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The pull-out torque of a salient pole synchronous motor occurs when the torque angle is about

The pull-out torque of a salient pole synchronous motor occurs when the torque angle is about Correct Answer 75°

Torque angle δ is the angle between Rotor flux and Stator fluxes, both are rotating at synchronous speed.

Pull-out torque:

  • It is maximum torque which the synchronous motor can develop without pulling out of step
  • When the synchronous motor is loaded, the rotor falls back by some angle a is called a load angle
  • The stator and rotor magnetic rotate at synchronous speed in spite of some load is applied on the rotor
  • The synchronous motor developed maximum torque when the rotor falls back by angle 90°
  • When the load increases beyond its maximum rating, the rotor steps out of synchronism and synchronous motor stop
  • The pull-out torque of a salient pole synchronous motor occurs when the torque angle is about 75°

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