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