DieselShip's Online Content Library

Q1. a) What precautions must be taken when testing the insulation of generator cables and wiring connected to an AVR unit? (6)

b) How could you monitor the correct instant for synchronising, if synchroscope and synchronising lamps are not working? (6)

c) How is the air gap of an alternator is measured and why the air gap of an alternator to be checked periodically? (4)

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)

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)

Q4. a) What design factor limits the maximum torque of a d.c. motor? (6)

(b) A shunt motor runs on no load at 700 r/min off a 440 V supply. The resistance of the shunt circuit is 240Ω. The following table gives the relationship between the flux and the shunt current:

Shunt current (A):      0.5   0.75   1.0   1.25   1.5   1.75   2.0

Flux per pole (mWb): 6.0   8.0   9.4   10.2   10.8   11.2   11.5

Calculate the additional resistance required in the shunt circuit to raise the no-load speed to 1000r/min (10)

Q5. (a) On what factors does the capacitance of a parallel-plate capacitor depend? (6)

(b) A tuned circuit consisting of a coil having an inductance of 200µH and a resistance of 20Ω in parallel with a variable capacitor is connected in series with a resistor of 8000Ω across a 60 V supply having a frequency of 1 MHz. Calculate: (10)

(a) The value of C to give resonance.

(b) The dynamic impedance and the Q factor of the tuned circuit.

(c) The current in each branch

Q6. (a) The capacitor-start induction run motor has a much higher starting torque than the resistance split-phase motor. Explain (6)

(b) An eight-pole armature is wound with 480 conductors. The magnetic flux and the speed are such that the average e.m.f. generated in each conductor is 2.2 V, and each conductor is capable of carrying a full load current of 100 A. Calculate the terminal voltage on no load, the output current on full load and the total power generated on full load when the armature is:

(i) Lap connected

(ii) Wave connected (10)

Q7. With reference to port State control

a) List the certificates which a Port State Control Officer (PSCO) may like to see during inspection. (8)

b) List the Life Saving Appliances and Fire Fighting Equipments which are likely to be inspected by PSCO. (8)

Q8. Explain the following with respect to MARPOL Annex-I

a) Pump room bottom protection. (6)

b) Intact stability of oil tankers. (5)

c) Subdivision and damage stability of oil tankers. (5)

Q9. With reference to MLC answer the following,

a) Briefly discuss DMLC Part I and Part II covering the welfare points for seafarers. (8)

b) Briefly discuss the grievance redressal mechanism for seafarers of Indian flagged vessel. (8)