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