ELECTRICAL TECHNOLOGY

• Content___

1. Electric Current and Ohm’s Law:

Electron Drift Velocity—Charge Velocity and Velocity of Field Propagation— The Idea of Electric Potential— Resistance—Unit of Resistance—Law of Resistance—Units of Resistivity—Conductance and Conductivity—

Effect of Temperature on Resistance—Temperature Coefficient of Resistance—Value of a at Different Temperatures Variation of Resistivity with Temperature—Ohm’s Law— Resistance in Series—Voltage Divider Rule—Resistance in Parallel—Types of Resistors—Nonlinear Resistors— Varistor—Short and Open Circuits—‘Shorts’ in a Series Circuit—‘Opens’ in Series Circuit—‘Open’s in a Parallel Circuit—‘Shorts’ in Parallel Circuits—Division of Current in Parallel Circuits—Equivalent Resistance—Duality Between Series and Parallel Circuits—Relative Potential— Voltage Divider Circuits—Objective Tests.

2. D.C Network and Theorems:

Electric Circuits and Network Theorems—Kirchhoff’s Laws—Determination of Voltage Sign—Assumed Direction of Current—Solving Simultaneous Equations— Determinants—Solving Equations with Two Unknowns— Solving Equations With Three Unknowns—Independent and Dependent Sources —Maxwell’s Loop Current Method—Mesh Analysis Using Matrix Form—Nodal Analysis with Voltage Sources—Nodal Analysis with Current Sources—Source Conversion—Ideal Constant- Voltage Source—Ideal Constant ,Current Source— Superposition Thevenins Theorem — How to thevenin Given Circuit ?—General Instructions for Finding Thevenin Equivalent Circuit

Reciprocity Theorem—Delta/Star Transformation Star/Delta Transformation—Compensation Theorem—Norton’s Theorem—How to Nortan a Given Circuit ?—General Instructions for Finding Norton Equivalent Circuit— Millman’s Theorem—Generalised Form of Mill man's Theorem—Maximum Power Transfer Theorem—Power Transfer Efficiency Objective Tests.

3. Work power and energy:

Effect of Electric Current—Joule’s Law of

Electric Heat- ing—Thermal Efficiency—S- I. Units—Calculation of Kilo- watt Power of a Hydroelectric Station—Objective tests.

4. Electrostatics:

Static Electricity—Absolute and Relative Permittivity of a Medium—Laws of Electrostatics—Electric Field— Electrostatic Induction—Electric Flux and Faraday Tubes—

—Field Strength or Field Intensity or Electric Intensity (E)— Electric Flux Density or Electric Displacement D—Gauss Law—The Equations of Poisson and Laplace—Electric

Potential and Energy—Potential and Potential Difference— Potential at a Point—Potential of a Charged Sphere—Equipotential Surfaces—Potential and Electric Intensity

Inside a Conducting Sphere—Potential Gradient— Breakdown Voltage and Dielectric Strength—Safety Factor of Dielectric Boundary Conditions—Objective Tests.

6. Magnetism and Electromagnetism:

Absolute and Relative Permeability of a Medium—Laws of Magnetic Force—Magnetic Field Strength (H)—Magnetic

Potential—Flux per Unit Pole—Flux Density (B)—— Absolute Permeability (m) and Relative Permeability (mr)—Intensity of Magnetisation (I)—Susceptibility (K) Relation

Between B, H, I and K—Boundary Conditions—Weber and Ewing’s Molecular Theory—Curie Point. Force on a Current- carrying

Conductor Lying in a Magnetic Field Ampere’s Work Law or Ampere’s Circuital Law—Biot-  Law—Application of  Law—Force Between two Parallel Conductors—Magnitude of Mutual Force—Definition of Ampere—Magnetic Circuit— Definitions—Composite Series Magnetic Circuit—How to Find Ampere-turns ?—Comparison Between Magnetic and Electric Circuits—Parallel Magnetic Circuits—Series

Parallel Magnetic Circuits—Leakage Flux and Hopkinson’s Leakage Coefficient—Magnetisation Curves— Magnetisation curves by Ballistic Galvanometer Magnetisation Curves by Flux mete Objective Tests.

7. Electromagnetic induction:

Relation Between Magnetism and Electricity—Production of Induced E.M.F. and Current—Faraday’s

Laws of Electromagnetic Induction—Direction of Induced E.M.F. and Current—Lenz’s Law—Induced E.M.F.—Dynamically- induced E.M.F.—Statically- induced E.M.F.—Self- Inductance—Coefficient of Self - Inductance (L)—Mutual Inductance—Coefficient of Mutual Inductance (M)—Coefficient of Coupling—Inductances in Series—Inductances in Parallel—Objective Tests.

8. Magnetic Hysteresis:

Magnetic Hysteresis—Area of Hysteresis Loop—Properties and Application of Ferromagnetic Materials—Permanent Magnet Materials—Steinmetz Hysteresis

Law—Energy Stored in Magnetic Field—Rate of Change of Stored Energy—Energy Stored per Unit Volume—Lifting Power of Magnet—Rise of Current in Inductive Circuit—Decay of Current in Inductive Circuit—Details of Transient Current Rise in R- L Circuit—Details of Transient Current Decay in R- L Circuit—Automobile Ignition System—Objective Tests.

9. Electrochemical power source:

 Faraday’s Laws of electrolysis—Polarisation or Back e.m.f.—Value of Back e.m.f.—Primary and Secondary Batteries—Classification of Secondary Batteries base on their Use—Classification of Lead Storage Batteries— Parts of a Lead- acid Battery—Active Materials of Lead- acid Cells—Chemical Changes—Formation of Plates of Lead- acid Cells—Plante Process—Structure of Plante Plates—Faure Process—Positive Pasted Plates—Negative Pasted Plates—Structure of Faure Plates—Comparison : Plante and Faure Plates—Internal Resistance and Capacity of a Cell—Two Efficiencies of the Cell— Electrical Characteristics of the Lead- acid Cell—Battery Ratings—Indications of a Fully- Charged Cell—Application of Lead- acid Batteries—Voltage Regulators—End- cell Control System—Number of End- cells—Charging Systems—Constant- current System- Constant- voltage System—Trickle Charging—Sulphation- Causes and Cure— Maintenance of Lead- acid Cells—Mains operated Battery Chargers—Car Battery Charger—Automobile Battery Charger—Static Power Systems—Alkaline Batteries—Nickel- iron or Edison Batteries—Chemical Changes—Electrical

Characteristics—Nickel- Cadmium Batteries—Chemical Changes—Comparison : Lead- acid and Edison Cells—Silver- zinc Batteries—High Temperature Batteries—Secondary Hybrid Cells—Fuel Cells— Hydrogen- Oxygen Fuel Cells—Batteries for Aircraft—Batteries for Submarines—Objective Tests.

10. Electrical Instrument and Measurement:

Classification of AC Motors—Induction Motor: General Principal—Construction—Squirrel- cage Rotor—Phase- wound Rotor—Production of Rotating Field—Three-phase Supply—Mathematical Proof—Why does the Rotor Rotate ?—Slip—Frequency of Rotor Current—Relation between Torque and Rotor Power Factor—Starting Torque—Starting Torque of a Squirrel- cage Motor—Starting Torque of a Slip- ring Motor—Condition for Maximum Starting Torque—Effect of Change in Supply Voltage on Starting Torque—Rotor E.M.F and Reactance under Running Conditions—Torque under Running Condition—Condition for Maximum Torque Under Running Conditions—Rotor Torque and Breakdown Torque—Relation between Torque and Slip—Effect of Change in Supply Voltage on Torque and Speed—Effect of Change in Supply Frequency Torque and Speed—Full- load Torque and Maximum Torque— Starting Torque and Maximum Torque—Torque/Speed Curve—Shape of Torque/Speed Curve Current/Speed Curve of an Induction Motor—Torque/Speed Characteristic Under Load—Plugging of an Induction Motor—Induction Motor Operating as a Generator—Complete Torque/Speed Curve of a Three-phase Machine Measurement of Slip— Power Stages in an Induction Motor—Torque Developed by an Induction Motor—Torque, Mechanical Power and Rotor Output—Induction Motor Torque Equation— Synchronous Watt—Variation in Rotor Current—Analogy with a Mechnical Clutch—Analogy with a D.C. Motor— Sector Induction Motor—Linear Induction Motor— Properties of a Linear Induction Motor—

Magnetic Levitation—Induction Motor as a Generalized Transformer—Rotor Output—Equivalent Circuit of the Rotor—Equivalent Circuit of an Induction Motor—Power Balance Equation—Maximum Power Output— Corresponding Slip—Objective Tests.

11. A.C Fundamentals:

Generation of Alternating Voltages and Currents—Equations of the Alternating Voltages and Currents—Alternate Method for the Equations of Alternating Voltages and currents—Simple Waveforms—Complex Waveforms—Cycle—Time- Period—Frequency—Amplitude—Different Forms of E.M.F. Equation—Phase— Phase Difference—Root Mean Square (R.M.S.) Value— Mid- ordinate Method—Analytical Method—R.M.S. Value of a Complex Wave—Average Value—Form Factor— Crest or Peak Factor—R.M.S. Value of H.W. Rectified A.C.—Average Value—Form Factor of H.W. Rectified —Representation of Alternating Quantities—Vector Diagrams

Using R.M.S. Values—Vector Diagrams of Sine Waves of Same Frequency—Addition of Two Alternating Quantities—Addition and Subtraction of Vectors—A.C. Through Resistance, Inductance and Capacitance—A.C. through Pure  Resistance alone—A.C. through Pure Inductance alone—Complex Voltage Applied to Pure Inductance—A.C. through Capacitance alone Objective Tests.

12. Complex Numbers:

Mathematical Representation of Vectors—Symbolic Notation—Significance of Operator j—Conjugate Complex Numbers

Trigonometrical Form of Vector—Exponential

Form of Vector—Polar Form of Vector Representation— Addition and Subtraction of Vector Quantities—Multiplication and Division of Vector Quantities—Power and Root of Vectors—The 120° Operator Objective Tests.

13. Series A.C circuits:

A.C. through Resistance and Inductance—Power Factor—Active and Reactive Components of Circuit Current- I—Active, Reactive and Apparent Power—Q- factor of a Coil—Power in an Iron- cored Chocking Coil—A.C. Through Resistance and Capacitance—Dielectric Loss and Power Factor of a Capacitor Resistance, Inductance and Capacitance in Series—Resonance in R- L- C Circuits— Graphical Representation of Resonance—Resonance Curve—Half- power Bandwidth of a Resonant Circuit— Bandwidth B at any Off- resonance Frequency—

Determination of Upper and Lower Half- Power Frequencies—Values of Edge Frequencies—Q- Factor of a Resonant Series Circuit—Circuit Current at Frequencies Other than Resonant Frequencies—Relation Between Resonant Power P 0 and Off- resonant Power P—Objective Test.

14. Parallel A.C Circuit:

Solving Parallel Circuits—Vector or Phasor Method—Admittance Method—Application of Admittance Method—Complex or Phasor

Algebra—Series- Parallel Circuits—Series Equivalent of a Parallel Circuit—Parallel of a Series Circuit—Resonance in Parallel Circuits— Graphic Representation of Parallel Resonance—Points to Remember—Bandwidth of a Parallel Resonant Circuit—Q- factor of a Parallel Circuit—Objective Tests.

15. A.C Network Analysis:

Introduction— KCL Laws—Mesh Analysis—Nodal

Analysis—Superposition Theorem—Thevenin’s

Theorem—Reciprocity Theorem—Norton’s Theorem— Maximum Power Transfer Theorem-Millman’s Theorem.

16. A.C Bridges:

A.C. Bridges—Maxwell’s Inductance Bridge—Maxwell- Wien Bridge—Anderson Bridge—

Hay’s Bridge—The Owen Bridge — side Comp bell Equal Ratio Bridge— Capacitance Bridge—De Bridge— S charing Bridge— Wien Series Bridge—Wien Parallel Bridge—Objective Tests.

17. A.C  Filter Networks:

Introduction—Applications—Different Types of Filters—Octaves and Decades of frequency—Decible System—Value of 1 dB—Low- Pass RC Filter—Other Types of Low- Pass Filters—Low- Pass RL Filter— High- Pass R C Filter—High Pass R L Filter—R- C Bandpass Filter—R- C Bandstop Filter—The- 3 dB Frequencies—Roll-off of the Response Curve—Bandstop and Bandpass Resonant

Filter Circuits—Series- and Parallel- Resonant Bandstop Filters—Parallel- Resonant Bandstop Filter—Series- Resonant Bandpass Filter—Parallel- Resonant Bandpass Filter—Objective Test.

18. Circle Diagrams:

Circle Diagram of a Series Circuit—Rigorous Mathematical Treatment—Constant Resistance but Variable

Reactance—Properties of Constant Reactance But Variable Resistance Circuit—Simple Transmission Line Circuit.

19. Poly phase circuits :

Generation of Poly phase Voltages—Phase Sequence—Phases Sequence At Load—Numbering of Phases— Interconnection of Three Phases—Star or Wye (Y) Connection—Values of Phase Currents—Voltages and Currents in Y- Connection—Delta (D) or Mesh Connection—Balanced Y/D and D/Y Conversions— Star and Delta Connected Lighting Loads—Power Factor Improvement—Power Correction Equipment—Parallel Loads—Power Measurement in 3-phase Circuits—Three Wattmeter Method—Two Wattmeter Method—Balanced or Unbalanced load—Two Wattmeter Method- Balanced Load—Variations in Wattmeter Readings—Leading Power Factor—Power Factor- Balanced Load—Balanced Load- L P F—Reactive Volt amperes with One Wattmeter— One Wattmeter Method—Copper Required for Transmitting Power Under Fixed Conditions—Double Subscript Notation—Unbalanced Loads—Unbalanced D- connected Load—Four- wire Star- connected Unbalanced

Load—Unbalanced Y- connected Load Without Neutral—Millman’s —Application of  KCL Laws—Delta/Star and Star/Delta Conversions—Unbalanced

Star- connected Non- inductive Load—Phase Sequence Indicators—Objective Tests.

20. Harmonics:

Fundamental Wave and Harmonics Different Complex Waveforms—General Equation of a Complex Wave— R.M.S. Value of a Complex Wave—Form Factor of a Complex Wave Power Supplied by a Complex Wave—

Harmonics in Single-phase A.C Circuits—Selective Resonance Due to Harmonics—Effect of Harmonic son Measurement of Inductance and Capacitance—Harmonics in Different Three-phase Systems—Harmonics in Single and 3-Phase Transformers—Objective Tests.

21. Fouries Series:

Harmonic Analysis—Periodic Functions—Trigonometric Fourier Series—Alternate Forms of Trigonometric Fourier Series—Certain Useful Integral Calculus Theorems— Evaluation of Fourier Constants—Different Types of Functional Symmetries—Line or Frequency Spectrum—

Procedure for Finding the Fourier Series of a Given Function—Wave Analyser—Spectrum Analyser—Fourier Analyser—Harmonic Synthesis—Objective Tests.

22. Transients :

Introduction—Types of Transients—Important Differ- ental Equations—Transients in R- L Circuits (D.C.),— Short Circuit Current—Time Constant—Transients in R- L Circuits (A.C.)—Transients in R- C Series Circuits (D.C.)—Transients in R- C Series Circuits (A.C)—Double Energy Transients—Objective Tests.

23. Symmetrical Components:

Introduction—The Positive- sequence Components— The Negative- sequence Components—The Zero- sequence Components—Graphical Composition of Sequence Vectors—Evaluation of VA 1 or V1 Evaluation of VA 2  or V2—Evaluation VA 0 or V 0—Zero Sequence Components of Current and Voltage—Unbalanced Star Load form Unbalanced Three-phase Three- Wire System—Unbalanced Star Load Supplied from Balanced Three-

phase Three- wire System—Measurement of Symmetrical Components of Circuits—Measurement of Positive and Negative- sequence Voltages—Measurement of Zero-

sequence Component of Voltage—Objective Tests.

24. Introduction to Electrical Energy Generation:

Preference for Electricity—Comparison of Sources of Power—Sources for Generation of Electricity—Brief Aspects of Electrical Energy Systems—Utility and Consumers—Why is the Three-phase a.c. system Most Popular?—Cost of Generation—Staggering of Loads during peak- demand Hours—Classifications of Power Transmission—Selecting A.C. Transmission Voltage for a Particular Case—Conventional Sources of Electrical Energy—Steam Power Stations (Coal-fired)—Nuclear Power Stations—Advantages of Nuclear Generation— Disadvantages—Hydroelectric Generation—Non- Conventional Energy Sources—Photo Voltaic Cells (P.V. Cells or SOLAR Cells)—Fuel Cells—Principle of

Operation—Chemical Process (with Acidic Electrolyte)—Schematic Diagram—Array for Large outputs—High Lights—Wind Power—Background—Basic Scheme— Indian Scenario.

Thank you. 

 Written by. Abhishek Singh (E.E)