stion 4: (12 marks) A 300 V DC separately excited motor has the parameters Ra=0.4 2, Ko= 1.90986 V.s. The motor drives a constant load torque of value 286.479 Nm at speed = 1200 rpm. Part I: If the motor needs to be braked using dynamic braking and that is by using a braking resistance of value Rb=0.6 2, calculate: a) The braking torque at the instant of braking b) The braking torque when the machine speed has decreased to 800 rpm c) The braking torque when the machine speed becomes zero. Part II: If the motor needs to be braked using the plugging technique in such away that the armature current is limited to 300 A, calculate: a) The braking resistance Rb b) The braking torque at the instant of applying the plugging c) The braking torque when the machine speed has decreased to 0 rpm Part III: In your opinion, which technique (dynamic braking or plugging technique) is faster. Justify your answer.