A 50 hp, 250 V, 1200 r/min DC Shunt Motor with an armature resistance of 0.08 Q. Its field circuit has a total resistance (Radj + R) of 100 N, which produces no-load speed of 1200 r/min. (i) (b) Calculate the motor speeds when the input current at 100A, 200A and 300A. (ii) Using the result obtained from Q3(b)(i) plot the torque-speed curve of the motor. (iii) The motor in Q3(b) is now connected separately excited. The motor is initially running VA = 250 V, IA = 120 A and n= 1103 r/min, while supplying a constant torque load. Determine the speed of this motor be if VA is reduced to 200 V.

Alternating Current (AC) winding is generally of the 3-phase type due to the inherent advantages of the 3-phase machine. Armature coils must be connected to the yield balance (equivalent in magnitude and 2/3 of the series phase difference of the rod) 3-p…