DC Motors MCQ Quiz - Multiple Choice Questions & Answers Page 5

41. Which of the following law/rule can he used to determine the direction of rotation of D.C. motor ?

1. Lenzs law
2. Faradays law
3. Coloumbs law
4. Flemings left-hand rule

42. Which of the following load normally needs starting torque more than the rated torque?

1. Blowers
2. Conveyors
3. Air compressors
4. Centrifugal pumps

43. Which of the following loss in a D.C. generator is dissipated in the form of heat?

1. Mechanical loss
2. Core loss
3. Copper loss
4. All of the above

44. Which of the following loss in a D.C. generator varies significantly with the load current ?

1. Field copper loss
2. Windage loss
3. Armature copper loss
4. None of the above

45. Which of the following losses are significantly reduced by laminating the core of aD.C. generator ?

1. Hysteresis losses
2. Eddy current losses
3. Copper losses
4. Windage losses

46. Which of the following method of speed control of D.C. machine will offer minimum efficiency ?

1. Voltage control method
2. Field control method
3. Armature control method
4. All above methods

47. Which of the following motor has the poorest speed regulation ?

1. Shunt motor
2. Series motor
3. Differential compound motor
4. Cumulative compound motor

48. Which of the following motor is preferred for operation in highly explosive atmosphere ?

1. Series motor
2. Shunt motor
3. Air motor
4. Battery operated motor

49. Which of the following motors is most suitable for signalling devices and many kinds of timers ?

1. D.C. shunt motor
2. D.C. series motor
3. Induction motor
4. Reluctance motor

50. Which of the following motors is usually used in house-hold refrigerators ?

1. D.C. shunt motor
2. D.C. series motor
3. Single phase induction motor (split phase start or induction run motor)
4. Reluctance motor