A DC motor has the following parameters: Number of armature conductors = 60, length of rotor = 30 cm, radius of rotor = 10 cm, field flux density = 1 T, armature resistance = 1.2-ohm. Neglect the armature inductance. The maximum armature current rating is 10 A. The motor is used to drive a load with a torque given by TL = 0.04ω Nm where ω is the speed in rad/sec. The combined inertia of the motor-load system is 0.1 kg.m2.
It is required to bring the load speed from 0 to 100 rad/sec as quickly as possible without exceeding any of the machine ratings.
(a) Calculate the time taken to bring the speed from 0 to 100 rad/sec.
(b) Express the required armature voltage from start to the time when ω reaches 100 rad/sec.