1. A 220 V, 21 A, 1000 rpm dc shunt motor has an armature resistance of 0.05 ohm and a field resistance of 220 ohms. The magnetization curve for the machine is given by the following table: Field current 0.2 0.4 0.6 0.8 1.0 1.2 1.4 (A) EMF at 1000 rpm (V) 50 100 150 190 219 235 245 Plot the speed-torque curve for the motor when ( a) no external resistances are included, (b) a resistance of 0.05 ohm is connected in series with the armature, and (c) a resistance of 110 ohms is included in series with the field winding