EE3303 ELECTRICAL MACHINES - I L T P C
3 0 0 3
COURSE OBJECTIVES:
To understand the concept of electromechanical energy conversion system.
To identify the appropriate machine for a given application based on its characteristics.
To identify the appropriate test to determine the performance parameters of a given machine.
To familiarize with the procedure for parallel operation of generators and transformers.
To deliberate the working of auto transformer and three phase transformers.
UNIT I ELECTROMECHANICAL ENERGY CONVERSION 9
Fundamentals of Magnetic circuits- Statically and dynamically induced EMF - Principle of
electromechanical energy conversion forces and torque in magnetic field systems- energy balance in
magnetic circuits- magnetic force- co-energy in singly excited and multi excited magnetic field system
mmf of distributed windings – Winding Inductances-, magnetic fields in rotating machines- magnetic
saturation and leakage fluxes. Introduction to Indian Standard Specifications (ISS) - Role and
significance in testing.
UNIT II DC GENERATORS 9
Principle of operation, constructional details, armature windings and its types, EMF equation, wave
shape of induced emf, armature reaction, demagnetizing and cross magnetizing Ampere turns,
compensating winding, commutation, methods of improving commutation, interpoles, OCC and load
characteristics of different types of DC Generators. Parallel operation of DC Generators, equalizing
connections- applications of DC Generators.
UNIT III DC MOTORS 9
Principle of operation, significance of back emf, torque equations and power developed by armature,
speed control of DC motors, starting methods of DC motors, load characteristics of DC motors, losses
and efficiency in DC machine, condition for maximum efficiency. Testing of DC Machines: Brake test,
Swinburne’s test, Hopkinson's test, Field test, Retardation test, Separation of core losses-applications
of DC motors.
UNIT IV SINGLE PHASE TRANSFORMER 9
Construction and principle of operation, equivalent circuit, phasor diagrams, testing - polarity test,
open circuit and short circuit tests, voltage regulation, losses and efficiency, all day efficiency, back-to-
back test, separation of core losses, parallel operation of single-phase transformers, applications of
single-phase transformer.
UNIT V AUTOTRANSFORMER AND THREE PHASE TRANSFORMER 9
Construction and working of auto transformer, comparison with two winding transformers, applications
of autotransformer. Three Phase Transformer- Construction, types of connections and their
comparative features, Scott connection, applications of Scott connection.
TOTAL : 45 PERIODS
72
TEXT BOOKS
1. I. J. Nagrath and D. P. Kothari, “Electric Machines”, McGraw Hill Education, 5 th Edition, 2017.
2. P. S. Bimbhra, “Electric Machinery”, Khanna Publishers, 2nd Edition, 2021.
REFERENCES
1. A. E. Fitzgerald and C. Kingsley, "Electric Machinery”, New York, McGraw Hill Education, 6 th
Edition 2017.
2. A. E. Clayton and N. N. Hancock, “Performance and design of DC machines”, CBS
Publishers, 2018.
3. M. G. Say, “Performance and design of AC machines”, CBS Publishers, First Edition 2008.
4. Sahdev S. K. “Electrical Machines”, Cambridge University Press, 2018.
COURSE OUTCOMES:
At the end of the course students will be able to:
CO1: Apply the laws governing the electromechanical energy conversion for singly and multiple
excited systems.
CO2: Explain the construction and working principle of DC machines.
CO3: Interpret various characteristics of DC machines.
CO4: Compute various performance parameters of the machine, by conducting suitable tests.
CO5: Draw the equivalent circuit of transformer and predetermine the efficiency and regulation.
CO6: Describe the working principle of auto transformer, three phase transformer with
different types of connections.
MAPPING OF COs WITH POs AND PSOs
COs POs PSOs
PO1 PO2 PO3 PO4 PO5 P06 P07 PO8 PO9 PO10 PO11 PO12 PS01 PS02 PS03
CO1 3 3 1 1 1 - - 1 - - - 1 3 2 2
CO2 3 3 1 1 1 - - 1 - - - 1 3 1 1
CO3 3 3 1 1 1 - - 1 - - - 1 3 1 1
CO4 3 3 1 1 1 - - 1 - - - 1 3 3 2
CO5 3 3 1 1 1 - - 1 - - - 1 3 3 2
CO6 3 3 1 1 1 - - 1 - - - 1 3 3 2
Avg 3 3 1 1 1 - - 1 - - - 1 3 3 3
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