What is Squirrel Cage Rotor?

What is the Squirrel Cage Rotor?

The rotor is having Cage kind of structure so that it is called squirrel cage rotor. This type of rotor is cylindrical laminated core. Rotor windings are made up of copper or aluminium bars which is uninsulated and it is placed inside the slots. The rotor bars are short-circuited at both the ends by end bearings Which is the same material of rotor bars without the rotor core.

What is Squirrel Cage Rotor-min
What is Squirrel Cage Rotor

The rotor conductor and end bearings look like cage type so that is called SCIM. The rotor slots not parallel to the shaft axis which is called skewed slots by using of skewed slots, we obtain

  • It reduces noise and vibration
  • It gives smooth operation
  • It increases starting torque and reduces starting current.

Rotor bars are short-circuited by end bearings so there is no provision to enter any external resistance. A number of rotor bars under one pole is equal to the rotor phase. Rotor phase may or may not be equal to the rotor phase.

Learn More:   Motor Power Calculation Calculator & DC, 1 Phase & 3 Phase Power Fromula

Advantages Squirrel Cage Rotor:

  • Low maintenance.
  • It having a mechanically strong structure
  • It having good running performance
  • Rotor poles are induced poles(ie) no of stator poles are induced in the rotor automatically.
  • Rotor phase can be determined from the rotor bar any pole.

Disadvantages Squirrel Cage Rotor:

  • It has poor starting performance.
  • Starting torque is low.


It is used in many industrial applications because it is reliable and self-starting. These are constant speed motor.

  • Fan & blower
  • Lathe machine
  • Grinder
  • Printing machine & drilling machine.

What is the Squirrel Cage Rotor [Video]:


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