A three-phase, 50-hp, 440-V, 60-Hz, four-pole, wound-rotor induction motor operates at a slip of 0.03 at full load, with its slip rings short-circuited. The motor is capable of developing a maximum torque of two times the full-load torque at rated voltage and frequency. The rotor resistance per phase referred to the stator is 0.1 Ω. Neglect the stator resistance and rotational and stray-load losses. Find the rotor copper loss at full load and the speed at maximum torque. Compute the value of the per-phase rotor resistance (referred to the stator) that must be added in series to produce a starting torque equal to the maximum torque.