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