The single phase induction motor

Replies

• 

  grsalvi

  zaveri

  If a capacitor of equal microfarads is connected in parallel with the existing capacitor of a single phase induction motor, then the speed increases drastically.
  
  then,
  
  1) does this increase the torque of the motor as well.
  
  2) if 3 or more capacitors of the same rating are connected in parallel, then will this damage the motor ?

  Zaveri we already discussed in a post, i believe same is true for your question asked now.See this post :
  
  #-Link-Snipped-#
  
  Now for your other question :
  
  1.The increase or decrease in torque depends upon the shift which your capacitor introduces.
  
  2.I donot think so it will damage motor however stop proper functioning of motor.
  
  Just note one thing that , the only intention of capacitor in single phase induction motor is to convert its stationary magnetic field into rotating one .
  
  However for speed control we use AC regulators.
• 

  zaveri

  grsalvi

  1.The increase or decrease in torque depends upon the shift which your capacitor introduces.
  
  \

  
  What is "shift" ? can you elaborate ?
• 

  grsalvi

  zaveri

  What is "shift" ? can you elaborate ?

  
  The term shift refers to the phase shift which is introduced in starting winding of single phase induction motor.
  
  Actually a single phase induction motor has two windings ,one is called main and another starting purpose.
  Since we cant achieve a rotating magnetic field with single phase supply.
  
  So the single phase supply is fed to two windings : main and auxiliary winding (starting winding ) . The auxiliary winding (starting winding ) has capacitor connected to it,hence its current leads that of main winding.
  This is as if two windings are receiving two different phases of supply.
  
  Hence a rotating magnetic field is produced which rotates rotor by principle if induction.
  
  So you see that main purpose of capacitor was to produce a leading current phase supply in auxiliary winding (starting winding ).
• 

  naveee

  capacitor is only used to increase the torque........rotation magnetic field is produced by the magnetic windings...... the how capacitor is used to convert stationary magnetic field into rotating one .??? #-Link-Snipped-#
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  grsalvi

  naveee

  capacitor is only used to increase the torque........rotation magnetic field is produced by the magnetic windings...... the how capacitor is used to convert stationary magnetic field into rotating one .??? #-Link-Snipped-#

  Winding are capable of producing rotating magnetic field in case of 3 phase induction motor.
  
  A minimum of two different phases are necessary to produce rotating magnetic field.
  Now to get two phase supply in single phase induction motor , we use capacitor (or inductance ).
  
  As far as torque effect of capacitor is concerned ,it is secondary use of capacitor and used in capacitor -run single phase induction motor.
• 

  Jeffrey Arulraj

  naveee

  capacitor is only used to increase the torque........rotation magnetic field is produced by the magnetic windings...... the how capacitor is used to convert stationary magnetic field into rotating one .??? #-Link-Snipped-#

  Current associated with the conductor is what generates the magnetic flux
  Next the capacitor offers a phase shift when current flows through it
  
  As a result the current through the auxilary windings are 90 out of phase with that in the primary winding
  
  This is needed to make the motor run