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 Fleming’s right-hand rule regarding direction of induced e.m.f. correlates magnetic flux direction of force and direction of motion of conductor 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 2 / 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 3 / 25 Permeance is the reciprocal of ampere-turns resistance flux density reluctance 4 / 25 In D.C. generators the cause of rapid brush wear may be rough commutator surface imperfect contact severe sparking any of the above 5 / 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 flux direction of motion of the conductor if forefinger points in the direction of generated e.m.f. direction of induced e.m.f. 6 / 25 In D.C. generators the pole shoes are fastened to the pole core by brazing counter sunk screws welding rivets 7 / 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 the same as that of the immediately preceding pole is neutral as these poles do not play part in generating e.m.f. 8 / 25 The commutator segments are connected to the armature conductors by means of brazing insulation pads copper lugs resistance wires 9 / 25 Iron losses in a D.C. machine are independent of variations in load voltage speed speed and voltage 10 / 25 In case of D.C. machines mechanical losses are primary function of current speed none of above voltage 11 / 25 Which of the following could be lamina-proximately the thickness of lamination’s of a D.C. machine ? 0.5 mm 5 mm 0.005 mm 0.05 mm 12 / 25 In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis when the generator runs on designed speed the generator runs on full load there is no load on|he generator the generator runs on overload 13 / 25 In a four-pole D.C. machine two north poles follow two south poles all the four poles are north poles all the four poles are south poles alternate poles are north and south 14 / 25 Copper brushes in D.C. machine are used in none of the above cases where low voltage and high currents are involved in both of the above cases where high voltage and small cur-rents are involved 15 / 25 The e.m.f. generated in a D.C. generator is directly proportional to all of the above flux/pole speed of armature number of poles 16 / 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 17 / 25 The resistance of armature winding depends on all of the above cross-sectional area of the conductor length of conductor number of conductors 18 / 25 The field coils of D.C. generator are usually made of cast iron carbon mica copper 19 / 25 A separately excited generator as compared to a self-excited generator has all above features is amenable to better voltage control has exciting current independent of load current is more stable 20 / 25 In a commutator none of the above copper is harder than mica mica is harder than copper mica and copper are equally hard 21 / 25 The armature of D.C. generator is laminated to reduce the bulk reduce eddy current loss provide the bulk insulate the core 22 / 25 In lap winding the number of brushes is always two same as the number of poles double the number of poles half the number of poles 23 / 25 Lamination’s of core are generally made of carbon case iron stainless steel silicon steel 24 / 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 r.p.m. is less than 300 number of poles is 4 number of poles is 2 25 / 25 The bearings used to support the rotor shafts are generally bush bearings magnetic bearmgs ball bearings needle bearings 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
