ELECTRIC MACHINE-I
EE-401
Credit: 4
Module-I
Electromechanical Energy Conversion Principle, Singly Excited Magnetic
System and Doubly Excited Magnetic system. Physical concept of torque
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production; Electromagnetic torque and Reluctance torque.
Concept of General terms pertaining to Rotating Machines: Electrical &
Mechanical degree, Pole pitch, Coil, Generated EMF in full pitched coil,
Generated EMF in a short pitched coil, EMF polygon,
Distribution factor, Pitch factor. MMF produced by Distributed Windings, MMF
of a coil, MMF of single phase distributed Winding, MMF waveform of
Commutator machines.
Module-II
DC Machines:
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EMF generated in the armature. Methods of Excitation, Armature reaction & its
effect in the performance, Methods of decreasing the effects of Armature
reaction, Effect of Brush shift.
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Commutation process, Resistance commutation, Delayed commutation, Voltage
commutation, Improvement of Commutation.
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Operating Characteristics of DC Generators: Separately Excited generators,
Shunt Generators, Series Generators and Compound Generators.
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Torque equation of D.C motor, Operating Characteristics of Shunt, Series &
Compound motors.
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Losses and efficiency of DC machines, Hopkinson’s and Swinburne’s test.
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D.C Machine application: Generator application, Motor application
Module-III
3-Phase Induction machine:
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Induction motor as a Transformer, Flux and MMF phasors in Induction motors,
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Equivalent circuit, Performance equations, Induction motor phasor diagram
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Toque-slip characteristic, Power slip characteristic, Determination of equivalent
circuit parameters.
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Methods of starting of squirrel Cage and Wound rotor Motors.
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Speed control of Induction motor
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Polarity Test, Application of Polyphase Induction motor.
Module-IV
3-Phase Transformer:
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Determination of polarity and connections (star/star, star/delta, delta/star,
star/zigzag, delta/zigzag, open delta), Phasor groups.
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Effect of unbalanced loading, Production of Harmonics in Transformer and its
suppression,
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3 phase to 2 phase transformation, Scott connection, 3 phase to 6 phase
connections, Double star and Double delta,
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3 winding transformer: Parameter estimation, application,
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Parallel operation of Transformers, Introduction to Tap changing transformer and
its function.
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Special Transformers: Potential transformer, Current transformer, Pulse
transformer, Audio frequency transformer, Grounding transformer, Pulse
transformer.
Numerical Problems to be solved in the tutorial classes.
Text Books:
1 Electrical Machinery, P.S. Bhimra, 6th Edition, Khanna Publishers.
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Electric machines, D.P. Kothari & I.J Nagrath, 3rd Edition, Tata Mc Graw-Hill Publishing
Company Limited.
Electrical Machines, P.K. Mukherjee & S. Chakrabarty, Dhanpat Rai Publication.
Reference Books:
1. Electric Machinery & Transformers, Bhag S. Guru and H.R. Hiziroglu, 3rd Edition,
Oxford University press.
2. Electrical Machines, R.K. Srivastava, Cengage Learning
3. Theory of Alternating Current Machinery, Alexander S Langsdorf, Tata Mc Graw Hill
Edition.
4. The performance and Design of Alternating Current Machines, M.G.Say, CBS
Publishers & Distributors.
5. Electric Machinery & transformer, Irving L Koskow, 2nd Edition, Prentice Hall
India