EP25401 Electrical Machines Syllabus:

EP25401 Electrical Machines Syllabus – Anna University UG Syllabus Regulation 2025

Course Objective:

• To educate students on the construction and operation of DC and AC machines, including generators, motors, and transformers. This course also aims to impart knowledge of testing methods and performance analysis.

Course Content

DC Generator – Constructional details, armature windings and types – Principle and EMF equation – Armature reaction – Commutation – OCC and load characteristics of various DC generators – Applications.

DC Motors – Principle of operation, significance of back emf, torque equation and power developed, speed control Types of starters, load characteristics, losses and efficiency , condition for maximum efficiency. Testing: Brake test, Swinburne’s test, Hopkinson’s test, Field test, Retardation test, Separation of core losses-applications

Single-Phase Transformers – Construction and principle – Equivalent circuit – Phasor diagrams – Open and short circuit tests – Voltage regulation – Losses and efficiency – All-day efficiency – Applications.

Auto and Three-Phase Transformers – Working principle – Comparison with twowinding transformers– Three-phase transformer connections(Vector group).

Induction Motor

• Three Phase: Construction – Principle of operation – Slip and torque-slip characteristics – Equivalent circuit – Losses and efficiency – Cogging and crawling – Load, no-load and blocked rotor tests – Starters and speed control.
• Single Phase: Construction – Double-field revolving theory – Equivalent circuit – Starting methods – Applications.

Synchronous Generator – Construction – Winding factors – EMF equation – Armature reaction – Voltage regulation (EMF method) – Synchronization and parallel operation.

Synchronous Motor – Principle of operation – Torque equation – V and Inverted V curves – Starting methods – Hunting – Applications.

TASKS:

T1. Analyze series and parallel magnetic circuits.
T2: Observe effect of: Flux variation, Number of turns, Frequency in Faraday’s Law of Induced EMF
T3: Explain energy conversion mechanism with examples.
T4 Compare: Lap winding & Wave winding
T5: Study the effect on terminal voltage due to armature reaction.
T6: Draw the Phasor diagram for Transformer for any one type of load.
T7: Study speed control methods of DC motors and Induction motors

Weightage: Continuous Assessment: 40%, End Semester Examinations: 60%.

Assessment Methodology: Assignments (20%), Solution to application-oriented problems using software (20%), Review of GATE questions (20%), Internal Examinations (40%).

References

1. Kothari, D. P., & Nagrath, I. L. (2021). Electric machines (5th ed., fully revised). Tata McGraw Hill.
2. Bimbhra, P. S. (2021). Electrical machinery (2nd ed.). Khanna Publishers.
3. Fitzgerald, A. E., & Kingsley, C. (2017). Electric machinery (6th ed.). McGraw Hill.
4. Clayton, A. E., & Hancock, N. N. (2018). Performance and design of DC machines. CBS Publishers.
5. Say, M. G. (2008). Performance and design of AC machines. CBS Publishers.

E-Resource:

• NPTEL: Electrical Machines – I