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 The field coils of D.C. generator are usually made of cast iron copper mica carbon 2 / 25 The e.m.f. generated in a D.C. generator is directly proportional to all of the above number of poles speed of armature flux/pole 3 / 25 In D.C. generators the polarity of the interpoles is neutral as these poles do not play part in generating e.m.f. 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 4 / 25 The resistance of armature winding depends on length of conductor all of the above number of conductors cross-sectional area of the conductor 5 / 25 The armature of D.C. generator is laminated to provide the bulk reduce eddy current loss reduce the bulk insulate the core 6 / 25 In a commutator mica is harder than copper copper is harder than mica none of the above mica and copper are equally hard 7 / 25 In a four-pole D.C. machine alternate poles are north and south all the four poles are north poles two north poles follow two south poles all the four poles are south poles 8 / 25 In D.C. generators the pole shoes are fastened to the pole core by welding brazing counter sunk screws rivets 9 / 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 number of poles is 4 r.p.m. is less than 300 10 / 25 The bearings used to support the rotor shafts are generally needle bearings magnetic bearmgs bush bearings ball bearings 11 / 25 The commutator segments are connected to the armature conductors by means of insulation pads resistance wires brazing copper lugs 12 / 25 Permeance is the reciprocal of ampere-turns flux density resistance reluctance 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. ? Depends on other features of design Lap winding Either of and above Wave winding 14 / 25 Copper brushes in D.C. machine are used in both of the above cases where low voltage and high currents are involved in none of the above cases where high voltage and small cur-rents are involved 15 / 25 Lamination’s of core are generally made of case iron silicon steel stainless steel carbon 16 / 25 A separately excited generator as compared to a self-excited generator is more stable has all above features is amenable to better voltage control has exciting current independent of load current 17 / 25 In D.C. generators the cause of rapid brush wear may be rough commutator surface any of the above severe sparking imperfect contact 18 / 25 Which of the following could be lamina-proximately the thickness of lamination’s of a D.C. machine ? 0.5 mm 0.05 mm 5 mm 0.005 mm 19 / 25 Fleming’s right-hand rule regarding direction of induced e.m.f. correlates magnetic flux direction of motion and the direction of e.m.f. induced magnetic field strength induced voltage and current magnetic flux direction of current flow and resultant force magnetic flux direction of force and direction of motion of conductor 20 / 25 Iron losses in a D.C. machine are independent of variations in speed load voltage speed and voltage 21 / 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 lines of force motion of conductor none of the above either of the above 22 / 25 While applying Fleming’s right-hand rule to And the direction of induced e.m.f. the thumb points towards direction of induced e.m.f. direction of motion of the conductor if forefinger points in the direction of generated e.m.f. direction of motion of conductor if forefinger points along the lines of flux direction of flux 23 / 25 In case of D.C. machines mechanical losses are primary function of voltage none of above speed current 24 / 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 25 / 25 In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis when the generator runs on overload the generator runs on designed speed the generator runs on full load there is no load on|he generator 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
