Electrical Circuits And Machines

TransformersSingle Phase Transformers : Ideal & Practical Transformers, Equivalent circuit, Determination of transformer parameters (O.C. and S.C. tests), Efficiency and regulation of transformer. Design of single phase transformer for instrument power supply. Coupled circuit. Special Transformer : (Theoretical treatment only) Auto transformer, Current transformer, Induction heating transformers, Isolation transformers, Ferrite core transformer, Welding transformer, Phase shift transformer, Three phase transformer, Star/Delta, Delta/Star, Application of each Type.D.C. MachinesD.C. Generator : Construction, Types, Role of commutator, Induced emf equation, Characteristics and applications. D.C. Motors : Operation, Types, Losses, Basic equations of DC motors, Torque-speed characteristics, Speed control methods, Speed regulation, Starters (manual, electronic), Braking and applications.Active, Reactive and Apparent PowerInstantaneous power, Active power, Reactive power, Power factor, Distinction between active and reactive power, Combined active and reactive loads (apparent power). Measurement and calculation of active, Reactive power and Power factor in 3 balanced circuit using two wattmeter and one wattmeter. Measurement of 1 and 3 power using CT and PT. Electronic meters for energy measurement. Introduction to energy audit.Three Phase Induction MotorsConstruction, Operation, Types, Equivalent circuit, Torque-slip characteristics, Slip and torque equations, Maximum torque, Starting torque, Full load torque, Condition for maximum torque, Power flow diagram, Starters for IM (manual and soft starters). Introduction to speed control, Braking, Protection circuits (e.g. single phase preventer, ELCB, MCB) and Applications.Synchronous MachinesSynchronous Generators : Construction, Types (rotating field & rotating armature), Synchronous speed and emf equation. Coil span factor and distribution factor (derivation not expected). Alternator on no load and on load, Armature reaction in 3-phase alternators, Regulation of alternator by synchronous impedance method. Synchronous Motors : Construction, Operation, Effect of variation of load, Hunting, V curves, Starting methods, Synchronous condenser, Applications.Special Purpose MachinesPrinciple of operation, Working, Types and applications of single phase IM, Universal motors, Reluctance motor, Stepper motors, AC & DC servomotors.