MCQOPTIONS
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MCQOPTIONS
This section includes 10 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. |
THE_AMPLITUDE_OF_ROTATING_MMF_WAVE_IS_PROPORTIONAL_TO?$ |
| A. | N<sub>ph</sub> and P |
| B. | I and P |
| C. | N<sub>ph</sub> and I |
| D. | N<sub>ph</sub>, I and P |
| Answer» D. N<sub>ph</sub>, I and P | |
| 2. |
If_F1_is_the_constant_amplitude_of_fundamental_rotating_MMF_wave,_the_space_harmonics_of_order_6K+1_(where_K=1,2,3….),_the_harmonic_MMF_wave_is_of______________$# |
| A. | Constant amplitude and stationary in space |
| B. | Constant amplitude and rotates along F<sub>1</sub> |
| C. | Varying amplitude and rotates along F<sub>1</sub> |
| D. | Constant amplitude and rotates against F<sub>1</sub> |
| Answer» C. Varying amplitude and rotates along F<sub>1</sub> | |
| 3. |
The magnitude of rotating flux _____________ at all instants of time? |
| A. | Changes |
| B. | Remains constant |
| C. | Pulsates |
| D. | Any of the mentioned |
| Answer» C. Pulsates | |
| 4. |
The effect of poly phase currents in poly phase winding can be compared to _______________ |
| A. | Mechanical rotation of permanent magnets at synchronous speed |
| B. | Mechanical rotation of DC excited field poles at synchronous speed |
| C. | Mechanical rotation of either permanent magnets or DC excited field poles, at synchronous speed |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 5. |
Which of the following statements are correct regarding individual phase MMF in rotating machines ? |
| A. | It is a rotating MMF wave |
| B. | It is not a rotating MMF wave and its amplitude doesn’t alternate along its own phase axis |
| C. | It is not a rotating MMF wave but its amplitude merely pulsates |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 6. |
If the phase sequence of supply currents are reversed, then the direction of rotation of the resultant MMF wave will |
| A. | Be reversed |
| B. | Remains unchanged |
| C. | Cannot be determined |
| D. | None of the mentioned |
| Answer» B. Remains unchanged | |
| 7. |
The peak of rotating MMF wave (FR) is directed along which of the following axis? |
| A. | The axis of that phase which carries the maximum current at that instant |
| B. | The axis of that phase which carries half of the maximum current at that instant |
| C. | The axis of that phase which carries minimum current at that instant |
| D. | Any of the mentioned |
| Answer» B. The axis of that phase which carries half of the maximum current at that instant | |
| 8. |
What is the amplitude of rotating MMF produced as a result of m-phase currents flowing in m-phase windings? |
| A. | (2/m)F<sub>m</sub> |
| B. | mF<sub>m</sub> |
| C. | (m/2)F<sub>m</sub> |
| D. | F<sub>m</sub> |
| Answer» D. F<sub>m</sub> | |
| 9. |
The speed at which rotating magnetic field revolves is called |
| A. | Induction speed |
| B. | Synchronous speed |
| C. | Relative speed |
| D. | Rotating speed |
| Answer» C. Relative speed | |
| 10. |
For a p-pole machine, which of the following statements are correct regarding the rotating field speed? |
| A. | The rotating field speed is 1/(p/2) revolutions in one cycle |
| B. | f/(p/2) revolutions in f cycles |
| C. | f/(p/2) revolutions in one second |
| D. | Any of the mentioned |
| Answer» E. | |