UNIT-I:
ELECTROMECHANICAL ENERGY CONVERSION
Introduction: Laws of magnetism, Electromechanical Energy Conversion,Forces and Torque
in Magnetic Field Systems,Energy Balance,Energy in a Singly Excited Magnetic Field
System, Determination of Magnetic Force and Torque from energy, Co-Energy,
Determination of Magnetic Force and Torque from co-energy,Multi Excited Magnetic Field
Systems, Forces and Torque in system with permanent magnets, Dynamic Equations,
Problems.

UNIT-II:
D.C. GENERATORS
D.C. Generators, Principle of Operation, Constructional Features,A rmature Windings, Lap
and Wave Windings, Simplex and Multiplex Windings, Use of Laminated Armature, E.M.F
Equation, Numerical Problems, Parallel Paths, Armature Reaction, Cross Magnetizing and
DeMagnetizing AT/Pole, Compensating Winding, Commutation, Reactance Voltage,
Methods of Improving Commutation.

UNIT-III:
CHARACTERISTICS OF D.C GENERATORS
Methods of Excitation, Separately Excited and Self Excited Generators, Build-Up of E.M.F,
Critical Field Resistance and Critical Speed, Causes for Failure to Self Excite and Remedial
Measures, Load Characteristics of Shunt, Series and Compound Generators, Parallel
Operation of D.C Series Generators, Use of Equalizer Bar and Cross Connection of Field
Windings, Load Sharing.

UNIT-IV:

D.C. MOTORS
D.C Motors, Principle of Operation, Back E.M.F, Torque Equation, Characteristics and
application of Shunt, Series and Compound Motors, Armature Reaction and Commutation.
Speed Control of D.C. Motors: Armature Voltage and Field Flux Control Methods, WardLeonard System, Braking of D.C Motors, 2- point, 3- Point and 4- Point Starters, Calculation of Starters Steps for D.C Shunt Motors.

UNIT-V:
TESTING OF DC MACHINES
Losses, Constant & Variable Losses, power stages, Calculation of Efficiency, Condition for
Maximum Efficiency, Methods of Testing, Direct, Indirect, BrakeTest, Swinburne’sTest,
Hopkinson’s Test, Field’s Test, Retardation Test, separation of stray losses in a d.c. motor
test.

TEXT BOOKS:
1. Electric Machines by I.J. Nagrath & D.P. Kothari, Tata Mc Graw,Hill Publishers, 3rd
Edition, 2004.
2. Electrical Machinery Fundamentals by Stephen J Chapman, Mc Graw Hills, 2005.

REFERENCE BOOKS:
1. Performance and Design of D.C Machines,by Clayton & Hancock, BPB Publishers, 2004.
2. Electrical Machines,S.K. Battacharya, TMH Edn Pvt. Ltd., 3rd Edition, 2009.
3. Electric Machinary,A. E. Fritzgerald, C. Kingsley and S. Umans, Mc Graw,Hill
Companies,5th Editon, 2003.
4. Electrical Machines,M.V Deshpande, Wheeler Publishing, 2004.
5. Electrical Machines,P.S. Bimbhra., Khanna Publishers, 2011.
6. Electromechanics,I, Kamakshaiah S., Overseas Publishers Pvt. Ltd, 3rd Edition, 2004