pillow block of the main shaft and the ring shaped armature keyed on outside the magnets to the main shaft like a flywheel, and the outer end of this shaft is supported as stated by an outward bearing. This machine is not provided with any especial commutator, the armature winding is on solid copper bars, on which the brushes rest. Owing to this company having only within the past year completed their works in this country, their machines are not introduced here yet very extensively, but the record they have made in Europe proves them to be well designed and good operating apparatus.

is mounted directly on the shaft of the engine, from which it operates, which shaft is supported at the outer end by an outboard bearing. In this type of machine the electro magnets are placed inside of the Gramme ring. By this arrangement the diameter of the armature is largely increased and the peripheral velocity is great even with a slow rate of speed, making the machine specially adapted for direct connection. The field magnets are bolted to the

In figure III. we illustrate two 200 K. W. generators directly connected to a 750 horse power marine type of automatic cut-off engine, operating at a speed of 120 revolutions. This generator is of the type developed by the old Edison Company for central power station work, and is what is termed the smooth body

type of armature. The armature bars consist of solid copper bars U shaped and slipped over the core or body of the armature, the brushes bearing on the head or end of the same. These machines have proved good operating machines, and there are a number operating on railway work in Milwaukee.

FIGURE 3.

In figure IV. we illustrate one of the large units in operation in the Intramural power station at the World's Fair. This generator is an 800 K. W. machine, manufactured by the General Electric Company, and is what they term their iron clad body type of armature, which is the type they are specially developing for railway power work. This machine is self-supporting in that the armature is not mounted on the engine shaft, but has its own separate shaft, and is coupled to a vertical type of compound marine type of automatic engine, manufactured by the Lake Erie Engineering Works. This unit is next to the largest which has been built for railroad work, and has been in continual service

in this power house since the day it started, the 4th of July, and has operated almost wholly the entire service of the electric elevated railroad at the Fair. The engine and generator have stood an overload as high as 80 per cent. above their rated capacity, and seem to be specially adapted to stand severe strains of railway power work. While the generator is not quite as compact in floor space as those which are mounted directly on the engine shaft, it seems to possess in many respects desirable points as regards engine and generator connections tor railroad power based on practical experience and its operation on this severe work, and has already resulted in its adoption for several large plants.

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power plants which are now being built, among them being that of the Brooklyn City Railroad, where six of these units are being put in operation. The particular one herein illustrated is at present operating in the power house of the Intramural road at the World's Fair. This generator is operating in connection with a cross-compound Reynolds-Corliss type of engine. On account

In figure V. we illustrate what may be termed the Jumbo generator for railroad work; this machine is double the capacity of that in figure IV.; is built by the General Electric Company, and is the same general type of machine as that shown in figure IV. This generator was designed and built for operating in several large

of the general construction arrangement of the engine, the generator is shown mounted directly on the engine and alongside of the flywheel. The field magnets on both this generator and the 800 K. W. machine shown in figure IV. are so arranged that by turning a crank the magnet frame can be moved to one side, leaving the armature entirely accessible for removal or repair. This generator has not as yet been extensively operated in regular service, but has been used sufficiently to demonstrate that it is a well designed machine and has shown its ability to carry the same proportion of overload as the 800 K. W. machine.

The foregoing different illustrated types of generators, from which the railway owner may select for operating his station, show the remarkable development which the manufacturers have made in such a short time in the practical development of these generators. There have been no failures. It is shown that designing of this apparatus has now reached a practical, commercial development. The machines require very little attention and are easy of repair.

TYPE OF ENGINE to Use.

The type of engine to use in connection with the operation of direct-driven generators is one of the serious factors to consider in this connection.

There are many points to be considered of economy, reliability, continuous service, good regulation, ability to stand the direct and severe shocks due to overloading generators, short circuits, economy in floor space, etc.

On the question of whether vertical or horizontal is better adapted, common sense seems to indicate that as we are laying out a compact plant in every respect, a vertical engine is best adapted for this work. The question of regulation is a very serious one. The engine is undoubtedly called upon to stand a test which no belted machine has had to do on account of being directly connected to the generator, and some one of the different types of shaft governors in use on some of the standard machines seems to be best adapted thereto, and will govern within a range for this work of, say, two to three per cent.

On the question of economy, so called high speed engines are in a measure out of date on this kind of work, as generators are reaching a size beyond the capacity of our old friend, the single valve automatic engine. This engine seems to have reached its limit in economy at about 200 to 300 horse power, that is, where controlled by a single valve. We are confined, then, to one or two types of engines. The old standard of general commercial practice, the Corliss engine, which, on account of our large experience with it, has been called upon more largely for service on this kind of work than any other, in general is meeting these requirements in most respects. There seems, though, to be some question of reasonable doubt as to whether it will regulate sufficiently close to meet the more exacting requirements of this class of work, where called upon to control very wide and sudden changes of load. On the question of economy they have shown in the past the highest economy obtainable, but that has been more especially on steady loads near their rated capacity. With loads which fluctuate as railroad work does, they cannot reach nearly their guaranteed economy. We also have the disadvantage of the control of the valve when cutting off over half stroke. In Europe, where their practice on direct connected work has extended over a much longer period than ours,