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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) 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)

Q5. a) Describe an accurate method of comparing the capacities of two condensers. (6)

b) A resistor of 0.525 ohms is connected to the terminals of a battery consisting of 4 cells, each e.m.f. 1.46 V joined in parallel. The circuit current is found to be 0.8 A. Find the internal resistance of each cell. (10)

Q6. a) How does change to frequency affect the operation of the transformer? What makes this ratio different from the ratio of transformer. (6)

b) The coils A and B are connected in series to 50 Hz mains. The current is 1 A and the voltage across each coil is measured to be 45 V and 70 V respectively. When the coils are connected in a d.c. supply, the current is also 1 A, but the voltages across the coils are now 20 V and 40 V respectively. Find the impedance, reactance and resistance of each coil, the total circuit impedance, the applied a.c. voltage and the power factor of the complete circuit. (10)

Q7. With reference to “emergency preparedness”, discuss. (16)

i) Search and rescue

ii) Evacuation of critically injured personnel

iii) Helicopter operation

iv) Rescue from enclosed spaces

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)