MCQOPTIONS
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MCQOPTIONS
This section includes 12 Mcqs, each offering curated multiple-choice questions to sharpen your Dc Machines knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
WHICH_OF_THE_FOLLOWING_IS_DYNAMIC_BRAKING??$ |
| A. | Reversal of field connections |
| B. | Reversal of armature connections |
| C. | Addition of equal and opposite field |
| D. | Removal of armature circuit from current machine circuit |
| Answer» E. | |
| 2. |
In dynamic braking, when braking is applied system acts as ___________$ |
| A. | Freely running machine |
| B. | Motor with slow speed |
| C. | Generator |
| D. | Motor with same speed in opposite direction |
| Answer» D. Motor with same speed in opposite direction | |
| 3. |
Braking_time_in_the_dynamic_braking_is_the_function_of______________$ |
| A. | System inertia |
| B. | Load torque |
| C. | Motor rating |
| D. | All- system inertia, load torque and motor rating |
| Answer» E. | |
| 4. |
In_which_of_the_following_electrical_braking_method,_energy_is_supplied_back_to_the_supply? |
| A. | Plugging |
| B. | Dynamic braking |
| C. | Regenerative braking |
| D. | In all electrical braking |
| Answer» D. In all electrical braking | |
| 5. |
Plugging is used in ___________? |
| A. | Small motors only |
| B. | Small and medium powered |
| C. | Only in large heavy machines |
| D. | Everywhere |
| Answer» B. Small and medium powered | |
| 6. |
Plugging is applied in a motor, if we don’t make the switch OFF what will happen?$ |
| A. | Motor will come to rest as a result of plugging |
| B. | Motor will come to rest and will start rotating in another direction |
| C. | Motor will burn |
| D. | Nothing will happen |
| Answer» C. Motor will burn | |
| 7. |
Electrical braking of any variety becomes less effective as ________________ |
| A. | Speed increases |
| B. | Speed decreases |
| C. | Independent of speed |
| D. | Depends on supply voltage |
| Answer» C. Independent of speed | |
| 8. |
Which of the following is correct formula for braking torque in plugging? |
| A. | n (ka<sup>2</sup>/R<sub>b</sub>) |
| B. | n<sup>2</sup> (ka<sup>2</sup>/Rb) |
| C. | n<sup>-1</sup> (ka<sup>2</sup>/Rb) |
| D. | (ka<sup>2</sup>/Rb) |
| Answer» B. n<sup>2</sup> (ka<sup>2</sup>/Rb) | |
| 9. |
Which of the following is the plugging method of braking? |
| A. | Reversal of field connections |
| B. | Reversal of armature connections |
| C. | Addition of equal and opposite field |
| D. | Removal of field circuit from current machine circuit |
| Answer» C. Addition of equal and opposite field | |
| 10. |
Which of the following is not the method of electrical braking? |
| A. | Plugging or counter-current |
| B. | Dynamic or rheostatic |
| C. | Regenerative |
| D. | Eddy current |
| Answer» E. | |
| 11. |
DC motor is still widely used in tractions due to its excellent braking properties. |
| A. | True |
| B. | False |
| Answer» C. | |
| 12. |
Which of the following is the best braking method? |
| A. | Friction |
| B. | Electromechanical action |
| C. | Eddy-currents |
| D. | Electric braking |
| Answer» E. | |