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