MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 12 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. |
Consider a dc machine having its armature wound in lap fashion having 12 coils and each resistance 0.1 ohms. If it is measured resistance between two adjacent commutator segments, the result will be _________ |
| A. | 0.092 ohms |
| B. | 1.1 ohms |
| C. | 1.8 ohms |
| D. | 0.92 ohms |
| Answer» B. 1.1 ohms | |
| 2. |
A 6-pole lap wound DC generator has a developed power of P watts and brush voltage of E volts. Three adjacent brushes of the machine had been found worn out and got open circuited. If the machine is operated with the remaining brushes, voltage and power that could be obtained from the machine are _________ |
| A. | E, P |
| B. | E, 2P/3 |
| C. | E/P, 2P/3 |
| D. | E, P/3 |
| Answer» B. E, 2P/3 | |
| 3. |
While doing regular checks on the dc machine with the lap connected winding, it is reported to have ammeter fluctuations, this can be due to _________ |
| A. | different air gaps under poles |
| B. | variable reluctances in the core |
| C. | irregular design deformations |
| D. | all of the mentioned |
| Answer» E. | |
| 4. |
For a given dc machine it is advised to use the dummy windings for a stable operation. But if it has be replaced as it unused component in the machine, then we must _________ |
| A. | S/P/2 should not be an integer |
| B. | S/P/2 should be integer |
| C. | S/P should be integer |
| D. | S/P should not be an integer |
| Answer» B. S/P/2 should be integer | |
| 5. |
In AC machines we should prefer double layer winding over single layer windings because _________ |
| A. | it requires identical coils |
| B. | it is economical to use |
| C. | it offers lower leakage reactance |
| D. | all of the mentioned |
| Answer» B. it is economical to use | |
| 6. |
We can employ dummy coils in a DC machine to _________ |
| A. | compensate reactance voltage |
| B. | reduce armature reaction |
| C. | provide mechanical balance to the armature |
| D. | improve the waveforms generated inside the commutator |
| Answer» B. reduce armature reaction | |
| 7. |
Commutator segments in a DC shunt machine is equal to the number of _________ |
| A. | coil sides |
| B. | turns |
| C. | coils |
| D. | slots |
| Answer» B. turns | |
| 8. |
The commutator pitch for a simplex lap winding is equal to _________ |
| A. | 1 and -1 |
| B. | 1 |
| C. | -1 |
| D. | 2 to -2 |
| Answer» B. 1 | |
| 9. |
The simplex lap winding has the range of winding pitch of _________ |
| A. | (-2,2) |
| B. | (-1,1) |
| C. | more than 2 |
| D. | less than 1 |
| Answer» B. (-1,1) | |
| 10. |
We can place closed windings in _________ |
| A. | ac commutator machine |
| B. | stepper motor |
| C. | ac machine |
| D. | dc machine |
| Answer» B. stepper motor | |
| 11. |
DC machines have ________ windings and synchronous machines use ______ windings. |
| A. | closed,open |
| B. | open, closed |
| C. | open, open |
| D. | closed, closed |
| Answer» B. open, closed | |
| 12. |
Concentrated winding differ from distributed winding with the concern of _________ |
| A. | identical magnetic axis |
| B. | two magnetic axis |
| C. | no magnetic axis |
| D. | physical spacing |
| Answer» B. two magnetic axis | |