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This section includes 9 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. |
THE_TOTAL_LOSSES_IN_A_WELL-DESIGNED_DC_GENERATOR_OF_10_KW_WILL_BE_NEARLY_EQUAL_TO_________?$ |
A. | 100 W |
B. | 500 W |
C. | 1000 W |
D. | 1500 W |
Answer» C. 1000 W | |
2. |
Which of the following losses are significantly reduced by laminating the core of a DC generator? |
A. | Hysteresis losses |
B. | Eddy current losses |
C. | Copper losses |
D. | Windage losses |
Answer» C. Copper losses | |
3. |
Which of the following loss/losses in a DC generator is dissipated in the form of heat? |
A. | Mechanical loss |
B. | Core loss |
C. | Copper loss |
D. | Mechanical, Copper and Core |
Answer» E. | |
4. |
Which of the following methods is likely to result in reduction of hysteresis loss in a DC generator? |
A. | Providing laminations in armature core |
B. | Providing laminations in stator |
C. | Using non-magnetic material for frame |
D. | Using material of low hysteresis co-efficient for armature core material |
Answer» E. | |
5. |
Which of the following loss in a DC generator varies significantly with the load current? |
A. | Field copper loss |
B. | Windage loss |
C. | Armature copper loss |
D. | Cannot be determined |
Answer» D. Cannot be determined | |
6. |
Which of the following loss is likely to have highest proportion at rated load of the DC generator? |
A. | Hysteresis loss |
B. | Field copper loss |
C. | Armature copper loss |
D. | Eddy current loss |
Answer» D. Eddy current loss | |
7. |
Which of the following is not the effect of iron loss? |
A. | Loss of efficiency |
B. | Excessive heating of core |
C. | Increase in terminal voltage |
D. | Rise in temperature of ventilating air |
Answer» D. Rise in temperature of ventilating air | |
8. |
The hysteresis loss in a DC machine least depends on _____________ |
A. | Frequency of magnetic reversals |
B. | Maximum value of flux density |
C. | Volume and grade of iron |
D. | Rate of flow of ventilating air |
Answer» E. | |
9. |
The efficiency of the DC motor at maximum power will be ___________________ |
A. | 100% |
B. | Around 90% |
C. | Anywhere between 75% and 90% |
D. | Less than 50% |
Answer» E. | |