Design Exercise Part 2 (10 points) For the same induction motor 3. Find (theoretically and graphically), the value of the rotor resistance R2 to give the maximum torque at starting. One way to do this graphically would be to plot the torque- speed equation for a number of values of RC2 (say 2 - 20 ohms) and find which one gives maximum toque at starting. Another way to do this graphically would be to set the slip-1 In the Torque-slip equation and instead vary the resistance R2 (ie. plot the torque-versus a number of values of R29 say 1- 30 ohms in steps of 0.1) and find the resistance that gives maximum toque. 4. Find (theoretically and graphically), the value of the rotor resistance R2 to give the maximum torque at half speed 5. If the load torque (a pump) characteristics are given as: TPUm 25.0 25.6(1-s) - 29.2(1-s)2+ 294.0(1-s)3-29.7(1-s) Plot the pump characteristics against the Torque-slip curve and find the point of intersection that defines the operating point of the motor for each of the three cases: (i) Normal RG (ie. RG = 2 W) (ii) R2 as found in part 3 above. (ii) Rc2 as found in in part 4 above