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