Note for Basic Electrical Engineering - BEE By MD WESH KARNI

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DEPARTMENT OF ELECTRICAL ENGINEERING BASIC ELECTRICAL ENGINEERING (4 credit) Course Code: BEE1101 (1ST AND 2ND SEMESTER) SYALLABUS MODULE-I (10 HOURS) DC Networks: Kirchhoff's laws, node and mesh analysis, Delta-star and star-delta transformations. Superposition, Thevenin’s and Norton's theorem. Transients in RL, R-C and R-L-C circuits with DC Excitation. Single Phase AC Circuits: Single phase EMF generation, average and effective values of sinusoids, j operations, complex representation of impedances, phasor diagrams, power factor, power in complex notation, solution of series and parallel circuits. Introduction to resonance in series RLC circuit. Three Phase AC Circuit: Three phase EMF generation, delta and star connection, Line and Phase quantities. Solutions of 3-phase circuits with balanced load. Power in 3-phase balanced circuits. MODULE-II (10 HOURS) Magnetic Circuits: B-H Curve, Hysteresis, Permeability and reluctance, solution of simple magnetic circuits, Hysteresis and Eddy current losses. DC Generator: Different types, Principle of Operation of DC generator, EMF equation, methods of excitation. DC Motor: Back e.m.f., speed and torque of a DC Motor, Conditions for maximum Power. Speed control of DC shunt motor. Transformers: Construction and Principle of operation of single-phase transformer, EMF equation, Single-phase autotransformer. MODULE-III (10 HOURS) Three phase Induction Motor: Construction and principle of operation, types; Sliptorque characteristics.

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Synchronous Machines: Construction & principle of operation of Synchronous generator and motor. EMF equation, Voltage regulation, Applications and starting of Synchronous motor. Introduction to single-phase induction Motor. MODULE-IV (10 HOURS) Measuring Instruments: DC PMMC instruments, Extension of range by shunts and multipliers. Moving iron ammeters and voltmeters, Dynamometer type Watt meters, Induction type Energy Meter. Power supply systems: Principle of generation - thermal, hydel and nuclear. Transmission and distribution of electric energy. Introduction to Electric Heating & Welding. TEXT BOOK [1]. Edward Hughes (revised by Ian McKenzie Smith). "Electrical & Electronics Technology" Pearson Education Limited. Indian Reprint 2002. REFERENCE BOOKS [2]. H.Cotton, “Advanced Electrical Technology", CBS Publishers, New Delhi, 7th Edition. [3]. C.L. Wadhwa, “Electrical Engineering”, New Age International Publishers. [4]. D.Kulshreshtha, “ Basic Electrical Engineering” TMH [5]. S. Parker Smith: “Problems in Electrical Engineering" Asia Publications.

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MODULE-I D.C NETWORKS 1.1 Kirchoff’s Laws:1.1.1. Kirchoff’s current law or point law (KCL) Statement:- In any electrical network, the algebraic sum of the currents meeting at a point is zero. Σ I = 0 ……………………at a junction or node Assumption:- Incoming current = positive Outgoing current = negative 1.1.2. Kirchoff’s voltage law or mesh law (KVL) Statement:- The algebraic sum of the products of currents and resistances in each of the conductors in any closed path (or mesh) in a network plus the algebraic sum of the emfs in that path is zero. Σ IR +Σemf = 0 …………………………..round the mesh Assumption:- i) Rise in voltage (If we go from negative terminal of the battery to positive terminal) = positive ii) Fall in voltage (If we go from positive terminal of the battery to negative terminal) = negative iii) If we go through the resistor in the same direction as current then there is a fall in potential. Hence this voltage is taken as negative. iv)If we go through the resistor against the direction of current then there is a rise in potential. Hence this voltage drop is taken as positive.

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Example:- Write the loop equation for the given circuit below (Supplementary exam 2004) r1 E1 i r2 E2 E3 r3 Solution: Apply KVL to the loop, − ir1 − E 1 − ir2 + E 2 − ir3 − E 3 = 0 ⇒ E 1 − E 2 + E 3 = − ir1 − ir2 − ir3 ⇒ E 1 − E 2 + E 3 = − i ( r1 + r2 + r3 ) 1.2. MAXWELL’S LOOP CURRENT METHOD (MESH ANALYSIS) Statement:- This method determines branch currents and voltages across the elements of a network. The following process is followed in this method:• Here, instead of taking branch currents (as in Kirchoff’s law) loop currents are taken which are assumed to flow in the clockwise direction. • Branch currents can be found in terms of loop currents • Sign conventions for the IR drops and battery emfs are the same as for Kirchoff’s law. • This method is easier if all the sources are given as voltage sources. If there is a current source present in a network then convert it into equivalent voltage source.