The Works Of Messrs. Schneider And Co.

120 MESSRS. SCHNEIDER AND GO.’S WORKS. serves to carry these insulators. The line, of hardened eopper wire, is 6.250 metres (20.6 ft.) above the track where the poles stand ; these are 35 to 40 metres apart, and the maximum deflection for this distance is not over .240 metre (say, 10 in.), so that the minimum height of the line above the track is 6 metres (19 ft. to 20 ft.). Outside the town wooden poles, impregnated with cupric-sulphate, are used, the arms being of the same type as those fixed on the iron poles. The feeders rest also on wooden poles, and along the track they rest on the same poles as those used for the trolley wire. The track is 1 metre (3 ft. 3| in.) gauge, with rails 36 kilogrammes per metre (72 Ib. per yard) in the interiør of the town ; outside the town it is formed of Vignole rails 20 kilogrammes per metre (40 Ib. per yard). As the return current is brought through the rails, these are connected by ineans of copper fishplates ; besicles this, transverse conductors join the two lines of rails forming the track. The rolling stock consista of nine automotor cars, each with two motors; nine hauling cars, and two goods vans. They have two driving axles and multiple suspension, the body resting on the frame with the interposition of springs, which insure a very smooth running. These cars hold 38 persons, namely 6 first dass and 32 second dass, of whom 20 stand on the platforms in front and in the rear. Couplings at each end enable the cars to be hauled, in case of accidents. The motor induetor and armature coils are wound in series; the motors are of tetrapolar type, with two inductor coils only, the east-iron shell being in two parts, hinged together. The toothed armature is ring-shaped, with two carbon brushes on the commutator. Each motor is sus- pended under the body of the car by two springs, which work in opposite directions ; and it rests besides on the axle, which it drives by toothed-wheel gearing at a ratio of 4.5 to 1. The motors run at a speed of 600 revolutions, and develop normally 25 horse-power. At the present time, owing to the use of cast steel instead of cast iron, tram motors of the same speed as those above, and taking up an equal amount of space, develop normally 30 horse - power. The circuit opening of the motors and the speed régulation are effected by the working of the starting gear, titted on both ends of the cars by means of a détachable lever. The motors are always grouped in multiple ; a special current reverser enables a damaged motor to be easily disconnected. Speed régulation is obtained by graclually inserting in the motor circuit, metallic résistances controlled by the driver. When the working lever is vertical, the motor circuit is cut off ; in moving it to the right, the current goes progressively to the motors ; wliile in moving it to the left, the motors are short-circuited on the résistances. If at that moment the cars are moving, the motors work on the résistances, which act as a brake, without wearing the mechanical parts, and especially without taking power from the central station. The trolley through which the current is taken by sliding contact is spoon-shaped ; it is fitted at the end of a metallic tube, and made to turn horizontally. The tube is movable round a centre, and is guided in a cast-iron socket, mounted on a pivot fixed on the roof on the centre line of the car. Two compensating springs unité the trolley bar to the cast-iron socket, and insure a generally constant pres- sure on the contact wires. Each car carries a safety arrangement for the motors; it consists of a lightning arrester and a fuse cut-out, each provided with a magnetic spark-arrester, which acts on the arc, produced in the safety I apparatus by atmospheric disturbances or by a short circuit I of the motors. The inside lighting of each car is insured by five incan- descent lamps, of 16 candle-power, connected in series on the 500 volts of the line, and arranged so that the extinction of one does not entail the extinction of the others. The car discs are lighted by five incandescent lamps of 10 candle- power, connected in the same way as the former. The tramway in question has been in work since April, I 1897, and gives füll satisfaction. Varions Electrical Work.—In Figs. 341 and 342, Plate LXXVII, are some fur ther examples of the work produced in the Electrical Department at Creusot. Fig. 341 is a view of one of the large armatures made by Messrs. Schneider and Co. ; Fig. 342 is a standard type of electrie light plant for the French Navy ; and Figs. 343 to 346, Plate LXXVIIL, are illustrations of a three-phase alter- nator and motor of which many are constructed in the j department. Three-phase Motor.—For sizes below 8 horse-power, j the field magnet in this type is fixed and the armature made to revolve with closed winding. The inductor winding is annular with star connections. It consists of a laniinated annular core, provided with grooves open on the inside circumference, and which receive the coils. The inductor core is on a gun-metal shell, on which are fitted east-iron bearing Blocks fixed to the motor frame. A grooved ring of plates on a cast-iron centre keyed to the shaft forms the revolving armature. The armature, drum- wound, is fitted with copper bars placed in the grooves and united, so as to establish a short-circuit winding. For motors above 8 horse-power the armature is fixed, and the inductor made to revolve. The fitting of the movable part is similar to that of the motors above described, but the winding is different. The inductor is dium-wound, and reçoives three-phase currents through the intermediary of rings placed on the shaft, and metallic brushes. The armature is drum-wound and two-phase in order to attenuate the variations in elements in the varions positions of the inductor with regard to the armature. The grooved plates, as with the small motors, are fitted together direct on a cast-iron shell bolted on the frame which carries also bearer Blocks, the bases of which are placed concentric with the shaft. For starting with an element superior to the normal, without occasioning the intensity to reach an excessive figure, liquid rhéostats are interposée! in the two-phase circuits of the armature. Increase in speed is obtained by