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Rheostat method of speed control of induction motor is used in which of the following induction motor?

Rheostat method of speed control of induction motor is used in which of the following induction motor? Correct Answer Slip ring

The speed of the induction motor can be controlled by the following methods:

1) V/f control (or) frequency control

2) Changing the number of stator poles

3) Controlling supply voltage

4) Changing winding resistance by adding rheostat in the stator circuit

We can apply all these methods to slip ring induction motors, but the adding resistance in the stator circuit is not possible for squirrel cage motors as rotor bars are short-circuited using end rings.

Important Points:

The speed control of three-phase induction motor from the stator side are classified as:

  • V/f control or frequency control
  • Changing the number of stator poles
  • Controlling supply voltage
  • Adding rheostat in the stator circuit

 

The speed controls of three-phase induction motor from rotor side are classified as:

  • Adding external resistance on the rotor side
  • Cascade control method
  • Injecting slip frequency emf into rotor side

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