Q.28- A DC shunt motor is running at 1200 rpm, when exited with 220 V DC. Neglecting the losses and saturation, the speed of the motor when connected to a 175 V DC supply is- (a) 750 RPM (b) 900 RPM (c) 1050 RPM (d) 1200 RPM (Gate EE 1999) Q.29- With the help of neat sketches the difference between the three phase slip ring induction motor and three phase squirrel cage induction motor. Discuss the merits of one over the other. Q.30- Explain the construction and working of three phase induction motor. Q.31- Discuss the concept of production of rotating magnetic field in a three phase induction motor. Q.32- Why does an induction motor never attains synchronous speed? Q.33- Write a short note on starting of induction motor. Q.34- An induction motor runs at 1460 rpm under full load condition when supplied by 50 HZ supply. Find the number of poles and slip of motor. Q.35- Explain the various methods of speed control of induction motor. Q.36- Explain the constructional features of DC machine.