A three phase, $50$ Hz induction motor has four poles and runs at a speed of $1440$ r$/$min when the total

torque developed by the rotor shaft is $70$ N$.$m$.$ The friction loss is $226$ W$.$ Calculate:

a$)$ the total input power to the rotor and

b$)$ the rotor copper losses.

$(11,231$ kW $)$

$(449,24$ W $)$