MCQOPTIONS
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MCQOPTIONS
This section includes 28 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. |
Ideally the voltage regulation of an alternator should be ___________ |
| A. | zero |
| B. | infinite |
| C. | 50% |
| D. | 100% |
| Answer» B. infinite | |
| 2. |
If the emf from the air gap line is the 3-phase alternator is 440V per phase and armature current is 110 A. The synchronous reactance is? |
| A. | 4 ohms |
| B. | 2 ohms |
| C. | 6.92 ohms |
| D. | 2.32 ohms |
| Answer» B. 2 ohms | |
| 3. |
In a calculation, the actual voltage regulation is 33.1% while the calculated value of the voltage regulation is 32.9%. This infers that the chosen method has been ___________ |
| A. | zpf or asa |
| B. | emf |
| C. | mmf |
| D. | mmf or zpf |
| Answer» B. emf | |
| 4. |
In a calculation, the actual voltage regulation is 33.1% while the calculated value of the voltage regulation is 25%. This infers that the chosen method has been ___________ |
| A. | emf |
| B. | mmf |
| C. | asa |
| D. | zpf |
| Answer» C. asa | |
| 5. |
In a calculation, the actual voltage regulation is 33.1% while the calculated value of the voltage regulation is 56.8%. This infers that the chosen method has been ___________ |
| A. | emf |
| B. | mmf |
| C. | asa |
| D. | zpf |
| Answer» B. mmf | |
| 6. |
The preferred order of calculating the voltage regulation is ___________ |
| A. | ZPF > ASA > MMF > EMF |
| B. | ZPF > MMF > ASA > EMF |
| C. | ASA > MMF > ASA > EMF |
| D. | EMF > ASA > ZPF > MMF |
| Answer» B. ZPF > MMF > ASA > EMF | |
| 7. |
Mmf method of voltage regulation is called _______ while the emf method is __________ |
| A. | optimistic, pessimistic |
| B. | pessimistic, pessimistic |
| C. | optimistic, optimistic |
| D. | pessimistic, optimistic |
| Answer» B. pessimistic, pessimistic | |
| 8. |
In mmf method ___________ |
| A. | all the emf is scaled to mmf |
| B. | only the mmf values are considered neglecting impedance drop |
| C. | all the emf are taken zero |
| D. | emf is converted to saturated impedance drops |
| Answer» B. only the mmf values are considered neglecting impedance drop | |
| 9. |
Emf method is also known as ___________ |
| A. | pessimistic method |
| B. | optimistic method |
| C. | zero power factor method |
| D. | none of the mentioned |
| Answer» B. optimistic method | |
| 10. |
The emf method of the voltage regulation is applicable only to cylindrical rotor alternator due to ___________ |
| A. | resultant air gap flux is not affected by angular position of rotor |
| B. | uniform angular position of rotor |
| C. | non uniform angular position of rotor |
| D. | saliency of the poles is a trouble while estimating the emf |
| Answer» B. uniform angular position of rotor | |
| 11. |
Alternator on infinite bus bar has constant ___________ |
| A. | terminal voltage and frequency |
| B. | frequency |
| C. | power factor |
| D. | power factor and terminal voltage |
| Answer» B. frequency | |
| 12. |
Voltage regulation for an alternator operating at leading power factor is negative due to ___________ |
| A. | magnetizing nature of armature reaction |
| B. | demagnetizing nature of armature reaction |
| C. | cross-magnetizing nature of armature reaction |
| D. | all of the mentioned |
| Answer» B. demagnetizing nature of armature reaction | |
| 13. |
When the load on an alternator is varied, its terminal voltage also changes due to _____________ |
| A. | armature resistance |
| B. | leakage reactance |
| C. | armature reaction |
| D. | all of the mentioned |
| Answer» B. leakage reactance | |
| 14. |
THE_PREFERRED_ORDER_OF_THE_CALCULATING_THE_VOLTAGE_REGULATION_IS?$ |
| A. | ZPF > ASA > MMF > EMF |
| B. | ZPF > MMF > ASA > EMF |
| C. | ASA > MMF > ASA > EMF |
| D. | EMF > ASA > ZPF > MMF |
| Answer» B. ZPF > MMF > ASA > EMF | |
| 15. |
In a calculation, the actual voltage regulation is 33.1% while the calculated value of the voltage regulation is 25%. This infers that the chosen method has been$ |
| A. | emf |
| B. | mmf |
| C. | asa |
| D. | zpf |
| Answer» C. asa | |
| 16. |
In_a_calculation,_the_actual_voltage_regulation_is_33.1%_while_the_calculated_value_of_the_voltage_regulation_is_56.8%._This_infers_that_the_chosen_method_has_been$ |
| A. | emf |
| B. | mmf |
| C. | asa |
| D. | zpf |
| Answer» B. mmf | |
| 17. |
Ideally the voltage regulation of an alternator should be |
| A. | zero |
| B. | infinite |
| C. | 50% |
| D. | 100% |
| Answer» B. infinite | |
| 18. |
If the machine size increases, the three phase alternator resistance _______ and synchronous reactance _______ |
| A. | increases, decreases |
| B. | decreases, increases |
| C. | remains constant, decreases |
| D. | decreases, decreases |
| Answer» B. decreases, increases | |
| 19. |
If the emf from the air gap line if the 3-phase alternator is 440V per phase and armature current is 110 A. The synchronous reactance is |
| A. | 4 ohms |
| B. | 2 ohms |
| C. | 6.92 ohms |
| D. | 2.32 ohms |
| Answer» B. 2 ohms | |
| 20. |
In_a_calculation,_the_actual_voltage_regulation_is_33.1%_while_the_calculated_value_of_the_voltage_regulation_is_32.9%._This_infers_that_the_chosen_method_has_been |
| A. | zpf or asa |
| B. | emf |
| C. | mmf |
| D. | mmf or zpf |
| Answer» B. emf | |
| 21. |
Mmf method of voltage regulation is called _______ while the emf method is _________? |
| A. | optimistic, pessimistic |
| B. | pessimistic, pessimistic |
| C. | optimistic, optimistic |
| D. | pessimistic, optimistic |
| Answer» B. pessimistic, pessimistic | |
| 22. |
In mmf method |
| A. | all the emf is scaled to mmf |
| B. | only the mmf values are considered neglecting impedance drop |
| C. | all the emf are taken zero |
| D. | emf is converted to saturated impedance drops |
| Answer» B. only the mmf values are considered neglecting impedance drop | |
| 23. |
Emf method is also known as |
| A. | pessimistic method |
| B. | optimistic method |
| C. | zero power factor method |
| D. | none of the mentioned |
| Answer» B. optimistic method | |
| 24. |
The emf method of the voltage regulation is applicable only to cylindrical rotor alternator due to |
| A. | resultant air gap flux is not affected by angular position of rotor |
| B. | uniform angular position of rotor |
| C. | non uniform angular position of rotor |
| D. | saliency of the poles is a trouble while estimating the emf |
| Answer» B. uniform angular position of rotor | |
| 25. |
Alternator on infinite bus bar has constant |
| A. | terminal voltage and frequency |
| B. | frequency |
| C. | power factor |
| D. | power factor and terminal voltage |
| Answer» B. frequency | |
| 26. |
Voltage regulation for an alternator operating at leading power factor is negative due to |
| A. | magnetizing nature of armature reaction |
| B. | demagnetizing nature of armature reaction |
| C. | cross-magnetizing nature of armature reaction |
| D. | all of the mentioned |
| Answer» B. demagnetizing nature of armature reaction | |
| 27. |
Voltage regulation for the alternator operating at leading power factor is negative. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 28. |
When the load on an alternator is varied, its terminal voltage also changes due to |
| A. | armature resistance |
| B. | leakage reactance |
| C. | armature reaction |
| D. | all of the mentioned |
| Answer» B. leakage reactance | |