July 28, 1911 & August 4, 1911
THE ELECTRICAL EQUIPMENT OF THE S.S. "OLYMPIC" AND "TITANIC."
Summary.In this article are described the various uses to which electricity is put on board the two latest White Star Liners “Olympic” and “Titanic.” These include, besides lighting, power for winches, cranes, fans water-tight doors and stoking and helm indicators. The clocks and heating equipment are also electrically worked, while a complete telephone and wireless installation is to be found on board. The differences between marine and land practice are noted.
The tendency with Atlantic liners as with many other things has been towards increasing size. Ships which were considered monsters only a few years ago are now quite outclassed, and here seems no likelihood of the progress in this direction being checked yet a while. The latest ships to head the lists as regards size are the “Olympic” and “Titanic,” the former of which made her maiden voyage from Southampton on June 14th last, while the latter will soon be completed. Both ships are products of Messrs. Harland & Wolff’s famous yard at Belfast.
Electricity is used in all departments of these mammoth ships, and before describing the large electrical installation in detail it will be of interest to the reader to enumerate the purposes to which electricity has been applied for power, quite apart from lighting. They are as follows:—Electric deck cranes, from 30 to 50 cwt.; cargo, boat and engine room winches; passenger elevators; stores, mail and pantry lifts; ventilating and stokehold fans; cabin fans; motors for cylinder lifting gear, turbine turning and lifting gear, and condenser sluice valves; pneumatic conveyor for Marconigrams; gymnastic apparatus; domestic machinery (such as ice rocker, dough mixers, potato peelers, roasters, knife cleaners, soup and sorbet machines, mincers); electric heaters and fires, hot plates, electric baths and irons; main steam whistles; sounding machines; stoking indicators; boiler room telegraphs; clocks; watertight doors; helm indicator; illuminated pictures and signs; chimes; bells; loud-speaking telephones and service telephones; submarine signaling; wireless telegraphy.
The main generating plant, which is probably the largest electrical equipment that has been installed up to the present for marine work, consists of four 400 kw. engines and dynamos, manufactured by Messrs. W. H. Allen, Son & Co., of Bedford, and having a collective output of 16,000 amps. at 100 volts, thus exceeding in current capacity many electrical central stations.
The sets are situated in a separate water-tight compartment aft of the turbine room at tank top level, their general disposition being as indicated in Fig. 2, one of the sets being illustrated in Fig. 3.
The engines develop 580 B.H.P. each, and are of the vertical, three-crank, compound, forced lubrication type, running at 325 revs. per min., with one high-pressure cylinder 17 in. diameter, and two low-pressure cylinders each 20 in. diameter and 13 in. stroke. They are supplied with steam at 185 lb. pressure per sq. in. and exhaust either into a surface heater, when at sea, or to a condenser. Each engine is direct-coupled to a 10-pole compound-wound dynamo, fitted with interpoles.
The field magnets are of annealed cast steel of high permeability and are cast in halves, being divided on a horizontal plane. The ten main poles are cast in one piece with the yoke, and are fitted with laminated pole-shoes, the yoke rings being of specially rigid design. The interpoles are secured by bolts to facings on the inner surface of the yoke ring. The series coils are of flat copper strip wound on edge, as are also the series coils of the commutating poles, and in all the windings great care has been taken to ensure ample ventilation, and also facilities for rapid disconnection and replacement of the different sections.
The armatures are of the slotted drum type, built up of mild steel plates on a cast iron hub, the “former-wound” coils being of flat copper strip. The commutators having to deal with an exceptionally large current are of exceedingly massive construction, and great care has been exercised in the design to ensure only a moderate degree of heating. The brushes are of carbon and graphite, and while giving good conductivity also run with small friction on the commutator, thus preserving the surface of the latter in good condition for long periods.
Besides the four main generating sets there are also two 30 kw. sets situated in a recess off the turbine room at saloon deck level, well above the water-line. These may be connected by means of a separate steam pipe to boilers situated in one of several boiler rooms, and will be available for emergency in case the main sets should be put temporarily out of action; the general features of their design are very similar to the main sets, but the engines are of the two-crank compound type, and the dynamos are not fitted with commutating poles.
From Fig. 1, showing the general arrangement of the plant, it will be seen that the four sets are arranged in pairs, one right-handed and one left-handed set, with the crankshafts in line and the stop valves inwards with a gangway passing between and another pair immediately behind. It will also be noticed that the platform by which access is gained to the cylinder covers, &c., extends right across the two units of one pair, the stairway being placed in the gangway between the two units.