Problem $6$:

$V_T=200V$ is applied to a shunt connected DC motor with $R_{\text{a}\text{d}\text{j}}=10.$ For the motor, $R_A=2$ and $R_F=30.$ The motor has negligible rotational losses and the magnetization curve shown below.

a$)$ What is the maximum torque, $T_{\text{s}\text{t}\text{a}\text{l}\text{l}},$ that the motor can provide? $(5$ points$)$

b$)$ Now you are told that the motor is operating at an efficiency of $50\%,$ what are the possible torque values? $(10$ points$)$