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Q1. Discuss the criteria of the classification of marine high voltage for A.C. and D.C. Systems. Sketch a Ships high voltage distribution system and explain its features. Discuss the various methods of testing the insulation of HV system, Mention the significance of PI test, why 3 terminals insulation testers are used in HV insulation measurements. (16)

Q2. a) Describe the circuit breaker for an A.C. generator using a sketch to show how arcing is controlled. (8)

b) Explain the sequence of events that might occur if the breaker opens on a short circuit and state the check you would require following such event. (4)

c) Give a safe procedure to follow should a main circuit breaker fail to open under fault Condition. (4)

Q3. a) Explain how the efficiency and regulation of a transformer can be assessed by open circuit and short circuit tests? (12)
b) What is meant by equivalent resistance. (4)

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 Watts. 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) A three phase, six pole, delta connected induction motor is supplied at 380 V, 60Hz. It draws a current of 45 A at a power factor of 0.85 lag. The stator losses are 4 kW and the windage and friction losses total 3 kW. It runs at 19 rev/s. Calculate EACH of the following:
a) the rotor copper loss. (3)
b) the shaft output power. (4)
c) the shaft output torque. (3)

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 identical coils are delta connected to a 3 ph, 440V, 60 Hz supply and consume a total power of 9 kW at a power factor of 0.8 lag.
a) Calculate the resistance and inductance of EACH coil. (5)
b) If the same three coils are now connected in star to the same supply, calculate the current in each line if: (i) one coil is short circuited; (ii) one coil is open circuited. (5)

Q7. With reference to Annex V of MARPOL 73/78 that deals with the prevention of pollution of the sea by garbage from ships –

a) Define the following terms.

i) Garbage

ii) Nearest land

iii) Special areas (8)

b) State the regulations governing the disposal of garbage outside special areas. (8)

Q8. a) Explain the working principle of a hyper mist fire suppression system on ships. How does this system differ from traditional water-based fire suppression methods? (8)

b) Discuss the installation, maintenance, and testing requirements for a hyper mist system on board ships. How does regular upkeep ensure the system’s effectiveness in an emergency? (8)

Q9. a) Briefly describe the environmental impact of Nox and Sox and allowable limitations as per Annex VI of MARPOL in emissions control areas and outside emission control areas. (8)

b) Briefly describe methods to control Nox emission. (8)