21scheme vtu syllabus of visveraya technological university
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1. INDUCTION MOTOR
GENERAL VIVA PRESENTATION
NAME : MINHAJ UDDIN SHAPNIL
MATRIC ID : ET-193050
SEMESTER : 08
SECTION : B
International Islamic University Chittagong
Department of Electrical and Electronics Engineering
2. CONTENTS OF THIS PRESENTETION
Introduction of induction motor
Historical background
Components
Working principle
Speed control
Types
Single phase vs three phase
Application
Advantages and disadvantages
3. INTRODUCTION
• An induction motor is an asynchronous
AC electric motor that converts
alternating current electricity into
mechanical energy. It is called an
induction motor because the electric
current in the rotor circuit required to
produce the deriving torque is obtained
through electromagnetic
induction from the rotating magnetic
field of the stator winding.
4. HISTORICAL BACKGROUND
The induction motor is one of the most important inventions
in modern history.
Nikola Tesla is credited with the invention of the induction
motor, dating back over 100 years. He was only 21 years old
when he realized that there must be a better way to create
more efficient and reliable motors, as the existing ones were
costly and not very powerful. Did you know that the power
generators at Niagara Falls are based entirely on Tesla’s
invention? And to this day, Tesla’s patented AC motor system is
still used in most electric motors.
Nikola Tesla’s ac induction motor
demonstrated in 1887
Nikola tesla
5. COMPONENTS OF AN INDUCTION MOTOR
Casting Coil
Stator Rotor
Bearing
Shaft
6. WORKING PRINCIPLE
• The working principle of an induction motor involves two main
parts:
1.Stator: The stationary part that generates a rotating magnetic field
when connected to the power supply.
2.Rotor: The rotating part that doesn't have a direct electrical
connection to the power supply. It experiences a magnetic field
from the stator, inducing currents in its conductive bars, which in
turn causes it to rotate.
• This interaction between the stator's rotating magnetic field and
the rotor's induced currents creates mechanical motion, making
the motor turn and produce mechanical work. It's a simple and
widely used design in various applications.
Rotor
7. SPEED REGULATION OF INDUCTION MOTORS
The speed regulation of an induction motor is defined as the charge in
the motor speed with a change in load. It is expressed as a fraction or
percentage of full load speed, i.e.,
Speed regulation =
𝑁𝑛𝑙 −𝑁𝑓𝑙
𝑁𝑓𝑙
× 100%
Where, 𝑁𝑛𝑙 is the no-load speed of the motor
And, 𝑁𝑓𝑙 is full load speed of the motor
The speed regulation of an induction motor is about 3% to 5%. Due to
this small speed regulation, the induction motor is classified as the
constant speed motors.
8. TYPES INDUCTION MOTOR
• SINGLE PHASE INDUCTION MOTOR
• Split phase induction motor
• Capacitor start induction motor
• Capacitor start capacitor run induction motor
• Shaded pole induction motor
• THREE PHASE INDUCTION MOTOR
• Squirrel cage induction motor
• Slip ring induction motor
9. SINGLE-PHASE VS THREE-PHASE
• The electrical power factor of single-phase induction motors is low as
compared to three-phase induction motors.
• Single-phase induction motors are simple in construction, reliable and
economical for small power ratings as compared to three-phase induction
motors.
• The efficiency of single-phase induction motors is less compared to that of
three-phase induction motors.
11. ADVANTAGE AND DISADVANTAGE OF INDUCTION MOTOR
Advantages of Induction Motors Disadvantages of Induction Motors
1. Reliability 1. Limited speed control
2. Low maintenance 2. Lower starting torque
3. High efficiency 3. Lower power factor
4. Self-starting 4. Noisy operation
5. Cost-effective 5. Efficiency at partial loads
6. Wide range of sizes 6. Inrush current
