By Surendra | June 10, 2020 0 Comment 0% 4 Created by Surendra DC Generators Quiz in English Set 1 All Important Question Answers for Electrician Related Exams 1 / 25 In D.C. generators the cause of rapid brush wear may be severe sparking rough commutator surface imperfect contact any of the above 2 / 25 The bearings used to support the rotor shafts are generally needle bearings ball bearings magnetic bearmgs bush bearings 3 / 25 In case of D.C. machines mechanical losses are primary function of speed current none of above voltage 4 / 25 Copper brushes in D.C. machine are used in both of the above cases where high voltage and small cur-rents are involved where low voltage and high currents are involved in none of the above cases 5 / 25 The e.m.f. generated in a D.C. generator is directly proportional to number of poles all of the above flux/pole speed of armature 6 / 25 According to Fleming’s right-hand rule for finding the direction of induced e.m.f. when middle finger points in the direction of induced e.m.f. forefinger will point in the direction of either of the above motion of conductor lines of force none of the above 7 / 25 The field coils of D.C. generator are usually made of copper mica carbon cast iron 8 / 25 In D.C. generators the pole shoes are fastened to the pole core by rivets counter sunk screws welding brazing 9 / 25 In a four-pole D.C. machine all the four poles are south poles two north poles follow two south poles all the four poles are north poles alternate poles are north and south 10 / 25 Lamination’s of core are generally made of case iron silicon steel carbon stainless steel 11 / 25 The commutator segments are connected to the armature conductors by means of copper lugs resistance wires insulation pads brazing 12 / 25 In a commutator mica and copper are equally hard mica is harder than copper copper is harder than mica none of the above 13 / 25 For a D.C. generator when the number of poles and the number of armature conductors is fixed then which winding will give the higher e.m.f. ? Either of and above Depends on other features of design Wave winding Lap winding 14 / 25 In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis when there is no load on|he generator the generator runs on overload the generator runs on designed speed the generator runs on full load 15 / 25 Permeance is the reciprocal of reluctance ampere-turns resistance flux density 16 / 25 In D.C. generators the polarity of the interpoles is opposite to that of the main pole ahead is neutral as these poles do not play part in generating e.m.f. is the same as that of the immediately preceding pole is the same as that of the main pole ahead 17 / 25 Fleming’s right-hand rule regarding direction of induced e.m.f. correlates magnetic field strength induced voltage and current magnetic flux direction of force and direction of motion of conductor magnetic flux direction of current flow and resultant force magnetic flux direction of motion and the direction of e.m.f. induced 18 / 25 Iron losses in a D.C. machine are independent of variations in speed load voltage speed and voltage 19 / 25 The armature of D.C. generator is laminated to provide the bulk reduce the bulk reduce eddy current loss insulate the core 20 / 25 While applying Fleming’s right-hand rule to And the direction of induced e.m.f. the thumb points towards direction of motion of conductor if forefinger points along the lines of flux direction of flux direction of induced e.m.f. direction of motion of the conductor if forefinger points in the direction of generated e.m.f. 21 / 25 A separately excited generator as compared to a self-excited generator is amenable to better voltage control is more stable has exciting current independent of load current has all above features 22 / 25 In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when r.p.m. is less than 300 number of poles is 2 number of poles is 4 r.p.m. is more than 300 23 / 25 Which of the following could be lamina-proximately the thickness of lamination’s of a D.C. machine ? 0.005 mm 5 mm 0.5 mm 0.05 mm 24 / 25 The resistance of armature winding depends on length of conductor all of the above cross-sectional area of the conductor number of conductors 25 / 25 In lap winding the number of brushes is always same as the number of poles double the number of poles half the number of poles two कृपया सही सूचना भरें ताकि सर्टिफिकेट ईमेल पर भेजा जा सकें। NameEmailPhone NumberDistrictSchool/Coaching Name Your score is LinkedIn Facebook VKontakte 0% Restart quiz आपको यह क्विज अच्छी लगी तो 5 स्टार रेटिंग जरुर दें । Send feedback
