Transformers and Generators (1BEE305)

Transformers and Generators

Course Code 1BEE305 
Scheme 2025
Type of Course Professional Core course 
Semester III
Teaching Hours/Week (L:T:P) 3:0:0 
CIE Marks 50
Total Hours of Pedagogy L /T/P/(SL&TW): 42: 0: 0 :48 
SEE Marks 50
Credits 3 
Total Marks 100
Examination type (SEE) Theory 
Exam Hours 3

Module-1

Single phase Transformers: Necessity of transformers, principle of operation, Constructional details of core and windings, EMF equation, equivalent circuit, Operation of practical transformer under no-load and on load with phasor diagrams. Losses, Variation of losses with load, methods of reducing losses. Efficiency and condition for maximum efficiency. Reasons for rating of transformers in kVA. Open circuit and short circuit tests, calculation of equivalent circuit parameters. Polarity test, Sumpner’s test. Predetermination of efficiency, voltage regulation and its significance. parallel operation of single-phase transformers. Numerical Problems.

Module-2

Three-phase Transformers: Introduction, Three phase transformers in single units or in bank of three, Transformer connection for three phase operation– star/star, delta/delta, star/delta, and delta/open delta, comparative features with reference to vector group, Labelling of three-phase transformer terminals, Parallel Operation of Transformers: Necessity of Parallel operation, conditions for parallel operation of three phase transformers including vector group conditions, Load sharing in case of similar and dissimilar transformers., Numerical Problems.

Module-3

Three-Phase Transformers(continued): Voltage regulation by Tap changing on load and on noload. Scott connected transformer, Necessity of transformers with tertiary windings. transformer Noise.

Autotransformers: Introduction, copper economy, equivalent circuits, numerical problems. Instrument transformers- Current Transformers (CT) and Potential Transformers (PT): Construction, Operation, and Applications. 

Welding transformers: construction and operation. Introduction to pulse transformer.

Module-4

Synchronous Generators: Constructional features of salient and cylindrical types, excitation systems – static and brushless, working, Armature windings, winding factors, EMF equation; Harmonics–causes, reduction and elimination; Armature reaction, Synchronous reactance, Equivalent circuit; Synchronous Generators Analysis: Open circuit and short circuit characteristics, short circuit ratio, Alternator on load; Voltage regulation, Voltage regulation by EMF, MMF, and ZPF methods; Excitation control for constant terminal voltage when operating on its own load and on infinite bus. Numerical Problems.

Module-5

Synchronous Generators (Salient Pole): Effects of saliency, two-reaction theory, Direct and quadrature axis reactances, slip test, electromagnetic power developed in the salient generators. Power angle characteristic (salient and non-salient pole), power angle diagram, reluctance power, capability curve for large turbo generators. Parallel operation of generators and load sharing; Methods of synchronization, Synchronizing power, Hunting and damper windings. Numerical Problems.

Textbooks:

(i)Electric Machines, D. P. Kothari, et al, 4th Edition, 2011.

(ii)Electric Machines, Ashfaq Hussain, Dhanpat Rai & Co, 2nd Edition, 2013.

(iii)Electric Machinery, P.S. Bimbhra, Khanna Publishers.

(iv) Theory & Performance of Electrical Machine, J.B. Gupta, S.K. Kataria & Sons.

Reference books:

(i)Electric Machinery, A E Fitzgerald, Charles Kingsley, Stephan Umans, McGraw-Hill.