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GATE 2019 EE – Question 20

Electrical Machines · Three-phase induction machines: principle of operation, types, performance, torque-speed characteristics, no-load and blocked-rotor tests, equivalent circuit, starting and speed control · 1 mark · Multiple choice

The parameter of an equivalent circuit of a three-phase induction motor affected by reducing the rms value of the supply voltage at the rated frequency is

  1. rotor resistance
  2. rotor leakage reactance
  3. magnetizing reactance
  4. stator resistance

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Show answer and explanation

Correct answer: (C) magnetizing reactance

Explanation

Lowering the supply voltage reduces the air-gap flux and the saturation of the core, which changes the magnetizing reactance. The resistances and leakage reactances are essentially constant.