EP25401 Electrical Machines – Semester IV – EEE(Comp) – R-2025

Subject Code & Name: EP25401 – Electrical Machines

Regulation: R-2025

Semester: IV (Fourth Semester)

Branch: B.E. Electrical and Computer Engineering (EEE(Comp))

Credits / L-T-P: 4 Credits | L-T-P: 3-1-0

Course Objectives

• 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.

Full Unit-wise Syllabus

Unit I – DC Generator

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

Unit II – 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

Unit III – Single-Phase Transformers

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

Unit IV – Auto and Three-Phase Transformers

Working principle – Comparison with two- winding transformers– Three-phase transformer connections(Vector group).

Unit V – 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.

Unit VI – Synchronous Generator

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

Unit VII – 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

Course Outcomes (COs)

• CO1: Explain construction, working principles, and performance of DC machines and transformers.
• CO2: Analyze operation, testing, losses, and efficiency of single-phase and three-phase transformers.
• CO3: Evaluate performance and characteristics of three-phase and single-phase induction motors.
• CO4: Analyze synchronous machines (generators and motors), including operation, regulation, and applications.

Assessment Pattern (Quick Note)

• Weightage: Continuous Assessment 40% | End Semester Examinations 60%
• Internal methodology: Assignments (20%), Solution to application-oriented problems using software (20%), Review of GATE questions (20%), Internal Examinations (40%)

Source: Official Anna University – B.E. Electrical and Computer Engineering R-2025 Syllabus
Last Updated: October 2026