A three-phase, four-pole, 50-hp, 480-V, 60-Hz, Y-connected induction motor has the following parameters per phase:
r1 = 0.10 ohm , x1 = 0.35 ohm , r2' = 0.12 ohm, x2' = 0.40 ohm.
It is known that the stator core losses amount to 1200 W and the rotational losses equal 950 W. Moreover, at no-load the motor draws a line current of 18 A at a power factor of 0.089 lagging.
When the motor operates at a slip of 3.5%, find :
a. The input line current and power factor
b. The developed electromagnetic torque in newton-meters
c. The horsepower output
d. The efficiency
e. Repeat the resuts a-d for the slip of 5%