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العنوان
Dynamic Analysis of Torsional Oscillations in Cascaded Connected Induction Motors /
المؤلف
Gomaa, Khaled Esmael Abd Al Aziz Amin.
هيئة الاعداد
باحث / خالد اسماعيل عبدالعزيز امين جمعه
مشرف / رزق محمد السيد حموده
مناقش / خيرى فرحات على حلوه
مناقش / احمد ضياء القشيرى
تاريخ النشر
2018.
عدد الصفحات
90 p.:
اللغة
الإنجليزية
الدرجة
ماجستير
التخصص
الهندسة الكهربائية والالكترونية
تاريخ الإجازة
1/1/2018
مكان الإجازة
جامعة عين شمس - كلية الهندسة - كهربه قوى
الفهرس
Only 14 pages are availabe for public view

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from 95

Abstract

This thesis presents an investigation of the electromechanical or torsional oscillations and stresses occurring in an electromechanical system consisting of two induction motors connected in cascade through elastic mechanical shafts to drive a large mechanical load.
The usage of a cascaded set of induction motors connected through mechanical shaft sections can be utilized to drive a large mechanical load. Different case studies were demonstrated to examine the transient performance of such electromechanical system during the start up. The usage of such electromechanical system in industrial applications is popular like mining, oil and gas industry. However, a little scope of work was presented to describe the root cause behind the hazard of torsional stresses that may be appeared on the mechanical shaft sections of such system while it starts against full load condition. The analysis of transient performance for such electromechanical system is crucial to ensure the operational reliability of the system. The importance of describing the root cause behind the torsional stresses appeared on the mechanical shaft sections is essential to mitigate its destructive effects. The effects of the excessive torsional stresses induced on the system may pose a high risk and hazard to mechanical shaft sections if no adequate countermeasure was introduced. An effective starting process technique was introduced by using variable frequency drives to mitigate such hazardous stresses.
The electromechanical system was implemented using Matlab/Simulink. A robust mathematical model for the electromechanical system of investigated induction motors using ABC reference frame was implemented on Matlab Simulink. Thanks to the robustness of the implemented electromechanical system and its similarity to practical and real cases, different case studies were described to analyze the transient performance of the system. The different case studies presents a complete investigation of the torsional stresses induced on mechanical shaft sections. The excessive torsional stresses may be the leading cause of mechanical shaft sections fatigue and loss of life time.
The evaluation of the results from different case studies leads to appearance of high torsional stresses induced on mechanical shaft sections when the two motors are starting against constant mechanical load during full load condition. The origin of the problem comes from the occurrence of electromechanical or torsional resonance. On the other hand, when the system is starting against loads increasing linearly with speed or loads vary with the speed squared under full load condition, the torsional oscillations are considered smaller than the constant load torque case study. The analysis of results was introduced with the aid of different curves for transmitted torques through mechanical shaft sections. More conviction and persuasion was introduced thanks to describing of the phenomena with the aid of frequency spectrums of transmitted torques through mechanical shaft sections.