A 220 V 8 pole 860 rpm 3phase induction motor has the follow

A 220 V, 8 pole, 860 rpm, 3-phase induction motor has the following per phase equivalent circuit. Neglecting stator resistance, determine: The full load slip. The slip at maximum torque The starling torque in pu. The maximum torque in pu.

Solution

from the given data,

N=860 rpm

Ns=(120*f)/p

here P=8, f=60 hz

Ns=(120*60)/8=7200/8=900 rpm.

1) s=(Ns-N)/Ns=(900-860)/900=40/900=0.0444

2) the slip at maximum torque S=R₂/X₂.

3) Tst=(KR₂E₂^2)/(R₂^2+X₂^2)

4)Tmax=(kE₂^2)/(2x₂)

these are the formulas.

but equivalent circuit is not given.