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? 6 slots 4 slots 8 slots 3 slotsQuestion 1 of 37Question 2 of 37 2. 71. What is the name of the diagram used for 3phase motor winding? Coil connection diagram End connection diagram Ring diagram Development diagramQuestion 2 of 37Question 3 of 37 3. 73. Which type of AC motor winding having the number of coil/pole/phase is more than one arranged in different slots? Concentrated winding Distributed winding Basket winding Concentric windingQuestion 3 of 37Question 4 of 37 4. 67. Which method of speed control is only applicable for 3 phase slipring induction motor? Changing the number of stator poles method Cascade operation method Changing the applied frequency method Rotor rheostat speed controlQuestion 4 of 37Question 5 of 37 5. 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 5 of 37Question 6 of 37 6. 68. What is the name of the winding? Diamond coil winding Skein winding Skew winding Involute coil windingQuestion 6 of 37Question 7 of 37 7. 81. Which fault condition thermal overload relay protects A.C induction motor? Short circuit Under voltage Open circuit Over currentQuestion 7 of 37Question 8 of 37 8. 79. What is the defect, if starter with single phasing preventer does not switch ‘ON’? Loose contact in supply lines Fluctuations in line voltage Wrong terminal connections at motor Improper phase sequenceQuestion 8 of 37Question 9 of 37 9. 84. What is the reason for frequent blowing of fuse after motor running some time? Improper earthing Poor insulation in winding Over loading of motor Heavy voltage fluctuationQuestion 9 of 37Question 10 of 37 10. 69. What is the name of 3 phase motor winding, if the coil pitch is less than pole pitch? Short chorded winding Whole coil winding Full pitch winding Long chorded windingQuestion 10 of 37Question 11 of 37 11. 74. Which type of testing of winding is illustrated? Polarity test Resistance test Short circuit test Voltage drop testQuestion 11 of 37Question 12 of 37 12. 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 slow speed Runs at very high speed Will not runQuestion 12 of 37Question 13 of 37 13. 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 13 of 37Question 14 of 37 14. 53. Which insulation is used for cuffing in AC winding? Empire fiber glass tape Fabric based adhesive tape Fibre glass tape Leatheroid paperQuestion 14 of 37Question 15 of 37 15. 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 15 of 37Question 16 of 37 16. 63. Where the panel boards are used? 3 phase domestic wiring Domestic wiring circuits Load distribution for AC & DC supply Industrial motor drivesQuestion 16 of 37Question 17 of 37 17. 86. Which is the cause for the 3 phase motor starter with single phase preventer trips frequently? Incorrect fuse ratings Incorrect settings of OLR Unbalanced line voltage Improper phase sequenceQuestion 17 of 37Question 18 of 37 18. 61. What is the reason long chord winding is avoided in AC motors? Low starting torque More winding wire required Less heat dissipation Low efficiencyQuestion 18 of 37Question 19 of 37 19. 52. Which type of insulating material is selected for binding the coils and over hangs? Fibre glass tape Terylene thread Cotton sleeves Empire sleevesQuestion 19 of 37Question 20 of 37 20. 60. Which type of winding wire is used to wind submersible pump motors? Super enamelled type Double cotton covered type Terylene thread type PVC covered typeQuestion 20 of 37Question 21 of 37 21. 85. What happens to a 3 phase induction motor, if one phase fails during starting? Motor runs and stop immediately Motor runs and draws more current Motor continues to run with irregular speed Motor runs in slow speed continuouslyQuestion 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 normally Motor stops at once Motor will run slow speed but winding will be burnt out shortly Motor runs with humming noise with slow speedQuestion 22 of 37Question 23 of 37 23. 55. Which type of AC winding has the number of coil/pole/phase more than one at different pitches? Flat loop over lapped winding Diamond coil winding Flat loop non-over lapped winding Involute coil windingQuestion 23 of 37Question 24 of 37 24. 65. Which type of handle design of rotary switch is illustrated? Knob Key operation Lever Coin slotQuestion 24 of 37Question 25 of 37 25. 58. Which type of starter is used to start and run the 3 phase slip ring induction motor? Rotor rheostat starter Direct on-line starter Manual star-delta starter Auto transformer starterQuestion 25 of 37Question 26 of 37 26. 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 repels against the slots Hacksaw blade gets over heated Attracted by the winding turns on the slotQuestion 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 Excess vibration of shaft Motor does not start Over heating in motorQuestion 27 of 37Question 28 of 37 28. 57. What is the type of rewinding process? Former winding Skein winding Machine winding Hand windingQuestion 28 of 37Question 29 of 37 29. 70. Which is the demerit of 3 phase concentric winding? More difficult to shape the coils uniformly A stepped former is required It is not easy to make the end connection More space is requiredQuestion 29 of 37Question 30 of 37 30. 62. Which type of winding has more space for cooling? Between overhanging coils Between overhanging coils and yoke Between overhanging coil and rotor Between overhanging coil and wedgeQuestion 30 of 37Question 31 of 37 31. 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 31 of 37Question 32 of 37 32. 51. Which is the main property of leatheroid paper insulation? Very good for class F insulation Highly non-hygroscopic Better ageing and dielectric strength Non moisturized materialQuestion 32 of 37Question 33 of 37 33. 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 33 of 37Question 34 of 37 34. 82. What happens to the rotor of a 3 phase induction motor if its speed attains to synchronous speed? Rotor speed increases Rotor speed reduces Rotor speed remains same Rotor bars get damagedQuestion 34 of 37Question 35 of 37 35. 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 35 of 37Question 36 of 37 36. 80. What is the defect in AC 3 phase induction motor runs at low speed if loaded? Partially shorted stator winding Wrong motor connection Wrong starter connection Open circuit in rotor windingQuestion 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 high starting torque To reduce the load current To get high running torque To get increased speed at startingQuestion 37 of 37 Loading...