Avoid working “live” Electrical testing must often be performed on energized circuits and equipment. But the safest technique for doing tasks such as repairing and replacing faulty components is to turn the power off. PPE isn’t needed when there are no electrical hazards to protect against. So, the simplest safety rule for electrical maintenance work […] Read more
While at anchor the vessel’s fire alarm sounded on one of the lower decks. The OOW sent the duty seaman down to investigate. The crew member found a deck-head fluorescent light releasing smoke. The appropriate circuit breakers were closed and the light was smothered, extinguishing the nascent fire. The company investigation found that a poor […] Read more
Typical power system architecture for a large cruise ship with integratedelectrical propulsion. The main generators power the propulsion motors and all service loads from one main bus. The industry standards require emergency power in all cruise ships. The emergency power distribution should have three buses as shown at the top. The temporary emergency power comes […] Read more
Electric power generation based on rotating prime movers and electric generators, is a mature technology, but there is continuously being evaluated alternatives to the traditional synchronous generator. The fuel cell technology is an area of great interest and research effort, mainly in the automotive industries.A fuel cell is an electrochemical device that combines a fuel, […] Read more
Intermittent Faults on ship electrical system When ships Electrical Engineer ETO need find and diagnose intermittent faults, where a short, open, or o... Read more
There are various types of diagram which attempt to show how an electrical Circuit operates on ship. Symbols are used to represent the various items o... Read more
Avoid working “live” Electrical testing must often be performed on energized circuits and equipment. But the safest technique for doing tasks such as... Read more
Many forms of electrical protection on ship are available which are designed to protect the distribution system when a fault occurs. Protection relays... Read more
URGENT ! ETO on AHTS DP2 – ARAMCO – 175 USD-Exp. 24 months on offshore DP class vessels... Read more
Embossed metal tags are used to identify cables throughout the vessel. The tags are located at the distribution panel and the component. Tags are also attached to the cables where penetration of the bulkhead is necessary. The tag code will start with the type of circuit it is. Vessels use P to indicate power distribution panel […] Read more
Short circuit calculations are done to ensure that fault current in short circuits does not exceed breaker’s and other equipment’s maximum ratings. Under short circuit, the mechanical stresses on bus-bars and cabling becomes much higher than under normal operation, and class rules and standards defines certain limits that the equipment shall be designed for.A typical […] Read more
If a single earth fault occurs on the live line of an earthed ship distribution system it would be equivalent to a short-circuit fault across the generator through the ship’s hull. The resulting large earth fault current would immediately cause the line protective device (fuse or circuit breaker) to trip out the faulty circuit. The […] Read more
The central section of the main switchboard is used for the control of the main generators. The switchgear cubicles on either side of the generator panels are used for essential services and flanking these are the grouped motor starter panels. Handles for opening the doors on switchboard cubicles are usually linked (or interlocked) to an isolating-switch. […] Read more
Low power motors for power tools, domestic equipment, refrigerators, vacuum cleaners etc are typically supplied at 220V a.c. 50/60Hz. Common types are: Split-phase induction motor Capacitor start / run induction motor Shaded pole induction motor a.c. commutator motor Split-phase induction motor on ship A single phase induction motor has a cage rotor similar to that […] Read more
To properly understand how these different grounds fit into the vessel’s electrical system, the word “ground” must be understood as it was originally used. Decades ago, when DC tugboats were designed, the term “earth” was used instead of ground. Still later, the tugboats were called positive ground systems. (Foreign cars used to be termed positive […] Read more
To successfully carry out the various test procedures suggested in this manual, certain test instruments are essential. The following lists detail the basic requirements in this respect. It should be noted that in addition to these instruments a comprehensive kit of tools is also essential. For fault finding purposes this need not include any specialised […] Read more
Most multimeters can only measure current up to 10 A maximum. The current measuring facility is intended only for small current components and, in particular, for electronic circuits. The instrument will almost certainly be damaged if it is used to measure the current to motors and other power circuits. The basic current range can be […] Read more
Power currents (a. c.) can be measured simply by means of a clamp meter which acts as a current transformer. The instrument tongs are clipped round a single insulated conductor – the circuit is not interrupted. The value of current is obtained from the magnetic flux strength around the conductor and is usually displayed on […] Read more
For each generator circuit breaker must be fitted with an overcurrent relay. On medium-voltage systems this is often an integral part of the circuit breaker, in In the form of direct-acting trips, although for high-voltage systems a separate relay is used. A n inverse time-current characteristic is normally employed. In the actual operating curve of […] Read more
Is battery technology – and its perceived high costs – slowing the widespread adoption of next-generation hybrid electric propulsion inthe marine world? “Today, the price of batteries is not the show-stopper it used to be.The question is whether a battery solution fits the operational profile or not.“If you have a small ferry on a limited, […] Read more
