ELECTRICIAN 2nd YEAR MODULE – AC. Three Phase Motor SET 02 ONLINE TEST July 2, 2025July 2, 2025 by admin TRANSLATE THIS QUIZ IN YOUR LANGUAGE इस प्रश्नोत्तरी का अपनी भाषा में अनुवाद करें <<12345678910111213141516171819202122232425262728293031323334353637>> 0% Question 1 of 37 1. 66. What is the purpose of using rotor resistance starter to start 3 phase slip ring induction motor? Reduce rotor voltage Reduce rotor current Increase the torque Reduce the power lossQuestion 1 of 37Question 2 of 37 2. 72. Calculate the phase displacement in terms of slots for a 3 phase, 36 slots, 12 coils, 4 pole stator winding? 4 slots 3 slots 8 slots 6 slotsQuestion 2 of 37Question 3 of 37 3. 55. Which type of AC winding has the number of coil/pole/phase more than one at different pitches? Flat loop non-over lapped winding Involute coil winding Diamond coil winding Flat loop over lapped windingQuestion 3 of 37Question 4 of 37 4. 71. What is the name of the diagram used for 3phase motor winding? End connection diagram Ring diagram Development diagram Coil connection diagramQuestion 4 of 37Question 5 of 37 5. 67. Which method of speed control is only applicable for 3 phase slipring induction motor? Changing the applied frequency method Rotor rheostat speed control Cascade operation method Changing the number of stator poles methodQuestion 5 of 37Question 6 of 37 6. 74. Which type of testing of winding is illustrated? Short circuit test Resistance test Voltage drop test Polarity testQuestion 6 of 37Question 7 of 37 7. 80. What is the defect in AC 3 phase induction motor runs at low speed if loaded? Wrong motor connection Open circuit in rotor winding Partially shorted stator winding Wrong starter connectionQuestion 7 of 37Question 8 of 37 8. 86. Which is the cause for the 3 phase motor starter with single phase preventer trips frequently? Improper phase sequence Incorrect settings of OLR Incorrect fuse ratings Unbalanced line voltageQuestion 8 of 37Question 9 of 37 9. 75. Why external resistance is included in the rotor circuit at starting through 3 phase slipring induction motor starter? To reduce the load current To get high running torque To get increased speed at starting To get high starting torqueQuestion 9 of 37Question 10 of 37 10. 78. What is the effect on 3 phase induction motor if one phase is cut-off during running with load? Motor will run normally Motor will run slow speed but winding will be burnt out shortly Motor runs with humming noise with slow speed Motor stops at onceQuestion 10 of 37Question 11 of 37 11. 87. What indication denotes the shorted coil defect in 3 phase motor stator winding while testing with internal growler by keeping hacksaw blade? Rapid vibration of hacksaw blade Hacksaw blade gets over heated Hacksaw blade repels against the slots Attracted by the winding turns on the slotQuestion 11 of 37Question 12 of 37 12. 69. What is the name of 3 phase motor winding, if the coil pitch is less than pole pitch? Short chorded winding Long chorded winding Whole coil winding Full pitch windingQuestion 12 of 37Question 13 of 37 13. 81. Which fault condition thermal overload relay protects A.C induction motor? Open circuit Over current Under voltage Short circuitQuestion 13 of 37Question 14 of 37 14. 70. Which is the demerit of 3 phase concentric winding? A stepped former is required It is not easy to make the end connection More space is required More difficult to shape the coils uniformlyQuestion 14 of 37Question 15 of 37 15. 57. What is the type of rewinding process? Skein winding Machine winding Former winding Hand windingQuestion 15 of 37Question 16 of 37 16. 60. Which type of winding wire is used to wind submersible pump motors? Super enamelled type Double cotton covered type PVC covered type Terylene thread typeQuestion 16 of 37Question 17 of 37 17. 56. Calculate the number of coils/phase/pole for a 3 phase double layer distributed winding for a motor having 36 slots, 36 coils and 4 poles. 12 coils/phase/pole 6 coils/phase/pole 9 coils/phase/pole 3 coils/phase/poleQuestion 17 of 37Question 18 of 37 18. 68. What is the name of the winding? Diamond coil winding Skein winding Skew winding Involute coil windingQuestion 18 of 37Question 19 of 37 19. 59. What is the function of collar? Provides insulation around field Provides insulation for heat transfer from coil Provides insulation for coil tapping Helps tightening material for flangeQuestion 19 of 37Question 20 of 37 20. 54. What refers coil in AC winding? Number of turns under two dissimilar poles Number of turns under two similar poles Number of turns connected in parallel Number of turns connected in seriesQuestion 20 of 37Question 21 of 37 21. 77. What happens to a 3 phase induction motor if one phase fails during running? Motor stop instantaneously Motor runs slowly, finally it burns Motor runs with irregular speed Motor runs normallyQuestion 21 of 37Question 22 of 37 22. 82. What happens to the rotor of a 3 phase induction motor if its speed attains to synchronous speed? Rotor speed increases Rotor speed remains same Rotor bars get damaged Rotor speed reducesQuestion 22 of 37Question 23 of 37 23. 64. Determine the torque in newton metres produced by a 7.5 HP squirrel cage motor rotating at 1440 rpm? 33.05 Nm 24.4 Nm 36.6 Nm 21.63 NmQuestion 23 of 37Question 24 of 37 24. 53. Which insulation is used for cuffing in AC winding? Empire fiber glass tape Fibre glass tape Fabric based adhesive tape Leatheroid paperQuestion 24 of 37Question 25 of 37 25. 85. What happens to a 3 phase induction motor, if one phase fails during starting? Motor continues to run with irregular speed Motor runs and draws more current Motor runs in slow speed continuously Motor runs and stop immediatelyQuestion 25 of 37Question 26 of 37 26. 62. Which type of winding has more space for cooling? Between overhanging coil and wedge Between overhanging coils Between overhanging coils and yoke Between overhanging coil and rotorQuestion 26 of 37Question 27 of 37 27. 63. Where the panel boards are used? Load distribution for AC & DC supply Industrial motor drives 3 phase domestic wiring Domestic wiring circuitsQuestion 27 of 37Question 28 of 37 28. 83. What is the effect of open circuit in rotor of an induction motor? Motor runs with very low speed Motor does not start Over heating in motor Excess vibration of shaftQuestion 28 of 37Question 29 of 37 29. 58. Which type of starter is used to start and run the 3 phase slip ring induction motor? Manual star-delta starter Rotor rheostat starter Auto transformer starter Direct on-line starterQuestion 29 of 37Question 30 of 37 30. 79. What is the defect, if starter with single phasing preventer does not switch ‘ON’? Fluctuations in line voltage Wrong terminal connections at motor Loose contact in supply lines Improper phase sequenceQuestion 30 of 37Question 31 of 37 31. 61. What is the reason long chord winding is avoided in AC motors? Low starting torque More winding wire required Low efficiency Less heat dissipationQuestion 31 of 37Question 32 of 37 32. 73. Which type of AC motor winding having the number of coil/pole/phase is more than one arranged in different slots? Concentric winding Concentrated winding Basket winding Distributed windingQuestion 32 of 37Question 33 of 37 33. 52. Which type of insulating material is selected for binding the coils and over hangs? Cotton sleeves Empire sleeves Terylene thread Fibre glass tapeQuestion 33 of 37Question 34 of 37 34. 51. Which is the main property of leatheroid paper insulation? Highly non-hygroscopic Better ageing and dielectric strength Non moisturized material Very good for class F insulationQuestion 34 of 37Question 35 of 37 35. 76. What is the effect of motor, if the rotor windings in slipring induction motor is open circuited at starting? Runs but not able to pull load Runs at very high speed Will not run Runs at slow speedQuestion 35 of 37Question 36 of 37 36. 65. Which type of handle design of rotary switch is illustrated? Key operation Coin slot Lever KnobQuestion 36 of 37Question 37 of 37 37. 84. What is the reason for frequent blowing of fuse after motor running some time? Over loading of motor Improper earthing Heavy voltage fluctuation Poor insulation in windingQuestion 37 of 37 Loading...