DieselShip's Online Content Library

Q1. (a) How busbar inspection and maintenance is carried out. (10)

(b) What are safety precautions taken while doing maintenance on the busbar? (6)

Q2. Draw and explain the shape of the characteristic curve of a p-n junction diode in forward and reverse bias modes (16)

Q3. a) Explain the working of a Megger with the aid of its internal circuit. (12)

b) What safety measures are taken while using a Megger? (4)

Q3. a) What is the purpose of preferential Tripping system on ship's electrical network? (6)

b) Explain the various stages of preferential trips with the loads connected to those stages. (10)

Q5. a) The current transformer (CT) and potential transformer (PT) or voltage transformer are both measuring devices. List their shipboard application. (6)

b) Sketch and describe any one type of current transformer. (10)

Q6. a) What are the safety devices provided on the steering gear system? (10)

b) What is the significance of the shaft hull earthing device on the shafting? (6)

Q9. a) Explain Fleming's Right hand rule. (6)

b) A one-turn armature coil has an axial length of 0.4m and a diameter of 0.2m. It is rotated at a speed 500 rev/min in a field of uniform flux density of 1.2 T. Calculate the magnitude of the e.m.f. induced in the coil. (10)

Q8. a) Describe in detail the method used to measure the capacitance of a capacitor.(6)

b) A circuit has a resistance of 3R and an inductance of 0.01 H. The voltage across its ends is 60V and the frequency is 50Hz. Calculate (a) the impedance. (b) the power factor (c) the power absorbed.(10)

Q7. a) What is the difference between a DC Generator and a DC motor? (6)

b) A 4-pole, 32 conductor, Lap-wound DC shunt generator with terminal voltage of 200 V delivering 12 A to the load has ra = 2 and field circuit resistance of 200 Ω. It is driven at 1000 RPM .

a) Calculate the flux per pole in the machine. (6)

b) If the machine has to be run as a motor with the same terminal voltage and drawing 5 A from mains, maintaining the same magnetic field, find the speed of the machine. (10)