If you have designed your transmission line for a drop of 5 volts at half-load, advance the rheostat handle still further, until the needle points to 115 volts. Let the machine run this way for some time. When assured all is right, throw on the main switch, and turn on the light at the switchboard. Then go to the house and gradually turn on lights. Come back and inspect the dynamo as the load increases. It should not run hot, nor even very warm, up to full load. Its brushes should not spark, though a little sparking will do no harm.
Your plant is now ready to deliver current up to the capacity of its fuses. See that it does not lack good lubricating oil, and do not let its commutator get dirty. The commutator should assume a glossy chocolate brown color. If it becomes dirty, or the brushes spark badly, hold a piece of fine sandpaper against it. Never use emery paper! If, after years of service, it becomes roughened by wear, have it turned down in a lathe. Occasionally, every few weeks, say, take the brushes out and clean them with a cloth. They will wear out in the course of time and can be replaced for a few cents each. The bearings may need replacing after several years' continuous use.
Otherwise your electric plant will take care of itself. Keep it up to speed, and keep it clean and well oiled. Never shut it down unless you have to. In practice, dynamos run week after week, year after year, without stopping. This one, so long as you keep it running true to form, will deliver light, heat and power to you for nothing, which your city cousin pays for at the rate of 10 cents a kilowatt-hour.
PART III
GASOLINE ENGINES, WINDMILLS, ETC. THE STORAGE BATTERIES