# A.C. Machines - II

#### Features Includes:

• 91 - 3D/2D Animation
• 750 Pages of Content
• 90 Lecture Hours
• 38 Solved Problems
• 166 Quiz
• Suitable for All Technical University Syllabus

#### Course Description

This course explains the basic principles of synchrnous motors, Single phase & three phase induction motors and their characteristics. And also it covers the selection of drives, braking and applications.

#### OBJECTIVES:

• Comprehend the working of synchronous motors
• Comprehend the working of 3 phase Induction Motors
• Comprehend the working of single phase motors
• Appreciate the different types of Electrical Drives
• Understand braking of electric motors
###### UNIT - I SYNCHRONOUS MOTORS

Introduction - Introduction to synchronous motor - Classification of A.C. motors. Production of rotating magnetic field - Production of rotating magnetic field. Construction of synchronous motor - Construction and classification of synchronous motor - Stator - Rotor - Difference between salient pole and non-salient pole rotor - Advantages of stationary armature. Principle operation of synchronous motor - Magnetic locking - Principle operation of synchronous motor - Procedure to start a synchronous motor. Vector diagram of synchronous motor - Vector diagram of synchronous motor on no load and load - Analysis of Phasor diagram - Phasor diagram of under excited synchronous motor on load - Problems. Effect of excitation - Effect of changing excitation on constant load. Power equation - Power equation. Power developed by a synchronous motor - Power developed by a synchronous motor - Power relations - Problems. V and inverted V curves of a synchronous motor - V and inverted V curves. Synchronous condenser - Synchronous condenser - Synchronous phase modifier - Problems. Hunting of synchronous motor - Hunting (or) surging (or) phase swinging. Prevention of hunting. Starting methods of synchronous motors - Starting methods of synchronous motors. Applications of synchronous motor - Synchronous motor applications.

###### UNIT - III SINGLE PHASE MOTORS

Construction and working single phase induction motor - Introduction to single phase induction motor - Construction - Working principle - Why is single phase induction motor not self starting - Starting of single phase induction motor. Double field revolving theory - Double field revolving theory. Cross field theory - Cross field theory. Split phase induction motor - Classification of single phase motor - Split -phase single phase induction motor. Capacitor -start induction motor - Capacitor -start single phase induction motor. Capacitor run induction motor - Capacitor run single phase induction motor. Capacitor start -capacitor run induction motor - Capacitor start - capacitor run single phase induction motor. Shaded pole induction motor - Shaded pole single phase induction motor - Comparison between different types of single phase induction motors - Speed control of single phase induction motor. Construction and working of A.C.Series motor - A.C. series motor - Working principle of a.c. series motor. Sparking and elimination methods of A.C. series motor - Sparking and elimination methods of A.C. series motor - Modifications in design of A.C. series motor - Sparking and elimination methods. Universal motor - Universal motors. Speed control and applications of universal motor - Speed control methods. Stepper motor - Introduction - Types of stepper motors - Variable reluctance stepper motor - Operation of stepper motor. Advantages and Applications of Stepper Motor - Advantages and Applications of Stepper Motor. Brushless D.C. motor - Introduction. Applications of brushless D.C. motors - Applications of brushless D.C. motors.

###### UNIT -IV ELECTRICAL DRIVES

Factors governing the selection of electric drive and its classification - Electrical drives - Classification of electric drives - Comparison between group drive and individual drive - Factors governing the selection of electric drive - Parts of electrical drives - Applications of electric drives. Types of loads and load curves - Types of loads for which drives are needed - Intermittent periodic duty - Load curves of different types of loads. Determination of rating of motor - Determination of the power of motor - Root mean torque method - Heating time curve - Cooling time curve - Problems. Need of load equalization and use of flywheel - Load equalization. Types of enclosures and bearings - Types of enclosures. Bearings and noise. Reduction of noise - Noise elimination. Motors used for different applications - Suitable motors for A.C. and D.C. drives.

###### UNIT -V BRAKING OF ELECTRICAL MOTORS

Electrical braking - Electric braking. Plugging - Plugging of D.C. shunt motor - Plugging of D.C. series motor - Plugging of three phase induction motor. Problems on plugging in D.C. motors - problems. Dynamic braking - Rheostatic braking of D.C. shunt motor - Rheostatic braking of D.C. series motor. Regenerative braking - Regenerative braking of D.C. motor - Regenerative braking of induction motor.