DieselShip's Online Content Library

Q1. a) Explain the working principle of an alkaline battery. (8)

b) Compare the alkaline battery with Lead-Acid battery. (8)

Q4. With the aid of a circuit diagram, explain how a Galvanometer can be used as an Ammeter. (16)

Q3. a) What are the benefits of 3 Ph supply over a single-phase supply system? (6)

b) Explain 3-wire and 4-wire 3 phase a.c. distribution systems. (10)

Q4. a) What is the purpose of AVR in an alternator? (6)

b) With the aid of a simple circuit diagram explain the basic working of a brushless alternator. (10)

Q5. a) Explain the working principle of a synchronous motor. (6)

b) What are the starting methods of a synchronous motor? (4)

c) List the merits and demerits of synchronous motor over induction motor. (6)

Q6. A coil of resistance 10 ohm and inductance 0.1H is connected in series with a capacitor of capacitance 150pF, across a 200 V, 50 Hz supply.

Calculate:

a) the inductive reactance. (3)

b) the capacitive reactance. (3)

c) the circuit impedance. (2)

d) the circuit current. (2)

e) the circuit power factor. (2)

f) the voltage drop across the coil. (2)

g) the voltage drop across the capacitor. (2)

Q7. In the following circuit, E1 = 13 V, E2 = 19.5 V, R1 = 5 W, R2 = 7 W, R3 = 9 W. Find the current flowing through each resistor. (16)

Q8. A 24 V emergency battery is to be charged from the 110 V ship’s mains when the e.m.f. per cell has fallen to a minimum value of 1.8 V. The battery consists of 12 cells in series, has a capacity of 100 Ahr at a 10 hr rate and the internal resistance is 0.03 ohm/cell. If charging continues until the voltage per cell rises to 2.2 V, find the value of the variable resistor needed to control the charging. The charging current can be assumed to be equal to the maximum allowable discharge current. (16)

Q9. A wooden ring having a mean diameter of 200 mm and a cross-sectional area of 400 mm2 is wound uniformly with a coil of 300 turns. If the current passed through the coil is 5 A calculate the value of flux produced in the coil. (16)