Related InterviewSolutions

• DC generators are disconnected/connected from/to the busbars only under the floating condition because ____________(a) To avoid sudden loading of the prime mover(b) To avoid burning of all switch contacts(c) To avoid mechanical jerk to the shaft(d) To avoid sudden loading of the prime mover, burning of all switch contacts and avoid mechanical jerking to the shaftThis question was addressed to me in an interview.The question is from Brushes and Commutator Assembly topic in portion DC Machines of DC Machines
• Specific resistance for a brush is given by _________(a) R = (E * W * T) / (I * L)(b) R = (E * W * I) / (T * L)(c) R = (E * W * I) * (T * L)(d) Doesn’t depend on E, W, T, I, L.I have been asked this question during an interview.This intriguing question comes from Brushes and Commutator Assembly topic in chapter DC Machines of DC Machines
• What is the range of the brush friction coefficients for medium category?(a) 0.40 and above(b) 0.22 to 0.40(c) 0.11 to 0.22(d) 0.08 to 0.11This question was addressed to me by my college director while I was bunking the class.This intriguing question comes from Brushes and Commutator Assembly topic in chapter DC Machines of DC Machines
• Spacing between the brushes for a 4-pole machine in terms of commutator segments for 12 conductor segments is _____(a) 48(b) 3(c) 2(d) 6This question was posed to me during a job interview.This intriguing question originated from Brushes and Commutator Assembly topic in portion DC Machines of DC Machines
• Reason behind the rapid wear of brushes is __________(a) Abrasion from dust(b) Excessive spring pressure(c) Rough commutator bars(d) Abrasion from dust, excessive spring pressure and rough commutator barsI had been asked this question by my school principal while I was bunking the class.My enquiry is from Brushes and Commutator Assembly in section DC Machines of DC Machines
• How to avoid grooves in the commutation of DC machine with the help of brush?(a) Brushes of opposite polarity should track each other(b) Brushes of same polarity should track each other(c) Brush position has no effect on the commutator grooving(d) Brushes should not track each otherI got this question by my college professor while I was bunking the class.My doubt is from Brushes and Commutator Assembly topic in section DC Machines of DC Machines
• What is the requirement of the good commutation?(a) Brushes should be of proper grade, size and material(b) Brushes should smoothly run in the holders(c) Smooth, concentric commutator properly undercut(d) Brushes should be of proper grade, size, material, run smoothly in the holders and concentric commutator properly undercutI got this question in an international level competition.Asked question is from Brushes and Commutator Assembly in section DC Machines of DC Machines
• In a DC generator the ripples in the direct emf generated can be reduced by________(a) Using conductor of annealed copper(b) Using commutator with large number of segments(c) Using carbon brushes of superior quality(d) Using equalizer ringsThis question was posed to me by my college director while I was bunking the class.My question comes from Brushes and Commutator Assembly topic in section DC Machines of DC Machines
• Which conductors are in point of contact with brushes?(a) Lie under south pole(b) Lie under north pole(c) Lie in inter polar region(d) Are farthest from the polesThe question was posed to me by my college director while I was bunking the class.The origin of the question is Brushes and Commutator Assembly topic in chapter DC Machines of DC Machines
• What are the number of the brushes in the wave winding?(a) Same or more than the number of poles(b) Same or less than the number of poles(c) Exactly half the number of poles(d) Depends on other parametersThe question was posed to me in final exam.Asked question is from Brushes and Commutator Assembly in division DC Machines of DC Machines