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More Questions on This Topic :

Question 1. The bearings used to support the rotor shafts are generally
  1.    Ball bearings
  2.    Bush bearings
  3.    Magnetic bearings
  4.    Needle bearings
Answer: Option A

Question 2. The insulating material used between the commutator segments is normally
  1.    Graphite
  2.    Paper
  3.    Mica
  4.    Insulating varnish
Answer: Option C

Question 3. If a self excited D.C. generator after being installed, fails to build up on its first trial run, the first thing to do is to
  1.    reverse the field connections
  2.    increase the field resistance
  3.    increase the speed of primemover
  4.    check armature insulation resistance
Answer: Option A

Question 4. The rapid wear of brushes takes place due to
  1.    Abrasion from dust
  2.    Excessive spring pressure
  3.    Rough commutator bars
  4.    All of the above factors
Answer: Option D

Question 5. The essential condition for parallel operation of two D.C. generators is that they have
  1.    Same kW rating
  2.    The same operation r.p.m.
  3.    The same drooping voltage characteristics
  4.    Same percentage regulation
Answer: Option C

Question 6. Which of the following could be lamina proximately the thickness of laminations of a D.C. machine?
  1.    0.005 mm
  2.    0.05 mm
  3.    0.5 m
  4.    5 m
Answer: Option C