95MET-4

Sr. No. 5

EXAMINATION OF MARINE ENGINEER OFFICER

Function: Electrical, Electronic & Control Engineering at Operational Level

MARINE ELECTROTECHNOLOGY

M.E.O. Class IV

(Time allowed - 3hours)

India (2004) Morning Paper Total Marks 100

NB : (1) Answer SIX Questions :

SECTION -1 :- Answer atleast TWO Questions

SECTION -2 :- Answer atleast TWO Questions

(2) All Questions carry equal marks

(3) Neatness in handwriting and clarity in expression carries weightage

(4) Illustration of an Answer with clear sketches / diagrams carries weightage.

SECTION – 1

1. (a) Sketch a diesel electric propulsion arrangement for a ship.

(b)Describe the operation of the propulsion arrangement sketched in (a), including in your description how reversal of the propulsion motor is achieved.

2. (a) With reference to the insulation testing of marine electrical plant:

(i) State the reason for insulation testing;

(ii) State the precautions to be observed when testing intrinsically safe equipment

(b) Describe the overhaul of a d.c. motor which has been subjected to excessively damp condition or flooding with seawater.

3. (a) Sketch a circuit diagram for an automatic voltage regulator illustrating how the A.V.R. utilizes a silicon-controlled rectifier to control the excitation system for an alternator.

(b) Describe how the A.V.R. monitors output and controls the excitation system.

4. Differentiate between squirrel cage and wound rotor motors, of the three phase a.c. induction type, in respect of the following:

(a) rotor construction;

(b) torque characteristics;

(c) speed variation.

5. Describe the action of a diode valve and give an example of its use.

SECTION – 2

6.A battery is formed of ten cells joined in series. When the external resistance is 8  the current is 1.5 A and when it is 18 , the current falls to 0.75 A. Find the e.m.f. of each cell and its internal resistance.

7. A circuit consists of two coils connected in series. One coil has a resistance of 17.32 ohms with a reactance of 4 ohms. The circuit is connected to a 240-v 50c/s A.C. supply. Calculate

(a)The total current in the circuit and its phase angle.

(b)The voltage across each coil and their phase angles.

8.If the resistance of 1.6 km of copper wire of 0.5mm diameter is 170 Ohms, Calculate the resistance of 1 km of iron wire of 1.0mm diameter, assuming that the resistivity of iron is 7 times that of copper.

  1. 100V A.C. is applied to a circuit of 3 Ohms resistance and 4 Ohms reactance. Find (a) the current in the circuit, (b) the active e.o.m. (resistive voltage drop) of the circuit, (c ) the e.m.f. of self –inductance (reactive voltage drop).
  1. Two capacitors of 0.02F and 0.04F are connected in series across a 100Vd.c. supply. Find the voltage drop across each unit.

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