PPT: Three-Phase Induction Motor | Basic Electrical Technology - Electrical Engineering (EE) PDF Download

 Page 1


Three Phase Induction Motor
?
Outlines:
      -  Introduction
      -  Basic Principle
      -  Types of 3-Ph Induction Motor
      -  Construction of an I.M.
      -  Squirrel cage I.M.
      -  Slip Ring I.M.
      -  Winding of an I.M.                                                 
                    -  Assembly of 3-ph I.M.                       
                                -  Rotating Magnetic Field of  
I.M.                             -  I.M. Speed                      
                                   -  I.M. and Transformer          
                                             -  Power losses in 
Induction Motor
Page 2


Three Phase Induction Motor
?
Outlines:
      -  Introduction
      -  Basic Principle
      -  Types of 3-Ph Induction Motor
      -  Construction of an I.M.
      -  Squirrel cage I.M.
      -  Slip Ring I.M.
      -  Winding of an I.M.                                                 
                    -  Assembly of 3-ph I.M.                       
                                -  Rotating Magnetic Field of  
I.M.                             -  I.M. Speed                      
                                   -  I.M. and Transformer          
                                             -  Power losses in 
Induction Motor
Induction Motors
Page 3


Three Phase Induction Motor
?
Outlines:
      -  Introduction
      -  Basic Principle
      -  Types of 3-Ph Induction Motor
      -  Construction of an I.M.
      -  Squirrel cage I.M.
      -  Slip Ring I.M.
      -  Winding of an I.M.                                                 
                    -  Assembly of 3-ph I.M.                       
                                -  Rotating Magnetic Field of  
I.M.                             -  I.M. Speed                      
                                   -  I.M. and Transformer          
                                             -  Power losses in 
Induction Motor
Induction Motors Introduction
?
Three-phase induction motors are the most 
common and frequently encountered machines in 
industry
-
simple design, rugged, low-price, easy maintenance
-
wide range of power ratings: fractional horsepower to 
10 MW 
-
run essentially as constant speed from no-load to full 
load
-
Its speed depends on the frequency of the power source
•
not easy to have variable speed control 
•
requires a variable-frequency power-electronic drive for 
optimal speed control
Page 4


Three Phase Induction Motor
?
Outlines:
      -  Introduction
      -  Basic Principle
      -  Types of 3-Ph Induction Motor
      -  Construction of an I.M.
      -  Squirrel cage I.M.
      -  Slip Ring I.M.
      -  Winding of an I.M.                                                 
                    -  Assembly of 3-ph I.M.                       
                                -  Rotating Magnetic Field of  
I.M.                             -  I.M. Speed                      
                                   -  I.M. and Transformer          
                                             -  Power losses in 
Induction Motor
Induction Motors Introduction
?
Three-phase induction motors are the most 
common and frequently encountered machines in 
industry
-
simple design, rugged, low-price, easy maintenance
-
wide range of power ratings: fractional horsepower to 
10 MW 
-
run essentially as constant speed from no-load to full 
load
-
Its speed depends on the frequency of the power source
•
not easy to have variable speed control 
•
requires a variable-frequency power-electronic drive for 
optimal speed control
Principle of Operation I.M
?
This rotating magnetic field cuts the rotor windings and 
produces an induced voltage in the rotor windings
?
Due to the fact that the rotor windings are short circuited, for 
both squirrel cage and wound-rotor, and induced current 
flows in the rotor windings
?
The rotor current produces another magnetic field
?
A torque is produced as a result of the interaction of those 
two magnetic fields
Where t
ind
 is the induced torque and B
R
 and B
S
 are the magnetic 
flux densities of the rotor and the stator respectively
ind R s
kB B t = ×
Page 5


Three Phase Induction Motor
?
Outlines:
      -  Introduction
      -  Basic Principle
      -  Types of 3-Ph Induction Motor
      -  Construction of an I.M.
      -  Squirrel cage I.M.
      -  Slip Ring I.M.
      -  Winding of an I.M.                                                 
                    -  Assembly of 3-ph I.M.                       
                                -  Rotating Magnetic Field of  
I.M.                             -  I.M. Speed                      
                                   -  I.M. and Transformer          
                                             -  Power losses in 
Induction Motor
Induction Motors Introduction
?
Three-phase induction motors are the most 
common and frequently encountered machines in 
industry
-
simple design, rugged, low-price, easy maintenance
-
wide range of power ratings: fractional horsepower to 
10 MW 
-
run essentially as constant speed from no-load to full 
load
-
Its speed depends on the frequency of the power source
•
not easy to have variable speed control 
•
requires a variable-frequency power-electronic drive for 
optimal speed control
Principle of Operation I.M
?
This rotating magnetic field cuts the rotor windings and 
produces an induced voltage in the rotor windings
?
Due to the fact that the rotor windings are short circuited, for 
both squirrel cage and wound-rotor, and induced current 
flows in the rotor windings
?
The rotor current produces another magnetic field
?
A torque is produced as a result of the interaction of those 
two magnetic fields
Where t
ind
 is the induced torque and B
R
 and B
S
 are the magnetic 
flux densities of the rotor and the stator respectively
ind R s
kB B t = ×
TYPES OF INDUCTION MOTER
?
Based on type of phase supply                       
                                                                    
                                                                    
                                                               
     
     - Three phase induction motor (self 
starting  in nature)                                 
                                - Squirrel cage I.M.        
                                        - Slip ring I.M.     
                                                                               
                    -  Single phase induction motor 
(not self starting)