Starting Of Synchronous Motor Multiple Choice Questions and Answers

41. Synchronous motors are generally not self-starting because

   A.The direction of rotation is not fixed

   B.The direction of instantaneous torque reverse after half cycle

   C.Startes cannot be used on these machiness

   D.Starting winding is not provided on the machines

42. A synchronous motor can be made self-starting by providing

   A.Damper winding on rotor poles

   B.Damper winding on stator

   C.Damper winding on stator as well as rotor poles

   D.None of the above

43. The synchronous motor is not inherently self-starting because

   A.The force required to accelerate the rotor to the synchronous speed in an instant is absent

   B.The starting device to accelerate the rotor to near synchronous speed is absent

   C.A rotating magnetic field does not have enough poles

   D.The rotating magnetic field is produced by only 50 Hz frequency currents

44. The armature current of the synchronous motor has higher values for

   A.High excitation only

   B.Low excitation only

   C.Both (a) and (b)

   D.None of the above

45. In a synchronous motor, the rotor Cu losses are met by

   A.Motor input

   B.Armature input

   C.Supply lines

   D.D.C. source

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