MCQOPTIONS
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MCQOPTIONS
This section includes 13 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 d.c. generator has been provided tappings on the armature winding at intervals of 120 degrees from the side of commutator. The connection will be __________ |
| A. | delta connected alternator |
| B. | star connected alternator |
| C. | star connected induction motor |
| D. | any of the mentioned |
| Answer» B. star connected alternator | |
| 2. |
A 200 V dc motor has external resistances of Ra and Rf in armature and field circuits respectively. The starting current is reduced when? |
| A. | Ra is maximum and Rf minimum |
| B. | Rf is maximum and Ra minimum |
| C. | Ra is minimum and Rf minimum |
| D. | Ra is maximum and Rf maximum |
| Answer» B. Rf is maximum and Ra minimum | |
| 3. |
If a dc shunt motor is stopped by forcing starter handle back to OFF position, then the __________ |
| A. | dangerous sparking occurs at last stud |
| B. | dangerous sparking occurs at all stud |
| C. | it stops normally |
| D. | heavy sparking |
| Answer» B. dangerous sparking occurs at all stud | |
| 4. |
Long back ago, magnetic casette were in use, having permanent magnet dc motors which had? |
| A. | magnets on stator and armature on rotor |
| B. | magnet on rotor and armature on stator |
| C. | electronic commutation |
| D. | all of the mentioned |
| Answer» B. magnet on rotor and armature on stator | |
| 5. |
Most commercial compound dc generator are normally supplied by manufacturers as ______ compounded machines. |
| A. | over |
| B. | under |
| C. | level |
| D. | none of the mentioned |
| Answer» B. under | |
| 6. |
Which of the following are applied with differential compound motor? |
| A. | Hoist |
| B. | Cranes |
| C. | Drilling machines |
| D. | None of the mentioned |
| Answer» B. Cranes | |
| 7. |
Most commercial compound dc generator are normally supplied by manufacturers as over compound machines because __________ |
| A. | degree of compounding can be adjusted by diverters acrosss series field |
| B. | they have ideally best for HVDC |
| C. | cost effective than shunt |
| D. | zero percent regulation |
| Answer» B. they have ideally best for HVDC | |
| 8. |
Centrifugal pumps, fans-blowers use __________ |
| A. | shunt as well as induction motor |
| B. | only shunt motors |
| C. | only induction motor |
| D. | none of the mentioned |
| Answer» B. only shunt motors | |
| 9. |
The manufacturer has mentioned a medium starting torque and 15% speed regulation. Which is the most appropriate motor for this requirement? |
| A. | dc shunt motor |
| B. | induction motor |
| C. | differential motor |
| D. | none of the mentioned |
| Answer» B. induction motor | |
| 10. |
There is an application which required pulsating loads, punch presses. The most preferred machines would be __________ |
| A. | compound dc machine |
| B. | series dc machine |
| C. | shunt dc machine |
| D. | all of the mentioned |
| Answer» B. series dc machine | |
| 11. |
Maximum torque in dc series motor is limited by __________ |
| A. | commutation |
| B. | heating |
| C. | field control |
| D. | all of the mentioned |
| Answer» B. heating | |
| 12. |
Separately excited dc generators are used in __________ |
| A. | Ward leonard system of speed control |
| B. | Hopkinson s testing |
| C. | Voltage control |
| D. | None of the mentioned |
| Answer» B. Hopkinson s testing | |
| 13. |
Inspite of heavy initial investments, dc motors are used due to _____________ |
| A. | flexibility and ease of control |
| B. | lower losses |
| C. | improved power factor of the system |
| D. | all of the mentioned |
| Answer» B. lower losses | |