- Title: Basic Electrical Technology
- Department: Electrical Engineering
- Author: Prof. L.Umanand
- University: IISc Bangalore
- Type: WebLink
- Abstract:
Introduction
1Sources of energy, Power generation: steam, hydel, gas, wind & nuclear; Power generation in Indian context.
2General structure of electrical power system; power transmission & voltage levels; power distribution through overhead lines & underground cables.
D.C Networks
3
Basic concepts; concepts of linear, nonlinear, active, passive, unilateral and bilateral elements; ideal and practical voltage & current sources – conversion from one from the other.
4
Kirchoff’s laws – statements & explanation with example.
Mesh current method – definition of mesh & loop, advantage; illustrative example.
5
Node voltage method – Definition of a node, formation of equations, advantage & illustrative example.
6
Delta-Star & Star-Delta conversion; necessity, equivalence & relations; illustration with example.
7
Superposition principle – statement, limitations; explanation & illustration with examples; practical verification.
8
Thevenin’s theorem – statement, advantages in case of complex networks; explanation & illustration with examples.
9
Norton’s theorem – concept of duality; explanation & illustration; practical verification.
10
Nonlinear circuits – d.c circuits with one nonlinear element; its solution with example.
D.C. Transients
11 & 12
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
13
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.
14
Representation of sinusoidal time varying quantities as phasors; concepts of reactance, impedance and their representation in complex forms using j operator.
15
Steady state analysis of series R-L-C circuit & its phasor diagram.
16
Concept of power & power factor; expression of power in complex notation.
17
Concept of admittance, susceptance in parallel circuits; calculation of branch currents in parallel circuits.
18
Analysis of series parallel circuits & phasor diagrams.
19
Resonance in series and parallel circuits.
Three phase A.C. Circuits
20
Generation of 3-phase balanced sinusoidal voltage; star & delta connections; line & phase quantities (current & voltage)
21
Solution of 3-phase star/delta circuits with balanced supply voltage and balanced load; phasor diagram; 3-phase, 4-wire circuits.
22
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
23
Ampere circuital law; magnetic circuit & its similarity with electric circuits; solution of series, parallel & series parallel magnetic circuits.
24
Iron losses – hysteresis & eddy current losses; relationship between B-H loop & hysteresis loss
25
Energy stored in a magnetic field and force of attraction between pole faces.
Transformer
26
Constructional features and principle of operation; concept of ideal transformer under no load & loaded conditions; its equivalent circuit.
27
Practical transformer rating & its equivalent circuit.
28 & 29
Regulation – definition & importance; derivation of expression for it: Losses & efficiency, condition for maximum efficiency.
30
O.C & S.C. tests and determination of equivalent circuit parameters.
31
Various types of three phase connections of transformers.
32
Autotransformer – principle of operation & relative advantages & disadvantages over a two winding transformer.
Rotating Machines
33
Introduction of general constructional features (stator, rotor & air gap); conditions for production of steady electromagnetic torque.
34
Multi polar machine & concept of mechanical & electrical angle and their relation; importance of the relation n = 2f/p.
35
Expression for generated emf in a coil rotating relative to a field.
Three phase induction motor.
36
Elementary balanced 3-phase distributed winding & production of revolving magnetic field; comment on its strength, speed and direction of rotation.
37
Constructional features and principle of operation; types of induction motors; definition of slip and its importance; relation between stator & rotor frequencies.
38
Per phase equivalent circuit; relation between air gap power, rotor copper loss and mechanical power developed; expression for electromagnetic torque developed.
39
Torque-slip characteristic, stable & unstable zones; modification of torque-slip characteristic for supply voltage, rotor resistance and frequency variation.
40
Basic principles of starting induction motor by direct on line, reactor, autotransformer, star-delta and rotor resistance starters.
D.C. Machines
41 & 42
Constructional features; elementary lap & wave windings; parallel paths in armature circuit.
43
EMF & torque expressions and their uses in both generating & motoring modes.
44 & 45
Classification of d.c. generators; characteristics of shunt, separately and compound generator; armature reaction & its effect.
46
Classification of d.c motors; characteristics of shunt & series motors.
47
Starting of d.c shunt motor; 3-point starter for shunt motor.
48
Speed control of shunt and series motors; field of applications.
Measuring Instruments
49 & 50
DC PMMC instruments – constructional feature and principle of operation; moving iron meters – construction and principle of operation.
51 & 52
Dynamometer type wattmeter; induction type energy meter construction & principle of operation.