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. 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 Hacksaw blade gets over heated Attracted by the winding turns on the slot Rapid vibration of hacksaw bladeQuestion 1 of 37Question 2 of 37 2. 73. Which type of AC motor winding having the number of coil/pole/phase is more than one arranged in different slots? Basket winding Distributed winding Concentric winding Concentrated windingQuestion 2 of 37Question 3 of 37 3. 81. Which fault condition thermal overload relay protects A.C induction motor? Under voltage Short circuit Over current Open circuitQuestion 3 of 37Question 4 of 37 4. 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 4 of 37Question 5 of 37 5. 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 5 of 37Question 6 of 37 6. 58. Which type of starter is used to start and run the 3 phase slip ring induction motor? Rotor rheostat starter Auto transformer starter Manual star-delta starter Direct on-line starterQuestion 6 of 37Question 7 of 37 7. 83. What is the effect of open circuit in rotor of an induction motor? Over heating in motor Excess vibration of shaft Motor does not start Motor runs with very low speedQuestion 7 of 37Question 8 of 37 8. 53. Which insulation is used for cuffing in AC winding? Empire fiber glass tape Fibre glass tape Leatheroid paper Fabric based adhesive 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 coils and yoke Between overhanging coils Between overhanging coil and rotorQuestion 9 of 37Question 10 of 37 10. 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 9 coils/phase/pole 6 coils/phase/pole 12 coils/phase/poleQuestion 10 of 37Question 11 of 37 11. 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 11 of 37Question 12 of 37 12. 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 Long chorded winding Full pitch windingQuestion 12 of 37Question 13 of 37 13. 67. Which method of speed control is only applicable for 3 phase slipring induction motor? Rotor rheostat speed control Changing the applied frequency method Changing the number of stator poles method Cascade operation methodQuestion 13 of 37Question 14 of 37 14. 60. Which type of winding wire is used to wind submersible pump motors? PVC covered type Double cotton covered type Super enamelled type Terylene thread typeQuestion 14 of 37Question 15 of 37 15. 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 get increased speed at starting To get high running torque To reduce the load currentQuestion 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 runs with humming noise with slow speed Motor stops at once Motor will run slow speed but winding will be burnt out shortlyQuestion 16 of 37Question 17 of 37 17. 77. What happens to a 3 phase induction motor if one phase fails during running? Motor stop instantaneously Motor runs with irregular speed Motor runs normally Motor runs slowly, finally it burnsQuestion 17 of 37Question 18 of 37 18. 52. Which type of insulating material is selected for binding the coils and over hangs? Terylene thread Empire sleeves Cotton sleeves Fibre glass tapeQuestion 18 of 37Question 19 of 37 19. 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 19 of 37Question 20 of 37 20. 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 20 of 37Question 21 of 37 21. 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 21 of 37Question 22 of 37 22. 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 A stepped former is required More space is requiredQuestion 22 of 37Question 23 of 37 23. 54. What refers coil in AC winding? Number of turns under two similar poles Number of turns connected in series Number of turns under two dissimilar poles Number of turns connected in parallelQuestion 23 of 37Question 24 of 37 24. 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 24 of 37Question 25 of 37 25. 68. What is the name of the winding? Skew winding Diamond coil winding Skein winding Involute coil windingQuestion 25 of 37Question 26 of 37 26. 80. What is the defect in AC 3 phase induction motor runs at low speed if loaded? Wrong motor connection Open circuit in rotor winding Wrong starter connection Partially shorted stator windingQuestion 26 of 37Question 27 of 37 27. 63. Where the panel boards are used? Industrial motor drives 3 phase domestic wiring Domestic wiring circuits Load distribution for AC & DC supplyQuestion 27 of 37Question 28 of 37 28. 65. Which type of handle design of rotary switch is illustrated? Knob Key operation Coin slot LeverQuestion 28 of 37Question 29 of 37 29. 64. Determine the torque in newton metres produced by a 7.5 HP squirrel cage motor rotating at 1440 rpm? 33.05 Nm 24.4 Nm 36.6 Nm 21.63 NmQuestion 29 of 37Question 30 of 37 30. 51. Which is the main property of leatheroid paper insulation? Very good for class F insulation Better ageing and dielectric strength Non moisturized material Highly non-hygroscopicQuestion 30 of 37Question 31 of 37 31. 79. What is the defect, if starter with single phasing preventer does not switch ‘ON’? Loose contact in supply lines Wrong terminal connections at motor Fluctuations in line voltage Improper phase sequenceQuestion 31 of 37Question 32 of 37 32. 57. What is the type of rewinding process? Former winding Skein winding Machine winding Hand windingQuestion 32 of 37Question 33 of 37 33. 71. What is the name of the diagram used for 3phase motor winding? End connection diagram Development diagram Ring diagram Coil connection diagramQuestion 33 of 37Question 34 of 37 34. 61. What is the reason long chord winding is avoided in AC motors? Less heat dissipation Low efficiency More winding wire required Low starting torqueQuestion 34 of 37Question 35 of 37 35. 76. What is the effect of motor, if the rotor windings in slipring induction motor is open circuited at starting? Will not run Runs but not able to pull load Runs at slow speed Runs at very high speedQuestion 35 of 37Question 36 of 37 36. 74. Which type of testing of winding is illustrated? Voltage drop test Short circuit test Resistance test Polarity testQuestion 36 of 37Question 37 of 37 37. 85. What happens to a 3 phase induction motor, if one phase fails during starting? Motor runs in slow speed continuously Motor runs and draws more current Motor continues to run with irregular speed Motor runs and stop immediatelyQuestion 37 of 37 Loading...