Basic Electrical Engg By U.A.Bakshi

Summary of Book

D.C.Circuits : Ohm’s law and Kirchhoff’s laws, Analysis of series, Parallel and series - parallel circuits excited by independent voltage sources. Power and energy. Illustrative examples. Electromagnetism : Review of field around a conductor and coil, Magnetic flux and flux density, Magnetomotive force and magnetic field intensity, Reluctance and permeability, Definition of magnetic circuit and basic analogy between electric and magnetic circuits. (These topics are not to be considered for setting the examination questions). Electromagnetic Induction : Definition of electromagnetic induction, Faradays laws, Fleming’s right hand rule, Lenz’s law, Statically and dynamically induced e.m.f. Self-inductance, Mutual inductance and coefficient of coupling. Energy stored in magnetic field. Illustrative examples. Force on current carrying conductor placed in a magnetic field, Fleming’s left hand rule. DC Machines : Working principle of DC machine as a generator and a motor. Types and constructional features. Types of armature windings, E.M.F. equation of generator, Relation between induced e.m.f. and terminal voltage with a mention of brush contact drop and drop due to armature reaction. Illustrative examples, Neglecting armature reaction. Operation of DC motor, Back e.m.f., Torque equation. Types of DC motors, Characteristics and applications. Significance of back e.m.f. Necessity of a starter for DC motor. Illustrative examples on back e.m.f. and torque. Measuring Instruments : Construction and principle of operation of dynamometer type wattmeter and single phase induction type energy meter. Single-phase AC Circuits : Generation of sinusoidal voltage, Frequency of generated voltage, Definition and numerical values of average value, Root mean square value, Form factor and peak factor of sinusoidally varying quantities, Phasor representation of alternating quantities. Analysis, with phasor diagrams, of R, L, C, R-L, R-C and R-L-C circuits and parallel and series-parallel circuits. Real power, Reactive power, Apparent power and power factor. Illustrative examples. Domestic Wiring : Service mains, Meter board and distribution board. Brief discussion on concealed conduit wiring. Two-way and three-way control. Elementary discussion on circuit protective devices : Fuse and Miniature Circuit Breaker (MCB’s). Electric shock, Precautions against shock, Objectives of earthing, Types of earthing; Pipe and plate earthing, Residual Current Circuit Breaker (RCCB). Three Phase Circuits : Necessity and advantages of three phase systems, Generation of three phase power. Definition of phase sequence, Balanced supply and balanced load. Relationship between line and phase values of balanced star and delta connections. Power in balanced three-phase circuits, Measurement of power by two-wattmeter method. Determination power factor using wattmeter readings. Illustrative examples. Three Phase Synchronous Generators : Principle of operation, Types and constructional features, Advantages of rotating field type alternator, Synchronous speed, Frequency of generated voltage, E.M.F. equation. Concept of winding factor (excluding the derivation of distribution and pitch factors). Illustrative examples on calculation of distribution factor, Pitch factor and e.m.f. equation. Single Phase Transformers : Necessity of transformer, Principle of operation and construction of single phase transformers (core and shell types). E.M.F. equation, Losses, Variation losses with respect to load, Efficiency, Condition for maximum efficiency, Voltage regulation and its significance (Open circuit and short circuit tests, Equivalent circuit and phasor diagrams are excluded). Illustrative problems on e.m.f. equation and efficiency only. Three Phase Induction Motors : Principle of operation, Concept and production of rotating magnetic field, Synchronous speed, Rotor speed, Slip, Frequency of the rotor induced e.m.f., Types and constructional features. Slip and its significance. Applications of squirrel - cage and slip - ring motors. Necessity of a starter, Starting of motor using stars-delta starter. Illustrative examples on slip calculations.

Table of Content

·         D.C.Circuits

·         Electromagnetism

·         Electromagnetic Induction

·         DC Machines

·         Measuring Instruments

·         Single-phase AC Circuits

·         Domestic Wiring

·         Three Phase Circuits

·         Single Phase Transformers

Three Phase Induction Motors