Sheet No 1

1. What is the voltage and frequency of ship?

Ans: 440V, 60Hz and 380V, 50Hz. For high voltage system 1kv, 3.3kv, 6.6kv even 11 kv is also available.

2. Who are the regulatory bodies of safety standard?

Ans: SOLAS: Safety of Life at Sea. BS, IEC, IEE, LLoyads, GL, BV, RINA, IRS etc.

3. What to do and not to doat ship in electrical view?

Ans: DO: Study of SLD (single line diagram), study of wiring diagram.

4. a) To become familiar with normal indications of switch board so that abnormal indications at faulty
state can easily be detectable.

(b) To collect manuals of manufacturers.

(c) To ensure all guards, cover, doors are securely fitted, all bolt & fixings are in place.

5. (a) Switch off, lock off supplies, removal of fuse and tagging before any maintenance work

(b) Do confirm the circuit is dead before touching conductors.

6. DO NOT: (a) Not to touch any live conductor.

(b) Not to touch any rotating parts.

(c) Not to leave live conductors or rotating parts exposed.

(d) Not to overload any equipment.

(e) Not to abuse any equipment.

7. What are shock voltage, shock current and body resistance?

Ans: 50V, 5mA, 10 k-ohm.

Our body skin resistance is 10 k-ohm or an average. It falls to 5 k-ohm at 25volt. Our body resistance
goes down as applied voltage increased. It falls to 2k-ohm at 250V applied voltage.

i.e.: V= Ishock × Rskin

Ishock = 25V/5kΩ=5mA

Say, Ishock = 250V/2kΩ= 125mA

5. Why control voltage is kept low?

Ans: During troubleshooting we have to mainly work with control circuit. As we know at relatively higher
voltage our skin resistance goes down so shocking current level increases. So, in control circuit if voltage
is kept low, if unfortunately, though we get shocked level of current would be low. If would not cause
fatal scenario.

6. What is insulation resistance? (I/R)

Ans: Resistance of any insulator substance is called insulation resistance. Generally, these substances
have more band gap between valance band and conduction band. i.e.: Insulation of cable has insulation
resistance. Varnish around winding has insulation resistance.

7. What is the standard value of I/R?

Ans: At least 1 MΩ.

8. How insulation is affected?

Ans: it is adversely affected by humidity, temperature, electrical and mechanical stress, vibration,
chemicals, oil, dirt & old age.

9. Name some insulation materials?

Ans: Mica, glass fiber, porcelain, PVC, XLPE (Cross linked polyethylene)

10. How can you measure insulation? Can you use multimeter to check insulation in “M-ohm” range?

Ans: Using megger meter we can check insulation level.

No, we can’t use multi meter to get resistance in M-ohm level. Since, multi meter can’t apply H/V to
make leakage current flow through insulation.

11. Draw a megger meter circuit.

Ans:
12. principle of megger meter?

Ans: Megger meter applies H/V. i.e.: 500V D.C or 1000V D.C or even 5000V D.C. If we find i.e.: 5 MΩ
good insulation resistance than,

V megger = I leak × R insulation

500V = Ileak × Rinsulation

500V = Ileak × 5MΩ

Ileak = 500V/5 MΩ = 100 micro-Amp.

So, 100 micro-Amp seems leakage current for a healthy insulation resistance. Megger make leakage
current flow to measure insulation value.

13. How would you know, your megger meter calibration is, ok?

Ans: Measuring a known resistance in Mega Ohm range. i.e.: 2M-ohm resistor will be shown 2M-ohm in
a good megger meter.

14. How to check cable insulation?

Ans:
15: How do you check motor I/R?

Ans:

16. How will you do continuity test?

Ans: Just connection between u1 & u2; v1 & v2; w1 &w2; if R= 0 ohm.

Continuity is observed of above figure.

17. Suppose your system is detected as earth fault. How do you find which particular location is faulted
to earth?

Ans: There will be a I/R monitor is switch board. Now, gradually we start switching off all the D. B’s. At a
particular D. B’s switching off will show I/R value back to high again. So, those load under that particular
D.B is earth faulted. Now reaching to that faulty D.B will gradually make C.B off. Under a particular C.B I
will detect that I/R remains high. So, that load needs care taking to remain earth fault.
18. how to test diode?

Ans:

Result: Diode is “OK”.

19. What is tester?

Ans: Tester is used to detect live system. It may be digital type, hand tester, probe type. In H/V system
long handle insulated probe tester is used to check the liveness of any line of the circuit.

20. Why clamp ammeter is used?

Ans: For power cable or any cable we can’t just break the cable to connect ammeter in series. Or, even
though it was possible, how to get a meter so measure such high current like 1000Amp or 1500Amp or
2000Amp. Rather we need instrumentation. So, clamp ammeter is a kind of C.T which shows current
simply just clamping.

21. Principle of clamp meter?

Ans:

22. What will be the output of following case?

Ans: Result: If there is no leakage or unbalanced winding then clamp will show “OA”. This is also a way to
find leakage/ earth fault. In case of any leak or fault to earth the clamp will show some amperes. i.e.:
“4amp”

23. What do you mean by marinized?

Ans: Equipment should withstand with regality of a sea life. (i.e.: vibration, humidity, temperature,
ozone, sea water)

24. What is insulated system or 3-phase 3-wire system?

Ans: The neutral is not connected to hull is called insulated system.

Advantages: Continuous operation of essential loads even on single earth fault.

25. What is non-insulated system or 3-phase 4-wire system?

Ans: If N+ Earthed.

Advantages: Auto fault detection.

No need of X-former for lighting loads. (i.e.: 220v)

26. What is preferential trip?

Ans: When a generator is overloaded in a particular mode, an over current relay put off some of the
non-essential loads gradually. Thus, essential operation is granted. This process is called preferential
trip.

27. What are essential loads & non-essential loads?

Ans: Essentials: steering gear system, alarm and control system, communication system, navigation
system, detection system, detection (fire) system, emergency lights, escape way lights, sprinkler system.

Non-essentials: HVAC system, refrigeration, accommodation, lights, bilge P/P, anchor motor, galley
items etc.

28. What is the regulation of emergency generator?

Ans: It should not depend on any other engine room supply. It must have internal combustion engine as
prime mover and have its’ own fuel supply task. Starting equipment & switch board in near vicinity. Btw:
In engine case it must be capable to get started automatically within 45 sec. Must be able to carry
essential loads for 18 hours.

29. What is the use of battery as emergency supply?

Ans: in the event of emergency, only the emergency services are supplied by emergency generator. But
when black out occurs. In this transitional period (beta) loss of main power and the connection of
emergency generator. The battery ensure that total blackout will never happen because it will take
some lights, Navigational equipment, commercial equipment.
30. Draw a S.L.D emergency switch board?

Ans:

# Extra Question

At earth fault:

Insulated: Nothing happens & motor runs smoothly.

Non-insulated: As same as short circuit, 22000 amp will flow through.

31. What are the major cause of Earth Fault?

Ans: Due to insulation failure, loose wire, conductive dust.

32. What is double earth fault?

Ans: In an insulated system, unfortunately if two phases of any system get connected to earth, is called
double earth fault.

33. Why neutral is must be earthed via a resistor in H/V system?

Ans: Due to unbalanced system neutral always have voltage. H/V system unbalanced voltage is also high
compared to MV/LV system. So, it must be earth via resistor. Again, earth fault in H/V cause high
current, which also needs to limited by “R”.

34. What should be the minimum value of “R” during “NER”?

Ans: Such that it would not cross the rated current limit of generator.
i.e.: Vphase = VL /√3 = 3.3kv/√3=1905 volt

i.e.: Irated of genset given = 437A

So, “R” = 1905/437= 4.4Ω

R= 4.4 Ω ensures, even in earth fault moment the current is less than or equal to rated current. So,
generator can sustain out of getting collapsed.
35. Draw a lamp test circuit. How does it work?

Ans: When no faults:

All lights glow at half brilliance as they are star connected to each light gets R-N, Y-N, B-N.

When faulted:

i.e.: B-line earthed.

So, light 01; Y-B, Double brilliance

Light 02; B-B, Dark

Light 03; R-B, Double brilliance.

36. What are MCCB, MCB, ACB?

Ans: MCB: Miniature Circuit Breaker, generally (5 to 100) A

MCCB: Molded Case Circuit Breaker, (0 to 1500) A

ACB: Air Circuit Breaker, greater than 1500 A

37. What are the maintenance of a transformer?

Ans: At regular specific intervals, transformer must be disconnected, removal of covers and all
accumulated dust and deposits removal by vacuum cleaner, brushes. Windings must be inspected for
any sings or damages or overheating. Continuity and resistance of winding must be measured. Recorded
and compared with previous values.

38. What is instrumentation? C.T, P.T?

Ans: To measure voltage and current some means of transformer are used, they are called instrument
transformer. i.e.: C.T- Current X-former. P.T/ V.T- Potential/Voltage transformer.

Caution: Secondary of C.T must be earthed. Otherwise without any load on C.T secondary there is no
back e.m.f. Hence, voltage at C.Ts’ secondary would cause shock or insulation stress at secondary.
39. Draw a shore connection box.

Ans: See D.T hall book.

Caution: Check phase sequence. Must connect earth terminal of shore to ship’s hall.

40. If you have 50 Hz at shore but your ship system is 60 Hz, 440V; what would you do?

Ans: I would request them to change their (Shore) transformer tapping to provide me 380V. As I have to
maintain V/f ratio.

41. What is breaking current and prospective fault current?

Ans: Breaking current: The maximum fault currents a C.B can safely interrupt. i.e.: A 50A breaker has
60000A breaking current at 220V.

Prospective fault current: Current that arises due to a short circuit at the point.

42. What factors determine the short circuit current level?

Ans: Total impedance of generator, cables & transformers in the Circuit between generator & fault.

43. What is discrimination?

Ans: The ability of protection system to disconnect the only faulted circuit and to maintain the electrical
supply to healthy circuit is called discrimination.

44. Why fuse wire melts?

Ans: If the high current flows through, it produces heat which it can’t dissipate. So, at last it melts.

45. Construction of HRC fuse?

Ans: HRC: High rupturing capacity. i.e.: 80,000A

Function of filling

Powder: Capacity to supper arch.

Tin- melt point- 240 degree Celsius

Silver- melt point- 980 degree Celsius.

46. Draw marine type cable construction.

Ans: See D.T hall Book.

47. How will you bring I/R back of a cable?

Ans: Using welding machine as a current injector. Voltage applied via welding machine is kept within 30
to 55V. The cable inject current must not exceed rated current. Temperature must be below 30 degrees
centigrade. When final megger rating shows 20M-ohm to 100M-ohm, heating is satisfactory.

48. What are the earthing system available?

Ans: TNC- Terra Neutral Combined

CNE- Combined Neutral Earth

PME- Protective Multiple Earthing

IT (Ship Earth)- Isolated Terra (Used in ship preferably)

TT- Terre – Terre Earthing

49. When a generator becomes motor or motor becomes generator?

Ans: Any speed more than synchronous speed makes the synchronous machine generator; below
synchronous speed it becomes motor.

50. For a 500kVA, .8 p.f lagging, 400V genset, find out nominal current and select a C.B?

Ans:

51. What is the function of condenser?

Ans: Condenser/ Capacitor: Supplies reactive power (+theta)

Inductor/ Reactor: Consumes reactive power (-theta)

52. How many types of rotors are there in generator?

Ans: Salient pole:

-Used in low speed. i.e.: diesel engine.

Cylindrical Pole:

-Used in large power high speed (1500-3600 r.p.m) steam/gas turbine drives.
53. What is diode plate?

Ans:

54. Draw a brushless Excitation scheme? (D.T Hall- 65)

Ans:

55. What is pilot excitation?

Ans: Some times to AID secondary exciter flux build up, one more small generator is used which is of
permanent magnet rotor. This is called pilot excitation.

56. What would happen if diode becomes shorted or opened/spoiled?

Ans: If diode is shorted, excitation is shorted. So, rapid over heating of excitation.

If diode is open circuited, another good diode has to take the load, A.V.R has to generate more D.C
current to maintain terminal A.C voltage. Exciter will gradually overheat.

57. What are the limited voltage regulation range for an A.V.R?

Ans: +- 2.5% at steady state or better.

+- 1.5% at transient state; recovery time must be before 1.5 second.

58. Draw an A.V.R block diagram?

Ans:

59. What are the function of A.V.R?

Ans: (a) It ensures rapid recovery to set voltage against any disturbances.

(b) It enables to share (kVAR) in parallel operation.

(c) Over voltage/ under voltage alarm/ trip protection.

60. What precaution must be taken during megger test of a generator?

Ans: All electronic connection must be disconnected. A.V.R circuit must be disconnected.

61. What are the basic parameters you need to check before parallel operation?

Ans: a) Voltage level should be equal

b) Phase sequence should be same

c) Frequency should be same

62. Explain bright lamp method and two bright one dark method?

Ans: All Bright

At proper synchronizing moment all lights will be dark, that means they won’t have any phase voltage
difference.

2 Bright 1 Dark

At proper moment 2 lights would be bright one would be dark.

63. What Happens if voltage of incoming generator is increased?

Ans: Suppose running generator is carrying load already. Now incoming generator has greater voltage
than running one. So, incoming generator will work as rotating capacitor. Which eventually improves the
power factor of the system. If both generators are in loading already then generator with greater
voltage would have poor power factor. While lower voltage generator power factor improved.

64. What happens if one generator is running at low frequency in parallel operation?

Ans: We know that for being a generator it should be run at synchronous speed. Ns = 120f/p

If r.p.m is decreased due to some reasons then the machine (synchronous) will act like a synchronous
motor having both fuel in and electrical power in from bus bar. As a motor, the load is the prime mover
itself. If the fuel delivery further decreased due to some reason again, then the load on motor further
increased. At last, if fuel delivery is lost, the whole generator will act as a motor. Where the load is the
shaft of prime mover. It is generally (10 to 40) % of the generator rating. i.e.: 500kw generator would be
(50kw to 200kw) motor. So as a common practice reverse relay is used. Which is permitted up to

(8to10) % setting within 5 sec trips.

As excitation of rotor is unchanged nothing happens to reactive power.

65. What is synchronoscope?

Ans: During parallel operation, proper synchronizing moment is found out by synchronoscope. So, this is
a device which helps to find the proper synchronous moment.
 Sheet No 2

1. Why compounding excitation needed?

Ans: In brushless alternator rotary exciter is used. They have relatively sluggish response to a sudden
load change. i.e.: against 15% dip due to transient disturbance during startup of motor, the rotary A.V.R
takes 1 sec as a recovery time. Static excitation would help us in this case which only takes .1 sec as a
recovery time. 10 times faster than rotary excitation system.

Note: Compounded means that the excitation is derived from the generator output voltage and current.

2. What factor causes delay to A.V.R regulation of voltage?

Ans: a) Inductance of rotor field winding

b) inductance of main exciter field winding

c) regulating response from A.V.R ckt.

3. What is the permissible regulation limit by A.V.R?

Ans: At transient: 15% voltage dip

At steady: ± 2.5% voltage dip.

4. Why terminal voltage of generator drop down?

Ans: At transient

At starting motor demands inrush current which as a result large current from generator. So, inside
generator and cable there is a large voltage drop. i.e.: (15%)

At steady

At steady state, if we keep making load switch on in parallel, line current increases. If also causes voltage
drop in generator internal impedance, cable impedance.
5. Draw a synchronizing instrumented switch board.

Ans: See D.T Hall.

6. Draw a generator protection scheme.

Ans: See D.T Hall.

7. What are the bus bar protections?

Ans: u/v, o/v, u/f, o/f, reverse power relay, preferential trip relay, difference relay, phase failure relay
etc.

8. What are the switch board personal protection?

Ans: Switch board is earthed. Celluloid glass cover protection before bus bar. Insulated (missing)

9. What are the allowable range of relays?

Ans: Under Voltage Relay: 90% of Vr but not less than that. Sometimes till 70% also accepted. Time:
within (300 to 500) m/s

Over Voltage Relay: 110% of Vn but not more than that.

Time: Within 5000 m/s.

Under Frequency Relay: 48Hz of 50Hz system. 58Hz of 60Hz system.

Time: 5 to 10 sec.

Over Frequency Relay: 52Hz of 50Hz system. 62Hz of 60Hz system.

Time: 5 to 10 sec.

Over Current (Inverse time) Relay: (1.1 to 1.3) In time allowable is (10sec to 2min) any value.
Over Current (Instant/ short circuited) Relay: (2 to 10) In time allowable is (100ms to 1000ms) any
value.

Reverse Power Relay: (5 to 15) % of generator rating. Time allowable is (500ms to 3000ms)

Negative Phase Sequence Relay: 20% of In.

Different Protection Relay: 10% of In.

10. How will you take care of generator maintenance?

Ans: We need to first ensure that main C.B is locked off and prime mover is shut down. Auto start of
engine or C.B is disabled. All auto start of engine or C.B is disabled. All electric heaters are switched off
and isolated.

Now all wiring needs inspection to find any damage, breaking of insulation, tightness of terminal
connection.

Now check the cooling air intake and exhaust opening are not blocked and are free of dirt and dust.

Using blower clean the dust on rotor and stator. If any spilled oils on winding surface, it may be cleaned
by detergent liquids.

Rotor’s slip ring must be checked out. Generator excitation transformer A.V.R Rotating diodes must be
kept free of dirt oil and dampness.

Take the insulation resistance value. Though 1M-ohm is minimum accepted value of fine insulation.
Sometimes 450k-ohm or .45M-ohm also accepted as per 1k-ohm/volt rule.

Note: In High voltage system the rule is H.V+1M-ohm. i.e.: for 6.6kV system.

Accepted IR value is 6.6+1 = 7.6M-ohm.

11. Why does rotor rotate?

Ans: Rotor of induction (Squirrel Cage) motor is short circuited Cu bar. When there is a current in short
it produces flux, which is cut in rotor. Rotor develops an e.m.f as it is stationary at starting. But as per
Lenz’s Law the cause produces it, it will oppose the cause. In motor the relative velocity set a stator field
and stationary rotor is cause of rotor e.m.f. So, to reduce the relative velocity the rotor starts moving in
the same direction and at slightly low speed.

12. Why more current drawn by the stator when rotor is loaded more?

Ans: When rotor is loaded more, its speed slows down. So, the rotor cuts the flux at an increasing rate.
So, like transformer if rotor as secondary demands more current to take extra load. Stator of motor acts
as primary to supply extra current. Generally, no load to full load, the slip varies 1% to 5%

i.e.: Synchronous speed, let’s say 1000 R.P.M at 1% slip on no load, rotor speed is 990 R.P.M.

At 5% slip on full load, rotor speed is 950 R.P.M.

i.e.: 5% = 5/100; 5% of 1000 = 5×1000/100 = 50 R.P.M

1000-50= 950 R.P.M

13. Draw a main switchboard layout? Or mention the sections in MSB?

Ans: a) starters & feeders or motor control center (MCC)

b) Shore supply port/ STBD

c) Emergency switchboard section

d) P/S generator switchboard

e) Bus tie

f) STBD generator switch board

g) 220V MSB

h) PMS section

14. What C.B are usually used in M.S.B of H/B?

Ans: SF6 -Sulphur Hexafluoride gas filled chamber. In Chamber the gas is maintained at 5 bar pressures.

15. Name some parts of a motor?

Ans: a) stator

b) Rotor

c) Bearing

d) Fan

e) terminal box

f) grease nipple

g) eye bolt

h) terminal box gasket

i) Fan cover

j) Drain plug

16. Why motor starting current is high?

Ans: At starting the rotor has no r.p.m. So, the frequency of e.m.f of rotor is same as supply frequency of
stator (i.e.: 50Hz or 60Hz). That time the reactance of rotor XL= 2 π fl is high. Due to high reactance the
lagging current is high with low power factor. So, to take load torque it demands much current from
stator.

If motor is started with no load, then starting current is negligible compared to with load.

17. How a star delta starter suppresses the starting inrush current of motor?
Ans: Generally motor greater than 10kw is started with star-delta starter. The benefit of (star-start) and
(delta-run) is that in star connection the motor receives 1/3 current that would be taken in delta
connection.

But at starting as there is star connection and 1/3 current reduced, the torque is also reduced to 1/3,
which causes the more run up time for the drive.

If the motor is designed to operate as delta-run, it must be made to run at delta after star-starting.
Otherwise, there will be overheating if it is made star run. It would take √ 3×Irated in star-connection. It
causes overheating and eventually leads to winding burnout.

18. Draw Star-Delta, DOL starter, Reverse Forward starting diagram for a motor. 10,000% see D.T Hall
Book.

19. What is soft starter?

Ans: With efficient electronic switching technique using thyristor/ triacs the applied voltage is reduced
at starting. After certain delay the full voltage drops occur.
20. Direct on-line start (used in below 10kw rated motor).

Ans:
21. Draw Reverse-Forward starter connection diagram.

Ans: Used in engine room fan or in crane motor.

22. Draw Star-Delta starter connection diagram.

Ans:

23. What will you do if an induction motor has been flooded with sea water?

Ans: The main thing is to bring the insulation resistance again which can be achieved in 3 stages.

Charging: Washing with clean fresh water. Any grease or oil on windings has to be removed.

i.e: Arma clean can be used/ electro cleaner may be used.

Drying: With low power electric heaters/ lamps dampers can be removed but plenty of ventilation is
ensured for dampers escaping.

Re-varnishing: After cleaning & drying if IR test shows high value after an hour. Then apply couple of
coats of good quality varnish.
24. Draw a motor protection scheme?

Ans:

25. What are the temperature sensors used in motor?

Ans: Thermocouple, resistance, temperature, desire thermistor.

26. What is single phasing of a motor? What are the effects of it?

Ans: If one of the 3-supply lines become disconnected called single phasing.

Motor will run on single phasing. But more current will be drawn by remaining 2 phases, motor become
very noisy due to uneven torque. At last OCR trips due to overheating.

27. Why single-phase motor has no self-starting torque?

Ans: To make a motor self-started it needs at least two phases as we need revolving magnetic field.
28. What are the maintenance of motor?

Ans: a) Keep insulation resistance high, contact resistance low.

b) Lubricate correctly and maintain air gap.

c) Ensure both the interior & exterior are always clean & dry.

29. Draw a florescent lamp circuit?

Ans:

30. What are the rules of navigation & signal lights?

Ans: Most common arrangement is to have five specially designed navigation running lights referred to
as foremost, mainmast (AFT mast), stern, port, star board.

Fore Mast: Has two anchor lights.

AFT Mast: Two anchor lights.

Port (left): Red light.

Starboard (right): Green light. See D.T Hall book.

Stern: White lights.

Vessel more than 50-meter length, Mast head lights must be visible from 6 nautical miles, other lights
from 3 nautical miles.

31. Write about battery & battery maintenance.

Ans: Battery is needed for essential supplies. i.e: radio equipment, telephone exchange, fire detection,
general alarm circuit etc. Emergency battery supplies for emergency battery start up & emergency
lighting. Ship battery is usually rated at 24v D.C. Sometimes 110v D.C or even 220v D.C also available.

Batteries are two types.

a) Lead Acid (2v per cell)

b) Alkaline (1.2v per cell)

The battery capacity is rated in A/H (ampere hour).

Usually, 10 hours is used for calculation. i.e.: 350 A/H battery will provide 35amp for 10 hours. After 10
hours 2v lead acid cell will be 1.73v and 1.2v alkaline call will be 1.14v.

Safety and maintenance: Battery room should be well ventilated, clean and dry. Both types of batteries
generate H2 gas. So, smoke or flames must be prohibited in the vicinity of batteries. Acid Cells must
never be place alkaline cells. Otherwise, rapid electrolytic corrosion to metal work, causing damage to
both batteries. So, maintenance tools/ gear (i.e.: hydrometer, topping up bottles) never be shared to
both.

32. What is Battery maintenance?

Ans: a) Keep the cell tops clean & dry.

b) Check tightness of terminals.

c) Sometimes apply the smear of petroleum jelly.

d) Use protective rubber gloves, eye goggles when handling electrolyte.

e) Insulated spanner should be used to prevent short circuiting.

f) Battery never to be overcharged, otherwise there will be gassing problem.

g) Battery never to be left unused for long time otherwise sulphation may be used.

h) Battery posts (connecting) and cable terminal should be of same material/ metal, otherwise corrosion
will take place.

33. What is the first aid treatment if electrolyte of battery splashed into your eye? Or skin?

Ans: a) Rapidly wash eyes & skin with plenty of water/ fresh water.

b) Electrolytes Alkaline cause burn. So, boracic powder is used in skin & its solution into eyes.

c) Sulfuric acid can be washed with saline solution.

d) First aid equipment should be in the battery compartment.

34. Draw a lead acid cell battery.

Ans:

35. How to check stage of charge?

Ans: A fully charged lead acid battery will show 1.27 to 1.3 SG (specific gravity). It falls to 1.1 of a
discharged battery.

For Alkaline battery: new battery SG is 1.19. This reduces to 1.15 after 5 to 10 years depending on duty
cycle.

36. Draw a battery charger.

Ans:

37. Mention about some machineries on board?

Ans: Main engine, auxiliary engine, wind loss motor, capstan motor, bilge p/p, ballast p/p, fi fi p/p,
hydrophore p/p, sea water supply p/p, bow thruster, stern thruster, azimuth thruster, engine room fan,
lube oil p/p, fuel oil p/p; [Note: most of the case all p/p are main p/p also having stand by p/p]

Steering gear, winches, propeller, RUDDER etc.

38. What are the department or section in ship?

Ans: Machinery section, HVAC (heat ventilation air conditioning) section, piping section, accommodation
section, electrical section.

39. What are the underwater sectors?

Ans: SONAR, Echo sounder, Speed logger, Hydro phone, Fish size indicator, ICCP, ICAF.

40. What are the navigation equipment?

Ans: RADAR – S Band, X Band, GPS, Magnetic Compass.

41. What is reverse power?

Ans: When a generator running and acting as a motor, it is called reverse power. E.G 500 kw generator
in reverse power 20% of 500kw.

42. What are the alarms on board ship?

Ans: General Alarm: 7 short blasts followed by 1 long blast. It is used to make aware the crew about fire,
collision, grounding etc. Which can lead to abandon the ship.

Fire Alarm: Automatic or by manual call point.

Man Over Board Alarm: When crew/ passenger fell in water at high seas.

Abandon Ship Alarm: Ship is no longer safe for the crew. Verbally given by master.

Navigational Alarm:

Ship Security Alarm: When attacked by pirates, silent alarm to notify the coastal authorities. Bilge alarm,
CO2 alarm.