At the end of this course the student will be able to have an insight into the construction, working principles and behavior of machines under different operating conditions and an awareness of their losses and efficiency. The knowledge gained will form basis for carrying out repair and maintenance of these machines, an area covered in the programme concurrently.
1 SINGLE PHASE TRANSFORMER 36 Hrs.
1.1 Definition, principle, basic parts.
1.2 EMF equation, transformation ratio.
1.3 Classification of transformer – core, mode of operation, use and cooling.
1.4 Transformer operation (ideal) – On No load, on load, with resistive load, phasor
diagram, with inductive, phasor diagram, with Capacitive load, phasor diagram.
1.5 Transformer operation (Practical) – parameters, primary resistance, secondary
resistance, primary leakage reactance, secondary leakage reactance, secondary,
equivalent resistance, equivalent reactance referred to secondary, referred to
primary, Exciting conductance and susceptance, equivalent circuit diagrams
referred to primary & secondary, operation of practical transformer on load of
different power factor, phasor diagram, approximate and exact voltage drop in
transformer, regulation, percent resistance, reactance and impedance.
1.6 Transformer losses & efficiency, Iron and copper losses. Ordinary and all – day
efficiencies, maximum efficiency, cooling of transformers.
1.7 Transformer tests and specifications – Insulation test, Ratio test, Polarity test, open
circuit test, short circuit test, Back-to-back/Sumpner’s test.
1.8 Parallel operation of 1 phase transformers
1.9 Special transformers, construction, principle and use – Instrument transformers,
Auto transformer (with its apparent power advantage), Welding transformer,
Rotating core transformer.
2. 3 -PHASE TRANSFORMER. 15 Hrs.
2.1 Construction and working of 3 phase transformer.
2.2 Connection groups of 3 phase transformer, name-plate rating.
2.3 Connection of single phase transformers for 3 phase & 2 phase transformation, –
Star-Star, Star-Delta, Delta-Star, Delta-Delta, open Delta, Scott, Transformation
of 3 phase to 6 phase & vice versa.
2.4 Calculation of 3-phase transformer.
3 A.C MOTORS INTRODUCTION
3.1. General. 1 Hr.
3.2 Preference of A.C motors over DC motors.
3.3 Classifications.
4. THREE PHASE INDUCTION MOTORS. 20 Hrs.
4.1 Production of rotating magnetic field by 3 phase & 2 phase EMFs.
4.2 Construction of squirrel cage & wound rotor induction motor.
4.3 Principle of rotation of S.C. rotor, synchronous speed, rotor speed, slip, frequency
of rotor induced current.
4.4 Motor parameters (stator resistance, reactance, rotor resistance, rotor reactance in
starting & running condition. Condition for maximum starting & running torque.
4.5 Power stages in induction motor, Resistance measurement, No load & blocked
rotor tests to determine losses, efficiency & parameters of motor. Equivalent
circuit.
4.6 Starting of 3 ph induction motor.
4.7 Speed control of induction motor.
5. SINGLE PHASE MOTOR. 12 Hrs.
5.1 Classification.
5.2 Split phase motor.
5.3 Shaded pole motor.
5.4 Repulsion motor.
5.5 Series motor.
5.6 Fan Motor as example of External Rotor motor
6. SYNCHRONOUS GENERATOR. 32 Hrs.
6.1. Construction – Stator, Rotor, Armature winding (single layer, two layer, chain),
Hydrogen cooling for large machines
6.2 Principle. EMF equation.
6.3. Performance of Synchronous Generator on Load.
6.4 Voltage variation on load
6.5 Armature Reaction
6.6 Synchronous impedance
6.7. Phasor Diagram of Loaded Synchronous Generator on different power factors.
6.8. Regulation & its Determination by Synchronous Impedance Method.
6.9 O.C. and S.C. tests
6.10 Calculation of voltage regulation
6.11 Synchronization of Generator by different methods (lamp bright, lamp dark,
synchroscope).
6.12 Load sharing.
6.13 Brushless A.C. Generator: Construction, Working & Uses.
7. SYNCHRONOUS MOTOR. 12 Hrs.
7.1. Principle, construction, operation & uses of 3 phase synchronous motor
7.2. Principle, construction operation, characteristics & uses of unexcited single phase synchronous motor (Reluctance & Hysteresis Motor).
7.3. Permanent magnet synchronous motor – efficiency considerations and starting of motor.
RECOMMENDED BOOKS:-
1. A.C Machines Fundamentals by J. Chapmann
2. B.L Theraja. Electrical Technology
3. Electrical Machines by V.U Bakhshi & V.A Bakhshi
4. A.C Machines by Afzal Bashir & Khalid Mahmood
5. Philips Kemp. Alternating Current Electrical Engineering
6. Drinkall Hadik Grant. Alternator Current Motors
7. Kates-Stafford. Electrical Generator
8. Coral H-Dunlop. Transformers