Problem $4$ A y$-$connected three phase $415$v $1460$ rev$/$min $50$hz $4-$pole induction motor has the following parameters R$1=0\mathrm{.}25$ R$2=0\mathrm{.}22$ X$1=$X$2=0\mathrm{.}42$ Xm$=4\mathrm{.}3$ use the thevenins equivalent representation and assume that Xm$>>($R$1$ and X$1)$ Rth$=$R$1$ and Xth$=$X$1($i$)$ the motor is driven with variable voltage in order to adjust its speed $.$ find the slip at which maximum torque will be developed if the motor is operated with rated voltage at $50$hz$.$ recall that the slip at which maximum torque occurs is given by