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 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=10 , r2=0.1 , 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=10 , r2=0.1 , 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 Transformer equivalent circuit referred to primary with converting two winding transformer in impedance forms is? |
| A. | <a href="https://www.sanfoundry.com/wp-content/uploads/2017/05/electrical-machines-questions-answers-transformer-as-magnetically-coupled-circuit-q12a.png"><img alt="Transformer equivalent converting two winding transformer in impedance forms - option a" class="alignnone size-full wp-image-161202" height="131" src="https://www.sanfoundry.com/wp-content/uploads/2017/05/electrical-machines-questions-answers-transformer-as-magnetically-coupled-circuit-q12a.png" width="300"/></a> |
| B. | <a href="https://www.sanfoundry.com/wp-content/uploads/2017/05/electrical-machines-questions-answers-transformer-as-magnetically-coupled-circuit-q12b.png"><img alt="Transformer equivalent converting two winding transformer in impedance forms - option b" class="alignnone size-full wp-image-161203" height="111" src="https://www.sanfoundry.com/wp-content/uploads/2017/05/electrical-machines-questions-answers-transformer-as-magnetically-coupled-circuit-q12b.png" width="300"/></a> |
| C. | <a href="https://www.sanfoundry.com/wp-content/uploads/2017/05/electrical-machines-questions-answers-transformer-as-magnetically-coupled-circuit-q12c.png"><img alt="Transformer equivalent converting two winding transformer in impedance forms - option c" class="alignnone size-full wp-image-161204" height="119" src="https://www.sanfoundry.com/wp-content/uploads/2017/05/electrical-machines-questions-answers-transformer-as-magnetically-coupled-circuit-q12c.png" width="300"/></a> |
| D. | <a href="https://www.sanfoundry.com/wp-content/uploads/2017/05/electrical-machines-questions-answers-transformer-as-magnetically-coupled-circuit-q12d.png"><img alt="Transformer equivalent converting two winding transformer in impedance forms - option d" class="alignnone size-full wp-image-161205" height="119" src="https://www.sanfoundry.com/wp-content/uploads/2017/05/electrical-machines-questions-answers-transformer-as-magnetically-coupled-circuit-q12d.png" width="300"/></a> |
| Answer» B. <a href="https://www.sanfoundry.com/wp-content/uploads/2017/05/electrical-machines-questions-answers-transformer-as-magnetically-coupled-circuit-q12b.png"><img alt="Transformer equivalent converting two winding transformer in impedance forms - option b" class="alignnone size-full wp-image-161203" height="111" src="https://www.sanfoundry.com/wp-content/uploads/2017/05/electrical-machines-questions-answers-transformer-as-magnetically-coupled-circuit-q12b.png" width="300"/></a> | |
| 6. |
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 | |
| 7. |
The voltage conversion ratio of the transformer is inverse of the current transformation. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 8. |
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 | |
| 9. |
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 | |
| 10. |
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 | |
| 11. |
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 | |