MCQOPTIONS
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MCQOPTIONS
This section includes 11 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. |
While the operation of dc motor, there are sparkings at the commutation observed. These can be happening due to ________ |
| A. | under commutation |
| B. | over commutation |
| C. | too rapid reversal of the current |
| D. | any of the mentioned |
| Answer» E. | |
| 2. |
Under commutation results ________ |
| A. | sparking at the trailing edge of brush |
| B. | sparking at the leading edge of brush |
| C. | sparking at the middle of brush |
| D. | any of the mentioned |
| Answer» B. sparking at the leading edge of brush | |
| 3. |
The armature rotation in the dc machine and the magnetic field are independent of each other and obey laws of conservation of energy. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 4. |
The brushes in dc machine are normally placed electrically in interpolar region to ________ |
| A. | make an angle of 90 deg. electrical |
| B. | make an angle of 90 deg. mechanical |
| C. | make an angle of 0 deg. electrical |
| D. | none of the mentioned |
| Answer» B. make an angle of 90 deg. mechanical | |
| 5. |
For a four pole, 16 slot armature with two coil-side/slot having wave connected progressive winding has single turn coils. The commutator pitch for the machine should be ________ |
| A. | 1 |
| B. | -1 |
| C. | +1 and 1 |
| D. | none of the mentioned |
| Answer» B. -1 | |
| 6. |
For a four pole, 16 slot armature with two coil-side/slot having lap connected progressive winding has single turn coils. Then number of commutator segment is? |
| A. | 16 |
| B. | 32 |
| C. | 4 |
| D. | 8 |
| Answer» B. 32 | |
| 7. |
A 200 V dc machine working at rated speed. Voltage across the commutating terminals should ideally be ________ |
| A. | zero |
| B. | 2 V |
| C. | 1 V |
| D. | 200 V |
| Answer» B. 2 V | |
| 8. |
Operation of a dc machine will ________ |
| A. | not be affected by commutating poles |
| B. | be affected by commutating poles |
| C. | be affected significantly upto 30% spread of commutating poles |
| D. | none of the mentioned |
| Answer» B. be affected by commutating poles | |
| 9. |
Inductive kick causes ________ |
| A. | sparking at the brushes of the machine |
| B. | similar problems when neutral phase shift takes place in the armature |
| C. | large current to flow in the equalizer rings |
| D. | none of the mentioned |
| Answer» B. similar problems when neutral phase shift takes place in the armature | |
| 10. |
What is Inductive kick? |
| A. | reactance voltage in commutator segments |
| B. | reactance voltage in shorted commutator segments |
| C. | impulsive voltage in commutator segments |
| D. | none of the mentioned |
| Answer» B. reactance voltage in shorted commutator segments | |
| 11. |
What is Commutator? |
| A. | rotating segment to which brushes are attached |
| B. | stationary segment to which rotating brushes are attached |
| C. | rotating segment to which rotating brush segment is attached |
| D. | any of the mentioned |
| Answer» B. stationary segment to which rotating brushes are attached | |