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 A separately excited generator as compared to a self-excited generator is amenable to better voltage control has exciting current independent of load current has all above features is more stable 2 / 25 In lap winding the number of brushes is always same as the number of poles double the number of poles half the number of poles two 3 / 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 overload the generator runs on full load the generator runs on designed speed 4 / 25 In D.C. generators the polarity of the interpoles is opposite to that of the main pole ahead 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 5 / 25 Copper brushes in D.C. machine are used where low voltage and high currents are involved where high voltage and small cur-rents are involved in none of the above cases in both of the above cases 6 / 25 The armature of D.C. generator is laminated to provide the bulk insulate the core reduce the bulk reduce eddy current loss 7 / 25 Iron losses in a D.C. machine are independent of variations in speed load voltage speed and voltage 8 / 25 The commutator segments are connected to the armature conductors by means of copper lugs brazing resistance wires insulation pads 9 / 25 In D.C. generators the pole shoes are fastened to the pole core by brazing welding rivets counter sunk screws 10 / 25 The resistance of armature winding depends on all of the above length of conductor number of conductors cross-sectional area of the conductor 11 / 25 In a commutator none of the above mica and copper are equally hard copper is harder than mica mica is harder than copper 12 / 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 flux direction of induced e.m.f. direction of motion of conductor if forefinger points along the lines of flux 13 / 25 The e.m.f. generated in a D.C. generator is directly proportional to flux/pole number of poles all of the above speed of armature 14 / 25 In D.C. generators the cause of rapid brush wear may be severe sparking rough commutator surface imperfect contact any of the above 15 / 25 The field coils of D.C. generator are usually made of copper mica carbon cast iron 16 / 25 Permeance is the reciprocal of flux density resistance ampere-turns reluctance 17 / 25 In a four-pole D.C. machine alternate poles are north and south all the four poles are north poles two north poles follow two south poles all the four poles are south poles 18 / 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 Wave winding Depends on other features of design Lap winding 19 / 25 Which of the following could be lamina-proximately the thickness of lamination’s of a D.C. machine ? 0.05 mm 5 mm 0.005 mm 0.5 mm 20 / 25 Lamination’s of core are generally made of stainless steel carbon silicon steel case iron 21 / 25 The bearings used to support the rotor shafts are generally ball bearings needle bearings magnetic bearmgs bush bearings 22 / 25 In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when number of poles is 2 r.p.m. is more than 300 r.p.m. is less than 300 number of poles is 4 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 lines of force none of the above either of the above motion of conductor 24 / 25 In case of D.C. machines mechanical losses are primary function of current voltage none of above speed 25 / 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 force and direction of motion of conductor magnetic flux direction of motion and the direction of e.m.f. induced magnetic flux direction of current flow and resultant force 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
