DC Motors MCQ Multiple Choice Questions Answers | Quiz for Practice
Dive into the world of DC Motors with our comprehensive collection of multiple-choice questions and answers. Whether you're a student studying electrical engineering, a technician working with motors, or simply intrigued by the principles of electromechanical systems, our meticulously curated selection covers a wide range of topics. Explore fundamental concepts such as motor types, operating principles, speed control methods, and practical applications in various industries. With our user-friendly interface and detailed explanations, mastering the intricacies of DC motors has never been more engaging and accessible. Start your journey towards understanding this essential component of electrical machinery today!
DC Motors MCQ Questions for Practice
1. The condition for maximum power in case of D.C. motor is
Correct Answer is: supply voltage = back e.m.f.
2. The current drawn by the armature of D.C. motor is directly proportional to
Correct Answer is: none of the above
3. The direction of rotation of a D.C. series motor can be changed by
Correct Answer is: None of the above
4. The hysteresis loss in a D.C. machine least depends on
Correct Answer is: Volume and grade of iron
5. The losses occurring in a D.C. generator are given below. Which loss is likely to have highest proportion at rated load of the generator ?
Correct Answer is: eddy current loss
6. The main disadvantage of the Ward-Leonard control method is
Correct Answer is: low efficiency at Hght loads
7. The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is
Correct Answer is: 1
8. The plugging gives the
Correct Answer is: none of the above
9. The power mentioned on the name plate of an electric motor indicates
Correct Answer is: the gross power
10. The purpose of retardation test on D.C. shunt machines is to find out
Correct Answer is: windage losses
11. The ratio of starting torque to full-load torque is least in case of
Correct Answer is: none of the above
12. The speed of a D.C. motor can be varied by varying
Correct Answer is: resistance in series with armature
13. The speed of a D.C. series motor is
Correct Answer is: proportional to field current
14. The speed of a D.C. shunt motor can be increased by
Correct Answer is: reducing the resistance in the armature circuit
15. The speed of a D.C. shunt motor is required to be more than full load speed. This is possible by
Correct Answer is: increasing the excitation current
16. The speed of a D.C. shunt motor more than its full-load speed can be obtained by
Correct Answer is: increasing the armature current
17. The speed of a motor falls from 1100 r.p.m. at no-load to 1050 r.p.m. at rated load. The speed regulation of the motor is
Correct Answer is: 8.84%
18. The starting resistance of a D.C. motor is generally
Correct Answer is: infinitely large
19. The total losses in a well designed D.C. generator of 10 kW will be nearly
Correct Answer is: 1500 W
20. The type of D.C. motor used for shears and punches is
Correct Answer is: differential compoutid D.C. motor
21. These days D.C. motors are widely used in
Correct Answer is: machine shops
22. Three point starter can be used for
Correct Answer is: compound motor only
23. To get the speed of D.C, motor below the normal without wastage of electrical energy is used.
Correct Answer is: none of the above method
24. Torque developed by a D.C. motor depends upon
Correct Answer is: current flow through the conductors
25. Usually wide and sensitive speed control is desired in case of
Correct Answer is: steel rolling mills
26. Ward-Leonard control is basically a
Correct Answer is: armature resistance control method
27. What will happen if the back e.m.f. of a D.C. motor vanishes suddenly?
Correct Answer is: The motor will run noisy
28. When the armature of a D.C. motor rotates, e.m.f. induced is
Correct Answer is: none of the above
29. When two D.C. series motors are connected in parallel, the resultant speed is
Correct Answer is: zero
30. Where D.C. motor of H.P. 12 or more requires frequent starting, stopping, reversingand speed control
