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