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Q10. (A) Explain the concept of dynamical stability.

B. A ship of 14000 tonne displacement is 125 m long and floats at draughts of 7.9 m forward and 8.5 m aft. The TPC is 19, GML 120 m and LCF 3 m forward of midships. It is required to bring the vessel to an even keel draught of 8.5m. Calculate the mass which should be added and the distance of the distance of the centre of the mass from midships.

Q6. A. What are factors on which the speed of a motor depends? Discuss them for series and shunt motors. (6)

b) Three equal resistors are connected to a three-phase system, if one resistor is removed find the reduction in load if they are connected in (a) Star, (b) Delta. (10)

Q9. A. Explain the effects on stability when a tank is partially filled with liquid. (6)

B) A box barge 45 m long and 15 m wide floats at a level keel draught of 2 m in sea water, the load being uniformly distributed over the full length. Two masses, each of 30 tonne, are loaded at 10 m from each end and 50 tonne is evenly distributed between them. Sketch the shear force diagram and give the maximum shear force. (10)

Q8. (a) Describe the function of the stern frame. (6)

(b) The water plane area of a ship at 8.4 m draught is 1670 m2. The area of successive water planes at 1.40 m intervals below this are 1600,1540, 1420, 1270, 1080 and 690 m2 respectively. Calculate the displacement in fresh water at 8.4 m draught and the draught at which the ship would lie in sea water with the same displacement. (10)

Q6. A ballast tank is 15 m long, 12 m wide and 1.4 m deep and is filled with fresh water. Calculate the load on the top and short side, if:

a) the tank is just completely full

b) there is a head of 7m of water above the tank top. (16)

Q9. (a) Shunt generators having drooping characteristics are best suited for parallel operation. Discuss (6)

(b) Two 220 V D.C. generators each having linear external characteristics, operated in parallel. One machine has a terminal voltage of 270 V, on no-load and 220 V at a load current of 35 A, while the other has a voltage of 280 V at no-load and 220 V at 50 A. Calculate the output current of each machine and the bus bar voltage when the total load is 60 A. What is the kW output of each machine under this condition. (10)

Q9). a) Define Work, power and efficiency (6)

b) A battery is charged with a constant current of 16 amperes for 11 hours after which time it is considered to be fully charged, its voltage per cell being recorded as 2.2V. Find its ampere hour efficiency if it is

(1) Discharged at a rate of 16 amperes for 10 hours, and

(2) 28 amperes for 4 hours.

In either case discharge was discontinued when the voltage per cell fell to 1.8 V.  (10)

Q8. (a) Define work, Power and Efficiency (6)
(b) A shunt motor has an armature resistance of 0.2 ohms and with an armature current of 120 amperes runs at 750 r.p.m. off a 400-volt supply. Calculate the speed and armature current of the motor if the flux per pole is reduced to 75 per cent of its initial value, the total torque remaining unaltered. (10)

Q7. The loads of a 4-wire, 3-phase systems are: Red line to neutral current = 50 A, power factor of 0.707 (lagging) Yellow line to neutral current = 40 A, power factor of 0.866 (lagging) Blue line to neutral current = 40 A, power factor 0.707 (leading). Determine the value of the current in the neutral wire. (16)

Q7. (a) What are the different types of stern used in ship construction? (6)

(b) A ship consumes 360t of fuel, stores and water when moving from sea water of 1.025 t/m3 into fresh water of 1.000 t/m3 and on arrival it is found that the draught has remained constant. Calculate the displacement in sea water. (10)

Q4. a) Why is a synchronous motor not self-starting? What are the various ways in which it can be started? (6)

b) A coil has a resistance of 4 ohms and an inductance of 0.00954 henry. Calculate the power the coil will absorb and its power factor when it is connected to a 100-volts 50-cycle supply. (10)

Q7. a) Explain what do you understand by the term ‘transducer’? (6)

b) A coil of resistance 10 ohms and inductance 100mH is connected in series with two parallel capacitors each of value 100 mF across a 250 V, 50Hz supply. determine (10)

i) The circuit current

ii) The total power factor

iii) The power taken from the supply.