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EEE :: Synchronous Motors

  1. The maximum value of torque that a synchronous motor, can develop without losing its synchronism, is known as
  2. A.
    breaking torque
    B.
    synchronizing torque
    C.
    pull out torque
    D.
    slip torque

  3. If a synchronous motor drops too far behind, the power it takes from the supply also increases too much, and the armature tries to get accelerated, until it is in correct position. Sometimes, some motor overshoots the marks and then the process of acceleration-retardation continues. This phenomenon is known as
  4. A.
    synchronization
    B.
    hunting
    C.
    pulling out
    D.
    swinging

  5. What is the ratio of no load speed to full load speed of a 200 kVA, 12 pole, 2200 V, 3 phase, 60 Hz synchronous motor ?
  6. A.
    1
    B.
    1.1
    C.
    1.21
    D.
    infinite

  7. The armature current of the synchronous motor has large values for
  8. A.
    low excitation only
    B.
    high excitation only
    C.
    both high and low excitation

  9. When the excitation of an unloaded salient-pole synchronous motor suddenly gets disconnected
  10. A.
    the motor stops
    B.
    it runs as a reluctance motor at the some speed
    C.
    it runs as a reluctance motor at a lower speed