Engineering Answers

A 3Ø, 2000KW, 480V ∆-connected alternator is short-circuited and is operated at rated speed to produce rated current at 4A excitation. With the short-circuit remove and with the excitation adjusted to 5A, the voltage between stator terminal is 330V. The effective resistance between terminal as measured with dc is 2Ω. Determine the %V.R. of the alternator at half-load and pf of 0.8 leading without changing any given values.

A three-phase, wye-connected 2300 kVA and 6.6 kV generator operates at full-load.

The per-phase armature resistance Ra and the synchronous reactance, Xd, are

(0.06+j10.5)W. Analyze to determine the voltage regulation

Carbon disulphide (CS2) is used to extract iodine from its aqueous solution. The distribution of iodine between Carbon disulphide (CS2) and Water at equilibrium is given by, Y=550.X. Calculate the concentration of iodine in aqueous phase of 1 liter of water is stirred with 50 ml of Carbon disulphide (CS2) for two stage extraction operation.

Evaluate the most probable values of angles A, B and C with the condition: A + B.The obscrved values are A= 68°12'36", B=58°01'16"and C= 53*46°12"

A high pressure boiler delivers steam at a pressure of 90 bar and temperature of 480C.the steam is expanded in two section of steam turbine, first to 12 bar and second then withdraw and passed on to a reheater, where it is reheated to the initial temperature. The expansion process takes place again in the remaining section of the steam turbine, down the condenser pressure of 0.007 bar determine the ideal cycle efficiency

A standard HS truck move across a 25 m simple span. The wheel loads are P₁ = 142 kN and P₂ = 142 kN separated by 7.6 m, and P₃ = 36 kN at 4.3 m from P₂.

1. Determine the maximum shear in kN.
2. Determine the maximum moment in kN – m under P₁.
3. Determine the maximum moment in kN – m under P₂.

A standard HS truck move across a 25 m simple span. The wheel loads are P₁ = 36 kN and P₂ = 142 kN separated by 4.3 m, and P₃ = 142 kN at 7.6 m from P₂.

1. Determine the maximum shear in kN.
2. Determine the maximum moment in kN – m under P₃.
3. Determine the maximum moment in kN – m under P₂.

Proof that the maximum deflection on a beam with load not placed at the center = Wa/9√3 *EIL (l²-a²)

4.32 (a) Nitrogen gas (C P =30 kJ/ kmol K) at 1 bar and 300 K is to be compressed to 10 bar and

450 K at a rate of 5000 kg/h. Cooling water (C_{P} = 4.1868kJ / k * gK) enters the compressor at 300 K at the rate of 7500 kg/h and leaves at 320 K. Determine the power required by the compressor. (b) For the same conditions of nitrogen as in the previous part, determine the minimum power required by the compressor. The rate of circulation and the inlet temperature of cooling water

remain the same as above.