EE3303 ELECTRICAL MACHINES - I LTPC 3 0 0 3
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-
toback 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: 30+15=45
PERIODS TEXT BOOKS
1. I. J. Nagrath and D. P. Kothari, “Electric Machines”, McGraw Hill Education, 5th 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, 6th
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.
