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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