McqMate
| 1. |
Which of the following component is usually fabricated out of silicon steel ? |
| A. | Bearings |
| B. | Shaft |
| C. | Statorcore |
| D. | None of the above |
| Answer» C. Statorcore | |
| 2. |
The frame of an induction motor is usually made of |
| A. | silicon steel |
| B. | cast iron |
| C. | aluminium |
| D. | bronze |
| Answer» B. cast iron | |
| 3. |
The shaft of an induction motor is made of |
| A. | stiff |
| B. | flexible |
| C. | hollow |
| D. | any of the above |
| Answer» A. stiff | |
| 4. |
The shaft of an induction motor is made of |
| A. | high speed steel |
| B. | stainless steel |
| C. | carbon steel |
| D. | cast iron |
| Answer» C. carbon steel | |
| 5. |
In an induction motor, no-load the slip is generally |
| A. | less than 1% |
| B. | 1.5% |
| C. | 2% |
| D. | 4% |
| Answer» A. less than 1% | |
| 6. |
In medium sized induction motors, the slip is generally around |
| A. | 0.04% |
| B. | 0.4% |
| C. | 4% |
| D. | 14% |
| Answer» C. 4% | |
| 7. |
In squirrel cage induction motors, the rotor slots are usually given slight skew in order to |
| A. | reduce windage losses |
| B. | reduce eddy currents |
| C. | reduce accumulation of dirt and dust |
| D. | reduce magnetic hum |
| Answer» D. reduce magnetic hum | |
| 8. |
In case the air gap in an induction motor is increased |
| A. | the magnetising current of the rotor will decrease |
| B. | the power factor will decrease |
| C. | speed of motor will increase |
| D. | the windage losses will increase |
| Answer» B. the power factor will decrease | |
| 9. |
Slip rings are usually made of |
| A. | copper |
| B. | carbon |
| C. | phospor bronze |
| D. | aluminium |
| Answer» C. phospor bronze | |
| 10. |
A 3-phase 440 V, 50 Hz induction motor has 4% slip. The frequency of rotor e.m.f. will be |
| A. | 200 Hz |
| B. | 50 Hz |
| C. | 2 Hz |
| D. | 0.2 Hz |
| Answer» C. 2 Hz | |
| 11. |
In Ns is the synchronous speed and s the slip, then actual running speed of an induction motor will be |
| A. | Ns |
| B. | s.N, |
| C. | (l-s)Ns |
| D. | (Ns-l)s |
| Answer» C. (l-s)Ns | |
| 12. |
The efficiency of an induction motor can be expected to be nearly |
| A. | 60 to 90% |
| B. | 80 to 90% |
| C. | 95 to 98% |
| D. | 99% |
| Answer» B. 80 to 90% | |
| 13. |
The number of slip rings on a squirrel cage induction motor is usually |
| A. | two |
| B. | three |
| C. | four |
| D. | none |
| Answer» D. none | |
| 14. |
The starting torque of a squirrel-cage induction motor is |
| A. | low |
| B. | negligible |
| C. | same as full-load torque |
| D. | slightly more than full-load torque |
| Answer» A. low | |
| 15. |
A double squirrel-cage induction motor has |
| A. | two rotors moving in oppsite direction |
| B. | two parallel windings in stator |
| C. | two parallel windings in rotor |
| D. | two series windings in stator |
| Answer» C. two parallel windings in rotor | |
| 16. |
Star-delta starting of motors is not possible in case of |
| A. | single phase motors |
| B. | variable speed motors |
| C. | low horse power motors |
| D. | high speed motors |
| Answer» A. single phase motors | |
| 17. |
The term 'cogging' is associated with |
| A. | three phase transformers |
| B. | compound generators |
| C. | D.C. series motors |
| D. | induction motors |
| Answer» D. induction motors | |
| 18. |
In case of the induction motors the torque is |
| A. | inversely proportional to (Vslip) |
| B. | directly proportional to (slip)2 |
| C. | inversely proportional to slip |
| D. | directly proportional to slip |
| Answer» D. directly proportional to slip | |
| 19. |
An induction motor with 1000 r.p.m. speed will have |
| A. | 8 poles |
| B. | 6 poles |
| C. | 4 poles |
| D. | 2 poles |
| Answer» B. 6 poles | |
| 20. |
The good power factor of an induction motor can be achieved if the average flux density in the air gap is |
| A. | absent |
| B. | small |
| C. | large |
| D. | infinity |
| Answer» B. small | |
| 21. |
An induction motor is identical to |
| A. | D.C. compound motor |
| B. | D.C. series motor |
| C. | synchronous motor |
| D. | asynchronous motor |
| Answer» D. asynchronous motor | |
| 22. |
The injected e.m.f. in the rotor of induction motor must have |
| A. | zero frequency |
| B. | the same frequency as the slip fre-quency |
| C. | the same phase as the rotor e.m.f. |
| D. | high value for the satisfactory speed control |
| Answer» B. the same frequency as the slip fre-quency | |
| 23. |
Which of the following methods is easily applicable to control the speed of the squirrel-cage induction motor ? |
| A. | By changing the number of stator poles |
| B. | Rotor rheostat control |
| C. | By operating two motors in cascade |
| D. | By injecting e.m.f. in the rotor circuit |
| Answer» A. By changing the number of stator poles | |
| 24. |
The crawling in the induction motor is caused by |
| A. | low voltage supply |
| B. | high loads |
| C. | harmonics develped in the motor |
| D. | improper design of the machine |
| Answer» C. harmonics develped in the motor | |
| 25. |
The auto-starters (using three auto transformers) can be used to start cage induction motor of the following type |
| A. | star connected only |
| B. | delta connected only |
| C. | (a) and (b) both |
| D. | none of the above |
| Answer» C. (a) and (b) both | |
| 26. |
The torque developed in the cage induction motor with autostarter is |
| A. | k/torque with direct switching |
| B. | K x torque with direct switching |
| C. | K2 x torque with direct switching |
| D. | k2/torque with direct switching |
| Answer» C. K2 x torque with direct switching | |
| 27. |
When the equivalent circuit diagram of doouble squirrel-cage induction motor is constructed the two cages can be considered |
| A. | in series |
| B. | in parallel |
| C. | in series-parallel |
| D. | in parallel with stator |
| Answer» B. in parallel | |
| 28. |
It is advisable to avoid line-starting of induction motor and use starter because |
| A. | motor takes five to seven times its full load current |
| B. | it will pick-up very high speed and may go out of step |
| C. | it will run in reverse direction |
| D. | starting torque is very high |
| Answer» A. motor takes five to seven times its full load current | |
| 29. |
Stepless speed control of induction motor is possible by which of the following methods ? |
| A. | e.m.f. injection in rotor eueuit |
| B. | Changing the number of poles |
| C. | Cascade operation |
| D. | None of the above |
| Answer» B. Changing the number of poles | |
| 30. |
Rotor rheostat control method of speed control is used for |
| A. | squirrel-cage induction motors only |
| B. | slip ring induction motors only |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» B. slip ring induction motors only | |
| 31. |
In the circle diagram for induction motor, the diameter of the circle represents |
| A. | slip |
| B. | rotor current |
| C. | running torque |
| D. | line voltage |
| Answer» B. rotor current | |
| 32. |
For which motor the speed can be controlled from rotor side ? |
| A. | Squirrel-cage induction motor |
| B. | Slip-ring induction motor |
| C. | Both (a) and (b) |
| D. | None of the above |
| Answer» B. Slip-ring induction motor | |
| 33. |
If any two phases for an induction motor are interchanged |
| A. | the motor will run in reverse direction |
| B. | the motor will run at reduced speed |
| C. | the motor will not run |
| D. | the motor will burn |
| Answer» A. the motor will run in reverse direction | |
| 34. |
An induction motor is |
| A. | self-starting with zero torque |
| B. | self-starting with high torque |
| C. | self-starting with low torque |
| D. | non-self starting |
| Answer» C. self-starting with low torque | |
| 35. |
The maximum torque in an induction motor depends on |
| A. | frequency |
| B. | rotor inductive reactance |
| C. | square of supply voltage |
| D. | all of the above |
| Answer» D. all of the above | |
| 36. |
In three-phase squirrel-cage induction motors |
| A. | rotor conductor ends are short-circuited through slip rings |
| B. | rotor conductors are short-circuited through end rings |
| C. | rotor conductors are kept open |
| D. | rotor conductors are connected to insulation |
| Answer» B. rotor conductors are short-circuited through end rings | |
| 37. |
In a three-phase induction motor, the number of poles in the rotor winding is always |
| A. | zero |
| B. | more than the number of poles in stator |
| C. | less than number of poles in stator |
| D. | equal to number of poles in stator |
| Answer» D. equal to number of poles in stator | |
| 38. |
DOL starting of induction motors is usually restricted to |
| A. | low horsepower motors |
| B. | variable speed motors |
| C. | high horsepower motors |
| D. | high speed motors |
| Answer» A. low horsepower motors | |
| 39. |
The speed of a squirrel-cage induction motor can be controlled by all of the following except |
| A. | changing supply frequency |
| B. | changing number of poles |
| C. | changing winding resistance |
| D. | reducing supply voltage |
| Answer» C. changing winding resistance | |
| 40. |
The 'crawling" in an induction motor is caused by |
| A. | high loads |
| B. | low voltage supply |
| C. | improper design of machine |
| D. | harmonics developed in the motor |
| Answer» D. harmonics developed in the motor | |
| 41. |
The power factor of an induction motor under no-load conditions will be closer to |
| A. | 0.2 lagging |
| B. | 0.2 leading |
| C. | 0.5 leading |
| D. | unity |
| Answer» A. 0.2 lagging | |
| 42. |
The 'cogging' of an induction motor can be avoided by |
| A. | proper ventilation |
| B. | using DOL starter |
| C. | auto-transformer starter |
| D. | having number of rotor slots more or less than the number of stator slots (not equal) |
| Answer» D. having number of rotor slots more or less than the number of stator slots (not equal) | |
| 43. |
If an induction motor with certain ratio of rotor to stator slots, runs at 1/7 of the normal speed, the phenomenon will be termed as |
| A. | humming |
| B. | hunting |
| C. | crawling |
| D. | cogging |
| Answer» C. crawling | |
| 44. |
Slip of an induction motor is negative when |
| A. | magnetic field and rotor rotate in opposite direction |
| B. | rotor speed is less than the syn-chronous speed of the field and are in the same direction |
| C. | rotor speed is more than the syn-chronous speed of the field and are in the same direction |
| D. | none of the above |
| Answer» C. rotor speed is more than the syn-chronous speed of the field and are in the same direction | |
| 45. |
Size of a high speed motor as compared to low speed motorfor the same H.P. will be |
| A. | bigger |
| B. | smaller |
| C. | same |
| D. | any of the above |
| Answer» B. smaller | |
| 46. |
A 3-phase induction motor stator delta connected, is carrying full load and one of its fuses blows out. Then the motor |
| A. | will continue running burning its one phase |
| B. | will continue running burning its two phases |
| C. | will stop and carry heavy current causing permanent damage to its winding |
| D. | will continue running without any harm to the winding |
| Answer» A. will continue running burning its one phase | |
| 47. |
A 3-phase induction motor delta connected is carrying too heavy load and one of its fuses blows out. Then the motor |
| A. | will continue running burning its one phase |
| B. | will continue running burning its two phase |
| C. | will stop and carry heavy current causing permanent damage to its winding |
| D. | will continue running without any harm to the winding |
| Answer» C. will stop and carry heavy current causing permanent damage to its winding | |
| 48. |
Low voltage at motor terminals is due to |
| A. | inadequate motor wiring |
| B. | poorely regulated power supply |
| C. | any one of the above |
| D. | none of the above |
| Answer» C. any one of the above | |
| 49. |
In an induction motor the relationship between stator slots and rotor slots is that |
| A. | stator slots are equal to rotor slots |
| B. | stator slots are exact multiple of rotor slots |
| C. | stator slots are not exact multiple of rotor slots |
| D. | none of the above |
| Answer» C. stator slots are not exact multiple of rotor slots | |
| 50. |
Slip ring motor is recommended where |
| A. | speed control is required |
| B. | frequent starting, stopping and reversing is required |
| C. | high starting torque is needed |
| D. | all above features are required |
| Answer» D. all above features are required | |
| 51. |
As load on an induction motor goes on increasing |
| A. | its power factor goes on decreasing |
| B. | its power factor remains constant |
| C. | its power factor goes on increasing even after full load |
| D. | its power factor goes on increasing upto full load and then it falls again |
| Answer» D. its power factor goes on increasing upto full load and then it falls again | |
| 52. |
If a 3-phase supply is given to the stator and rotor is short circuited rotor will move |
| A. | in the opposite direction as the direction of the rotating field |
| B. | in the same direction as the direction of the field |
| C. | in any direction depending upon phase squence of supply |
| D. | none |
| Answer» B. in the same direction as the direction of the field | |
| 53. |
It is advisable to avoid line starting of induction motor and use starter because |
| A. | it will run in reverse direction |
| B. | it will pick up very high speed and may go out of step |
| C. | motor takes five to seven times its fullload current |
| D. | starting torque is very high |
| Answer» C. motor takes five to seven times its fullload current | |
| 54. |
The speed characteristics of an induction motor closely resemble the speedload characteristics of which of the following machines |
| A. | D.C. series motor |
| B. | D.C. shunt motor |
| C. | universal motor |
| D. | none of the above |
| Answer» B. D.C. shunt motor | |
| 55. |
Which type of bearing is provided in small induction motors to support the rotor shaft ? |
| A. | Ball bearings |
| B. | Cast iron bearings |
| C. | Bush bearings |
| D. | None of the above |
| Answer» A. Ball bearings | |
| 56. |
A pump induction motor is switched on to a supply 30% lower than its rated voltage. The pump runs. What will eventually happen ? It will |
| A. | stall after sometime |
| B. | stall immediately |
| C. | continue to run at lower speed without damage |
| D. | get heated and subsequently get damaged |
| Answer» D. get heated and subsequently get damaged | |
| 57. |
5 H.P., 50-Hz, 3-phase, 440 V, induction motors are available for the following r.p.m. Which motor will be the costliest ? |
| A. | 730 r.p.m. |
| B. | 960 r.p.m. |
| C. | 1440 r.p.m. |
| D. | 2880 r.p.m. |
| Answer» A. 730 r.p.m. | |
| 58. |
A 3-phase slip ring motor has |
| A. | double cage rotor |
| B. | wound rotor |
| C. | short-circuited rotor |
| D. | any of the above |
| Answer» B. wound rotor | |
| 59. |
The starting torque of a 3-phase squirrel cage induction motor is |
| A. | twice the full load torque |
| B. | 1.5 times the full load torque |
| C. | equal to full load torque |
| Answer» B. 1.5 times the full load torque | |
| 60. |
Short-circuit test on an induction motor cannot be used to determine |
| A. | windage losses |
| B. | copper losses |
| C. | transformation ratio |
| D. | power scale of circle diagram |
| Answer» A. windage losses | |
| 61. |
In a three-phase induction motor |
| A. | iron losses in stator will be negligible as compared to that in rotor |
| B. | iron losses in motor will be neg¬ligible as compared to that in rotor |
| C. | iron losses in stator will be less than that in rotor |
| D. | iron losses in stator will be more than that in rotor |
| Answer» D. iron losses in stator will be more than that in rotor | |
| 62. |
In case of 3-phase induction motors, plugging means |
| A. | pulling the motor directly on line without a starter |
| B. | locking of rotor due to harmonics |
| C. | starting the motor on load which is more than the rated load |
| D. | interchanging two supply phases for quick stopping |
| Answer» D. interchanging two supply phases for quick stopping | |
| 63. |
Which is of the following data is required to draw the circle diagram for an induction motor ? |
| A. | Block rotor test only |
| B. | No load test only |
| C. | Block rotor test and no-load test |
| D. | Block rotor test, no-load test and stator resistance test |
| Answer» D. Block rotor test, no-load test and stator resistance test | |
| 64. |
In three-phase induction motors sometimes copper bars are placed deep in the rotor to |
| A. | improve starting torque |
| B. | reduce copper losses |
| C. | improve efficiency |
| D. | improve power factor |
| Answer» A. improve starting torque | |
| 65. |
In a three-phase induction motor |
| A. | power factor at starting is high as compared to that while running |
| B. | power factor at starting is low as compared to that while running |
| C. | power factor at starting in the same as that while running |
| Answer» B. power factor at starting is low as compared to that while running | |
| 66. |
The vafcie of transformation ratio of an induction motor can be found by |
| A. | open-circuit test only |
| B. | short-circuit test only |
| C. | stator resistance test |
| D. | none of the above |
| Answer» B. short-circuit test only | |
| 67. |
The power scale of circle diagram of an induction motor can be found from |
| A. | stator resistance test |
| B. | no-load test only |
| C. | short-circuit test only |
| D. | noue of the above |
| Answer» C. short-circuit test only | |
| 68. |
The shape of the torque/slip curve of induction motor is |
| A. | parabola |
| B. | hyperbola |
| C. | rectangular parabola |
| D. | straigth line |
| Answer» C. rectangular parabola | |
| 69. |
A change of 4% of supply voltage to an induction motor will produce a change of appromimately |
| A. | 4% in the rotor torque |
| B. | 8% in the rotor torque |
| C. | 12% in the rotor torque |
| D. | 16% in the rotor torque |
| Answer» D. 16% in the rotor torque | |
| 70. |
The stating torque of the slip ring induction motor can be increased by adding |
| A. | external inductance to the rotor |
| B. | external resistance to the rotor |
| C. | external capacitance to the rotor |
| D. | both resistance and inductance to rotor |
| Answer» B. external resistance to the rotor | |
| 71. |
A 500 kW, 3-phase, 440 volts, 50 Hz, A.C. induction motor has a speed of 960 r.p.m. on full load. The machine has 6 poles. The slip of the machine will be |
| A. | 0.01 |
| B. | 0.02 |
| C. | 0.03 |
| D. | 0.04 |
| Answer» D. 0.04 | |
| 72. |
The complete circle diagram of induetion motor can be drawn with the help of data found from |
| A. | noload test |
| B. | blocked rotor test |
| C. | stator resistance test |
| D. | all of the above |
| Answer» D. all of the above | |
| 73. |
In the squirrel-cage induction motor the rotor slots are usually given slight skew |
| A. | to reduce the magnetic hum and locking tendency of the rotor |
| B. | to increase the tensile strength of the rotor bars |
| C. | to ensure easy fabrication |
| D. | none of the above |
| Answer» A. to reduce the magnetic hum and locking tendency of the rotor | |
| 74. |
The torque of a rotor in an induction motor under running condition is maximum |
| A. | at the unit value of slip |
| B. | at the zero value of slip |
| C. | at the value of the slip which makes rotor reactance per phase equal to the resistance per phase |
| D. | at the value of the slip which makes the rotor reactance half of the rotor |
| Answer» C. at the value of the slip which makes rotor reactance per phase equal to the resistance per phase | |
| 75. |
What will happen if the relative speed between the rotating flux of stator and rotor of the induction motor is zero ? |
| A. | The slip of the motor will be 5% |
| B. | The rotor will not run |
| C. | The rotor will run at very high speed |
| D. | The torque produced will be very large |
| Answer» B. The rotor will not run | |
| 76. |
The circle diagram for an induction motor cannot be used to determine |
| A. | efficiency |
| B. | power factor |
| C. | frequency |
| D. | output |
| Answer» A. efficiency | |
| 77. |
Blocked rotor test on induction motors is used to find out |
| A. | leakage reactance |
| B. | power factor on short circuit |
| C. | short-circuit current under rated voltage |
| D. | all of the above |
| Answer» D. all of the above | |
| 78. |
Lubricant used for ball bearing is usually |
| A. | graphite |
| B. | grease |
| C. | mineral oil |
| D. | molasses |
| Answer» B. grease | |
| 79. |
An induction motor can run at synchronous speed when |
| A. | it is run on load |
| B. | it is run in reverse direction |
| C. | it is run on voltage higher than the rated voltage |
| D. | e.m.f. is injected in the rotor circuit |
| Answer» D. e.m.f. is injected in the rotor circuit | |
| 80. |
Which motor is preferred for use in mines where explosive gases exist ? |
| A. | Air motor |
| B. | Induction motor |
| C. | D.C. shunt motor |
| D. | Synchronous motor |
| Answer» A. Air motor | |
| 81. |
The torque developed by a 3-phase induction motor least depends on |
| A. | rotor current |
| B. | rotor power factor |
| C. | rotor e.m.f. |
| D. | shaft diameter |
| Answer» D. shaft diameter | |
| 82. |
In an induction motor if air-gap is increased |
| A. | the power factor will be low |
| B. | windage losses will be more |
| C. | bearing friction will reduce |
| D. | copper loss will reduce In an induction motor |
| Answer» A. the power factor will be low | |
| 83. |
In induction motor, percentage slip depends on |
| A. | supply frequency |
| B. | supply voltage |
| C. | copper losses in motor |
| D. | none of the above |
| Answer» C. copper losses in motor | |
| 84. |
When /?2 is tne rotor resistance, .X2 the rotor reactance at supply frequency and s the slip, then the condition for maximum torque under running condi-tions will be |
| A. | sR2X2 = 1 |
| B. | sR2 = X2 |
| C. | R2 = sX2 i |
| D. | R2 = s2X2 |
| Answer» C. R2 = sX2 i | |
| 85. |
In case of a double cage induction motor, the inner cage has |
| A. | high inductance arid low resistance |
| B. | low inductance and high resistance |
| C. | low inductance and low resistance |
| D. | high inductance and high resis¬tance |
| Answer» A. high inductance arid low resistance | |
| 86. |
The low power factor of induction motor is due to |
| A. | rotor leakage reactance |
| B. | stator reactance |
| C. | the reactive lagging magnetizing current necessary to generate the magnetic flux |
| D. | all of the above |
| Answer» D. all of the above | |
| 87. |
Insertion of reactance in the rotor circuit |
| A. | reduces starting torque as well as maximum torque |
| B. | increases starting torque as well as maximum torque |
| C. | increases starting torque but maxi-mum torque remains unchanged |
| D. | increases starting torque but maxi-mum torque decreases |
| Answer» A. reduces starting torque as well as maximum torque | |
| 88. |
Insertion of resistance in the rotcir of an induction motor to develop a given torque |
| A. | decreases the rotor current |
| B. | increases the rotor current |
| C. | rotor current becomes zero |
| D. | rotor current rernains same |
| Answer» D. rotor current rernains same | |
| 89. |
For driving high inertia loods best type of induction motor suggested is |
| A. | slip ring type |
| B. | squirrel cage type |
| C. | any of the above |
| D. | none of the above |
| Answer» A. slip ring type | |
| 90. |
Temperature of the stator winding of a three phase induction motor is obtained by |
| A. | resistance rise method |
| B. | thermometer method |
| C. | embedded temperature method |
| D. | all above methods |
| Answer» D. all above methods | |
| 91. |
The purpose of using short-circuit gear is |
| A. | to short circuit the rotor at slip rings |
| B. | to short circuit the starting resis¬tances in the starter |
| C. | to short circuit the stator phase of motor to form star |
| D. | none of the above |
| Answer» A. to short circuit the rotor at slip rings | |
| 92. |
In a squirrel cage motor the induced e.m.f. is |
| A. | dependent on the shaft loading |
| B. | dependent on the number of slots |
| C. | slip times the stand still e.m.f. induced in the rotor |
| D. | none of the above |
| Answer» C. slip times the stand still e.m.f. induced in the rotor | |
| 93. |
Less maintenance troubles are experienced in case of |
| A. | slip ring induction motor |
| B. | squirrel cage induction motor |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» B. squirrel cage induction motor | |
| 94. |
A squirrel cage induction motor is not selected when |
| A. | initial cost is the main consideration |
| B. | maintenance cost is to be kept low |
| C. | higher starting torque is the main consideration |
| D. | all above considerations are involved |
| Answer» C. higher starting torque is the main consideration | |
| 95. |
Reduced voltage starter can be used with |
| A. | slip ring motor only but not with squirrel cage induction motor |
| B. | squirrel cage induction motor only but not with slip ring motor |
| C. | squirrel cage as well as slip ring induction motor |
| D. | none of the above |
| Answer» C. squirrel cage as well as slip ring induction motor | |
| 96. |
Slip ring motor is preferred over squirrel cage induction motor where |
| A. | high starting torque is required |
| B. | load torque is heavy |
| C. | heavy pull out torque is required |
| D. | all of the above |
| Answer» A. high starting torque is required | |
| 97. |
In a star-delta starter of an induction motor |
| A. | resistance is inserted in the stator |
| B. | reduced voltage is applied to the stator |
| C. | resistance is inserted in the rotor |
| D. | applied voltage per1 stator phase is 57.7% of the line voltage |
| Answer» D. applied voltage per1 stator phase is 57.7% of the line voltage | |
| 98. |
The torque of an induction motor is |
| A. | directly proportional to slip |
| B. | inversely proportional to slip |
| C. | proportional to the square of the slip |
| D. | none of the above |
| Answer» A. directly proportional to slip | |
| 99. |
The rotor of an induction motor runs at |
| A. | synchronous speed |
| B. | below synchronous speed |
| C. | above synchronous speed |
| D. | any of the above |
| Answer» B. below synchronous speed | |
| 100. |
The starting torque of a three phase induction motor can be increased by |
| A. | increasing slip |
| B. | increasing current |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» C. both (a) and (b) | |
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