Q1. Choose the correct answer. 1- The disadvantage of starting an induction motor with a star-delta starter is (a) the starting torque is one-third of the torque in case of delta connection (b) during starting high losses result (c) the starting torque increases and the motor runs with vibration (d) the starting current is high 2- In the 3-phase induction motor, the resultant flux of rotating magnetic field is equal to .......... (a) the maximum value of flux due to any phase (b) 3/2 times maximum value of flux due to any phase (c) 1/2 times maximum value of flux due to any phase (d) 3 times maximum value of flux due to any phase 3- If an induction machine is run at speed above the synchronous speed it works in............ region of torque-speed characteristic. (a) induction generator (b) induction motor (c) brake (d) unstable 4- The rotor slots are slightly skewed in squirrel cage induction motor to (a) provide ease of fabrication .... (b) reduce the magnetic hum and locking tendency of rotor (c) increase the strength of rotor bars (d) decrease the amount of copper to be used 5- Crawling in an induction motor is caused by (a) harmonics (b) low voltage (c) high voltage (d) overheating 6- In the 3-phase induction motor, the external type of braking is (a) DC braking (b) plugging (c) mechanical braking (d) AC braking 7- The highest starting torque in three phase'squirrel cage induction motor is found in motor type NEMA (a) Design A 8- The speed control method type (a) pole changing (b) Design B (c) Design C (d) Design D _ cannot be applied on wound rotor induction motor. (c) rotor resistance control (b) stator voltage control- (d) variable frequency variable voltage control 9- The iron losses is represented in the equivalent circuit of three-phase induction motor by (a) R1 (b) R2 (c) Rc (d) RL 10- If supply voltage of a 3-phase induction motor is increased 2 times, then torque is ----------... (a) increased 2 times (b) decreased 2 times (c) increased 4 times (d) decreased 4 times