A 320-V, 60-Hz, 4-pole, Delta-connected, three-phase induction motor has the following parameters in ohms/phase referred

[answerhappygod]

A 320-V, 60-Hz, 4-pole, Delta-connected, three-phase induction
motor has the following parameters in ohms/phase referred to the
stator circuit: R1 = 0.3 Ohm, X1 = 0.9 Ohm, R2 = 0.6 Ohm, X2 = 0.9
Ohm, Rc = 150 Ohm, Xm = 60 Ohm. The rotational loss is 4% of the
power developed. If the motor runs at 4% slip, Determine: (a) Rotor
Speed (b) Stator current (c) Power factor (d) Efficiency (e) the
slip at which the motor develops maximum torque (f) If the
rotational losses are kept constant at 500 W, what is the required
rotor current to operate the motor at maximum efficiency?