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. |
A recording of the output of the emf induced for star and delta are recorded. Then shape of the emf induced in Y-connected 3-phase transformer is non sinusoidal in nature due to ___________ |
| A. | 3rd harmonic component of currents is absent |
| B. | 3rd harmonic component of currents is present |
| C. | negative sequence component of current is present |
| D. | none of the mentioned |
| Answer» B. 3rd harmonic component of currents is present | |
| 2. |
While using three phase transformers, it is taken care about the third harmonics current in the system. This is present when transformer set is delta on either side. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 3. |
A 400 V, 10 KVA transformer at 50 Hz, is operated at the frequency of 40 Hz, then the humming ___________ |
| A. | increases |
| B. | decreases |
| C. | remains same |
| D. | increases to very high |
| Answer» B. decreases | |
| 4. |
When we magnetize the ferromagnetic core of the transformer, core length_______ and it ______ when demagnetized. |
| A. | decreases, increases |
| B. | decreases, decreases |
| C. | increases,increases |
| D. | none of the mentioned |
| Answer» B. decreases, decreases | |
| 5. |
If para magnetic core is used in the place of the ferromagnetic core of the transformer, then magnetostriction will ___________ |
| A. | be vanished |
| B. | reduce |
| C. | increase |
| D. | not be affected |
| Answer» B. reduce | |
| 6. |
If one of the transformers is removed from the bank of only delta-delta, then it behaves with 58% power delivery. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 7. |
Open delta transformers can be obtained from ___________ |
| A. | delta-delta |
| B. | star-delta |
| C. | delta-star |
| D. | any of the mentioned |
| Answer» B. star-delta | |
| 8. |
The delta-delta connections are used in applications of ___________ |
| A. | large l.v. transformers |
| B. | small h.v. transformers |
| C. | large h.v. transformers |
| D. | small l.v. transformers |
| Answer» B. small h.v. transformers | |
| 9. |
The transformer which is more feasible to use in the distribution ends should be ___________ |
| A. | star-delta |
| B. | delta-star |
| C. | scott |
| D. | delta-delta |
| Answer» B. delta-star | |
| 10. |
Three units of single phase transformers and one single three-phase transformer rating ___________ |
| A. | will be same for one rating |
| B. | can never be made same |
| C. | may be same |
| D. | none of the mentioned |
| Answer» B. can never be made same | |
| 11. |
A V-V connected transformer can be connected in parallel to delta-delta connected transformer but not to ___________ |
| A. | delta-star |
| B. | star-delta |
| C. | star-V |
| D. | all of the mentioned |
| Answer» B. star-delta | |