Synchronous Motor Multiple Choice Questions and Answers

26. A synchronous motor can be used as a synchronous capacitor when it is

   A.Under-loaded

   B.Over-loaded

   C.Under-excited

   D.Over-excited

27. As the load is applied to synchronous motor, the motor takes more armature current because

   A.The increased load has to take more current

   B.The rotor by shifting its phase backward causes motor to take more current

   C.The back e.m.f. decreases causing an increase in motor current

   D.The rotor strengthens the rotating field causing more motor current

28. Under which of the following conditions hunting of synchronous motor is likely to occur

   A.Periodic variation of load

   B.Over-excitation

   C.Over-loading for long periods

   D.Small and constant load

29. The oscillations in a synchronous motor can be damped out by

   A.Maintaining constant excitation

   B.Running the motor on leading power factors

   C.Providing damper bars in the rotor poles faces

   D.Oscillations cannot be damped

30. A synchronous machine with large air gap has

   A.A higher value of stability limit

   B.A small value of inherent regulation

   C.A higher synchronizing power which makes the machine less sensitive to load variations

   D.All of the above

< 1 2 3 4 5 6 7 8 9 10 Next>