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 bearings used to support the rotor shafts are generally bush bearings needle bearings ball bearings magnetic bearmgs 2 / 25 In D.C. generators the pole shoes are fastened to the pole core by rivets counter sunk screws brazing welding 3 / 25 Which of the following could be lamina-proximately the thickness of lamination’s of a D.C. machine ? 5 mm 0.5 mm 0.005 mm 0.05 mm 4 / 25 In a commutator none of the above mica is harder than copper mica and copper are equally hard copper is harder than mica 5 / 25 In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when number of poles is 4 number of poles is 2 r.p.m. is less than 300 r.p.m. is more than 300 6 / 25 The commutator segments are connected to the armature conductors by means of copper lugs resistance wires insulation pads brazing 7 / 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 designed speed the generator runs on overload the generator runs on full load 8 / 25 The e.m.f. generated in a D.C. generator is directly proportional to all of the above flux/pole speed of armature number of poles 9 / 25 The field coils of D.C. generator are usually made of copper mica carbon cast iron 10 / 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. ? Lap winding Depends on other features of design Wave winding Either of and above 11 / 25 Iron losses in a D.C. machine are independent of variations in speed voltage speed and voltage load 12 / 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 current flow and resultant force magnetic flux direction of motion and the direction of e.m.f. induced magnetic flux direction of force and direction of motion of conductor 13 / 25 The armature of D.C. generator is laminated to reduce the bulk insulate the core reduce eddy current loss provide the bulk 14 / 25 In a four-pole D.C. machine all the four poles are south poles all the four poles are north poles alternate poles are north and south two north poles follow two south poles 15 / 25 In case of D.C. machines mechanical losses are primary function of speed voltage current none of above 16 / 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 flux direction of motion of conductor if forefinger points along the lines of flux direction of motion of the conductor if forefinger points in the direction of generated e.m.f. 17 / 25 Lamination’s of core are generally made of silicon steel case iron carbon stainless steel 18 / 25 In lap winding the number of brushes is always half the number of poles double the number of poles same as the number of poles two 19 / 25 Permeance is the reciprocal of reluctance resistance ampere-turns flux density 20 / 25 A separately excited generator as compared to a self-excited generator is more stable is amenable to better voltage control has all above features has exciting current independent of load current 21 / 25 In D.C. generators the polarity of the interpoles is the same as that of the immediately preceding pole 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 main pole ahead 22 / 25 The resistance of armature winding depends on cross-sectional area of the conductor length of conductor all of the above number of conductors 23 / 25 In D.C. generators the cause of rapid brush wear may be severe sparking any of the above imperfect contact rough commutator surface 24 / 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 none of the above lines of force 25 / 25 Copper brushes in D.C. machine are used in both of the above cases where low voltage and high currents are involved where high voltage and small cur-rents are involved in none of the above cases 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
