electricity, power, generator, alternator, fault, batteries, protection, supply,
restore, dc, blackout, brownout, emergency, loads, electro, technology,
engineer, distribution, essential, trip
Heavier loads need additional generators
Electrical power on a ship is essential. All machinery runs on electrical
supply. That's why the generator sets are so important. Without electrical
power, the ship will have no propulsion and steering. It would be a
disaster both in rough weather and in narrow waters.
There are many components of a generator set - the engine, the alternator,
the fuel, the cooling system, the electrical wiring, etc. All of these can
develop its own problems. The generator sets are usually maintained by the
Third Engineer, because he is the most senior watch keeping engineer.
When electrical faults develop in the distribution, protection devices can
trip and cause interruption to the electrical supply. The watch keeping
engineer on duty at that time will then have to quickly restore the power back to the ship.
Whenever there is a blackout that involves the interruption of electrical
supply to the whole ship, the emergency power supply from the storage
batteries will take over some of the most essential services.
A typical ship will use 24 Volt DC supply from the batteries in the
battery room to supply for:
The duration of the battery supply follows the regulations for Passenger
Ships and Cargo Ships - being longer for passenger ships. The battery
supply will enable the engineers to move around and start back standby
generators, energize circuit breakers and do other troubleshooting works
to restore the power.
- Main engine and auxiliary engine control consoles
- Engine room, accommodation lighting
- Inverter for navigation lights
- Signal lights and boat station lights
- Public address system and telephone systems
- Other systems like auxiliary engines, emergency generator start circuits,
fire detection systems, locked-in alarm for cold room and lift, lift
telephone and lighting.
For bigger ships, emergency generators are sometimes fitted that will
start by themselves automatically. These can supply more high powered
machinery like emergency fire pumps, air compressors, lift, steering gear,
gyro compass, radar, engine room control console, boat winches, cargo
control console, and engine room ventilation fans, lighting, and
The electrical distribution system on board a ship is usually arranged so
that in case of heavy overloaded usage, non-essential loads will trip
first. Machinery is classified as essential and non-essential.
Examples of non-essential loads are: fans, refrigerator compressor, crane,
lathe, grinder, arc welder, air conditioning, deck powered equipment like
cooking, baking oven, etc.
In between non-essential and essential, there may be some machinery like
boiler feed water pump, boiler water circulating pump, fuel transfer pump,
oil purifier, sludge, ballast pump, hot water circulating pump,
distillation pump, freshwater and potable pumps that could be tripped off
to reduce the load. These may be set to trip
if tripping the non-essential loads could not reduce the overall
Essential loads are mostly equipment that is related to the working of the
main engine, steering gear and the safety of the ship. Examples of these
are: Cooling seawater pump, jacket cooling water pump, piston cooling
water pump, lubrication oil pump, fuel valve cooling water pump,
turbocharger oil pump, stern tube lubrication oil pump, stern tube seal
oil pump, steering gear pump, fire and general service pump, bilge pump,
main air compressor, auxiliary seawater pump, auxiliary air compressor,
condensate water pump, fuel oil booster pump.
Electro-technology is a subject that Licensed Marine Engineers need
Download "Electro-Technology Questions & Answers"
e-book. This e-book
is useful not only to marine engineers, but for any engineer on