MCQOPTIONS
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MCQOPTIONS
This section includes 20 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. |
_____________ is responsible for mechanical power output of a DC motor. |
| A. | Electrical input power |
| B. | Any of the mentioned |
| C. | Air-gap flux |
| D. | Armature emf |
| Answer» B. Any of the mentioned | |
| 2. |
A dc series generator as armature and field connections are reversed, the generator __________ |
| A. | stops |
| B. | opposite direction |
| C. | same direction |
| D. | none of the mentioned |
| Answer» B. opposite direction | |
| 3. |
The number of parallel paths in the armature is increased by __________ |
| A. | increasing number of magnetic poles |
| B. | decreasing number of magnetic poles |
| C. | lap number of magnetic poles |
| D. | using more brushes |
| Answer» B. decreasing number of magnetic poles | |
| 4. |
A series generator, having external characteristics which is a straight line through 0 to 50 V at 200 A is connected as a booster, between a station bus-bar and feeders of 0.5 ohm resistors. The voltage at the far end of feeder at current of 50 A is? |
| A. | 25 V |
| B. | 17 V |
| C. | 8 V |
| D. | 50 V |
| Answer» B. 17 V | |
| 5. |
Flashing is used to __________ |
| A. | temporarily excited field from a battery source for large DC generator |
| B. | temporarily excited field from a battery source for small DC generator |
| C. | temporarily excited field from a battery source for large DC motor |
| D. | temporarily excited field from a battery source for large DC motor |
| Answer» B. temporarily excited field from a battery source for small DC generator | |
| 6. |
If a DC shunt generator fails to start, the most primitive action would be __________ |
| A. | reversing field connection to armature |
| B. | reversing direction of rotation |
| C. | any of the mentioned applicable ways |
| D. | none of the mentioned |
| Answer» B. reversing direction of rotation | |
| 7. |
The critical resistance refers to __________ |
| A. | the resistance above which machine does not excite |
| B. | the resistance below which machine does not excite |
| C. | the resistance at which machine does not excite |
| D. | any of the mentioned |
| Answer» B. the resistance below which machine does not excite | |
| 8. |
The self-excited dc generator with gradual build up of residual voltage and EMF corresponds to __________ |
| A. | positive feedback |
| B. | negative feedback |
| C. | saturation |
| D. | any of the mentioned |
| Answer» B. negative feedback | |
| 9. |
If a self excited DC generator is failed to run, this refers to ________________ |
| A. | zero residual voltage |
| B. | field MMF, that it is not cumulative |
| C. | resistance is greater than critical resistance |
| D. | any of the mentioned |
| Answer» B. field MMF, that it is not cumulative | |
| 10. |
Consider a DC generator running at the rated speed of 2000 rpm, suddenly there is an insulator falls on the field circuit and breaks it. Then __________ |
| A. | the motor stops in a few rounds |
| B. | it continues to run but as dc motor |
| C. | it continues to run as a motor |
| D. | none of the mentioned |
| Answer» B. it continues to run but as dc motor | |
| 11. |
A_DC_SERIES_GENERATOR_AS_ARMATURE_AND_FIELD_CONNECTIONS_ARE_REVERSED,_THE_GENERATOR?$ |
| A. | stops |
| B. | opposite direction |
| C. | same direction |
| D. | none of the mentioned |
| Answer» B. opposite direction | |
| 12. |
____ is responsible for mechanical power output of a DC motor$ |
| A. | Electrical input power |
| B. | Any of the mentioned |
| C. | Air-gap flux |
| D. | Armature emf |
| Answer» B. Any of the mentioned | |
| 13. |
The number of parallel paths in the armature is increased b? |
| A. | increasing number of magnetic poles |
| B. | decreasing number of magnetic poles |
| C. | lap number of magnetic poles |
| D. | using more brushes |
| Answer» B. decreasing number of magnetic poles | |
| 14. |
A series generator, having external characteristics which is a straight line through 0 to 50 V at 200 A is connected as a booster, between a station bus-bar and feeders of 0.5 ohm resistors. The voltage at the far end of feeder at current of 50 A is |
| A. | 25 V |
| B. | 17 V |
| C. | 8 V |
| D. | 50 V |
| Answer» B. 17 V | |
| 15. |
Flashing is used to |
| A. | temporarily excited field from a battery source for large DC generator |
| B. | temporarily excited field from a battery source for small DC generator |
| C. | temporarily excited field from a battery source for large DC motor |
| D. | temporarily excited field from a battery source for large DC motor |
| Answer» B. temporarily excited field from a battery source for small DC generator | |
| 16. |
If a DC shunt generator fails to start, the most primitive action would be |
| A. | reversing field connection to armature |
| B. | reversing direction of rotation |
| C. | any of the mentioned applicable ways |
| D. | none of the mentioned |
| Answer» B. reversing direction of rotation | |
| 17. |
The critical resistance refers to |
| A. | the resistance above which machine does not excite |
| B. | the resistance below which machine does not excite |
| C. | the resistance at which machine does not excite |
| D. | any of the mentioned |
| Answer» B. the resistance below which machine does not excite | |
| 18. |
The self-excited dc generator with gradual build up of residual voltage and EMF corresponds to |
| A. | positive feedback |
| B. | negative feedback |
| C. | saturation |
| D. | any of the mentioned |
| Answer» B. negative feedback | |
| 19. |
If a self excited DC generator is failed to run, this refers to |
| A. | zero residual voltage |
| B. | field MMF, that it is not cumulative |
| C. | resistance is greater than critical resistance |
| D. | any of the mentioned |
| Answer» B. field MMF, that it is not cumulative | |
| 20. |
Consider a DC generator running at the rated speed of 2000 rpm, suddenly there is an insulator falls on the field circuit and breaks it. Then |
| A. | the motor stops in a few rounds |
| B. | it continues to run, but as dc motor |
| C. | it continues to run as a motor |
| D. | none of the mentioned |
| Answer» B. it continues to run, but as dc motor | |