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This set of Electrical and Electronics Engineering Multiple Choice Questions & Answers (MCQs) focuses on Electrical And Electronics Engineering Set 9
Q1 | For 3phase I.M,the synchronous speed of rotating magnetic field is 1000 rpm,speed of rotor is 970 rpm ,then slip is
- 0.01
- 0.06
- 0.03
- 0.05
Q2 | For 3phase I.M,the synchronous speed of rotating magnetic field is 1500 rpm,speed of rotor is 1440 rpm ,then slip is
- 0.01
- 0.06
- 0.03
- 0.04
Q3 | For 3phase I.M,the synchronous speed of rotating magnetic field is 750 rpm, speed of rotor is 731.25 rpm ,then slip is
- 0.025
- 0.06
- 0.03
- 0.04
Q4 | For 3phase I.M.,the synchronous speed of rotating magnetic field is 1000 rpm, slip is 3% ,speed of rotor is----------
- 970rpm
- 1000
- 250
- 500
Q5 | For 3phase I.M,the synchronous speed of rotating magnetic field is 750 rpm, slip is 2.5% ,speed of rotor is----------
- 500rpm
- 731.25rpm
- 1150rpm
- 300
Q6 | For I.M. running with 731.25rpm with slip of 2.5%, the synchronous speed of rotating magnetic field
- 750
- 1000
- 500
- 1500
Q7 | For I.M. running with 1440rpm with slip of 4% the synchronous speed of rotating magnetic field
- 750
- 1000
- 1500
- 500
Q8 | For I.M. running with 970rpm with slip of 3%, the synchronous speed of rotating magnetic field
- 750
- 1000
- 1500
- 500
Q9 | A 6pole ,3 phase 50Hz I.M is running with 970 rpm. The slip of I.M is
- 0.03
- 0.05
- 0.02
- 0.01
Q10 | A 8 pole ,50Hz ,3phase I.M ,If full load slip is 2.5%. Rotor speed is
- 200
- 731
- 600
- 1000
Q11 | A 8pole ,3 phase 50Hz I.M is running with 731.25 rpm. The slip of I.M is
- 0.0256
- 1.975
- 0.025
- none of the above
Q12 | A 6pole ,3 phase 50Hz I.M is running with s=3%,runs with
- 200
- 600
- 1000
- 970
Q13 | A 3-phase slip-ring induction motor has ……………… rotor.
- short circuited
- wound
- squirrel cage
- double cage
Q14 | A wound rotor induction motor can be distinguished from a squirrel cage induction motor by
- presence of slip-rings.
- frame size
- shaft diameter
- any of the above
Q15 | The operation of an induction motor is based on
- len\s law
- ampere law
- principle of mutual induction
- principle of self induction
Q16 | The rotating magnetic field produced by stator currents rotates at
- synchronous speed , ns
- rotor speed n
- speed = ns - n
- a speed higher than synchronous speed
Q17 | The relative speed between stator flux and rotor is equal to
- synchronous speed , ns
- rotor speed n
- zero
- ns - n
Q18 | Two of the supply terminals to a 3-phase induction motor get interchanged during reconnection after normal maintenance. When switched on to supply, the motor will
- rotate in the same direction as before maintenance.
- rotate in a direction opposite to that before maintenance.
- not start at all.
- get heated and damaged.
Q19 | The direction of rotation of a 3-phase induction motor can be reversed by
- interchanging any two leads from supply.
- interchanging any two leads from slip-rings.
- interchanging all the three leads from the supply
- disconnecting any one phase
Q20 | The speed of rotor of an induction motor is always ………………… synchronous speed.
- equal to
- more than
- less than
- half of
Q21 | Synchronous speed is defined as the speed at which the
- stator magnetic field rotates.
- rotor rotates on no-load.
- rotor rotates on full load.
- none of the above.
Q22 | A 3-phase, 4-pole induction motor has a no-load slip of 2% when connnected to a 25 Hz source, the no-load speed in rpm is
- 730
- 735
- 765
- 1430
Q23 | A 4-pole, 3-phase induction motor is running at 4 percent slip at full load. If the speed of the motor is 720 rpm, the supply frequency is
- 16hz
- 25hz
- 16
- 20
Q24 | The speed of rotating field due to rotor currents relative to rotor surface in an induction motor is
- n
- s.n
- ns
- s.ns
Q25 | The speed of rotating field due to rotor currents relative to stator core in an induction motor is
- s
- ns
- sn
- sns