A 3-phase, 4160 V, 50-Hz, 660 HP, 8-pole, Y-connected induction motor has its per-phase equivalent circuit when referred to stator side as shown below. The total friction, windage, and core losses can be assumed to be constant at 1000 W. For a per-unit slip of 0.015, when the motor is operated at rated voltage and frequency; (a) Sketch and find the value of the components of the per-phase Thevenin's equivalent circuit of an Induction motor (b) What are the starting current and the starting torque of this motor? (e) Find the slip at pull-out torque. (d) Find the pull-out torque of this motor. (e) Find the value of the external resistance required in each phase of the rotor circuit such that the maximum torque occurs at starting.

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?