MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 8 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Machines knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
IN_ALL_ROTATING_ELECTRICAL_MACHINE,_ELECTRICAL_TORQUE_IS_DEVELOPED_WHEN_RELATIVE_SPEED_BETWEEN_STATOR_FIELD_AND_ROTOR_FIELD_IS_____________?$ |
| A. | zero |
| B. | equal to rotor speed |
| C. | equal and opposite to rotor speed |
| D. | dependent upon the type of electrical machine |
| Answer» B. equal to rotor speed | |
| 2. |
Consider the principle that the torque in a rotating machine is proportional to peak of stator MMF(Fs), rotor MMF(Fr) and the angle between them(δ). Following statements relate to Fs,Fr and δ in different machine?# |
| A. | δ is fixed in DC machine |
| B. | F<sub>s</sub> is fixed in DC shunt machine |
| C. | δ is variable in induction machine |
| D. | F<sub>r</sub> is fixed in synchronous machne |
| Answer» C. ‚âà√≠¬¨‚Ä¢ is variable in induction machine | |
| 3. |
In the design of electromagnetic devices, the maximum value of MMF is limited from the considerations of ____________ |
| A. | temperature rise |
| B. | limitation on flux density in teeth |
| C. | torque production rise |
| D. | power rating |
| Answer» B. limitation on flux density in teeth | |
| 4. |
Torque angle λ is the angle between ____________$ |
| A. | stator MMF F<sub>s</sub> and resultant MMF F<sub>R</sub> |
| B. | stator MMF F<sub>s</sub> and rotor MMF F<sub>r</sub> |
| C. | rotor MMF F<sub>r</sub> and resultant MMF F<sub>R</sub> |
| D. | Any of the mentioned |
| Answer» C. rotor MMF F<sub>r</sub> and resultant MMF F<sub>R</sub> | |
| 5. |
In practice, electromagnetic torque acting on the stator |
| A. | rotate in opposite direction to rotor |
| B. | is transmitted to ground |
| C. | makes it rotate in same direction as of rotor |
| D. | None of the mentioned |
| Answer» C. makes it rotate in same direction as of rotor | |
| 6. |
Which of the following statements are correct regarding the torque equation in non salient pole machines, Te =-(P/2)(μoΠrl/g)(FsFr)sinλNm?$ |
| A. | stator experiences less torque than rotor and in opposite directions |
| B. | rotor experiences less torque than stator and in same directions |
| C. | stator and rotor experiences equal and opposite torques |
| D. | stator and rotor experiences equal torque and in same directions |
| Answer» D. stator and rotor experiences equal torque and in same directions | |
| 7. |
The torque equation for non salient pole machine is Te =-(P/2)(μoΠrl/g)(FsFr)sinλNm. What does the negative sign in the torque expression indicates?$ |
| A. | stator and rotor MMF tend to reduce angle λ |
| B. | stator and rotor MMF tend to increase angle λ |
| C. | stator tend to reduce the air gap g |
| D. | rotor tend to reduce the air gap g |
| Answer» B. stator and rotor MMF tend to increase angle ‚âà√≠¬¨‚Ñ¢ | |
| 8. |
The electromagnetic torque in non salient pole machines depends on |
| A. | number of poles |
| B. | machine dimensions at the air gap |
| C. | peak value of stator and rotor MMF |
| D. | Any of the mentioned |
| Answer» E. | |