Q1) 3-phase , 50 HZ. 400 V, 6-pole, delta connection, slip-ring induction motor has : R2=0.22, X2=1 per phase referred to stator, when driving a fan load (TL a W 2) it runs at full-load slip of 4%, what resistance must be inserted in the rotor circuit to obtain a speed of 850 rpm (stator to rotor = 2,2) (W is the angular speed rad/sec) ?(36 mark)