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. 72. Calculate the phase displacement in terms of slots for a 3 phase, 36 slots, 12 coils, 4 pole stator winding? 4 slots 8 slots 3 slots 6 slotsQuestion 1 of 37Question 2 of 37 2. 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 2 of 37Question 3 of 37 3. 53. Which insulation is used for cuffing in AC winding? Leatheroid paper Fibre glass tape Empire fiber glass tape Fabric based adhesive tapeQuestion 3 of 37Question 4 of 37 4. 57. What is the type of rewinding process? Machine winding Hand winding Former winding Skein windingQuestion 4 of 37Question 5 of 37 5. 61. What is the reason long chord winding is avoided in AC motors? More winding wire required Low efficiency Low starting torque Less heat dissipationQuestion 5 of 37Question 6 of 37 6. 60. Which type of winding wire is used to wind submersible pump motors? Terylene thread type Super enamelled type PVC covered type Double cotton covered typeQuestion 6 of 37Question 7 of 37 7. 51. Which is the main property of leatheroid paper insulation? Better ageing and dielectric strength Highly non-hygroscopic Non moisturized material Very good for class F insulationQuestion 7 of 37Question 8 of 37 8. 77. What happens to a 3 phase induction motor if one phase fails during running? Motor runs normally Motor runs with irregular speed Motor stop instantaneously Motor runs slowly, finally it burnsQuestion 8 of 37Question 9 of 37 9. 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 increases Rotor speed reduces Rotor speed remains sameQuestion 9 of 37Question 10 of 37 10. 65. Which type of handle design of rotary switch is illustrated? Coin slot Key operation Lever KnobQuestion 10 of 37Question 11 of 37 11. 84. What is the reason for frequent blowing of fuse after motor running some time? Heavy voltage fluctuation Poor insulation in winding Over loading of motor Improper earthingQuestion 11 of 37Question 12 of 37 12. 62. Which type of winding has more space for cooling? Between overhanging coil and wedge Between overhanging coils and yoke Between overhanging coil and rotor Between overhanging coilsQuestion 12 of 37Question 13 of 37 13. 74. Which type of testing of winding is illustrated? Short circuit test Voltage drop test Resistance test Polarity testQuestion 13 of 37Question 14 of 37 14. 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 Flat loop over lapped winding Diamond coil windingQuestion 14 of 37Question 15 of 37 15. 67. Which method of speed control is only applicable for 3 phase slipring induction motor? Changing the number of stator poles method Changing the applied frequency method Rotor rheostat speed control Cascade operation methodQuestion 15 of 37Question 16 of 37 16. 52. Which type of insulating material is selected for binding the coils and over hangs? Terylene thread Fibre glass tape Empire sleeves Cotton sleevesQuestion 16 of 37Question 17 of 37 17. 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 Rotor rheostat starter Auto transformer starterQuestion 17 of 37Question 18 of 37 18. 59. What is the function of collar? Provides insulation for coil tapping Provides insulation around field Provides insulation for heat transfer from coil Helps tightening material for flangeQuestion 18 of 37Question 19 of 37 19. 70. Which is the demerit of 3 phase concentric winding? More difficult to shape the coils uniformly It is not easy to make the end connection More space is required A stepped former is requiredQuestion 19 of 37Question 20 of 37 20. 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 Wrong motor connection Partially shorted stator windingQuestion 20 of 37Question 21 of 37 21. 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. 9 coils/phase/pole 12 coils/phase/pole 3 coils/phase/pole 6 coils/phase/poleQuestion 21 of 37Question 22 of 37 22. 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 stops at once Motor runs with humming noise with slow speedQuestion 22 of 37Question 23 of 37 23. 86. Which is the cause for the 3 phase motor starter with single phase preventer trips frequently? Unbalanced line voltage Improper phase sequence Incorrect fuse ratings Incorrect settings of OLRQuestion 23 of 37Question 24 of 37 24. 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 series Number of turns connected in parallelQuestion 24 of 37Question 25 of 37 25. 79. What is the defect, if starter with single phasing preventer does not switch ‘ON’? Fluctuations in line voltage Loose contact in supply lines Wrong terminal connections at motor Improper phase sequenceQuestion 25 of 37Question 26 of 37 26. 71. What is the name of the diagram used for 3phase motor winding? Ring diagram Coil connection diagram End connection diagram Development diagramQuestion 26 of 37Question 27 of 37 27. 83. What is the effect of open circuit in rotor of an induction motor? Motor runs with very low speed Motor does not start Excess vibration of shaft Over heating in motorQuestion 27 of 37Question 28 of 37 28. 87. What indication denotes the shorted coil defect in 3 phase motor stator winding while testing with internal growler by keeping hacksaw blade? Attracted by the winding turns on the slot Rapid vibration of hacksaw blade Hacksaw blade gets over heated Hacksaw blade repels against the slotsQuestion 28 of 37Question 29 of 37 29. 81. Which fault condition thermal overload relay protects A.C induction motor? Over current Under voltage Open circuit Short circuitQuestion 29 of 37Question 30 of 37 30. 64. Determine the torque in newton metres produced by a 7.5 HP squirrel cage motor rotating at 1440 rpm? 24.4 Nm 33.05 Nm 36.6 Nm 21.63 NmQuestion 30 of 37Question 31 of 37 31. 76. What is the effect of motor, if the rotor windings in slipring induction motor is open circuited at starting? Will not run Runs at slow speed Runs at very high speed Runs but not able to pull loadQuestion 31 of 37Question 32 of 37 32. 66. What is the purpose of using rotor resistance starter to start 3 phase slip ring induction motor? Increase the torque Reduce rotor current Reduce the power loss Reduce rotor voltageQuestion 32 of 37Question 33 of 37 33. 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 Concentrated winding Distributed windingQuestion 33 of 37Question 34 of 37 34. 85. What happens to a 3 phase induction motor, if one phase fails during starting? Motor runs in slow speed continuously Motor runs and stop immediately Motor continues to run with irregular speed Motor runs and draws more currentQuestion 34 of 37Question 35 of 37 35. 68. What is the name of the winding? Diamond coil winding Involute coil winding Skew winding Skein windingQuestion 35 of 37Question 36 of 37 36. 63. Where the panel boards are used? 3 phase domestic wiring Domestic wiring circuits Industrial motor drives Load distribution for AC & DC supplyQuestion 36 of 37Question 37 of 37 37. 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 reduce the load current To get high starting torqueQuestion 37 of 37 Loading...