MCQOPTIONS
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MCQOPTIONS
This section includes 25 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 10 KVA, 2000/200 V, single phase transformer operating at 50 Hz with a current of 50 A flowing through the l.v. winding. Then the Self inductance of l.v. winding is? |
| A. | 12.7mH |
| B. | 1.27 mH |
| C. | 12.7H |
| D. | 0.127 H |
| Answer» B. 1.27 mH | |
| 2. |
There is a 10 KVA, 2000/200 V, single phase transformer operating at 50 Hz. Maximum flux linkages in secondary will be? |
| A. | 0.9 AT |
| B. | 9 AT |
| C. | 1 AT |
| D. | 0.09 AT |
| Answer» B. 9 AT | |
| 3. |
There is a 10 KVA, 2000/200 V, single phase transformer having below following parameters are r1=10Ω, r2=0.1Ω, l1 = 40mH, l2=0.4 mH, M = 10H. Then the expected secondary self inductance will be? |
| A. | 100.04H |
| B. | 99.06H |
| C. | 1.0004H |
| D. | 10.04H |
| Answer» D. 10.04H | |
| 4. |
Consider a 10 KVA, 2000/200 V, single phase transformer having below following parameters are r1=10Ω, r2=0.1Ω, l1 = 40mH, l2=0.4 mH, M = 10H. Then the expected primary self inductance will be? |
| A. | 100.04H |
| B. | 99.06H |
| C. | 1.0004H |
| D. | 10.04H |
| Answer» B. 99.06H | |
| 5. |
The voltage regulation of a transformer at full-load 0.8 p.f lagging is 2%. Its voltage regulation at full load 0.8 p.f leading _____________ |
| A. | will be positive |
| B. | will be negative |
| C. | may be positive |
| D. | may be negative |
| Answer» C. may be positive | |
| 6. |
The voltage conversion ratio of the transformer is inverse of the current transformation. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 7. |
In a transformer,eddy-current loss is 1000 watts which is half of the total core loss. If thickness of lamination and frequency are increased by 10%, What is the new core-losses? |
| A. | 3200W |
| B. | 3300W |
| C. | 2200W |
| D. | 3100W |
| Answer» B. 3300W | |
| 8. |
Which of the following matches are matched correctly? |
| A. | II, III |
| B. | II, III, IV |
| C. | I, IV |
| D. | II, IVView Answer |
| Answer» B. II, III, IV | |
| 9. |
Choose the matching which is not matched correctly? |
| A. | I, II, III |
| B. | I, III |
| C. | II, I |
| D. | IIIView Answer |
| Answer» D. IIIView Answer | |
| 10. |
Identify the matching which is not matched correctly? |
| A. | I, II, III |
| B. | I, III |
| C. | II, I |
| D. | None of the mentionedView Answer |
| Answer» E. | |
| 11. |
Transients currents are maximum in the transformer when it is switched on with secondary ______ and when input voltage wave is passing through ________ |
| A. | open, zero |
| B. | open, peak |
| C. | closed, zero |
| D. | closed, peak |
| Answer» B. open, peak | |
| 12. |
Primary and the secondary winding of the transformer are interlaced mainly for __________ |
| A. | reducing leakage flux |
| B. | reducing cost |
| C. | reducing heating |
| D. | saving the copper of the winding |
| Answer» B. reducing cost | |
| 13. |
It is advised to coat the laminations of the core with some enamel, to ensure __________ |
| A. | insulation |
| B. | adhesion of laminations |
| C. | reduction in humming sound |
| D. | all of the mentioned |
| Answer» B. adhesion of laminations | |
| 14. |
In power transformers, it is found that the iron or core losses practically varies very less, this is because ____________ |
| A. | constant core flux |
| B. | constant leakage flux |
| C. | constant leakage and core flux |
| D. | constant load current |
| Answer» B. constant leakage flux | |
| 15. |
IN_A_TRANSFORMER,EDDY-CURRENT_LOSS_IS_1000_WATTS_WHICH_IS_HALF_OF_THE_TOTAL_CORE_LOSS.?$ |
| A. | |
| B. | 3200W |
| C. | 3300W |
| Answer» B. 3200W | |
| 16. |
The voltage regulation of a transformer at full-load 0.8 p.f lagging is 2%. Its voltage regulation at full load 0.8 p.f leading$ |
| A. | will be positive |
| B. | will be negative |
| C. | may be positive |
| D. | may be negative |
| Answer» C. may be positive | |
| 17. |
The_voltage_conversion_ratio_of_the_transformer_is_inverse_of_the_current_transformation.$ |
| A. | True |
| B. | False |
| Answer» B. False | |
| 18. |
A 10 KVA, 2000/200 V, single phase transformer operating at 50 Hz with a current of 50 A flowing through the l.v. winding. Then the Self inductance of l.v. winding is |
| A. | 12.7mH |
| B. | 1.27 mH |
| C. | 12.7H |
| D. | 0.127 H |
| Answer» B. 1.27 mH | |
| 19. |
There is a 10 KVA, 2000/200 V, single phase transformer operating at 50 Hz. Maximum flux linkages in secondary will be |
| A. | 0.9 AT |
| B. | 9 AT |
| C. | 1 AT |
| D. | 0.09 AT |
| Answer» B. 9 AT | |
| 20. |
There is a 10 KVA, 2000/200 V, single phase transformer having below following parameters: |
| A. | |
| B. | 100.04H |
| C. | 99.06H |
| Answer» D. | |
| 21. |
Consider a 10 KVA, 2000/200 V, single phase transformer having below following parameters: |
| A. | |
| B. | 100.04H |
| C. | 99.06H |
| Answer» B. 100.04H | |
| 22. |
Transients currents are maximum in the transformer when it is switched on with secondary ______ and when input voltage wave is passing through ________ |
| A. | open, zero |
| B. | open, peak |
| C. | closed, zero |
| D. | closed, peak |
| Answer» B. open, peak | |
| 23. |
Primary and the secondary winding of the transformer are interlaced mainly for |
| A. | reducing leakage flux |
| B. | reducing cost |
| C. | reducing heating |
| D. | saving the copper of the winding |
| Answer» B. reducing cost | |
| 24. |
It is advised to coat the laminations of the core with some enamel, to ensure |
| A. | insulation |
| B. | adhesion of laminations |
| C. | reduction in humming sound |
| D. | all of the mentioned |
| Answer» B. adhesion of laminations | |
| 25. |
In power transformers, it is found that the iron or core losses practically varies very less, this is because |
| A. | constant core flux |
| B. | constant leakage flux |
| C. | constant leakage and core flux |
| D. | constant load current |
| Answer» B. constant leakage flux | |