Question

A 6-pole, 50 Hz, 3-phase induction motor running on full load develops a useful torque of 160 N-m and the rotor emf is absorbed to make 120 cycle/min. If the torque loss in windage and friction is 12 N-m. The net mechanical power developed is ________ kW.

• A. 16.08

Answer 1

The correct option is A 16.08
$N_p=1000rpm$

${\omega }_s=104.7rad/s$

$f_2=sf$

$\frac{120}{60}=s\times 50$

$s=\frac{120}{60\times 50}=0.04$

$\omega =(1-s){\omega }_s=(1-0.04)\times 104.7$

$=100.5rad/s$

$\text{Mechanical power developed (net)}$

$=160\times 100.5=16.08kW$