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