A25-hp three-phase induction motor operates for a 440-vrms (line-to-line) three phase source and draws a line current of 35 a rms at a power factor of 83 percent lagging under rated full load conditions. the full load speed is 1750 rpm. under no load conditions the speed is 1797 rpm and the line current is 6.5 a rms at a power factor of 30 percent lagging. find the power loss and efficiency with full load, the input power with no load and the speed regulation.

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?

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

Machinery that is a key part of the process and without which the plant or process cannot function is classifed as: (clo4) a)-critical machinery b)-essential machinery c)-general purpose machinery d)-none of the specified options.