Electromechanical Energy Conversion - I
Principles of Electromechanical Energy ConversionIntroduction, Flow of energy in electromechanical devices, Energy in magnetic systems (defining energy and co-energy), Singly excited systems; Determination of mechanical force, Mechanical energy, Torque equation, Doubly excited systems ; Energy stored in magnetic field, Electromagnetic torque, Generated e.m.f. in machines ; Torque in machines with cylindrical air gap.D.C. MachinesConstruction of D.C. machines, Armature winding, E.M.F and torque equation, Armature reaction, Commutation, Interpoles and compensating windings, Performance characteristics of D.C. generators.D.C. Machines (Contd.)Performance characteristics of D.C. motors, Starting of D.C. motors; Concept of starting (3 point and 4 point starters), Speed control of D.C. motors; Field control, Armature control and voltage control (Ward-Leonard method), Efficiency and testing of D.C. machines (Hopkinson's and Swinburn's test).Transformer Three phase transformer connection, Three phase unit transformer and Bank of three single phase transformers with their advantages, Three phase transformer groups (Phasor groups) and their connections, Y- connection, Open delta connection, Three phase/2 phase Scott connection and it s application.Transformer (Contd.)Sumpner s test, All day efficiency, Polarity test, Excitation phenomenon in transformers, Harmonics in single phase and 3 phase transformers, Parallel operation and load sharing of single phase and three phase transformers, Three winding transformers, Tertiary winding.Autotransformer : Single phase Autotransformer, Volt-amp relation, Efficiency, Conversion of a two-winding transformer to an autotransformer, Saving in conductor material, Advantages, Disadvantages and applications of autotransformers.