24 July 2016

EXAMINATION OF ELECTRO TECHNICAL OFFICER-2015-ETO-NO-1

QUESTION PAPER FOR MARINE ELECTRO TECHNICAL OFFICER-2015-ETO


EXAMINATION OF ELECTRO TECHNICAL OFFICER
Function: Electrical, Electronic & Control Engineering
MARINE ELECTROTECHNOLOGY & SSEP
 
India (2015)                                                                                                           Total Marks 100
NB:
1) Answer any SIX Questions. Not more than TWO from Each Section
(2)  Neatness in handwriting and clarity in expression carries weightage
(3)  Illustration of an Answer with clear sketches / diagrams carries weightage.



 SECTION — I

 Q. I Answer the following: (16) (compulsory)

  i). An over -excited AC generator will produce a lagging pf current from that Generator.
 (a) True
 (b) False.

  ii). Two alternators are running in parallel. If the field of one of the alternator  is adjusted, it will
 (a) Reduce its speed
 (b) Change its load
 (c) Change its power factor
 (d) Change its frequency.

 iii). The division of kilowatt load between two paralleled alternators is determined by the
 (a) Amount of field excitation to the leading machine
 (b) Load -speed characteristics of the governors
 (c) Amount of field excitation to the lagging machine.
 (d) Number of field poles per alternator
               
iv). In squirrel cage induction motors, the rotor slots are usually given slight  skew (overlapping) order to
 (a) Reduce windage losses.
 (b) Reduce eddy currents.
 (c) Reduce accumulation of dirt and dust.
 (d) Reduce magnetic hum.

 v) SF6 gas
 (a) Is yellow in color
 (b) Has pungent odor
 (c) Is highly toxic v
 (d) Is non -inflammable.

vi) Sparking occurs when a load is switched off because the circuit has
(a) high inductance
(b) high capacitance
(c) high resistance.

vii). HRC fuses are
(a) High resistance and Capacitance fuses
(b) Heat reflecting cool fuses
(c) Holding and Resisting current fuses
(d) High rupturing capacity fuses.

viii) You have a hot plate(with negligible inductance) at your ship, the rating will be 440 volts,
3 kw, 60 hz if the same hot plate connected to shore supply in dry dock with 440 volt and
50 hz then the rate of change of heat will be,
(a) decrease .
(b) increase
(c) same
(d) none of the above

ix) In star delta kind of starter with 3 nos. power contactors changing over from star to delta state
is a closed state of transition:
(a) true
(b) false.

x) Which of the substances listed should be applied to battery terminals to help prevent corrosion?
(a) inc chromate
(b) Naval jelly
(c) Lead peroxide
(d) Petroleum jelly

xi) When a megohmmeter is used to test insulation, the gradual rise of the pointer
reading as a result of continued cranking, is caused by
(a) Good conductor resistance
(b) The leakage of current along the surface of dirty insulation
(c) The inductive reactance of the windings
(d) The dielectric -absorption effect of the insulation

xii) The program scan time generally depends on the amount of memory taken by
the control program and type of instructions used in the program. The time to
make a single scan can vary from
(a) 1 pis to 1001.ts
(b) lms to 100ms
(c) lsec to 100 sec
(d) lms to 1000ms

xiii) Which resistor will be physically larger in Size?
N..(0)10 ohm, 50 W —
(b) 100 ohm, 10 W
(c) 1 kohm, 1 W
(d) 10 Mohm, I/ 2 W.

xiv). The Maxwell equation is
(a) Ampere's law
(b) Gauss low
(e) Faraday's law
(d) Coulomb's law -

xv) When current flows through heater coil it glows but supply wiring does not glow
because
(a) supply wiring is covered with insulation layer
(b) current through supply line flows at slower speed.
(c) supply wires arc made of superior material
(d) resistance of heater coil is more than that supply wires.

xvi) A reverse -current relay will prevent AC generator motorization by
(a) automatically redirecting the load
(b) automatically speeding up the prime mover
(c) tripping the panel board main switch
(d) tripping the gerierator circuit breaker

2. The power input to a 500 V, 50 Hz, 6 pole 3 phase squirrel cage induction motor running at
975 rpm is 40 KW. The stator losses are 1 KW a- -1 the friction and windage losses are 2 KW.
Calculate
(i) Slip (ii) Rotor copper loss (iii) Mechanical power developed (iv) The efficiency.
(Note: Assume that the core loss is included in friction and windage loss and the total loss
under this head is 2.0 kW) (16)

3. Explain the working operation of thyrister? Explain the use of thyrister in voltage regulation of
diesel generator. (16)

SECTION -II

4. Discuss the various starting methods of induction motors. With neat diagrams explains the
working of any two types of starters used for Squirrel cage type 3 phase induction motor. (16)

5. Explain the construction and principle of operation of 3 -phase alternator (16)

6. What are the advantages of high voltage transmission and its limitations? (16)


SECTION - III

7. 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 (16)

8. State how safety is achieved with regard to gas emission in battery rooms where a large number
of lead acid cells are stored with reference to:
(a) provision of lighting;
(b) ventilation if a fan is fitted;
(c) type of distilled water container for topping up;
(d) use of tools and replacement of defective batteries. (16)

9. Sketch and describe the following detectors, explaining their mode of operation and stating
where they would be fitted in the machinery spaces:
(a) flash or sudden flare up fire detector;
(b) combustion or smoke detector. (16)





"We must free ourselves of the hope that the sea will ever rest. We must learn to sail in high winds."
— Aristotle Onassis, Shipping Magnate

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