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

If the thermal strain developed in polyimide film during deposition is given as 0.0044. assume room temperature is kept at 17.3 c, and thermal coefficient of expansion for the film and the substrate are 54 x 10^-6c^-1 and 3.3 x 10^-6c^-1respectively. calculate the deposition temperature.

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Heat transfer by is the fastest mode of heat transfer that requires no intervening medium. a)-conduction b)-convection c)-radiation d)-conduction and convection