[amp_mcq option1=”Vacuum cleaners” option2=”Fan motors” option3=”Pistol drills” option4=”All of the above” correct=”option4″]
Detailed SolutionWhich of the following applications always have some load whenever switched on ?
Single phase induction motors
42. In a split phase motor, the running winding should have
[amp_mcq option1=”high resistance and low inductance” option2=”low resistance and high inductance” option3=”high resistance as well as high inductance” option4=”low resistance as well as low inductiance” correct=”option1″]
Detailed SolutionIn a split phase motor, the running winding should have
43. In which single-phase motor, the rotor has no teeth or winding ?
[amp_mcq option1=”Split phase motor” option2=”Reluctance motor” option3=”Hysteresis motor” option4=”Universal motor” correct=”option2″]
Detailed SolutionIn which single-phase motor, the rotor has no teeth or winding ?
44. A centrifugal switch is used to disconnect starting winding when motor has
[amp_mcq option1=”run for about 1 minute” option2=”run for about 5 minutes” option3=”picked up about 50 to 70 per cent of rated speed” option4=”picked up about 10 to 25 per cent of rated speed” correct=”option3″]
Detailed SolutionA centrifugal switch is used to disconnect starting winding when motor has
45. In repulsion motor direction of rotation of motor
[amp_mcq option1=”Is opposite to that of brush shift” option2=”Is the same as that of brush shift” option3=”Is independent of brush shift” option4=”nan” correct=”option3″]
Detailed SolutionIn repulsion motor direction of rotation of motor
46. Which of the following statements regarding repulsion-start induction motor is incorrect ?
[amp_mcq option1=”It requires more maintenance of commutator and other mechanical devices” option2=”It makes quite a bit of noise on starting” option3=”In fractional horse power motors, it has replaced the capacitor motors” option4=”It is not easily reversed” correct=”option4″]
47. In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will
[amp_mcq option1=”Become unstable” option2=”Draw excessive armature current and may burn out” option3=”Fall out of synchronism and come to stand still” option4=”Run as induction motor” correct=”option3″]
48. In a
[amp_mcq option1=”through resistance” option2=”through reactances” option3=”series motor armature coils are usually connected to commutator A. through resistance B. through reactances C. through capacitors” option4=”solidly” correct=”option4″]
49. If the centrifugal switch does not open at 70 to 80 percent of synchronous speed of motor, it would result in
[amp_mcq option1=”Damage to the starting winding” option2=”Damage to the centrifugal switch” option3=”Overloading of running winding” option4=”None of the above” correct=”option1″]