DieselShip's Online Content Library

Q1. What is Zener diode and how does it regulate the voltage? What happens to the series current, load current and Zener current when the d.c input voltage of a Zener regulator increases? Draw a neat diagram of Zener regulator and explain. (16)

Q3. With Respect to PLC’s used onboard ships:

a) Draw and explain the block diagram of a PLC. (8)

b) Name the onboard ship equipment where PLC’s are used. (4)

c) What are the advantages of PLC controllers over other type of controllers? (4)

Q6. A 100 KVA, 2400/240 V, 50 Hz, 1-phase transformer has no- load current of 0.64 A and a core loss of 700 W, when its high voltage side is energized at rated voltage and frequency . calculate the two components of no-load current. If this transformer supplies a load current of 40 amp at 0.8 lagging power factor at its low voltage side, determine the primary current and its power factor. Ignore leakage impedance drop. (16)

Q9. With reference to MARPOL Annex IV
a) Draw a biological sewage treatment plant and explain the principle of operation. (8)
b) Periodical maintenance and checks and tests required to be done to verify the effectiveness of the above system. (8)

Q8. With reference to entry into enclosed spaces onboard:
a) Define “Enclosed space” and give example of enclosed spaces onboard (6)
b) Describe the checks done for testing the atmosphere inside such enclosed spaces. (5)

c) Explain safety precautions taken prior to entry into enclosed spaces onboard vessel. (5)

Q8. a) Describe CO2 Fixed fire fighting system for machinery spaces and cargo spaces of a bulk carrier. (8)

b) Explain safety precautions taken prior to release of CO2 to the engine room. (8)