By Surendra | June 10, 2020 0 Comment 0% 1 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 case iron silicon steel stainless steel carbon 2 / 25 The armature of D.C. generator is laminated to provide the bulk reduce eddy current loss insulate the core reduce the bulk 3 / 25 In D.C. generators the polarity of the interpoles is the same as that of the immediately preceding pole is the same as that of the main pole ahead is neutral as these poles do not play part in generating e.m.f. is opposite to that of the main pole ahead 4 / 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 motion of the conductor if forefinger points in the direction of generated e.m.f. direction of flux 5 / 25 In D.C. generators the pole shoes are fastened to the pole core by brazing counter sunk screws welding rivets 6 / 25 Fleming’s right-hand rule regarding direction of induced e.m.f. correlates magnetic flux direction of force and direction of motion of conductor magnetic flux direction of current flow and resultant force magnetic field strength induced voltage and current magnetic flux direction of motion and the direction of e.m.f. induced 7 / 25 Which of the following could be lamina-proximately the thickness of lamination’s of a D.C. machine ? 0.005 mm 0.5 mm 0.05 mm 5 mm 8 / 25 Copper brushes in D.C. machine are used where high voltage and small cur-rents are involved in none of the above cases in both of the above cases where low voltage and high currents are involved 9 / 25 The bearings used to support the rotor shafts are generally magnetic bearmgs bush bearings needle bearings ball bearings 10 / 25 In case of D.C. machines mechanical losses are primary function of none of above speed voltage current 11 / 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 12 / 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 13 / 25 The field coils of D.C. generator are usually made of carbon copper mica cast iron 14 / 25 In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis when there is no load on|he generator the generator runs on designed speed the generator runs on full load the generator runs on overload 15 / 25 A separately excited generator as compared to a self-excited generator has all above features is more stable is amenable to better voltage control has exciting current independent of load current 16 / 25 In D.C. generators the cause of rapid brush wear may be any of the above rough commutator surface imperfect contact severe sparking 17 / 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 none of the above either of the above lines of force motion of conductor 18 / 25 Permeance is the reciprocal of ampere-turns reluctance flux density resistance 19 / 25 The resistance of armature winding depends on all of the above length of conductor cross-sectional area of the conductor number of conductors 20 / 25 The commutator segments are connected to the armature conductors by means of insulation pads copper lugs resistance wires brazing 21 / 25 Iron losses in a D.C. machine are independent of variations in load speed and voltage speed voltage 22 / 25 In a commutator none of the above mica and copper are equally hard mica is harder than copper copper is harder than mica 23 / 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 24 / 25 In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when r.p.m. is less than 300 number of poles is 4 r.p.m. is more than 300 number of poles is 2 25 / 25 The e.m.f. generated in a D.C. generator is directly proportional to number of poles flux/pole all of the above speed of armature कृपया सही सूचना भरें ताकि सर्टिफिकेट ईमेल पर भेजा जा सकें। Your score is LinkedIn Facebook Twitter 0% Restart quiz आपको यह क्विज अच्छी लगी तो 5 स्टार रेटिंग जरुर दें । Send feedback
