Question#4 a 100-kva 8000/277-v distribution transformer has the following resistances and reactances:
rp = 5 ohm
rs = 5 miliohm
xp = 6 ohm
xs = 6 miliohm
rc = 50 kilo ohm
xm = 10 kilo ohm
the excitation branch impedances are given referred to the high-voltage side of the transformer.
(a) find the equivalent circuit of this transformer referred to the low-voltage side.
(b) find the per-unit equivalent circuit of this transformer.
(c) assume that this transformer is supplying rated load at 277 v a

Heat is added to a piston-cylinder device filled with 2 kg of air to raise its temperature 400 c from an initial temperature of t1 27 cand pressure of pi 1 mpa. the process is isobaric process. find a)-the final pressure p2 b)-the heat transfer to the air.

On a average work day more than work place firs are reorted

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?