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Q3. a) Sketch a main engine shaft driven generator arrangement with an electronic system for frequency correction. (8)

b) Describe the operation of the generator arrangement sketched in (a). (8)

Q2. It is proposed to operate a bow thrusters’ unit from a 3.3 KV electrical supply online suitable option for the design of installation under each of the following heading.

a) Protection of main switch board:

b) Overload of a bow thrusters motor:

c) Cable Protection. (16)

Q3. Explain the matching of an induction electric motor to a pump required for main circulating duty, with the aid of pump characteristic and torque/ship diagrams (16)

Q4. a) Why is it important to maintain high efficiency of operation? And low values of voltages regulation for power transformers? (6)

b) A shunt motor supplied at 230 V runs at 900 rpm. When the armature current is 30 A, the resistance of the armature circuit is 0.4 Ω. Calculate the resistance required in series with the armature circuit to reduce the speed to 500 rpm. Assume that the armature current is 25 Amps. (10)

Q5. a) What is back emf? Derive the relation for the back emf and the supplied voltage in terms of armature resistance (6)

b) The earth-lamps on a main switchboard comprise two 240 V 60 W lamps connected in the usual manner. The potential difference at the busbars is 220 V. Damage by sea water occurs to a distribution cable so that the insulation resistance to the earth is reduced to 16 ohms and 6 ohms for +ve and -ve cables respectively. Find by calculation:

a) Which of the two lamps burns the brighter:

b) The additional load on the generators occasioned by the fault. The resistance of the cables and the ship’s structure may be neglected, and that of the lamps taken as constant at the value corresponding to the 60 W rating. (10)

Q6.a) Derive an expression for the emf induced in an a.c. generator. (6)

b) A 3000 KVA, 6-pole alternator runs at 1000 r.p.m. in parallel with other machines on 3300V bus-bars. The synchronous reactance is 25%. Calculate the synchronizing power for one mechanical degree of displacement and the corresponding synchronizing torque. (10)

Q7. Explain the following terms / statement:

a) SEEMP.

b) Special Area as defines in MARPOL 73/78

c) EEDI /EEOI (16)

Q8. With Reference to the Maritime Labour Convention (MLC) 2006, discuss the requirements for seafarers regarding:

a) Seafarers Employment Agreements.

b) Repatriation

c) Seafarers Wages. (16)

Q7. Write reference to gravity lifeboat davits; state the purpose of the following:

a) Centrifugal brake.

b) Dead man’s handle.

c) Davit limit switch. (16)