Electrical system on Board Ship

Submitted by Rey Pascual Ongoco on Sat, 02/08/2014 - 06:18

The electrical equipment aboard ship is inspected and tested during the complete engine survey which occurs every four years.

Such a survey is prescribed under the Rules and Regulations for the Classification of the Ship (depending where your ship is registered)

The electrical survey guidance in this report is based on the periodical survey regulations of Lloyd’s Register of Shipping, London.

Other classification societies have their own rules which although similar to Lloyd’s,shouldbe consulted prior to an electrical survey.

Classification Societies

American Bureau of Shipping, New York

Bureau Veritas, Paris

GermanischerLloyd, Germany

Nippon KaijiKyokai, Tokyo

DetNorske Veritas, Oslo

RegistroItalianoNavale, Genoa

USSR Register of Shipping, Moscow


Electrical equipment and services aboard ship must also meet the minimum standards by various national and international organization.

For UMS operation, a survey of the associated alarms, controls and fire detection is required.

For tankers/gas carriers and other ships transporting flammable cargo, an additional survey of all electrical equipment in hazardous areas is carried out during each docking survey and annual survey.

*The surveyorwill require that main and emergency generators are clean, respond correctly to controls and load changes, and show stable operation when required to run in parallel with other generators.

Generator windings on stator and rotor must be free of:

     Dust

     Oil

     Moisture

A visual check will be made for any obvious deterioration, abrasion, or cracking of the insulation around the end winding coils of the stator.

An insulation testto earth and between stator phase windings (if neutral point can be disconnected at the terminal box) should be carried out while the machine is still hot after running on load.


Question:
Would IR reading of 0.5 MΩ to earth be acceptable?

Answer:

Although a minimum of 1MΩ is generally specified for new equipment, Lloyd’s rules suggest that 0.1 MΩis acceptable. However, most surveyors would insist on at least 2kΩ/volt, i.e. 440kΩ, say, 0.5MΩ as a reasonable minimum value for a 440V generator.


Subjects:

Comments

JeromePurificacion

Wed, 03/12/2014 - 02:33

Sir, if this is to be discussed here and to normal students without any knowledge about the subject matter, I think sir that it will be better if there will be like a 'term bank' to avoid confusion on the subject matter. With that, I think it will be more understandable and better sir. Thanks!

Brensien Asdain

Wed, 03/12/2014 - 02:42

This article is very comprehensive. It has given the readers the idea of how and why electrical system on board is inspected thoroughly. there different rules for inspection and it depends on the classification societies. the article also highlighted the idea that the generator windings is supposed to be free from dust, oil, moisture since it is a part of the inspection. the article also provided a very good explanation about .5M ohms is acceptable as the minimum standard. I love this article.

Jamar Salahuddin

Wed, 03/12/2014 - 02:54

thank you sir, i learned a lot regarding electrical equipment and electrical survey guidance :D

Brensien Asdain

Wed, 03/12/2014 - 03:02

This article is very comprehensive. It has given the readers the idea of how and why electrical system on board is inspected thoroughly. there different rules for inspection and it depends on the classification societies. the article also highlighted the idea that the generator windings is supposed to be free from dust, oil, moisture since it is a part of the inspection. the article also provided a very good explanation about .5M ohms is acceptable as the minimum standard. I love this article.

aq po c aran

Wed, 03/12/2014 - 07:10

The article, in itself is quite supplementary in providing the basics of what is done on the electrical systems on board. But...this is so only for those who does not necessarily need to understand the subject matter. It would have been an improvement if there are samples of the specific surveys done on board for the students to fully comprehend what is taking place on board the vessel. However, this article is, all in all, quite informative and I gained new knowledge on this.

Roed_P

Wed, 03/12/2014 - 08:08

The article is marvelous. It provides us engine cadets the information needed for us to observe during inspections and for a longer engine life.

Aaron John Barcelo

Mon, 03/31/2014 - 07:40

The generators form the heart of the electrical design and their correct sizing is the key to a safe, workable and economical system. When sizing a marine generator cognisance must be given to the nature of the load. The generator often works on its own and is accordingly susceptible to large system load swings, loads causing distortion, the connection of motors and the connection of large heater elements for air conditioning systems. In addition to satisfying the apparent system load requirements, consideration must be given to the special requirements of any large loads, unusual operational requirements, spare capacity requirements and the required system operating philosophy.

ejmediavillo

Mon, 03/31/2014 - 07:56

This article gives its readers basic knowledge about how safe an electronic equipment should be aboard a ship. Resulting to, a safer working environment to everyone who will be boarding a vessel.

Celino Mangundayao

Tue, 04/01/2014 - 01:47

This article gives a basic knowledge about the electrical systems onboard a ship. This may helps many marine engineer students as well as the electrical engineering students who wants to go onboard. But one thing i've seen is that this article can be more comprehensive if it includes a more specific details about what it is discussing. All in all, this article really helps!

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