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