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