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 case of D.C. machines mechanical losses are primary function of none of above speed voltage current 2 / 25 Iron losses in a D.C. machine are independent of variations in voltage load speed speed and voltage 3 / 25 Copper brushes in D.C. machine are used where high voltage and small cur-rents are involved where low voltage and high currents are involved in both of the above cases in none of the above cases 4 / 25 The resistance of armature winding depends on cross-sectional area of the conductor all of the above number of conductors length of conductor 5 / 25 In a commutator copper is harder than mica mica and copper are equally hard mica is harder than copper none of the above 6 / 25 In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when number of poles is 4 r.p.m. is less than 300 number of poles is 2 r.p.m. is more than 300 7 / 25 In a four-pole D.C. machine all the four poles are north poles alternate poles are north and south two north poles follow two south poles all the four poles are south poles 8 / 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 motion of the conductor if forefinger points in the direction of generated e.m.f. direction of induced e.m.f. direction of motion of conductor if forefinger points along the lines of flux 9 / 25 The bearings used to support the rotor shafts are generally needle bearings magnetic bearmgs ball bearings bush bearings 10 / 25 In lap winding the number of brushes is always same as the number of poles two half the number of poles double the number of poles 11 / 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 the same as that of the main pole ahead is opposite to that of the main pole ahead 12 / 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 is more stable has all above features 13 / 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 flux direction of current flow and resultant force magnetic flux direction of force and direction of motion of conductor magnetic field strength induced voltage and current 14 / 25 Lamination’s of core are generally made of stainless steel silicon steel carbon case iron 15 / 25 Permeance is the reciprocal of flux density ampere-turns resistance reluctance 16 / 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 17 / 25 In D.C. generators the pole shoes are fastened to the pole core by counter sunk screws rivets brazing welding 18 / 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 Either of and above Depends on other features of design 19 / 25 The field coils of D.C. generator are usually made of cast iron mica carbon copper 20 / 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 21 / 25 In D.C. generators the cause of rapid brush wear may be any of the above rough commutator surface imperfect contact severe sparking 22 / 25 In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis when the generator runs on overload there is no load on|he generator the generator runs on full load the generator runs on designed speed 23 / 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 either of the above motion of conductor none of the above 24 / 25 The commutator segments are connected to the armature conductors by means of insulation pads copper lugs brazing resistance wires 25 / 25 The armature of D.C. generator is laminated to reduce eddy current loss insulate the core reduce the bulk provide the bulk 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
