This course describes the Synchronous machines and its characteristics, Procedure for parallel operations, Starting methods for synchronous motor. And also it explains the special electrical machines such as stepper motor, A.C. series motor, Reluctance motor, Repulsion motors etc.,
Introduction to synchronous generator - Introduction to alternator - Types of alternators - Advantages of polyphase alternator - Difference between D.C. generator and alternator. Principle of operation of alternator - Working principle of synchronous generator - Mechanical and electrical angle - Frequency of induced E.M.F - Synchronous speed (Ns). Construction of alternator - Construction and classification of alternators - Stator - Rotor - Difference between salient pole and non-salient pole rotor - Advantages of stationary armature. Three phase windings in A.C. machines - Armature windings - Coil or winding element - Pole Pitch. Types of three phase windings - Types of armature windings - Coil span - Pitch factor (or) coil span (kc) - Chording of winding. E.M.F equation - Shape of the E.M.F. wave - Problems based on E.M.F equation of alternator - Exercises based on E.M.F equation of alternator. Exciter - Definition Excitation - Armature reaction of alternators on load at various power factor - Power factors - Alternator on load - Armature leakage reactance - Synchronous reactance - Synchronous impedance - Worked example - Vector diagram of alternators on load. Voltage regulation - Determination of voltage regulation - Regulation for large machines - EMF method or alternator test - Synchronous impedance method - Worked example using synchronous method / EMF method - Ampere - Turn method - General case: for any value of PF(Zero to 1)lagging or leading - Poitier’s triangle method or zero power factor method - Zero power factor test - ASA (American Standards Association) method - Vector diagram and regulation for lagging, leading and unity power factor load. Methods of cooling of alternator - Losses and efficiency of alternator.
Necessity of parallel operation of alternators- Parallel operation of alternator - Three-phase alternators. Conditions for parallel operation of alternators - Parallel operation of alternators. Synchroscope - Dark lamp method - Bright lamp method - Dark and bright lamp method - Synchroscope method. Synchronizing current, synchronizing power - Parallel operation of two alternators - Problem. Load sharing - Load sharing between two alternators - Alternators connected to infinite bus-bars - Alternative expression for synchronizing power - Effect of unequal voltages - Effect of change in steam supply. Problems on load sharing - Problems.
Introduction to synchronous motor - Classification of A.C. motors - Production of rotating magnetic field. Construction of synchronous motor - Construction and classification of synchronous motor - Stator - Rotor - Difference between salient pole and non-salient pole rotor - Advantages of stationary armature. Principle of operation - Magnetic locking - Principle operation of synchronous motor. Vector diagram of synchronous motor - Vector diagram of synchronous motor on no load and load - Analysis of Phasor diagram - Phasor diagram of under excited synchronous motor on load - Problems. Effect of variation of load - Torque-Speed characteristics of synchronous motor. Effect of excitation - Effect of changing excitation on constant load - Power equation. Power developed by a synchronous motor - Power relations (Neglecting armature resistance) - Problems - V-curves and inverted V-curves. Synchronous condenser - Synchronous phase modifier - Problems. Hunting of synchronous motor - Hunting (or) surging (or) phase swinging - Prevention of hunting. Methods of startings - Starting methods of synchronous motor - Starting of synchronous motor - Procedure for starting a synchronous motor - Comparison between synchronous motor and three phase induction motor - Synchronous Motor Applications.
Stepper motor - Introduction - Types of stepper motor - Variable reluctance stepper motor - Operation of stepper motor - Multi stack variable reluctance motor - Construction - Hybrid stepper motor - Introduction - Type of linear induction motor - Applications where the primary is stationary and secondary Moves - Magnetic levitation. Reluctance, Hysteresis, Repulsion and A.C series motor - Reluctance Motor - Hysteresis Motor - Repulsion Principle - A.C. Series Motor - Working principle of A.C. Series Motor. Universal motor - Speed control and applications of universal motors - Advantages of universal motors - Trouble shooting for universal motor. Synchros - Applications of Synchros. Two phase servo motor - Servomotors - D.C. Servomotors. Special Motors - Scharge motor - Brushless D.C. motor - Applications of brushless D.C. motor.
