Basic Electrical Technology

Indian Institute of Science Bangalore

Course contents:

  • Introduction:
    1. Sources of energy, Power generation: steam, hydel, gas, wind & nuclear; Power generation in Indian context.
    2. General structure of electrical power system; power transmission & voltage levels; power distribution through overhead lines & underground cables.
  • D.C Networks:
    1. Basic concepts; concepts of linear, nonlinear, active, passive, unilateral and bilateral elements; ideal and practical voltage & current sources – conversion from one from the other.
    2. Kirchoff’s laws – statements & explanation with example.
      Mesh current method – definition of mesh & loop, advantage; illustrative example.
    3. Node voltage method – Definition of a node, formation of equations, advantage & illustrative example.
      Delta-Star & Star-Delta conversion; necessity, equivalence & relations; illustration with example.
    4. Superposition principle – statement, limitations; explanation & illustration with examples; practical verification.
      Thevenin’s theorem – statement, advantages in case of complex networks; explanation & illustration with examples.
    5. Norton’s theorem – concept of duality; explanation & illustration; practical verification.
    6. Nonlinear circuits – d.c circuits with one nonlinear element; its solution with example.
  • D.C. Transients:
    R-L & R-C transients – solution for current , voltage or charge as a function of time; time constants; R-L-C transients – under damped, over damped and critically damped conditions.
  • Single Phase A.C. Circuits:
    1. Generation of single phase a.c. voltage and determination of average (mean) and RMS (effective) values of voltage and current with special reference to sinusoidal waveforms; Form factor and peak factor for various waves.
    2. Representation of sinusoidal time varying quantities as phasors; concepts of reactance, impedance and their representation in complex forms using j operator.
    3. Steady state analysis of series R-L-C circuit & its phasor diagram.
    4. Concept of power & power factor; expression of power in complex notation.
    5. Concept of admittance, susceptance in parallel circuits; calculation of branch currents in parallel circuits.
    6. Analysis of series parallel circuits & phasor diagrams.
    7. Resonance in series and parallel circuits.
  • Three phase A.C. Circuits:
    1. Generation of 3-phase balanced sinusoidal voltage; star & delta connections; line & phase quantities (current & voltage).
    2. Solution of 3-phase star/delta circuits with balanced supply voltage and balanced load; phasor diagram; 3-phase, 4-wire circuits.
    3. Measurement of three phase power by two wattmeter method; phasor diagram with balanced load and determination of load power factor from wattmeter readings.
  • Magnetic Circuit:
    1. Ampere circuital law; magnetic circuit & its similarity with electric circuits; solution of series, parallel & series parallel magnetic circuits.
    2. Iron losses – hysteresis & eddy current losses; relationship between B-H loop & hysteresis loss.
    3. Energy stored in a magnetic field and force of attraction between pole faces.
  • Transformer:
    1. Constructional features and principle of operation; concept of ideal transformer under no load & loaded conditions; its equivalent circuit.
      Practical transformer rating & its equivalent circuit.
    2. Regulation – definition & importance; derivation of expression for it: Losses & efficiency, condition for maximum efficiency.
    3. O.C & S.C. tests and determination of equivalent circuit parameters.
      Various types of three phase connections of transformers.
    4. Autotransformer – principle of operation & relative advantages & disadvantages over a two winding transformer.
  • Rotating Machines:
    1. Introduction of general constructional features (stator, rotor & air gap); conditions for production of steady electromagnetic torque.
    2. Multi polar machine & concept of mechanical & electrical angle and their relation; importance of the relation n = 2f/p.
    3. Expression for generated emf in a coil rotating relative to a field.
  • Three phase induction motor:
    1. Elementary balanced 3-phase distributed winding & production of revolving magnetic field; comment on its strength, speed and direction of rotation.
    2. Constructional features and principle of operation; types of induction motors; definition of slip and its importance; relation between stator & rotor frequencies.
    3. Per phase equivalent circuit; relation between air gap power, rotor copper loss and mechanical power developed; expression for electromagnetic torque developed.
    4. Torque-slip characteristic, stable & unstable zones; modification of torque-slip characteristic for supply voltage, rotor resistance and frequency variation.
    5. Basic principles of starting induction motor by direct on line, reactor, autotransformer, star-delta and rotor resistance starters.
  • D.C. Machines:
    1. Constructional features; elementary lap & wave windings; parallel paths in armature circuit.
    2. EMF & torque expressions and their uses in both generating & motoring modes.
    3. Classification of d.c. generators; characteristics of shunt, separately and compound generator; armature reaction & its effect.
    4. Classification of d.c motors; characteristics of shunt & series motors.
      Starting of d.c shunt motor; 3-point starter for shunt motor.
    5. Speed control of shunt and series motors; field of applications.
  • Measuring Instruments:
    1. DC PMMC instruments – constructional feature and principle of operation; moving iron meters – construction and principle of operation.
    2. Dynamometer type wattmeter; induction type energy meter construction & principle of operation.
Course Lectures