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This section includes 20 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. |
For a 220-V level compound generator the terminal voltage at the half load is? |
A. | more than 220-V |
B. | same as no-load voltage |
C. | more than no-load voltage |
D. | lesser than no-load voltage |
Answer» C. more than no-load voltage | |
2. |
Mark the correct order for the external characteristics of compound generators from the below graph. |
A. | 1: over compound, 2: level compound, 3: under compound, 4: differential compound |
B. | 1: under compound, 2: level compound, 3: over compound, 4: differential compound |
C. | 1: differential compound, 2: level compound, 3: under compound, 4: over compound |
D. | 1: over compound, 2: differential compound, 3: under compound, 4: level compound |
Answer» B. 1: under compound, 2: level compound, 3: over compound, 4: differential compound | |
3. |
The voltage drop in terminal voltage from no-load to full load in a shunt generator can be compenated using _________ |
A. | aiding series field |
B. | long-shunt, diferential field |
C. | aiding shunt field |
D. | any of the measures |
Answer» B. long-shunt, diferential field | |
4. |
Identify the machines by observing their external characteristics for (i) and (ii) respectively.(i) (ii) |
A. | Separately excited dc generator, shunt generator |
B. | Shunt generator, separately excited dc generator |
C. | Differentially compound dc generator, separately excited |
D. | Series dc generator, shunt generator |
Answer» B. Shunt generator, separately excited dc generator | |
5. |
For a given dc generator, the external characteristic is plotted. Without using further plots, how can we obtain internal characteristic? |
A. | By adding the IaRa drop to the plot |
B. | By adding armature reaction |
C. | By reducing IaRa drop |
D. | All of the mentioned |
Answer» B. By adding armature reaction | |
6. |
The air gap line represents _________ |
A. | magnetic behaviour of the air gap of the dc machine |
B. | magnetic behaviour of the air gap of the induction machine |
C. | magnetic behaviour of the iron core |
D. | all of the mentioned |
Answer» B. magnetic behaviour of the air gap of the induction machine | |
7. |
Armature characteristic is also known as _________ |
A. | regulation characteristic |
B. | magnetization characteristic |
C. | external characteristic |
D. | load characteristic |
Answer» B. magnetization characteristic | |
8. |
A student forgot to mark the x-y axes in his experiments but he just noted down the cause and the effect for each. How will he conclude about the armature characteristic out of the all plotted graphs? |
A. | By marking graph for constant terminal voltage |
B. | By marking graph for constant field current |
C. | By marking graph for constant armature current |
D. | By marking graph for constant speed |
Answer» B. By marking graph for constant field current | |
9. |
The external characteristic is plotted between ____________ |
A. | terminal voltage vs armature current at constant excitation |
B. | terminal voltage vs field current at constant armature current |
C. | induced armature emf vs armature current at constant excitation |
D. | none of the mentioned |
Answer» B. terminal voltage vs field current at constant armature current | |
10. |
THE_VOLTAGE_DROP_IN_TERMINAL_VOLTAGE_FROM_NO-LOAD_TO_FULL_LOAD_IN_A_SHUNT_GENERATOR_CAN_BE_COMPENATED_USING?$ |
A. | aiding series field |
B. | long-shunt, diferential field |
C. | aiding shunt field |
D. | any of the measures |
Answer» B. long-shunt, diferential field | |
11. |
For a 220-V level compound generator the terminal voltage at the half load is |
A. | more than 220-V |
B. | same as no-load voltage |
C. | more than no-load voltage |
D. | lesser than no-load voltage |
Answer» C. more than no-load voltage | |
12. |
What losses occur in the teeth of dc generator? |
A. | To reduce hysteresis loss |
B. | To reduce eddy current loss |
C. | To reduce eddy current as well as hysteresis losses |
D. | To achieve high permeability |
Answer» D. To achieve high permeability | |
13. |
Why is armature of a dc machine made of silicon steel stampings? |
A. | To reduce hysteresis loss |
B. | To reduce eddy current loss |
C. | For the ease with which slots can be created |
D. | To achieve high permeability |
Answer» B. To reduce eddy current loss | |
14. |
For a given dc generator, the external characteristic is plotted . Without using further plots, how can we obtain internal characteristic? |
A. | By adding the IaRa drop to the plot |
B. | By adding armature reaction |
C. | By reducing IaRa drop |
D. | All of the mentioned |
Answer» B. By adding armature reaction | |
15. |
The air gap line represents |
A. | magnetic behaviour of the air gap of the dc machine |
B. | magnetic behaviour of the air gap of the induction machine |
C. | magnetic behaviour of the iron core |
D. | all of the mentioned |
Answer» B. magnetic behaviour of the air gap of the induction machine | |
16. |
Armature characteristic is also known as |
A. | regulation characteristic |
B. | magnetization characteristic |
C. | external characteristic |
D. | load characteristic |
Answer» B. magnetization characteristic | |
17. |
A student forgot to mark the x-y axes in his experiments but he just noted down the cause and the effect for each. How will he conclude about the armature |
A. | |
B. | By marking graph for constant terminal voltage |
C. | By marking graph for constant field current |
Answer» B. By marking graph for constant terminal voltage | |
18. |
The external characteristic is plotted between |
A. | terminal voltage vs armature current at constant excitation |
B. | terminal voltage vs field current at constant armature current |
C. | induced armature emf vs armature current at constant excitation |
D. | none of the mentioned |
Answer» B. terminal voltage vs field current at constant armature current | |
19. |
Choose the most inappropriate out of the following for the no-load characteristics of the dc generator. |
A. | It is the open circuit characteristic of the machine |
B. | It is magnetization characteristic of the machine |
C. | It is conducted on the unloaded machine |
D. | None of the mentioned |
Answer» E. | |
20. |
Which of the following characteristics reveal about the magnetization nature of the machine? |
A. | No-load characteristics |
B. | Load characteristics |
C. | Armature characteristics |
D. | Both no-load and load characteristics |
Answer» E. | |