DC Motors MCQ Multiple Choice Questions Answers - Page 2 for Practice
31. Which D.C. motor has got maximum self loading property?
Correct Answer is: Differentially compounded motor
32. Which D.C. motor has got maximum self relieving property ?
Correct Answer is: Series motor
33. Which D.C. motor is generally preferred for cranes and hoists ?
Correct Answer is: Series motor
34. Which D.C. motor is preferred for elevators ?
Correct Answer is: Cumulative compound motor
35. Which D.C. motor will be preferred for machine tools ?
Correct Answer is: Shunt motor
36. Which D.C. motor will be suitable alongwith flywheel for intermittent light and heavy loads?
Correct Answer is: Cumulatively compounded motor
37. Which method of braking is generally used in elevators ?
Correct Answer is: Plugging
38. Which motor has the poorest speed control?
Correct Answer is: Series motor
39. Which motor should not be started on no-load ?
Correct Answer is: Series motor
40. Which of the following application requires high starting torque ?
Correct Answer is: Locomotive
41. Which of the following law/rule can he used to determine the direction of rotation of D.C. motor ?
Correct Answer is: Flemings left-hand rule
42. Which of the following load normally needs starting torque more than the rated torque?
Correct Answer is: Conveyors
43. Which of the following loss in a D.C. generator is dissipated in the form of heat?
Correct Answer is: All of the above
44. Which of the following loss in a D.C. generator varies significantly with the load current ?
Correct Answer is: Armature copper loss
45. Which of the following losses are significantly reduced by laminating the core of aD.C. generator ?
Correct Answer is: Eddy current losses
46. Which of the following method of speed control of D.C. machine will offer minimum efficiency ?
Correct Answer is: Armature control method
47. Which of the following motor has the poorest speed regulation ?
Correct Answer is: Series motor
48. Which of the following motor is preferred for operation in highly explosive atmosphere ?
Correct Answer is: Air motor
49. Which of the following motors is most suitable for signalling devices and many kinds of timers ?
Correct Answer is: Reluctance motor
50. Which of the following motors is usually used in house-hold refrigerators ?
Correct Answer is: Single phase induction motor (split phase start or induction run motor)
51. Which of the following motors one will choose to drive the rotary compressor ?
Correct Answer is: Synchronous motor
52. Which of the following steps is likely to result in reduction of hysteresis loss in a D.C. generator ?
Correct Answer is: Using material of low hysteresis co-efficient for armature core material
53. Which of the following tests will be suitable for testing two similar D.C. series motorsof large capacity ?
Correct Answer is: Field test
54. Which one of the following is not necessarily the advantage of D.C. motors over A.C. motors ?
Correct Answer is: Low cost
55. Which one of the following is not the function of pole shoes in a D.C. machine ?
Correct Answer is: To reduce eddy current loss
56. Why are the D.C. motors preferred for traction applications ?
Correct Answer is: The speed is inversely proportional to the torque and the torque is proportional to square of armature current
57. A D.C. series motor is that which
Correct Answer is: has its field winding consisting of thick wire and less turns
58. A direct on line starter is used: for starting motors
Correct Answer is: iip to 5 H.P.
59. A three point starter is considered suitable for
Correct Answer is: shunt as well as compound motors
60. According to Flemings left-hand rule, when the forefinger points in the direction of the field or flux, the middle finger will point in the direction of
Correct Answer is: current in the conductor aovtaat of conductor
