenar di mana kuasa reaktif ditentukan secara berasingan. Pemfasaan tunggal ditentukan menggunakan mesin aruhan dan faktor jumlah herotan harmonik diambil kira .Perubahan yang ketara dikenal pasti dalam herotan harmonik yang disebabkan oleh pemfasaan tunggal.

Isn’t all loss consequential?

2015 ◽  
Vol 7 (3) ◽  
pp. 176-194 ◽  
Author(s):  
Adam Connell ◽  
Jim Mason
Keyword(s):  
Sources Of Information ◽  
Breach Of Contract ◽  
Content Type ◽  
Legal Principles ◽  
Secondary Sources ◽  
Legal Position ◽  
Construction Law ◽  
Definition Of ◽  
First Time

Purpose – The purpose of this paper is to demystify the meaning of the term “consequential loss” in relation to the practice of construction law. Parties may have different understandings of the term and typically an exclusion clause will not solely relate to consequential loss, but will also include other heads of losses for which the party will not be liable for, such as loss of profit, loss of revenue and loss of business. Design/methodology/approach – The question emerges as to whether the term consequential loss has a definitive legal meaning in its own right. This study seeks to ascertain the definition of the term consequential loss within the construction industry through a review of the legal position regarding liability for breach of contract and consequential loss through the consideration of the case law relating to this topic and the associated secondary sources of information. Findings – The study concludes by elucidating a clear interpretation of the term consequential loss and guidance of how it should be used in contract law. Originality/value – Recent cases and established authorities are considered together for the first time in this work which assists in the development of legal principles of direct and indirect losses and the determination of how they apply to the built environment.

Diatomic centrifugal distortion constants for large orders at any level: application to the state

1993 ◽  
Vol 71 (3) ◽  
pp. 313-317 ◽  
Author(s):  
Mahmoud Korek ◽  
Hafez Kobeissi
Keyword(s):  
Vibrational Energy ◽  
Rotational Constant ◽  
Centrifugal Distortion ◽  
Jones Potential ◽  
Similar Good ◽  
Centrifugal Distortion Constants ◽  
Schrödinger Perturbation ◽  
First Time ◽  
Analytical Expressions

The determination of the centrifugal distortion constants (CDC) of a diatomic molecule is sought for high orders. When the vibrational energy e0 = Ev is known for a vibrational level v, the use of Rayleigh–Schrödinger perturbation theory gives the rotational constant [Formula: see text] and the CDC,[Formula: see text] [Formula: see text] [Formula: see text] where Φn(r) is the solution of the nth rotational Schrödinger equation. The problem of the determination of a function Φn is solved by deriving exact analytical expressions for the initial values Φn(r0) and [Formula: see text] at an arbitrary "origin" r0, the determination of any Φn(r) becoming as easy as that of Φn(r) when e0 is known; that of en becomes as easy as that of [Formula: see text] The application of the present formulation to the model Lennard–Jones potential function allows the numerical computation of Dv, Hv, Lv, Mv, Nv, Ov, Pv, Qv for low and high v; the CDC beyond Mv are given for the first time; higher order CDC may be reached. The results for the four lowest order constants are in good agreement with those from previously confirmed methods. Appropriate tests for all orders show that the present method provides an elegant and competitive solution to the diatomic CDC problem even for large orders and high levels (near dissociation). Similar good results are obtained for an RKR potential of the [Formula: see text] state bounded by 109 levels.

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