MCQOPTIONS
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MCQOPTIONS
This section includes 5 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. |
Each of the following statements regarding interpoles is true except______________________ |
| A. | They are small yoke-fixed poles spaced in between the main poles |
| B. | They are connected in parallel with the armature so that they carry part of the armature current |
| C. | Their polarity, in the case of generators is the same as that of the main pole ahead |
| D. | They automatically neutralize not only reactance voltage but cross-magnetisation as well |
| Answer» C. Their polarity, in the case of generators is the same as that of the main pole ahead | |
| 2. |
The most likely cause(s) of sparking at the brushes in a DC machine is /are ____________ |
| A. | Open coil in the armature |
| B. | Defective interpoles |
| C. | Incorrect brush spring pressure |
| D. | Open coil in armature, defective interpoles and incorrect brush spring pressure |
| Answer» E. | |
| 3. |
Why dummy coils are connected in DC machine? |
| A. | To reduce eddy current losses |
| B. | To enhance flux density |
| C. | To amplify voltage |
| D. | To provide mechanical balance for the rotor |
| Answer» E. | |
| 4. |
Function of interpole flux is_________ |
| A. | Neutralise the commutating self-induced emf |
| B. | Neutralise the armature reaction flux |
| C. | Neutralise both the armature reaction flux as well as commutating emf induced in the coil |
| D. | Perform none of the above functions |
| Answer» D. Perform none of the above functions | |
| 5. |
Exact purpose of compensating winding in a DC generator is _________ |
| A. | Mainly to reduce the eddy currents by providing local short-circuits |
| B. | To provide path for the circulation of cooling air |
| C. | To neutralise the cross-magnetising effect of the armature reaction |
| D. | Cannot be determined |
| Answer» D. Cannot be determined | |