Electrical Machines II

EE3405

ELECTRICAL MACHINES - II

COURSE OBJECTIVES:

To impart knowledge on the following Topics

• Construction and performance of salient and non-salient type synchronous generators.

• Principle of operation and performance of synchronous motor.

• Construction, principle of operation and performance of induction machines.

• Starting and speed control of three-phase induction motors.

• Construction, principle of operation and performance of single phase induction motors and special machines.

UNIT I

SYNCHRONOUS GENERATOR

Constructional details - Types of rotors -winding factors- EMF equation - Synchronous reactance - Armature reaction - Phasor diagrams of non-salient pole synchronous generator connected to infinite bus--Synchronizing and parallel operation Synchronizing torque -Change of excitation and mechanical input- Voltage regulation - EMF, MMF, ZPF and A.S.A method steady state power- angle characteristics- Two reaction theory -slip test -short circuit transients - Capability Curves.

UNIT II

SYNCHRONOUS MOTOR

Principle of operation - Torque equation - Operation on infinite bus bars - V and Inverted V curves - Power input and power developed equations - Starting methods - Current loci for constant power input, constant excitation and constant power Developed-Hunting - natural frequency of oscillations - damper windings- synchronous condenser.

UNIT III

THREE PHASE INDUCTION MOTOR

 Constructional details - Types of rotors - Principle of operation Slip -cogging and crawling- Equivalent circuit - Torque-Slip characteristics - Condition for maximum torque - Losses and efficiency Load test - No load and blocked rotor tests - Circle diagram - Separation of losses - Double cage induction motors -Induction generators - Synchronous induction motor.

UNIT IV

STARTING AND SPEED CONTROL OF THREE PHASE INDUCTION MOTOR

Need for starting - Types of starters - DOL, Rotor resistance, Autotransformer and Star delta starters - Speed control - Voltage control, Frequency control and pole changing - Cascaded Connection-V/f control Slip power recovery Scheme-Braking of three phase induction motor: Plugging, dynamic braking and regenerative braking.

UNIT V

KNOWLED SINGLE PHASE INDUCTION MOTORS AND SPECIAL MACHINES

Constructional details of single phase induction motor - Double field revolving theory and operation - Equivalent circuit - No load and blocked rotor test - Performance analysis - Starting methods of single-phase induction motors - Capacitor-start capacitor run Induction motor- Shaded pole induction motor - Linear induction motor - Repulsion motor - Hysteresis motor - AC series motor- Servo motors- Stepper motors - introduction to magnetic levitation systems.

TOTAL: 45 PERIODS

COURSE OUTCOMES:

Upon the successful completion of the course, students will have the:

CO1: Ability to understand the construction and working principle of Synchronous generator

CO2: Ability to understand the construction and working principle of Synchronous Motor

CO3: Ability to understand the construction and working principle of Three Phase Induction Motor

CO4: Acquire knowledge about the starting and speed control of induction motors.

CO5: To gain knowledge about the basic principles and working of Single phase induction motors and Special Electrical Machines.

TEXT BOOKS:

1. A.E. Fitzgerald, Charles Kingsley, Stephen. D. Umans, 'Electric Machinery', Mc Graw Hill publishing Company Ltd, 6th Education 2017.

2. Stephen J. Chapman, 'Electric Machinery Fundamentals'4th edition, McGraw Hill Education Pvt. Ltd, 4th Edition 2017.

3. D.P. Kothari and I.J. Nagrath, 'Electric Machines', McGraw Hill Publishing Company Ltd, 5th Edition 2017

4. P.S. Bhimbhra, 'Electrical Machinery', Khanna Publishers, edition 2, 2021.

REFERENCES

1. Vincent Del Toro, 'Basic Electric Machines' Pearson India Education, 2016.

2. M.N. Bandyo padhyay, Electrical Machines Theory and Practice, PHI Learning PVT LTD., New Delhi, 2011.

3. B.R.Gupta, 'Fundamental of Electric Machines' New age International Publishers, 3rd Edition, Reprint 2015.

4. Murugesh Kumar, 'Electric Machines', Vikas Publishing House Pvt. Ltd, First edition 2010. 5. Alexander S. Langsdorf, 'Theory of Alternating-Current Machinery', McGraw Hill Publications, 2001.