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