The two-pole machine has a field winding located on the stator and an armature winding on the rotor, with nf = 800 turns and na = 50 turns, respectively. it has a uniform air gap of 0.5 mm. the armature has a diameter of 0.5 m, and it is 1.5 m long. the field winding carries a current of 2 a. the rotor is driven at 3600 rpm.1) find the maximum flux linking one loop of winding.
2) find the frequency of the rotor induced voltage.
3) find the instantaneous voltage voltage induced in the rotor coil.
4) determine the rms voltage induced in the rotor coil.

The y form of iron is known as: a) ferrite b) cementite c) perlite d) austenite

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.

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?