Q1//A 4-pole, 400 V, 1710 rpm, 60 Hz, 3-phase induction motor star connected has the following circuit model parameters: $R_1 = 2R_2' = 0.2 \Omega$, $X_1 = 0.5 \Omega$, $X_2' = 0.2 \Omega$, $X_o = 20 \Omega$ and rotational loss = 800 W ($R_o$ is negligible). Calculate:
a) The mechanical power developed, gross torque and efficiency of motor.
b) The maximum gross power and the slip at which it occurs when exciting circuit is omitted. [7M.]
