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95MET-2
Sr. No. 9
EXAMINATION OF MARINE ENGINEER OFFICER
Function: Electrical, Electronic & Control Engineering at Management Level
MARINE ELECTROTECHNOLOGY
India (2003)
M.E.O. Class II
(Time allowed - 3hours)
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.
With reference to electronic control systems:
(a) Draw a simple block diagram for temperature control;
(b) Describe each component shown in the diagram in (a).
2. Describe an emergency electrical power generating plant for use in the event of a complete failure of
the main electrical power and make reference to (a) location
(b)starting arrangements
(c) fuel oil and its supply
(d)cooling system
(e) periodic attention required
3. (a) Describe a brush less alternator with a.c. exciter and static A.V.R.
(b) State the output voltage characteristics for this type of machine.
4. (a) The UMS monitoring and control system of your ship has recently started to give false alarms and
Incorrect data printouts. State, with reasons, possible causes if the false alarms and reading are:
(i) Localized to a particular area of engine operation;
(ii) General to the engine room.
(b) State, with reasons, the action you, as Chief Engineer, would take to ensure continued safe
operation of the vessel if the defects were general to the engine room.
(c) Explain the procedure you, as Chief Engineer, would adopt in order to locate and rectify a general
fault in the UMS system.
5. Autotransformer starters or compensators are sometimes used with polyphase induction motors to
______________ .
(a) reduce the voltage applied to the motor during the starting period
(b) increase the volt age for "across-the-line starting"
(c) provide a backup means of voltage regulation for emergency starting
(d) allow the voltage to be either stepped up or down, depending on the application, to ensure full
torque
Justify your answer by explaining why the other option were not considered
SECTION – 2
6. The terminal voltage of a three-phase alternator is set at 440V, by adjusting the field excitation when
the speed is correct and when the full-load current is supplied at a power factor of 0.8 (lagging). When
the machine circuit breaker is opened and the load thrown-off, the terminal voltage is seen to rise to
506V. Estimate the voltage regulation.
7. How do you determine electric flux density? Explain the limitations of Guass’s law in finding D.
Find the charge in the volume defined by 0  x  1 m, 0  y  1 m and 0  z  1 if  = 30 x2y C/m3.
What change occurs for the limits –1  y  0 m?
8. Derive the expression for current and voltage relations between line and phase values in the star and
delta cases. Draw vector diagram. Three impedances Z = 5 + j 4 are connected in the form of a delta to
the three loads of a balanced 3-phase circuit. The line voltage is 120 volts. Find (a) the phase current,
(b) power factor, (c) the volt-ampere in the circuit.
9. A shunt motor runs at 900 rev/min when connected to a 440 V supply, the armature current being
60 A and armature resistance 0.4 ohm. At what speed will it run on a 220 V supply with an current of
40 A. Assume 60 percent reduction in flux for the 220 V connection.
10. A 175 kVA, 6600 / 440 V, single-phase transformer has an iron loss of 2.75 kW. The primary and
secondary windings have resistances of 0.4 Ohms and 0.0015 Ohms respectively. Calculate the
efficiency on full load when the power factor is 0.9 (lagging).
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