PPT: Induction Machines | Electrical Machines - Electrical Engineering (EE) PDF Download

 Page 1


Induction Machines
Page 2


Induction Machines
History and Basic Concepts
The induction machine was invented by Nikola Tesla in 1888. Its ease of manufacture and robustness has made it a very 
strong candidate for electromechanical energy conversion from the beginning.
Available from fractional horsepower to megawatt levels, the induction machine is an AC electromechanical energy 
conversion device that interfaces with the external world through two connections: a mechanical port (rotating shaft) and 
an electrical port (terminals for AC supply).
Operating Modes
Can function as both a motor and 
generator, though it's primarily 
used as a motor due to superior 
performance in this mode.
Power Range
Available from small fractional 
horsepower ratings to massive 
megawatt levels for industrial 
applications.
Supply Options
Available in three-phase or 
single-phase versions, with three-
phase dominating larger 
applications.
Page 3


Induction Machines
History and Basic Concepts
The induction machine was invented by Nikola Tesla in 1888. Its ease of manufacture and robustness has made it a very 
strong candidate for electromechanical energy conversion from the beginning.
Available from fractional horsepower to megawatt levels, the induction machine is an AC electromechanical energy 
conversion device that interfaces with the external world through two connections: a mechanical port (rotating shaft) and 
an electrical port (terminals for AC supply).
Operating Modes
Can function as both a motor and 
generator, though it's primarily 
used as a motor due to superior 
performance in this mode.
Power Range
Available from small fractional 
horsepower ratings to massive 
megawatt levels for industrial 
applications.
Supply Options
Available in three-phase or 
single-phase versions, with three-
phase dominating larger 
applications.
Understanding Induction Motors
An induction motor (also known as an asynchronous motor) is a commonly used AC electric motor where the electric 
current in the rotor needed to produce torque is obtained via electromagnetic induction from the rotating magnetic field of 
the stator winding.
Rotating Magnetic 
Field
Stator creates a 
rotating magnetic field 
when connected to AC 
power
Electromagnetic 
Induction
Field induces current in 
the rotor through 
electromagnetic 
induction
Torque 
Generation
Interaction between 
stator field and rotor 
current produces 
torque
Asynchronous 
Operation
Rotor always runs 
slower than 
synchronous speed, 
creating "slip"
Page 4


Induction Machines
History and Basic Concepts
The induction machine was invented by Nikola Tesla in 1888. Its ease of manufacture and robustness has made it a very 
strong candidate for electromechanical energy conversion from the beginning.
Available from fractional horsepower to megawatt levels, the induction machine is an AC electromechanical energy 
conversion device that interfaces with the external world through two connections: a mechanical port (rotating shaft) and 
an electrical port (terminals for AC supply).
Operating Modes
Can function as both a motor and 
generator, though it's primarily 
used as a motor due to superior 
performance in this mode.
Power Range
Available from small fractional 
horsepower ratings to massive 
megawatt levels for industrial 
applications.
Supply Options
Available in three-phase or 
single-phase versions, with three-
phase dominating larger 
applications.
Understanding Induction Motors
An induction motor (also known as an asynchronous motor) is a commonly used AC electric motor where the electric 
current in the rotor needed to produce torque is obtained via electromagnetic induction from the rotating magnetic field of 
the stator winding.
Rotating Magnetic 
Field
Stator creates a 
rotating magnetic field 
when connected to AC 
power
Electromagnetic 
Induction
Field induces current in 
the rotor through 
electromagnetic 
induction
Torque 
Generation
Interaction between 
stator field and rotor 
current produces 
torque
Asynchronous 
Operation
Rotor always runs 
slower than 
synchronous speed, 
creating "slip"
Types of Induction Motors
Induction motors are classified based on their power supply requirements into single-phase and three-phase categories, 
each with several subtypes designed for specific applications.
Single Phase Motors
Split Phase Induction Motor
Capacitor Start Induction Motor
Capacitor Start and Run 
Induction Motor
Shaded Pole Induction Motor
Three Phase Motors
Squirrel Cage Induction Motor
Slip Ring Induction Motor
Key Differences
Three-phase motors are self-
starting
Single-phase motors require 
starting mechanisms
Three-phase offers higher power 
ratings
Page 5


Induction Machines
History and Basic Concepts
The induction machine was invented by Nikola Tesla in 1888. Its ease of manufacture and robustness has made it a very 
strong candidate for electromechanical energy conversion from the beginning.
Available from fractional horsepower to megawatt levels, the induction machine is an AC electromechanical energy 
conversion device that interfaces with the external world through two connections: a mechanical port (rotating shaft) and 
an electrical port (terminals for AC supply).
Operating Modes
Can function as both a motor and 
generator, though it's primarily 
used as a motor due to superior 
performance in this mode.
Power Range
Available from small fractional 
horsepower ratings to massive 
megawatt levels for industrial 
applications.
Supply Options
Available in three-phase or 
single-phase versions, with three-
phase dominating larger 
applications.
Understanding Induction Motors
An induction motor (also known as an asynchronous motor) is a commonly used AC electric motor where the electric 
current in the rotor needed to produce torque is obtained via electromagnetic induction from the rotating magnetic field of 
the stator winding.
Rotating Magnetic 
Field
Stator creates a 
rotating magnetic field 
when connected to AC 
power
Electromagnetic 
Induction
Field induces current in 
the rotor through 
electromagnetic 
induction
Torque 
Generation
Interaction between 
stator field and rotor 
current produces 
torque
Asynchronous 
Operation
Rotor always runs 
slower than 
synchronous speed, 
creating "slip"
Types of Induction Motors
Induction motors are classified based on their power supply requirements into single-phase and three-phase categories, 
each with several subtypes designed for specific applications.
Single Phase Motors
Split Phase Induction Motor
Capacitor Start Induction Motor
Capacitor Start and Run 
Induction Motor
Shaded Pole Induction Motor
Three Phase Motors
Squirrel Cage Induction Motor
Slip Ring Induction Motor
Key Differences
Three-phase motors are self-
starting
Single-phase motors require 
starting mechanisms
Three-phase offers higher power 
ratings
Self-Starting Capability
A self-starting motor begins running automatically without any external force applied to the machine. For example, when 
you turn on a switch and a fan starts rotating automatically, it's using a self-starting mechanism.
Interestingly, household fans use single-phase induction motors which are inherently not self-starting but include 
additional components to enable this capability.
Phase A Energized
Magnetic field builds in first 
phase winding, attracting rotor
Phase B Energized
120° later, second phase builds 
magnetic field, pulling rotor 
further
Phase C Energized
Another 120° later, third phase 
creates field, continuing rotation
Continuous Rotation
Process repeats, creating smooth rotating magnetic field and continuous torque