Chapter 4. Maintenance aboard ship (техобслуживание на борту)

Exercise 1. Read and translate the text, using the words below.

Maintenance of electrical equipment aboard ship begins immediately after the ship is commissioned and continues throughout its entire life. It is an endless job but, if properly done, it will greatly ease the difficulties and the troubles likely to arise when the ship is at sea.

The electrician’s first work on a new ship is to check over every single piece of electrical equipment on board to see that it has been properly installed. All the apparatus should be thoroughly cleaned, as it is being inspected, to remove the dirt and grime that may have accumulated in the shipyard. All the electrical equipment is tested and tried out before the ship leaves the yard, but notwithstanding this, the ship’s electrician should satisfy himself that everything is in good order. Sometimes small articles such as screws, washers, nuts, etc are carelessly dropped into a piece of equipment after the yard test crew has completed its work.

At regular intervals, usually weekly, a Megger test is made on all essential lighting, power, and I.C. circuits. The Megger readings are recorded and compared to enable the electrician to anticipate any possible breakdown of the cable insulation. All electrical connections must be checked regularly to see that the vibration of the ship has not loosened them. This is particularly necessary in wartime, as the firing of guns often causes connections to break if they are not well secured. Ground connections in particular must be watched to see that they are not only tight but free from corrosion. Moisture, especially salt water spray, must be guarded against.

All rotating equipment is regularly checked at periodic intervals. The bearing lubrication system, as well as the bearings themselves, is overhauled at least once every six months. The lubricating system is examined from time to time for oil leaks. Overlubrication as well as underlubrication should be avoided. The cables within the machines, between the armature and pole pieces, must be frequently inspected. Brushes, brush holders, springs, and the commutator are also to be examined. Should any uneven wear be observed, it must be corrected promptly. As said before, moisture and spray are the enemies to be guarded against. Should any water enter the machine, it must be removed at once and the windings properly dried. The details of motor and generator maintenance discussed in the previous chapter apply to machinery aboard ship as well as to machinery in the shipyard.

The automatic emergency equipment is tested by actual operation at least once each week. The emergency generator and the transfer switching apparatus are tested at this time and the output is checked to make sure that the generator is capable of carrying the emergency load. All electrical navigation equipment must be checked daily. This equipment is obviously very important and if the operation is not inspected daily, serious trouble may result. Many of the I.C. devices have audible alarms and indicating lights. These must all be tested frequently to be sure they are in working order. Sometimes dry batteries are used in alarm circuits – gyrocompass for example – which must be tested frequently and changed every six months, whether they have been used or not.

Storage batteries are provided to start the emergency generator and to operate certain alarm circuits. These must be kept fully charged and maintained in accordance with the manufacturer’s instructions.

All winches are tested just before the ship reaches port and are checked again immediately after leaving, regardless of how often the ship docks. Most ships remain in port only long enough to load and unload cargo. Should any winch be out of working order, costly delays may result. The anchor winch is checked immediately after each use. Brake drums must be free from rust and oil. Brake shoes should be checked for wear, and the springs holding them in place must be examined frequently.

Circuit breakers, contact makers, and other switch gear require constant inspection to determine if they are in proper operating condition. Their maintenance has already been discussed. All parts subject to wear must be closely examined. Parts making electrical contact must be kept bright and clean. Springs must be checked regularly to see that they have not been tampered with.

Meters on the main switchboard should be read frequently during the day. These meters will indicate if any circuit is overloaded and whether each generator is carrying its share of the load. In the case of a three-wire distribution system, the ammeter in the grounded neutral circuit will give the electrician a clear picture of any unbalanced condition. Meters on all auxiliary equipment must be read at regular intervals to make sure that everything is working properly.

All of these routine tests, checks, and inspections are part of preventive maintenance. Should any electrical trouble develop at sea, then the ship’s electrician must really go to work. He should have the necessary knowledge and the requisite mechanical equipment as well as the spare parts to remedy the trouble, or if that is not possible, at least to keep things working until the ship reaches the next port. To facilitate his work, the electrician is provided with blueprints of the entire electrical system of the ship and with instruction books and wiring diagrams covering each piece of electrical apparatus on the ship.

For making repairs, the electrician has a fully equipped work bench and a testing panel. On the testing panel are outlets and terminal posts from which the various voltages available on the ship may be obtained. With it are provided all the necessary meters, indicating lamps, switches, etc that facilitate testing operations. The testing panel is, in effect, a miniature electrical laboratory which together with the work bench, tools, and equipment constitutes a very complete repair shop. This is the ship electrician’s headquarters when he is not otherwise engaged.

A limited number of essential spare parts are carried on ship board to enable the electrician to make quick replacements. The number of each part in stock depends on the size of the ship and the amount of electrical equipment aboard.