The Works Of Messrs. Schneider And Co.

124 MESSES. SCHNEIDER AND CO.’S WORKS. is effected by a wheel, which works a screw that acts on a nut forming part of an arm fitted to the plate. These dynamos are perfectly driven by a turbine, the speed of which is 260 revolutions ; it carries a wheel keyed direct on the dynamo shaft. 500 Horse-Power Dynamo. — Twelve-pole Thury dynamos have been constructed for eleetrolytic soda manu- f'actories. They can each supply a current of 5,000 amperes, at 75 volts ; they are built with two commutators, and two different armature windings, placed across the same core. The armatures are ring-wound, and the coils enclose bars lodged in open grooves. The carbons, 360 in number, are arranged on each brush-holder, in the same manner as in the last machine above described. Their displacement is also effected by two screwing devices. The turbine wheel is keyed on the end of the dynamo shaft ; it runs at 250 revolutions per minute. 700 Horse-Power Alternator.—Several of these alter- nators, built by Messrs. Schneider and Co., are in use at varions works for the manufacture of Carbide of calcium. They are of the Thury type, with undulatory current ; they include two armatures, without movable coils. The shell is of cast i ron, in two parts, fitted together horizontally. It carries two cast-iron sookets, in which are fitted the armature coil core-plates ; each of the armature windings consista of a certain number of coils, formed of bars United together by evolvent joints. The ends of the coils are welded on copper coupling-circles placed each side of the dynamo and pro- vided with movable connections which allow of obtaining, by a simple shifting, a variable voltage as required in the varions phases of manufacture. Strong copper rods unité the coupling-circles to the terminals ; each of these consista of two gun-metal Blocks fitted together and lixed to the frame. (See Fig. 356, Plate LXXX.) The inductor constitutes the rotary part of the machine ; it consists of a cast-steel block, carefully balanced, provided with polar projections, which revolve opposite the armature cores. The magnetic current necessary for working is created by an annular exciting coil, held in a groove inside the shell, between the two armatures. In füll load, the exciting does not exceed .2 per cent., and the efficiency reaches 95 per cent. This dynamo combines strength with high efficiency under a wide range of conditions, in quite a remarkable manner. It was originally clesigned for a speed of 600 revolutions, and exhaustive trials have proved that it can be allowed, with- out any danger, to run at more than double that speed.