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