Q) How do you test emergency generator?
Ans.) Regular or weekly testing of the emergency generator should include simulation of the loss of normal power. The start up equipment may be provide a push button to interrupt the normal voltage supply to the panel which then triggers the start sequence.Loss of main power supply can easily be simulated by pulling a fuse in the auto-start panel which supplies the under voltage or under frequency relay.This no load running checks should, when practicable, be supplemented occasionally by a proper load test. This requires the disconnection of the normal mains power while the emergency generator is loaded upto near its rated value.
In some ships a breaker is available switching off which disconnect emergency equipments from main switch board and emergency generator comes live
Q) If you get earth fault alarm what you do?
Ans.)
- Accept the alarm
- First of start isolate the breakers one by one.
- Then, check where the alarm has came & should be eliminated when located.
- Damaged conductor insulation must be repaired.
- Dampness or moisture in insulation must be dried out by gentle heat & precautions should be taken to prevent future ingress of moisture.
- If dirt is the cause, then a thorough cleaning with electro cleaner solvent should be applied & clean.
Q)If on starting Generator you find that voltage is not building up what you do?
Ans.) This means that the residual magnetism is lost. So supply power from outside by connecting battery. the battery is connected in the exciter coil in the AVR.
Q)What equipment emergency generator supplies?
Ans.)
(a) For a period of 3 Hrs at Emergency lighting at every muster & embarkation station.
(b) For a period of 18 hrs at:-
(i) In all service & accommodation alleyways, stairways & exits, personal lift cars & personnel lift trunks.
(ii) In the machinery spaces & main generating stations including their control positions.
(iii) In all control stations, machinery control rooms, and at each main & emergency switchboard.
(iv) At all stowage positions.
(v) At the steering gear.
(vi) At the fire pump & in all cargo pump rooms.
(vii) The navigational lights.
(viii) VHF & MF Radio installation.
(ix) The ship earth radio station.
(x) At all internal communication equipment
(xi) The fire detection & fire alarm system.
(xii) Intermittent operation of the daylight signalling lamp & all integral signals that are required in an emergency.
Q) What is rms value?
Ans.) The RMS value of an alternating current is also known as its heating value, as it is a voltage which is equivalent to the direct current value that would be required to get the same heating effect.
Q)What maintenance carried out on Lead acid batteries?
Ans.)1.Connection to be checked for tightness.
2.Casing surface to be kept clean.
3.Terminals are protected with petroleum jelly or Vaseline.
4.Specific gravity to be check with hydrometer.
5. Charged Condition
6. Discharged Condition
6.1Batteries to be topped up with distilled water.
6.2Check & clear vents to ensure H2 gas produced is vented.S
Safeties to be observed while operation & maintenance.
- Use hand gloves & safety goggles while adding distilled water, shifting of battery, or checking sp. Gravity.
- Use insulated spanners to tighten terminals (No Sparking, short-circuiting should take place)
3.Use plastic bottle or jar to add distilled water.
4. Should not be left in discharged condition for long period.
5.If adding acid, then first put little Acid, then add water & do the same process.
6.No naked lights to be taken inside.
7.No smoking inside battery room.
Q)What precautions you will take before entering battery room?
Ans.)
a.Inform the bridge & the engine control room
b. Check the oxygen content of the room.
c.Should be ventilated properly.
d.All PPE to be donned properly & rubber hand gloves to be used.
e.No Naked lamps to be taken inside.
Q)What is meaning of power factor. What is best value. What is normal value onboard. How do you improve?
Ans.)Power Factor :- The power factor of an AC electric power system is defined as the ratio of the real power flowing to the load to the apparent power and is a dimensionless number between 0 and 1.The best value is 0.85. The normal value onboard varies in between 0.8 to 0.9. Power factor can be improved by connecting a Capacitor in parallel.
Q).What happens to resistance of conductor when temp rises?
Ans.)Resistance is directly proportional to temperature. So, resistance will increase if temperature rises.
Q)Types of starters in ERoom
Ans.)
DOL (Direct On-Line)
Star-delta
Auto-transformer.
Face plate starter
Q)Types of Motors in Eroom
Ans.)Induction Motor.
Synchronous Speed Motor.
DC Motor.
Shunt motor
Series Motor
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What happen if air gap is more in alternator