A machine runs at 1500' rpm that gives a train a speed of 20 mfs

A machine runs at 1500' rpm that gives a train a speed of 20 mfs. The armature terminal voltage and current of the machine are 790 V and 50 A respectively. The armature resistance of the machine is 0.29. a. Obtain the product of the motor constant and the pole ?ux, i.e. KID, in this operating point and then calculate the torque. b. When the ?eld excitation current is halved while the terminal voltage remains constant, by assuming the motor constant K unchanged, obtain the new steady state speed of the motor (in rpm).