All the machinery in the yard, and in several departments in the engine and boiler works, is run from one central station, of which two views are given on Plate XLVIII., opposite. The electric generators occupy one side of the power station, and the air compressors and hydraulic pumps the other. Steam at 200 lb. pressure is supplied by one marine cylindrical, and four Babcock and Wilcox water-tube, boilers, with superheater, coal conveyors, and mechanical stokers.
[Illustration: Plate XLVIII. ELECTRIC GENERATORS IN THE POWER STATION. HYDRAULIC PUMPS AND AIR COMPRESSORS IN THE POWER STATION.]
There are three electric generating sets, with a total capacity of 1200 kilowatts, the voltage being 240. They are illustrated on Plate XLVIII., facing this page. The engines are of the high-speed, enclosed, forced lubrication, condensing type. The current is distributed from a switchboard in the power station by overhead mains, with three-way distributing panels in the various departments. The motors, of which there are about 130 in the shipbuilding department alone, are of the two- and four-pole type, partly or entirely enclosed, and mostly of 10 to 20 electric horse-power. Arc lamps are used for lighting, but the shops and offices are also illumined by 16 and 32 candle-power incandescent lamps. Plugs are arranged at various points throughout the yard for portable lights, and for connecting mains for lighting the various ships while being completed in the docks.
Hydraulic power at 800 lb. pressure is generated by two high-pressure pumps, with steam cylinders 15 in. in diameter, and rams 4 in. in diameter. There are separate accumulators for each. The pressure pipes are led underground throughout the Works to the various hydraulic tools already referred to.
There are two air compressors for supplying power for the pneumatic tools. The combined capacity is 1800 cubic feet of free air per minute. Each has two steam cylinders 6 in. in diameter, working respectively high- and low-pressure air cylinders 15-1/4 in. and 21-1/4 in. in diameter, the stroke being 18 in. The hydraulic pumps and the air compressors are illustrated on Plate XLVIII., facing page 104.
As we have already stated, part of the power generated in this station is utilised at the engine works, to which we may now turn our attention.