Page:Incandescent electric lighting- A practical description of the Edison system.djvu/116

 similar to those installed in the Providence station. In guaranteed economy it will equal the Corliss engine, as installed in the Narragansett station, and give it to you under a wider range of load.

In connection with the triple expansion engine mentioned, we have to consider, again, the problem of the dynamos to be used. We can stay as at present, and belt our dynamos, but I believe that the next large incandescent station will not only include compound or triple expansion engines of 300 or 400 h.p., but will also have multi-polar dynamos, one or two being directly connected to the engine. By this I do not mean belted, but direct shaft connection through a flexible coupling. This of course, necessitates the multi-polar machine, in order to secure the output with a slower speed. Engines and dynamos of this type can be installed in the space at present occupied by the engines alone. This means not only economy in building and real estate, but also in operating expenses.

In regard to boilers for such a plant,