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 a four-pole D.C. machine all the four poles are north poles all the four poles are south poles alternate poles are north and south two north poles follow two south poles 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 lines of force none of the above motion of conductor 3 / 25 Permeance is the reciprocal of flux density resistance ampere-turns reluctance 4 / 25 In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when number of poles is 2 r.p.m. is less than 300 number of poles is 4 r.p.m. is more than 300 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. ? Wave winding Lap winding Depends on other features of design Either of and above 6 / 25 In lap winding the number of brushes is always same as the number of poles two double the number of poles half the number of poles 7 / 25 In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis when the generator runs on full load the generator runs on overload the generator runs on designed speed there is no load on|he generator 8 / 25 The armature of D.C. generator is laminated to reduce eddy current loss reduce the bulk insulate the core provide the bulk 9 / 25 Iron losses in a D.C. machine are independent of variations in load speed speed and voltage voltage 10 / 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 11 / 25 The e.m.f. generated in a D.C. generator is directly proportional to flux/pole all of the above number of poles speed of armature 12 / 25 Lamination’s of core are generally made of stainless steel carbon case iron silicon steel 13 / 25 In case of D.C. machines mechanical losses are primary function of voltage speed current none of above 14 / 25 In a commutator copper is harder than mica none of the above mica is harder than copper mica and copper are equally hard 15 / 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 force and direction of motion of conductor magnetic flux direction of current flow and resultant force magnetic flux direction of motion and the direction of e.m.f. induced 16 / 25 In D.C. generators the polarity of the interpoles is the same as that of the immediately preceding pole is opposite to 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 main pole ahead 17 / 25 In D.C. generators the cause of rapid brush wear may be rough commutator surface severe sparking any of the above imperfect contact 18 / 25 The field coils of D.C. generator are usually made of mica copper carbon cast iron 19 / 25 The resistance of armature winding depends on number of conductors length of conductor cross-sectional area of the conductor all of the above 20 / 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. 21 / 25 The commutator segments are connected to the armature conductors by means of brazing insulation pads copper lugs resistance wires 22 / 25 In D.C. generators the pole shoes are fastened to the pole core by rivets counter sunk screws brazing welding 23 / 25 Copper brushes in D.C. machine are used where high voltage and small cur-rents are involved in both of the above cases where low voltage and high currents are involved in none of the above cases 24 / 25 Which of the following could be lamina-proximately the thickness of lamination’s of a D.C. machine ? 0.05 mm 5 mm 0.5 mm 0.005 mm 25 / 25 The bearings used to support the rotor shafts are generally needle bearings magnetic bearmgs ball bearings bush 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
