By Surendra | June 10, 2020 0 Comment 0% 2 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 pole shoes are fastened to the pole core by rivets welding brazing counter sunk screws 2 / 25 In a commutator none of the above mica is harder than copper copper is harder than mica mica and copper are equally hard 3 / 25 The bearings used to support the rotor shafts are generally magnetic bearmgs ball bearings bush bearings needle bearings 4 / 25 Lamination’s of core are generally made of stainless steel silicon steel carbon case iron 5 / 25 Copper brushes in D.C. machine are used where high voltage and small cur-rents are involved in none of the above cases where low voltage and high currents are involved in both of the above cases 6 / 25 The resistance of armature winding depends on number of conductors all of the above cross-sectional area of the conductor length of conductor 7 / 25 In case of D.C. machines mechanical losses are primary function of speed voltage none of above current 8 / 25 The commutator segments are connected to the armature conductors by means of resistance wires copper lugs brazing insulation pads 9 / 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 full load the generator runs on designed speed the generator runs on overload 10 / 25 Permeance is the reciprocal of ampere-turns resistance flux density reluctance 11 / 25 In D.C. generators the cause of rapid brush wear may be imperfect contact rough commutator surface any of the above severe sparking 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 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 13 / 25 While applying Fleming’s right-hand rule to And the direction of induced e.m.f. the thumb points towards direction of flux direction of induced e.m.f. 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. 14 / 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 Wave winding Depends on other features of design Either of and above 15 / 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 16 / 25 In a four-pole D.C. machine all the four poles are north poles two north poles follow two south poles all the four poles are south poles alternate poles are north and south 17 / 25 The field coils of D.C. generator are usually made of copper mica carbon cast iron 18 / 25 Iron losses in a D.C. machine are independent of variations in voltage speed speed and voltage load 19 / 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 the same as that of the immediately preceding pole is opposite to that of the main pole ahead is the same as that of the main pole ahead 20 / 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 none of the above motion of conductor lines of force 21 / 25 In lap winding the number of brushes is always double the number of poles two same as the number of poles half the number of poles 22 / 25 Which of the following could be lamina-proximately the thickness of lamination’s of a D.C. machine ? 0.005 mm 0.05 mm 5 mm 0.5 mm 23 / 25 A separately excited generator as compared to a self-excited generator is amenable to better voltage control has all above features is more stable has exciting current independent of load current 24 / 25 The armature of D.C. generator is laminated to insulate the core reduce eddy current loss reduce the bulk provide the bulk 25 / 25 The e.m.f. generated in a D.C. generator is directly proportional to flux/pole number of poles all of the above speed of armature कृपया सही सूचना भरें ताकि सर्टिफिकेट ईमेल पर भेजा जा सकें। NameEmailPhone NumberDistrictSchool/Coaching Name Your score is LinkedIn Facebook Twitter VKontakte 0% Restart quiz आपको यह क्विज अच्छी लगी तो 5 स्टार रेटिंग जरुर दें । Send feedback
