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Q1. a) State essential electrical services on board that are able to be operable under fire conditions. (5)

b) Explain how electric cables for the essential services in part (a) pass through bulkheads whilst maintaining gas tight and watertight integrity. (5)

c) State the requirements for the cables which supply electrically driven emergency fire pumps. (6)

Q2. a) Sketch a circuit diagram of a push button direct online contactor starter for a three phase Incorporating overload and short circuit protection. (8)

b) Indicate, on a sketch of the typical characteristic curves of current and torque against Speed, disadvantages of a direct online start squirrel cage induction motor. (8)

Q1. Differentiate between half and full wave rectification. State where half wave rectification may be used and the purpose for which it is not well adapted. Sketch a bridge connection by which full wave rectification may be obtained. (16)

Q4. A) Explain the potential hazards if liquid-cooled transformers are used. (6)
b) What are the losses in transformers? Mention the various factors which affect these losses. In a 25 KVA, 3300/233 V, single phase transformer, the iron and full-load Cu. Losses are respectively 350 and 400 w. Calculate the efficiency at half-full load 0.8 power factor. (10)

Q5. a) List the factors that determine the starting torque of the three-phase induction motor. How does this torque generally compare with the value of the rated torque? (6)
b) The low-voltage release of an a.c. motor-starter consists of a solenoid into which an iron plunger is drawn against a spring. The resistance of the solenoid is 35 ohm. When connected to a 220 V, 50 Hz, a.c. supply the current taken is at first 2 A, and when the plunger is drawn into the “full-in” position the current falls to 0.7 A. Calculate the inductance of the solenoid for both positions of the plunger, and the maximum value of flux-linkages in weber-turns for the “full-in” position of the plunger. (10)

Q6. A) With the aid of delta and star connection diagrams, state the basic equation from which the delta-star and star- delta conversion equation can be derived. (6)
B) Three batteries A, B, and C have their negative terminals connected together. Between the positive terminals of A and B there is a resistor of 0.5 ohm and between B and C there is a resistor of 0.3 ohm
Specifications of the three batteries are given below.
Battery A 105 V, Internal resistance   0.25 ohm
Battery B 100 V, Internal resistance   0.2 ohm
Battery C   95 V, Internal resistance   0.25 ohm
Determine the current values in the two resistors and the power dissipated by them. (10)

Q9. With respect to MARPOL 73/78, Annex-ll, Noxious liquid chemicals are divided into categories.

a) State the number of categories, and what does each category signify. (8)

b) State the requirement of procedures and Arrangements Manual, and what information is available. (8)

Q9. With reference to free fall lifeboat of an ocean-going ships:
a) Periodical maintenance, tests and checks on lifeboat and releasing gear. (6)
b) Secondary means of lowering. (5)
c) Lifeboat Drills. (5)

Q9. Briefly discuss the following with respect to safety of navigation:

a) Bridge Navigation Watchkeeping Alarm System (BNWAS) (6)

b) Long Range Identification and Tracking of ships (LRIT). (5)

c) Voyage Simplified Voyage Recorder (VDR/S-VDR) (5)