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 In lap winding the number of brushes is always two half the number of poles same as the number of poles double the number of poles 2 / 25 The armature of D.C. generator is laminated to provide the bulk reduce eddy current loss reduce the bulk insulate the core 3 / 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 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 4 / 25 In D.C. generators the pole shoes are fastened to the pole core by welding counter sunk screws rivets brazing 5 / 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 6 / 25 In a commutator mica is harder than copper none of the above copper is harder than mica mica and copper are equally hard 7 / 25 The bearings used to support the rotor shafts are generally ball bearings magnetic bearmgs bush bearings needle bearings 8 / 25 The field coils of D.C. generator are usually made of mica cast iron copper carbon 9 / 25 Lamination’s of core are generally made of case iron silicon steel stainless steel carbon 10 / 25 While applying Fleming’s right-hand rule to And the direction of induced e.m.f. the thumb points towards direction of motion of conductor if forefinger points along the lines of flux direction of induced e.m.f. direction of flux direction of motion of the conductor if forefinger points in the direction of generated e.m.f. 11 / 25 Permeance is the reciprocal of resistance flux density reluctance ampere-turns 12 / 25 The e.m.f. generated in a D.C. generator is directly proportional to flux/pole speed of armature number of poles all of the above 13 / 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 14 / 25 The commutator segments are connected to the armature conductors by means of resistance wires insulation pads brazing copper lugs 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 4 r.p.m. is less than 300 number of poles is 2 16 / 25 In D.C. generators the polarity of the interpoles 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 is neutral as these poles do not play part in generating e.m.f. 17 / 25 Which of the following could be lamina-proximately the thickness of lamination’s of a D.C. machine ? 0.5 mm 5 mm 0.05 mm 0.005 mm 18 / 25 Iron losses in a D.C. machine are independent of variations in speed and voltage speed voltage load 19 / 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 20 / 25 The resistance of armature winding depends on cross-sectional area of the conductor number of conductors length of conductor all of the above 21 / 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 full load there is no load on|he generator the generator runs on designed speed 22 / 25 In case of D.C. machines mechanical losses are primary function of none of above voltage current speed 23 / 25 In D.C. generators the cause of rapid brush wear may be severe sparking rough commutator surface any of the above imperfect contact 24 / 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. ? Either of and above Wave winding Lap winding Depends on other features of design 25 / 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 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
