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30° Curtis steam turbine; one 300-kilowatt generator di- rect-connected to a Ham- ilton-Corliss compound condensing engine; and one 200-kilowatt Bullock generator also driven by a Hamilton-Corliss en- gine. For operating pneu- matic hammers, drills, caulkers, etc., used in ship work there are two com- pressors, one of the Rand type having a capacity of 6000 cu. ft. per minute, and another of the Inger- soll-Sargeant type deliv- ering 1,000 cu. ft., both being operated by cross- compound Hamilton-Cor- liss engines. The apparatus of the power house is of very simple construction, only one variety of current being gen- Tae MARINE REVIEW FIG, 4.--MOTOR-DRIVEN BORING MILLS. cording. to-the number of tools actually in opera- tion or in idleness but the figures here given are a fair illustration of. the economy of the system of power distribution and subdivision employed. in the yard. One of the most -inter- esting features of the electric equipment of the Fore River ship yard is the system for speed. var- iations. This is known as the H. Ward Leonard multiple-voltage system. The generator is operated on the two-wire plan sup-. plying the highest vol- tage, 240 volts, and on this voltage are operated all the constant speed motors, the crane motors and the lighting system of the erated for all classes of service--direct current at 240 volts. yard. For variations of speed this voltage is divided Current is generated for about 275 motors varying in size from % to 100 H. P., the major portion being sup- plied by the Bullock Elec- tric Mfg. Co. (the Allis- Chalmers Co.), and also for about 4,000 incandes- cent lamps and 350 arc lamps. About seventy- five per cent of the mo- tors are direct-coupled to the tools which they drive. Some of the re- mainder are belted and in one or two cases are coun- ter-belted to obtain a high speed, this practice being almost entirely confined to wood-working tools re- quiring a different meth- od of power application. There are a number of into three by means of a balancing transformer located in the engine room and con- sisting of three similar machines mounted upon a common base. This en- ables pressures of 60, 80 and 110 volts to be car- ried between the various pairs of the four wires. By proper combinations a number of pressures may <be.. obtained 'and with the aid of a small range of shunt field regu- lation a range of speeds the highest of which is six and one-half times the lowest may be se- cured. The -system is thus one in which the im- pressed electro4motive special motor-driven tools FIG. 5.--HEAD OF STOCKS OF SOME OF THE MOTOR-DRIVEN LATHES. force upon the armature _ designed to facilitate ship of a motor is changed to building operations. One of these is a counter-sinking meet the requirements of speed regulation, or in other machine consisting of a motor geared to a drill stock which holds . the tool, the whole being 'mounted on a hand bar- row so that the entire ap- paratus can be rolled by hand over a plate placed in a horizontal position and the tool brought to its work by merely press- ing down in the proper positions. : While the aggregate load of all the motors in the yard is not far from 3,800 H. P. the average load upon the generators is only about 2,400 am- peres for both power and lighting, or about 800 H. P, The load varies ac- FIG. 6.--PORTABLE COUNTER-SINKING MACHINE, words change of speed is secured by increasing or diminishing the pressure and not by varying the resistance as is the usual practice. The current is distrib- uted to the various build- ings by means of about 1,000 ft.. of subway and nearly a mile of pole line. The average center of distribution in each build- ing is about 500 ft. from the power house switch- board, and each shop has its own set of mains com- ing up through the floor to a distributing board and the feeders are led in various directions to the individual tools. The