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. 53. Which insulation is used for cuffing in AC winding? Fibre glass tape Empire fiber glass tape Fabric based adhesive tape Leatheroid paperQuestion 1 of 37Question 2 of 37 2. 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 2 of 37Question 3 of 37 3. 52. Which type of insulating material is selected for binding the coils and over hangs? Cotton sleeves Empire sleeves Fibre glass tape Terylene threadQuestion 3 of 37Question 4 of 37 4. 74. Which type of testing of winding is illustrated? Voltage drop test Resistance test Polarity test Short circuit testQuestion 4 of 37Question 5 of 37 5. 75. Why external resistance is included in the rotor circuit at starting through 3 phase slipring induction motor starter? To get high running torque To reduce the load current To get increased speed at starting To get high starting torqueQuestion 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? Manual star-delta starter Rotor rheostat starter Auto transformer starter Direct on-line starterQuestion 6 of 37Question 7 of 37 7. 86. Which is the cause for the 3 phase motor starter with single phase preventer trips frequently? Incorrect fuse ratings Unbalanced line voltage Improper phase sequence Incorrect settings of OLRQuestion 7 of 37Question 8 of 37 8. 64. Determine the torque in newton metres produced by a 7.5 HP squirrel cage motor rotating at 1440 rpm? 21.63 Nm 36.6 Nm 24.4 Nm 33.05 NmQuestion 8 of 37Question 9 of 37 9. 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 9 of 37Question 10 of 37 10. 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 10 of 37Question 11 of 37 11. 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 Partially shorted stator winding Wrong starter connectionQuestion 11 of 37Question 12 of 37 12. 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 12 of 37Question 13 of 37 13. 67. Which method of speed control is only applicable for 3 phase slipring induction motor? Changing the applied frequency method Changing the number of stator poles method Rotor rheostat speed control Cascade operation methodQuestion 13 of 37Question 14 of 37 14. 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 Will not run Runs at very high speedQuestion 14 of 37Question 15 of 37 15. 63. Where the panel boards are used? 3 phase domestic wiring Industrial motor drives Load distribution for AC & DC supply Domestic wiring circuitsQuestion 15 of 37Question 16 of 37 16. 77. What happens to a 3 phase induction motor if one phase fails during running? Motor runs slowly, finally it burns Motor runs normally Motor runs with irregular speed Motor stop instantaneouslyQuestion 16 of 37Question 17 of 37 17. 79. What is the defect, if starter with single phasing preventer does not switch ‘ON’? Wrong terminal connections at motor Fluctuations in line voltage Loose contact in supply lines Improper phase sequenceQuestion 17 of 37Question 18 of 37 18. 73. Which type of AC motor winding having the number of coil/pole/phase is more than one arranged in different slots? Distributed winding Basket winding Concentric winding Concentrated windingQuestion 18 of 37Question 19 of 37 19. 68. What is the name of the winding? Skein winding Diamond coil winding Skew winding Involute coil windingQuestion 19 of 37Question 20 of 37 20. 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. 12 coils/phase/pole 6 coils/phase/pole 3 coils/phase/pole 9 coils/phase/poleQuestion 20 of 37Question 21 of 37 21. 62. Which type of winding has more space for cooling? Between overhanging coil and rotor Between overhanging coils Between overhanging coil and wedge Between overhanging coils and yokeQuestion 21 of 37Question 22 of 37 22. 65. Which type of handle design of rotary switch is illustrated? Key operation Knob Coin slot LeverQuestion 22 of 37Question 23 of 37 23. 66. What is the purpose of using rotor resistance starter to start 3 phase slip ring induction motor? Reduce the power loss Reduce rotor voltage Reduce rotor current Increase the torqueQuestion 23 of 37Question 24 of 37 24. 71. What is the name of the diagram used for 3phase motor winding? Ring diagram Coil connection diagram End connection diagram Development diagramQuestion 24 of 37Question 25 of 37 25. 72. Calculate the phase displacement in terms of slots for a 3 phase, 36 slots, 12 coils, 4 pole stator winding? 6 slots 8 slots 4 slots 3 slotsQuestion 25 of 37Question 26 of 37 26. 60. Which type of winding wire is used to wind submersible pump motors? Double cotton covered type Super enamelled type PVC covered type Terylene thread typeQuestion 26 of 37Question 27 of 37 27. 51. Which is the main property of leatheroid paper insulation? Better ageing and dielectric strength Very good for class F insulation Highly non-hygroscopic Non moisturized materialQuestion 27 of 37Question 28 of 37 28. 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 28 of 37Question 29 of 37 29. 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 29 of 37Question 30 of 37 30. 55. Which type of AC winding has the number of coil/pole/phase more than one at different pitches? Diamond coil winding Flat loop non-over lapped winding Involute coil winding Flat loop over lapped windingQuestion 30 of 37Question 31 of 37 31. 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 31 of 37Question 32 of 37 32. 81. Which fault condition thermal overload relay protects A.C induction motor? Over current Under voltage Short circuit Open circuitQuestion 32 of 37Question 33 of 37 33. 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 gets over heated Rapid vibration of hacksaw blade Attracted by the winding turns on the slot Hacksaw blade repels against the slotsQuestion 33 of 37Question 34 of 37 34. 57. What is the type of rewinding process? Machine winding Skein winding Former winding Hand windingQuestion 34 of 37Question 35 of 37 35. 82. What happens to the rotor of a 3 phase induction motor if its speed attains to synchronous speed? Rotor speed increases Rotor speed remains same Rotor speed reduces Rotor bars get damagedQuestion 35 of 37Question 36 of 37 36. 83. What is the effect of open circuit in rotor of an induction motor? Excess vibration of shaft Over heating in motor Motor does not start Motor runs with very low speedQuestion 36 of 37Question 37 of 37 37. 54. What refers coil in AC winding? Number of turns under two similar poles Number of turns under two dissimilar poles Number of turns connected in parallel Number of turns connected in seriesQuestion 37 of 37 Loading...