Electrical And Electronics Engineering Set 13

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This set of Electrical and Electronics Engineering Multiple Choice Questions & Answers (MCQs) focuses on Electrical And Electronics Engineering Set 13

Q1 | Various methods for starting a three phase induction motor are given, which method will required six stator terminals
  • dol
  • auto transformer
  • start delta
  • rheostat
Q2 | Which of the following parameters of induction motor varies inversely as the supply freq
  • full load speed
  • starting current
  • slip
  • maximum running torque
Q3 | When the supply voltage for an induction motor is reduced by 10%, the maximum running torque will be
  • decrease by 10%
  • decrease by 20%
  • increase by 10%
  • increase by 20%
Q4 | If the supply freq of an induction motor is increased by 5%, the synchronous speed will
  • decrease by 10%
  • decrease by 5%
  • increase by 5%
  • increase by 10%
Q5 | The direction of rotation of field in a 3-ph induction motor depends upon
  • number of poles
  • magnitude of supply voltage
  • supply freq
  • phase sequence of supply voltage
Q6 | The maximum voltage is induced in the rotor of 3-ph induction motor when it----
  • runs at no load
  • runs at full load
  • is blocked
  • none of the above
Q7 | When an induction motor is running at full load, rotor reactance is ------rotor resistance
  • low comparable to
  • very large compared to
  • large compared to
  • none of the above
Q8 | If an induction motor is running at slip s ( in decimal) the rotor output is
  • (1+s) x rotor input
  • (s-1) x rotor input
  • s x rotor input
  • (1-s) x rotor input
Q9 | The conditions of induction motor at no load resembles those of transformer whose secondary is……
  • short circuited
  • open circuited
  • supplying a variable resistive load
  • none of the above
Q10 | The input to a 3-ph induction motor is 50KW. The stator losses amount to 800W. The rotor cu loss per phase is (slip = 3%)
  • 576w
  • 492w
  • 1050w
  • 728w
Q11 | The input to a 3-ph induction motor is 50KW. The stator losses amount to 800W. The mechanical power developed (slip = 3%)
  • 59hp
  • 69hp
  • 47hp
  • 64hp
Q12 | An 8-pole , 50Hz,3-ph indduction motor running with a slip of 4% is taking 20KW. Stator losses amount 0.5KW. The total torque develped is
  • 248nm
  • 312nm
  • 195nm
  • 214nm
Q13 | A 6pole, 3-ph induction motor is runs at a speed of 960rpm & the shaft torque is 135.7Nm. Calculate the rotor cu loss if the friction and windage losses amount to 150W. The suppy freq is 50Hz.
  • 625w
  • 785w
  • 425w
  • 574w