DieselShip's Online Content Library

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) Explain briefly about checks and calibration of a thermostat which is used to step an air compressor, when cooling water temperature goes too high? (8)

b) what is the significance of earth faults in an isolated neutral system? Explain with a suitable diagram. (8)

Q2. a) Explain with the aid of a diagram, a controller utilizing proportional plus integral action. (6)

b) List out the Advantages and Disadvantages of electric propulsion system. (5)

c) Explain briefly what you know about “Pulse Width Modulation” and how it can be applied for propulsion control. (5)

Q5. A 400V, 4-pole, 50 Hz, 3-phase, 10 hp, star connected induction motor has a no load slip of 1% and full load slip of 4%, find the following:

(i) Syn speed

(ii) No -load speed

(iii) Full load speed

(iv) Frequency of rotor current at full load

(v) Full – load torque (16)

Q5. A) By means of a schematic circuit diagram illustrate the peak rectifier. If the supply voltage is v(t) = Vm Sinwt, what is the voltage across the load resistor? (6)

b) A battery-charging circuit is shown below in fig. The forward resistance of the diode can be considered negligible and the reverse resistance infinite. The internal resistance of the battery is negligible. Calculate the necessary value of the variable resistance R so that the battery charging current is 1.0 A. (10)

Q4. a) Explain the significance of the root-mean-square value of an alternating current or voltage waveform. Define the form factor of such a waveform. (6)

b) A total load of 8000 kW at 0.8 power factor is supplied by two alternators in parallel. One alternator supplies 6000 kW at 0.9 power factor. Find the KVA rating of the other alternator and the power factor. (10)

Q7. a) Explain working of galley CO2 firefighting control system (8)

b) sketch circuit diagram and explain working of electrical oven fitted in a ship’s galley. (8)

Q7. (a) With reference to working onboard the Deck Cargo crane, elaborate the hazards associated with working at heights? (5)

(b) What risk mitigation measures will you take to mitigate the hazards identified by you while working at heights? (6)

(c) Which all risk assessment checklists, work checklists and work Permits will you fill up before commencing the work and who will authorize the work permits? (5)

Q7. a) Describe the routine tests required for self-contained breathing apparatus sets (8)

b) Describe the procedure to be adopted to find missing personnel in a smoke-filled accommodation area. (8)