1. Various methods for starting a three phase induction motor are given, which method will required six stator terminals
Correct : C. start delta
2. Which of the following parameters of induction motor varies inversely as the supply freq
Correct : B. starting current
3. When the supply voltage for an induction motor is reduced by 10%, the maximum running torque will be
Correct : B. decrease by 20%
4. If the supply freq of an induction motor is increased by 5%, the synchronous speed will
Correct : C. increase by 5%
5. The direction of rotation of field in a 3-ph induction motor depends upon
Correct : D. phase sequence of supply voltage
6. The maximum voltage is induced in the rotor of 3-ph induction motor when it----
Correct : A. runs at no load
7. When an induction motor is running at full load, rotor reactance is ------rotor resistance
Correct : A. low comparable to
8. If an induction motor is running at slip s ( in decimal) the rotor output is
Correct : D. (1-s) x rotor input
9. The conditions of induction motor at no load resembles those of transformer whose secondary is……
Correct : A. short circuited
10. 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%)
Correct : B. 492w
11. The input to a 3-ph induction motor is 50KW. The stator losses amount to 800W. The mechanical power developed (slip = 3%)
Correct : D. 64hp
12. 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
Correct : A. 248nm
13. 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.