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Department of Electronics and Communication Engineering
EE
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Question 1 : When load is placed on a 3 phase induction motor its speed
Option-1 :increases
Option-2 :decreases
Option-3 :remains same
Option-4 :none of the above
Question 2 : A three phase,4 pole,50 Hz induction motor runs at a speed of 1440 RPM. the rotating field produced by the rotor rotates at a speed of_________RPM with respect to the rotor.
Option-1 :1500
Option-2 :60
Option-3 :0
Option-4 :1440
Question 3 : In a three phase induction motor,the rotor field rotates at synchronous speed with respect to
Option-1 :stator
Option-2 :rotor
Option-3 :stator flux
Option-4 :none of the above
Question 4 : Irrespective of the supply frequency,the torque developed by a squirrel cage induction motor is the same whenever___________is the same.
Option-1 :supply voltage
Option-2 :external load
Option-3 :rotor resistance
Option-4 :slip speed
Question 5 : Power factor of a squirrel cage induction motor is
Option-1 :low at light loads only
Option-2 :low at heavy loads only
Option-3 :low at light loads and heavy loads both
Option-4 :low at rated load only
Question 6 : The efficiency of a three phase induction motor is approximately proportional to
Option-1 :(1-S)
Option-2 :S
Option-3 :N
Option-4 :Ns
Question 7 : The principle of operation of a three phase induction motor is most similar to that of a
Option-1 :synchronous motor
Option-2 :repulsion-start induction motor
Option-3 :transformer with a shorted secondary
Option-4 :capacitor-start,induction -run motor
Question 8 : The effect of increasing the length of air gap in an induction motor will be to increase the
Option-1 :speed
Option-2 : power factor
Option-3 :magnetising current
Option-4 :air gap flux
Question 9 : In a three phase induction motor,the relative speed of stator flux with respect to_________is zero.
Option-1 :stator winding
Option-2 :rotor
Option-3 :rotor flux
Option-4 :space
Question 10 : Regarding skewing of motor bars in squirrel-cage induction motor.Which statement is false?
Option-1 :it prevents cogging
Option-2 :it increases starting torque
Option-3 :it produces more uniform torque
Option-4 :it reduces motor 'hum' during its operation.
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