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. 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 1 of 37Question 2 of 37 2. 53. Which insulation is used for cuffing in AC winding? Fibre glass tape Leatheroid paper Empire fiber glass tape Fabric based adhesive tapeQuestion 2 of 37Question 3 of 37 3. 68. What is the name of the winding? Diamond coil winding Involute coil winding Skew winding Skein windingQuestion 3 of 37Question 4 of 37 4. 62. Which type of winding has more space for cooling? Between overhanging coils Between overhanging coil and wedge Between overhanging coils and yoke Between overhanging coil and rotorQuestion 4 of 37Question 5 of 37 5. 83. What is the effect of open circuit in rotor of an induction motor? Excess vibration of shaft Motor does not start Over heating in motor Motor runs with very low speedQuestion 5 of 37Question 6 of 37 6. 71. What is the name of the diagram used for 3phase motor winding? End connection diagram Ring diagram Coil connection diagram Development diagramQuestion 6 of 37Question 7 of 37 7. 52. Which type of insulating material is selected for binding the coils and over hangs? Terylene thread Empire sleeves Cotton sleeves Fibre glass tapeQuestion 7 of 37Question 8 of 37 8. 80. What is the defect in AC 3 phase induction motor runs at low speed if loaded? Wrong motor connection Partially shorted stator winding Wrong starter connection Open circuit in rotor windingQuestion 8 of 37Question 9 of 37 9. 84. What is the reason for frequent blowing of fuse after motor running some time? Over loading of motor Poor insulation in winding Heavy voltage fluctuation Improper earthingQuestion 9 of 37Question 10 of 37 10. 74. Which type of testing of winding is illustrated? Resistance test Polarity test Voltage drop test Short circuit testQuestion 10 of 37Question 11 of 37 11. 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 11 of 37Question 12 of 37 12. 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 12 of 37Question 13 of 37 13. 73. Which type of AC motor winding having the number of coil/pole/phase is more than one arranged in different slots? Concentrated winding Basket winding Concentric winding Distributed windingQuestion 13 of 37Question 14 of 37 14. 51. Which is the main property of leatheroid paper insulation? Very good for class F insulation Non moisturized material Highly non-hygroscopic Better ageing and dielectric strengthQuestion 14 of 37Question 15 of 37 15. 69. What is the name of 3 phase motor winding, if the coil pitch is less than pole pitch? Full pitch winding Short chorded winding Whole coil winding Long chorded windingQuestion 15 of 37Question 16 of 37 16. 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 16 of 37Question 17 of 37 17. 81. Which fault condition thermal overload relay protects A.C induction motor? Under voltage Over current Short circuit Open circuitQuestion 17 of 37Question 18 of 37 18. 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 will run slow speed but winding will be burnt out shortly Motor stops at onceQuestion 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 increases Rotor speed remains same Rotor speed reduces Rotor bars get damagedQuestion 19 of 37Question 20 of 37 20. 66. What is the purpose of using rotor resistance starter to start 3 phase slip ring induction motor? Reduce rotor current Reduce the power loss Increase the torque Reduce rotor voltageQuestion 20 of 37Question 21 of 37 21. 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 high running torque To reduce the load current To get increased speed at startingQuestion 21 of 37Question 22 of 37 22. 54. What refers coil in AC winding? Number of turns connected in parallel Number of turns under two dissimilar poles Number of turns connected in series Number of turns under two similar polesQuestion 22 of 37Question 23 of 37 23. 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 gets over heated Rapid vibration of hacksaw blade Hacksaw blade repels against the slotsQuestion 23 of 37Question 24 of 37 24. 63. Where the panel boards are used? Domestic wiring circuits 3 phase domestic wiring Industrial motor drives Load distribution for AC & DC supplyQuestion 24 of 37Question 25 of 37 25. 70. Which is the demerit of 3 phase concentric winding? More space is required It is not easy to make the end connection More difficult to shape the coils uniformly A stepped former is requiredQuestion 25 of 37Question 26 of 37 26. 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 12 coils/phase/pole 9 coils/phase/pole 6 coils/phase/poleQuestion 26 of 37Question 27 of 37 27. 67. Which method of speed control is only applicable for 3 phase slipring induction motor? Rotor rheostat speed control Cascade operation method Changing the number of stator poles method Changing the applied frequency methodQuestion 27 of 37Question 28 of 37 28. 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 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? 36.6 Nm 33.05 Nm 21.63 Nm 24.4 NmQuestion 29 of 37Question 30 of 37 30. 77. What happens to a 3 phase induction motor if one phase fails during running? Motor runs with irregular speed Motor runs slowly, finally it burns Motor stop instantaneously Motor runs normallyQuestion 30 of 37Question 31 of 37 31. 85. What happens to a 3 phase induction motor, if one phase fails during starting? Motor runs and draws more current Motor runs and stop immediately Motor runs in slow speed continuously Motor continues to run with irregular speedQuestion 31 of 37Question 32 of 37 32. 59. What is the function of collar? Provides insulation for heat transfer from coil Helps tightening material for flange Provides insulation for coil tapping Provides insulation around fieldQuestion 32 of 37Question 33 of 37 33. 57. What is the type of rewinding process? Hand winding Skein winding Former winding Machine windingQuestion 33 of 37Question 34 of 37 34. 76. What is the effect of motor, if the rotor windings in slipring induction motor is open circuited at starting? Runs at slow speed Runs but not able to pull load Runs at very high speed Will not runQuestion 34 of 37Question 35 of 37 35. 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 Flat loop over lapped winding Involute coil windingQuestion 35 of 37Question 36 of 37 36. 79. What is the defect, if starter with single phasing preventer does not switch ‘ON’? Improper phase sequence Wrong terminal connections at motor Loose contact in supply lines Fluctuations in line voltageQuestion 36 of 37Question 37 of 37 37. 65. Which type of handle design of rotary switch is illustrated? Coin slot Knob Key operation LeverQuestion 37 of 37 Loading...