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 Lamination’s of core are generally made of carbon stainless steel case iron silicon steel 2 / 25 Iron losses in a D.C. machine are independent of variations in speed and voltage load speed voltage 3 / 25 Permeance is the reciprocal of ampere-turns reluctance resistance flux density 4 / 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 5 / 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 Depends on other features of design Wave winding Lap winding 6 / 25 Which of the following could be lamina-proximately the thickness of lamination’s of a D.C. machine ? 0.5 mm 0.05 mm 0.005 mm 5 mm 7 / 25 The field coils of D.C. generator are usually made of mica cast iron copper carbon 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 A separately excited generator as compared to a self-excited generator is more stable has all above features has exciting current independent of load current is amenable to better voltage control 10 / 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. 11 / 25 Fleming’s right-hand rule regarding direction of induced e.m.f. correlates magnetic flux direction of current flow and resultant force magnetic flux direction of motion and the direction of e.m.f. induced magnetic flux direction of force and direction of motion of conductor magnetic field strength induced voltage and current 12 / 25 In a four-pole D.C. machine alternate poles are north and south all the four poles are south poles all the four poles are north poles two north poles follow two south poles 13 / 25 In a commutator copper is harder than mica none of the above mica and copper are equally hard mica is harder than copper 14 / 25 In lap winding the number of brushes is always two double the number of poles half the number of poles same as the number of poles 15 / 25 Copper brushes in D.C. machine are used in none of the above cases where high voltage and small cur-rents are involved where low voltage and high currents are involved in both of the above cases 16 / 25 The armature of D.C. generator is laminated to insulate the core provide the bulk reduce eddy current loss reduce the bulk 17 / 25 The bearings used to support the rotor shafts are generally ball bearings needle bearings bush bearings magnetic bearmgs 18 / 25 The resistance of armature winding depends on number of conductors length of conductor all of the above cross-sectional area of the conductor 19 / 25 In case of D.C. machines mechanical losses are primary function of none of above speed current voltage 20 / 25 In D.C. generators the polarity of the interpoles is the same as that of the immediately preceding pole is neutral as these poles do not play part in generating e.m.f. is opposite to that of the main pole ahead is the same as that of the main pole ahead 21 / 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 22 / 25 In D.C. generators the pole shoes are fastened to the pole core by welding brazing counter sunk screws rivets 23 / 25 The commutator segments are connected to the armature conductors by means of resistance wires copper lugs insulation pads brazing 24 / 25 In D.C. generators the cause of rapid brush wear may be rough commutator surface severe sparking any of the above imperfect contact 25 / 25 In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when number of poles is 4 number of poles is 2 r.p.m. is less than 300 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
