A 3, 460 V, 60 Hz, 20 kW induction machine draws 25 A at a power factor

A 3φ, 460 V, 60 Hz, 20 kW induction machine draws 25 A at a power factor of 0.9 lagging when

connected to a 3φ, 460 V, 60 Hz power supply. The core loss is 900 W, stator copper loss is 1100 W,

rotor copper loss is 550 W, and friction and winding loss is 300 W. Calculate

(a) The air gap power, Pag.

(b) The mechanical power developed, Pmech.

(c) The output horse power.

(d) The efficiency.