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A balanced 3 – phase induction motor runs at slip s. If ωs is its synchronous speed, what is the relative speed between the stator mmf and rotor mmf ?

A balanced 3 – phase induction motor runs at slip s. If ωs is its synchronous speed, what is the relative speed between the stator mmf and rotor mmf ? Correct Answer Zero

Concept:

In a three-phase induction motor,

  • The stator is stationary, and the rotor is a rotating part
  • Both the stator field and rotor field rotate with synchronous speed
  • The rotor rotates with a speed less than synchronous speed

 

Application:

  • The relative speed between the rotor field and a stator is synchronous speed
  • The relative speed between the rotor field and stator field is zero
  • The relative speed between stator field and stator is synchronous speed

Important Points

 

Relative Speed of
With respect to

Stator

Stator Magnetic Field

Rotor

Rotor Magnetic field

Stator

0

Ns

Ns(1 - s)

Ns

Stator Magnetic Field

- Ns

0

- sNs

0

Rotor

- Ns(1-s)

sNs

0

sNs

Rotor Magnetic field

- Ns

0

- sNs

0

Related Questions

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