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