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Articles 1 - 17 of 17
Full-Text Articles in Engineering
Application Of Geometric Programming To The Power Systems Economic Dispatch Optimization, Mulukutla S. Sarma, Charles E. Bayless, Eldon K. Stanek
Application Of Geometric Programming To The Power Systems Economic Dispatch Optimization, Mulukutla S. Sarma, Charles E. Bayless, Eldon K. Stanek
Sarma Mulukutla
This paper presents a new method of obtaining an approximate optimized solution of the economic dispatch problem of a power system using the output of a standard loadflow computer program along with a geometric programming algorithm. This digital-computer method is much faster than the existing methods requiring only about thirty seconds on an IBM 360-75 system to obtain a loadflow solution as well as optimize the economic dispatch problem for a system of 203 buses, and requires little additional core storage over the requirements of the loadflow routine.
Digital Computer Simulation Of Electromagnetic Field Problems As Applied To The Design Of Electrical Machinery, K. S. Demirchian, V. V. Dombrovski, V. L. Chechurin, M. Sarma
Digital Computer Simulation Of Electromagnetic Field Problems As Applied To The Design Of Electrical Machinery, K. S. Demirchian, V. V. Dombrovski, V. L. Chechurin, M. Sarma
Sarma Mulukutla
The problem of electromagnetic field calculation in the end-zone of electrical machines is considered in this paper. A three-dimensional field requires using new methods of computing because the existing methods with the concept of vector potential demand unacceptable computer time. The new method consists of replacing the eddy magnetic field by the potential field of magnetic charges for the calculation of field, forces and associated inductances. Electrical currents of the rotor and stator windings are replaced by magnetic charges. it is possible to use just one scalar potential function for the computation instead of three components of the vector potential. …
Accelerating The Magnetic Field Iterative Solutions, Mulukutla S. Sarma, James C. Wilson
Accelerating The Magnetic Field Iterative Solutions, Mulukutla S. Sarma, James C. Wilson
Sarma Mulukutla
Recent years have witnessed considerable research activity in the application of digital-computer methods for the determination of the electromagnetic fields in electrical devices through the solution of Maxwell's equations, while taking full account of the magnetic saturation. Slow rate of convergence towards a meaningful solution and consequent demand for prohibitively large computer time are some of the chief drawbacks of the numerical iterative procedures. Many efforts have been made to find satisfactory methods of accelerating the convergence and thereby minimize the computer time needed for the solution. Various methods such as application of relaxation factors, block-relaxation procedures; and alternating-direction iterative …
Computing Models For The Magnetic Field Calculation Of Superconducting Electric Machines With The Help Of Scalar Magnetic Potential, V. L. Chechurin, M. Sarma
Computing Models For The Magnetic Field Calculation Of Superconducting Electric Machines With The Help Of Scalar Magnetic Potential, V. L. Chechurin, M. Sarma
Sarma Mulukutla
The method of scalar magnetic potential using imaginary magnetic charges is employed effectively for the calculation of the electromagnetic fields in superconducting electric machines. The computing model consists of several single layers of magnetic charges. Finite-difference numerical techniques are utilized for the computation. The cylindrical coordinate system has been used for the calculation of the electromagnetic losses inside the electromagnetic shield of the rotor winding. The tangential and axial components of eddy currents have been taken into account. Linear magnetic charges replace rotor and stator currents; and surface magnetic charges replace the eddy currents inside the electromagnetic shield of the …
Introducing Nonlinear Problems To Undergraduate Engineering Students, Mulukutla S. Sarma, Karl E. Lonngren
Introducing Nonlinear Problems To Undergraduate Engineering Students, Mulukutla S. Sarma, Karl E. Lonngren
Sarma Mulukutla
It is argued that preparing good engineers to the present day challenging industry should involve the extension of homework problems to include realistic complications of nonlinearity and extensive use of the available computing facilities. This point of view has been illustrated through a simple Faraday's law problem of an electromechanical system that exhibits nonlinear effects if the resistance of the rails is taken into account. The procedure that is employed in this paper to solve the nonlinear equation is simple enough to be introduced at an undergraduate level for the engineering students
Scalar Potential Concept For Calculating The Steady Magnetic Fields And Eddy Currents, Kamo Demirchian, Vladimir Chechurin, Mulukutla Sarma
Scalar Potential Concept For Calculating The Steady Magnetic Fields And Eddy Currents, Kamo Demirchian, Vladimir Chechurin, Mulukutla Sarma
Sarma Mulukutla
The concept of scalar potential has been used for magnetic field calculation in the USSR during the last decade. It is based on treating the eddy component of the magnetic field separately and calculating the potential field with the help of the scalar potential by introducing imaginary magnetic charges. This method has been developed for digital calculations of magnetic fields in various electromagnetic devices, by solving linear and nonlinear partial-differential equations through mathematical simulation. This paper presents the mathematical formulation of the method. It is advantageous to use the scalar potential method for two-dimensional eddy-current calculations because of the possibility …
Computer-Aided Analysis Of Magnetic Fields In Nonlinear Magnetic Bearings, Mulukutla S. Sarma, Akira Yamamura
Computer-Aided Analysis Of Magnetic Fields In Nonlinear Magnetic Bearings, Mulukutla S. Sarma, Akira Yamamura
Sarma Mulukutla
The high magnetic energy stored in rare earth-cobalt magnets allows the design of lightweight motors and magnetic bearings for high speed rotors. Not subject to wear and with the ability to operate under high vacuum conditions, magnetic bearings appear ideal for applications requiring high rotational speeds such as 100,000 rpm. Important applications are for turbo-molecular pumps, laser scanners, centrifuges, momentum rings for satellite stabilizations, and other uses in space technology. It is the purpose of this paper to present a two-dimensional nonlinear numerical analysis of the magnetic fields in a magnetic bearing, based on magnetostatic assumptions and finite-difference iterative techniques.
Current-Density Distribution In Solid-Rotor Induction Motor, Mulukutla S. Sarma
Current-Density Distribution In Solid-Rotor Induction Motor, Mulukutla S. Sarma
Sarma Mulukutla
The interaction between the eddy currents induced in the solid cylindrical rotor steel structure and the revolving field of the airgap produces the electrodynamic torque. The polyphase induction machine with solid-iron rotor offers advantages in ease of manufacture, in high torque per ampere at standstill, in withstanding high rotational stresses, and in operating in unusual environments. It is the purpose of this paper to present an approximate three-dimensional nonlinear numerical analysis of the solid-rotor induction motor for finding the three-dimensional current-density distribution in the solid rotor, in order to calculate the performance characteristics, based on finite-difference iterative techniques.
Developments In Finite-Element Method For Calculating Electromagnetic Fields In Electrical Machines, Mulukutla S. Sarma
Developments In Finite-Element Method For Calculating Electromagnetic Fields In Electrical Machines, Mulukutla S. Sarma
Sarma Mulukutla
In order to meet the specifications of an electrical apparatus, the designer must be able to analyze and modify several fields of interest such as the electromagnetic fields, with the ultimate aims of safety, reliability, simplicity, efficiency and economy. The numerical finite-element method is proving to be an accurate, economical and useful design tool for the field analysis in electrical machinery. This paper presents briefly the formulation of the finite-element technique for solving two- and three-dimensional field problems in nonlinear devices, and reviews various applications made so far, while putting forth some new developments. These developments along with the progress …
Finite Element Formation For The Numerical Solution Of Three-Dimensional Nonlinear Magnetostatic Field Problems As Applied To The Design Of Electric Machinery, Mulukutla S. Sarma
Finite Element Formation For The Numerical Solution Of Three-Dimensional Nonlinear Magnetostatic Field Problems As Applied To The Design Of Electric Machinery, Mulukutla S. Sarma
Sarma Mulukutla
Recent years have witnessed considerable research activity in the application of digital-computer methods for the determination of the electromagnetic fields in electrical machinery through the solution of Maxwell's equations, while taking full account of the magnetic saturation. Two distinct numerical approaches are evident in the literature: Finite-Difference Method and Finite-Element method. The author has presented in the recent years a finite-difference formulation for 3-dimensional numerical solutions of the nonlinear electromagnetic field problems in terms of potential functions, and has applied for the analysis of the end-zone fields of aerospace homopolar alternators and solid-rotor induction motors. The present work is directed …
Magnetostatic Field Computation By Finite Element Formulation, Mulukutla S. Sarma
Magnetostatic Field Computation By Finite Element Formulation, Mulukutla S. Sarma
Sarma Mulukutla
Recent years have witnessed considerable research activity in the application of digital-computer methods for the determination of the electromagnetic fields in electrical machinery through the solution of Maxwell's equations, while taking full account of the magnetic saturation. Two distinct numerical approaches are evident in the literature: Finite-Difference Method and Finite Element Method. The author has presented in the recent years a finite-difference formulation for 3-dimensional numerical solutions of the nonlinear electromagnetic field problems in terms of potential functions, and has applied for the analysis of the end-zone fields of aerospace homopolar alternators and solid-rotor induction motors. The present work is …
Three-Dimensional Nonlinear Numerical Analysis Of Solid-Rotor Induction Motor, Mulukutla S. Sarma
Three-Dimensional Nonlinear Numerical Analysis Of Solid-Rotor Induction Motor, Mulukutla S. Sarma
Sarma Mulukutla
The most elementary type of rotor for the polyphase induction machine is the solid-iron rotor, which offers advantages in ease of manufacture, in high torque per ampere at standstill, in withstanding high rotational stresses, and in operating in unusual environments. Since conventional induction machine theory has proven inadequate for such machines, the need has arisen for improved methods of investigation. It is the purpose of this paper to present an approximate three-dimensional nonlinear numerical analysis for the solid-rotor induction motor, based on magnetostatic assumptions and finite-difference iterative techniques.
Analysis And Design Considerations For Permanent-Magnet Aerospace-Instrument Devices, Mulukutla S. Sarma
Analysis And Design Considerations For Permanent-Magnet Aerospace-Instrument Devices, Mulukutla S. Sarma
Sarma Mulukutla
The range of permanent magnet materials for electromagnetic-device applications has recently been augmented by the commercial development of Samarium Cobalt. Of particular importance is the magnetic characteristic of SmCo5 in relation to other available hard magnetic materials. The most striking aspects of the material are its coercivity and possible maximum energy level; while the most gratifying aspect is its predictable performance. In order to make best use of a high quality and relatively expensive magnetic material such as SmCo5, one should strive for optimized designs. In view of the complicated geometries involved, significant leakage-flux particularly caused by compact design, and …
Application Of Modern Control Theory For The Power-System Analysis And Control, Mulukutla S. Sarma, Earl D. Eyman
Application Of Modern Control Theory For The Power-System Analysis And Control, Mulukutla S. Sarma, Earl D. Eyman
Sarma Mulukutla
With the current rise in the demand of electrical energy, present-day power systems which are large and complex, will continue to grow both in size and complexity. Also, our dependence on electrical energy is so great that it is essential to have uninterrupted supply of electrical power within set limits of frequency and voltage levels, and that it becomes a dire necessity to develop methods for effective control and operation of power systems. Modern control theory concepts have been effectively used and will continue to be utilized for the power system analysis and control. This paper attempts in assessing the …
New Developments In The Computer-Aided Analysis Of Three-Dimensional Electromagnetic Field Problems As Applied To The Design Of Electrical Machinery, Mulukutla S. Sarma
New Developments In The Computer-Aided Analysis Of Three-Dimensional Electromagnetic Field Problems As Applied To The Design Of Electrical Machinery, Mulukutla S. Sarma
Sarma Mulukutla
An accurate knowledge of the magnetic as well as other field distributions is of great importance in design optimization. In two dimensional problems with the current flow in only one direction, the magnetic field can be solved by computing a scalar potential or one component of the vector potential, The general formulation for three-dimensional solutions, including nonlinearities, is more complex and requires all three components of the vector potential as well as a scalar potential for the description of the fields. It is the purpose of this paper to present a general systematic, novel formulation at low frequencies feasible for …
End-Winding Leakage Of Aerospace Homopolar Alternators, Mulukutla S. Sarma
End-Winding Leakage Of Aerospace Homopolar Alternators, Mulukutla S. Sarma
Sarma Mulukutla
An accurate knowledge of the magnetic field distribution is of great importance in finding the best designs for electrical machinery. It is the purpose of this paper to present a new numerical method for the determination of three-dimensional flux distribution in the end zone of a high-speed aerospace homopolar alternator, and for the calculation of end leakage reactance. The new analysis is applied to an experimental 95 kVA, 115/200 V, 3400 Hz, 40,800 r/min, three-phase, wye-connected, homopolar alternator.
On-Line Optimum Load Scheduling Of Power Systems Using Modified Fletcher-Powell Method, Divakaruni P. Sudhakar, Mulukutla S. Sarma
On-Line Optimum Load Scheduling Of Power Systems Using Modified Fletcher-Powell Method, Divakaruni P. Sudhakar, Mulukutla S. Sarma
Sarma Mulukutla
The problem of optimum power dispatch has been the object of constant attention of power-system engineers in modern times and its importance is understandably enhanced in these times of energy shortage. This paper presents a new approach for obtaining on-line optimum load scheduling of power systems. The suggested algorithm could be used in conjunction with any standard load-flow routine, requiring little additional core storage. The output of the load-flow program is utilized to acquire a first hand knowledge of the total losses in an integrated power system, which in turn enables one to make an accurate estimate of the loss …