scholarly journals Thermal modes of the automated electric drive system during burning under load

2021 ◽  
pp. 14-23
Author(s):  
O.A. Khrebtova ◽  
N.V. Zachepa
Keyword(s):  
Induction Motor ◽  
Supply Voltage ◽  
Heating Temperature ◽  
Low Frequency ◽  
Stator Winding ◽  
Stator Windings ◽  
Temperature Regimes ◽  
Start Up ◽  
First Time ◽  
Starting Torque

Purpose. Conducting experimental studies of temperature regimes of an induction motor during start-up on a laboratory complex. Obtaining real characteristics of the heating process during the start of the start, assessing its impact on the insulation state of the induction motor, confirming the adequacy of the indirect method of determining the heating temperature of the induction motor windings during the formation of the cyclic starting torque during the start. Methodology. To solve these problems, we used mathematical modeling based on the first mathematical expressions that calculate the temperature of the stator winding during start-up, taking into account the influence of the frequency of the supply voltage on the parameters of the induction motor. Physical modeling on the developed laboratory stand of modes of movement on fixing of temperature during each stage of experiment for confirmation of theoretical researches of movement at pulse character of the starting moment. Findings. The use of different methods of constructing equivalent thermal circuits (ETS) to calculate the temperature of an induction motor requires significant resource consumption, which is unprofitable when the rotor of the machine is stationary as in the case of failure. Using the method of determining losses in steel in the deep saturation mode, the mathematical dependences of the calculation of the temperature regime during the algorithm, taking into account the change in the properties of the stator winding during heating, calculated the allowable current overload parameters taking into account the allowable heating of stator windings. The paper obtains mathematical dependences for calculating the temperature regimes of the stator windings during the formation of the cyclic starting torque for the movement, taking into account the change of the initial conditions of the movement for each cycle and the change in the properties of the stator windings during heating. The developed laboratory complex allows to carry out research of temperature modes of a stator winding at movement of the induction motor with the braked rotor, at assignment of various values ​​of amplitude and frequency of supply voltage. The results of research indicate that the mathematical dependences derived in the work allow to control the heating temperature by the analytical method. Analysis of the modes of operation of the induction motor during the execution of the movement confirmed the need to control the temperature of the stator windings to prevent accidents. In general, when starting with a step-by-step supply of low frequency supply voltage to obtain increased starting torque, the heating of the stator windings is slower compared to heating during prolonged operation of an induction motor with a braked rotor, which allows multiple attempts to move at low frequency. nutrition. Originality. For the first time, mathematical dependences for calculating the temperature of stator windings during start-up with a braked rotor of an asynchronous machine are obtained and experimentally confirmed, which take into account the change in stator winding properties during heating and the influence of supply voltage frequency. Practical value.  For the first time, an indirect method of controlling the heating temperature of the stator windings of an asynchronous machine during start-up is proposed to prevent emergencies on process equipment that is started under load.

Diagnostics of Stator Winding Faults in a Three-Phase Asynchronous Motor Using Park’s Vector Analysis

Vestnik MEI ◽  
2021 ◽  
pp. 69-74
Author(s):  
Muhammad Deeb ◽  
◽  
Gassan Ibragim ◽  
Talal Assaf ◽  
◽  
...  
Keyword(s):  
Induction Motor ◽  
Short Circuit ◽  
Asynchronous Motor ◽  
Vector Model ◽  
Stator Winding ◽  
Stator Windings ◽  
Stator Current ◽  
Experimental Part ◽  
Three Phase ◽  
Short Circuit Fault

The study addresses the problem of detecting a short circuit fault in the three-phase induction motor winding by monitoring the stator current Park vector (Lissajous curves). Park's vector model is implemented using the Matlab software package. The experimental part of the study was carried out on an 11 kW three-phase induction motor. The Lissajous curves obtained for a healthy motor and a motor with short-circuited turns under various load conditions were compared with each other. The obtained results have demonstrated the effectiveness of the proposed method for detecting interturn short circuit faults in the three-phase stator windings of induction motors.

scholarly journals Analysis of electric drive systems for performance of driving and starting under load

2020 ◽  
pp. 18-25
Author(s):  
O.A. Khrebtova ◽  
N.V. Zachepa
Keyword(s):  
Control Systems ◽  
Electric Drive ◽  
Phase Control ◽  
Drive System ◽  
Transport Mechanisms ◽  
Starting Current ◽  
Electric Drive System ◽  
Start Up ◽  
First Time ◽  
Starting Torque

Purpose. Perform an analysis of existing automated control systems of the electric drive and methods of forming the starting torque to determine the compliance of the selected system and method to the requirements for trouble-free mode of start and start of the technological mechanism in difficult conditions or breakaway and start under load.. Methodology. Comparison of energy performance and capabilities of control systems and methods for the formation of starting torque, mathematical calculations, analysis of the properties of systems and methods in accordance with the requirements of technological operations during the start. Findings. To obtain the results of the analysis of the current methods of starting induction motors, autotransformer start was considered, which can significantly reduce the starting current, and also connect a capacitor with a reactance to reduce the current and increase the starting torque; the use of soft start with amplitude-phase control allows you to reduce the starting current and reached the absence of its impulses. The vector-pulse method of controlling the converting device increases the starting torque in the absence of an increase in starting current, such advantages have a quasi-frequency starting mode, but the application is limited by special technological equipment. Thyristor voltage regulator using the phase control method, despite its widespread use in control systems, has a low value of the starting torque. To carry out starting in difficult conditions, according to the results of the analysis of existing systems of controlled starting, it was found that a rational electric drive system for hoisting-and-transport mechanisms is a frequency-controlled electric drive system according to the "frequency converter - asynchronous motor" (FC - IM) scheme. Originality.  For the first time it is proposed to improve the existing control systems of hoisting and transport mechanisms that perform start-up in difficult conditions when using the modes of movement to form the starting torque that exceeds the passport value by 3-4 times. Increasing energy efficiency based on increasing their efficiency, information content and data reliability. For the first time, the reasons for the shortcomings of existing control systems during start-up under load in modern production are analyzed. Practical value. The choice of a rational electric drive system for lifting and transport mechanisms is substantiated when starting in difficult conditions, which will provide maximum efforts in the transmission of a technological mechanism with permissible current and thermal overloads of asynchronous machines.

scholarly journals Determining an additional diagnostic parameter for improving the accuracy of assessment of the condition of stator windings in an induction motor

2021 ◽  
Vol 5 (5 (113)) ◽  
pp. 21-29
Author(s):  
Oleg Gubarevych ◽  
Sergey Goolak ◽  
Olena Daki ◽  
Yuriy Yakusevych
Keyword(s):  
Induction Motor ◽  
Induction Motors ◽  
Short Circuit ◽  
Rotation Frequency ◽  
Additional Parameter ◽  
Stator Winding ◽  
Diagnostic Parameter ◽  
Stator Windings ◽  
Shaft Rotation ◽  
Additional Diagnostic Parameter

This paper has proposed and substantiated the application of an additional diagnostic parameter for assessing the state of stator windings of induction motors during operation. The dependences of the values of phase shifts between phase currents and phase voltages have been obtained. These dependences showed that when an inter-turn short circuit occurs in the stator windings, the phase shifts are the same for all phases of the motor. That has made it possible to obtain the dependence of the change in phase shift on the change in the engine shaft rotation frequency. This study's result has established the dependence of the rates of change of the phase angle on the engine shaft rotation frequency for both one and two damaged phases with varying degrees of damage. When analyzing these dependences, it was found that with an increase in the number of damaged phases of the electric motor, the linear section of the dependences decreases. In addition, with an increase in the degree of phase damage, the angle of inclination of the linear sections of the characteristics decreases. That has made it possible to determine an additional parameter for diagnosing the place and degree of an inter-turn short circuit of the windings in an induction motor with a squirrel-cage rotor. The values of the additional parameter, termed by this paper's authors as a "phase criterion" can be used to assess the condition and degree of damage to the stator winding of induction motors. The values of the phase criteria for various types of damage were: when phase A is damaged by 90 %, ξ=0.634, (deg)2/(rpm)2; when phase A is damaged by 80 %, ξ=0.393, (deg)2/(rpm)2; when phase A is damaged by 80 % and phase B is damaged by 90 %, ξ=0.25, (deg)2/(rpm)2; when phase A is damaged by 80 % and phase B is damaged by 90 %, ξ=0.173, (deg)2/(rpm)2. The results of this research could be used to select an effective method for diagnosing an inter-turn short circuit in the stator winding when building a diagnostic system for induction motors as part of drives of transport equipment

scholarly journals Modeling of Balanced and Unbalanced Three-Phase Induction Motor under Balanced and Unbalanced Supply Based on Winding Function Method

2015 ◽  
Vol 5 (4) ◽  
pp. 644 ◽  
Author(s):  
Mohammad Jannati ◽  
Tole Sutikno ◽  
Nik Rumzi Nik Idris ◽  
Mohd Junaidi Abdul Aziz
Keyword(s):  
Induction Motor ◽  
Function Method ◽  
Stator Winding ◽  
Electromagnetic Torque ◽  
Matlab Simulation ◽  
Stator Windings ◽  
Open Phase ◽  
Squirrel Cage ◽  
Three Phase ◽  
Simulation Results

<p>An accurate model of balanced and unbalanced three-phase Induction Motor (IM) under balanced and unbalanced supply conditions based on Winding Function Method (WFM) is presented in this work. In this paper, the unbalanced condition in three-phase IM is limited to stator winding open-phase fault. The analysis of presented models is shown in details which allow predicting the performance of 3-phase IM under different conditions. Computer simulations were obtained using the MATLAB software for a three-phase squirrel cage IM. MATLAB simulation results show that the oscillation of the speed and electromagnetic torque has increased considerably due to the open-phase fault in stator windings.</p>

Invasive Methods to Diagnose Stator Winding and Bearing Defects of an Induction Motors

2019 ◽  
pp. 122-130
Author(s):  
Muhammad Aman Sheikh ◽  
Nordin B. Saad ◽  
Nursyarizal Mohd Nor ◽  
Sheikh Tahir Bakhsh ◽  
Muhammad Irfan
Keyword(s):  
Induction Motor ◽  
Condition Monitoring ◽  
Failure Modes ◽  
Short Circuit ◽  
Raw Material ◽  
Maintenance Cost ◽  
Stator Winding ◽  
Stator Windings ◽  
Bearing Defects ◽  
Bearing Failures

Condition monitoring in an induction motor must concentrate on the root causes of the failure modes that exhibit a slow failure sequence. According to published surveys, two-fifths of the faults are due to bearing failures. Inter-turn short circuit faults in stator windings are approximately responsible for one-third of the motor faults. In the last few decades, various methods and alternative techniques have been proposed and implemented to diagnose induction motor faults. In an induction motor, stator winding and bearing faults account the largest percentage of motor failure. Due to the fact these faults can lead the motor to catastrophic failure that are expensive in term of maintenance cost, wastage raw material, and unplanned shutdown. Thus, to diagnose the state of motor and overcome existing problem, the chapter provides detailed invasive methods which are proposed and are currently in practice. Moreover, the chapter also highlights the limitation, scope, and the challenges of existing invasive condition monitoring techniques.

scholarly journals Mathematical Modelling of Induction Motor Transient Processes During Stator Winding Interruption

2010 ◽  
Vol 26 (1) ◽  
pp. 74-77 ◽  
Author(s):  
Marina Konuhova ◽  
Guntis Orlovskis ◽  
Karlis Ketners
Keyword(s):  
Mathematical Modeling ◽  
Experimental Data ◽  
Mathematical Model ◽  
Mathematical Modelling ◽  
Coordinate System ◽  
Induction Motor ◽  
Transient Processes ◽  
Stator Winding ◽  
Stator Windings ◽  
Coordinate Axis

Mathematical Modelling of Induction Motor Transient Processes During Stator Winding InterruptionThis research presents induction motor mathematical model in coordinate axis's α, β, which allows to learn transient processes in rotor and stator circuits in the conditions of stator windings opening. Such kind of researches is nowadays actual due to impossibility of main calculated values measuring directly, but only on the stator terminals. Induction motor mathematical model forms Park-Gorev equations in α, β coordinate axis. It is preferable to use this coordinate system because it allows comparing the results of mathematical modeling in one of the phases with experimental data without transformations.

scholarly journals THERMAL STATE ANALYSIS OF ADJUSTABLE SPEED INDUCTION MOTOR

2020 ◽  
Vol 33 (109) ◽  
pp. 9-15
Author(s):  
V. Petrushin ◽  
◽  
Y. Plotkin ◽  
A. Yakimets ◽  
R. Yenoktaiev ◽  
...  
Keyword(s):  
Induction Motor ◽  
Thermal State ◽  
Supply Voltage ◽  
Experimental Studies ◽  
Thermodynamic Characteristics ◽  
Voltage Source ◽  
Stator Winding ◽  
Structural Elements ◽  
Differential Heat ◽  
Frontal Part

An equivalent thermal circuit is presented, which makes it possible to analyze the thermal state of a speed-controlled induction motor fed by a PWM voltage-source inverter in static and dynamic modes. It is taken into account that the losses in the structural elements of the engine and thermal conduc- tivity, the values of which depend on the speed, change at different points of the control range. The tempera- tures of seven structural elements of the machine are determined: the stator steel package, the groove part of the stator winding, the rotor, the frame, the internal air, the end shields, and the frontal part of the stator winding. Theoretical and experimental studies of thermal indicators - the temperature of the stator winding frontal part and the temperature of the bearing shield of the AIP71A2 induction motor with self-cooling were carried out. The temperature characteristics are determined, which are the dependences of the over- heating of the structural parts of a frequency-controlled induction motor on the load torque for different fre- quencies of the supply voltage. These characteristics are compared with those obtained from thermal exper- iments. Non-stationary heat calculations are performed by solving a system of differential heat balance equations. The transition to temperature control characteristics has been completed. Thermodynamic processes are considered theoretically and experimentally during the operation of a controlled drive at a given tachogram. Thermodynamic characteristics are determined by load tachograms and can be plotted for different intermittent modes.

scholarly journals Stator windings condition diagnosis of voltage inverter-fed induction motor in open and closed-loop control structures

2015 ◽  
Vol 64 (1) ◽  
pp. 67-79 ◽  
Author(s):  
Marcin Wolkiewicz ◽  
Grzegorz Tarchała ◽  
Czesław T. Kowalski
Keyword(s):  
Induction Motor ◽  
Closed Loop ◽  
Early Stage ◽  
Motor Drive ◽  
Stator Winding ◽  
Induction Motor Drive ◽  
Loop Control ◽  
Control Structures ◽  
Stator Windings ◽  
Condition Diagnosis

AbstractThis paper deals with detection of the stator windings shorted turns in an induction motor drive working under open (scalar) and closed loop (Direct Field Oriented DFO) control structures. In order to detect the early stage of stator winding fault, the analysis of symmetrical and principal components of stator voltages and currents is used. Experimental results obtained from a specially prepared induction motor are presented.

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