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 The e.m.f. generated in a D.C. generator is directly proportional to speed of armature flux/pole all of the above number of poles 2 / 25 In D.C. generators the pole shoes are fastened to the pole core by brazing welding rivets counter sunk screws 3 / 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 4 / 25 The armature of D.C. generator is laminated to reduce eddy current loss provide the bulk insulate the core reduce the bulk 5 / 25 In a commutator copper is harder than mica mica is harder than copper mica and copper are equally hard none of the above 6 / 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 lines of force either of the above motion of conductor none of the above 7 / 25 Iron losses in a D.C. machine are independent of variations in speed speed and voltage voltage load 8 / 25 The bearings used to support the rotor shafts are generally magnetic bearmgs ball bearings bush bearings needle bearings 9 / 25 In D.C. generators the cause of rapid brush wear may be severe sparking any of the above rough commutator surface imperfect contact 10 / 25 Copper brushes in D.C. machine are used in both of the above cases where low voltage and high currents are involved where high voltage and small cur-rents are involved in none of the above cases 11 / 25 The resistance of armature winding depends on cross-sectional area of the conductor length of conductor number of conductors all of the above 12 / 25 The field coils of D.C. generator are usually made of mica carbon cast iron copper 13 / 25 The commutator segments are connected to the armature conductors by means of brazing insulation pads copper lugs resistance wires 14 / 25 In a four-pole D.C. machine all the four poles are south poles alternate poles are north and south all the four poles are north poles two north poles follow two south poles 15 / 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 16 / 25 Lamination’s of core are generally made of silicon steel carbon stainless steel case iron 17 / 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 induced e.m.f. direction of flux direction of motion of conductor if forefinger points along the lines of flux 18 / 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 19 / 25 In D.C. generators the polarity of the interpoles 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 is neutral as these poles do not play part in generating e.m.f. 20 / 25 Permeance is the reciprocal of reluctance flux density resistance ampere-turns 21 / 25 In case of D.C. machines mechanical losses are primary function of speed none of above voltage current 22 / 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 23 / 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. ? Either of and above Depends on other features of design Wave winding Lap winding 24 / 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 25 / 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 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
