WHAT SIZE PLANT TO INSTALL
The farmer's wife his partner—Little and big plants—Limiting factors—Fluctuations in water supply—The average plant—The actual plant—Amount of current required for various operations—Standard voltage—A specimen allowance for electric light—Heating and cooking by electricity—Electric power: the electric motor.
The farmer's wife becomes his partner when he has concluded the preliminary measurements and surveys for building his water-power electric plant. Now the question is, how big a plant is necessary, or how small a plant can he get along with. Electricity may be used for a multitude of purposes on the farm, in its sphere of furnishing portable light, heat and power; but when this multitude of uses has been enumerated, it will be found that the wife shares in the benefits no less than the farmer himself. The greatest dividend of all, whether dividends are counted in dollars or happiness, is that electricity takes the drudgery out of housework. Here, the work of the farmer himself ends when he has brought electricity to the house, just as his share in housework ends when he has brought in the kerosene, and filled the woodbox. Of the light and heat, she will use the lion's share; and for the power, she will discover heretofore undreamed-of uses. So she must be a full partner when it comes to deciding how much electricity they need.
How much electricity, in terms of light, heat, and power, will the farmer and his wife have use for? How big a plant should be installed to meet the needs of keeping house and running the farm?
The answer hangs mainly on how much water-power there is available, through all the seasons of the year, with which to generate electricity. Beyond that, it is merely a question of the farmer's pocketbook. How much money does he care to spend? Electricity is a cumulative "poison." The more one uses it, the more he wants to use it. After a plant has been in operation a year, the family have discovered uses for electricity which they did not think of in the beginning. For this reason, it is well to put in a plant larger than the needs of the moment seem to require. An electrical horsepower or two one way or another will not greatly change the first cost, and you will always find use for any excess.
Once for all, to settle the question of water-power, the water wheel should be twice the normal capacity of the dynamo it drives, in terms of power. This allows for overload, which is bound to occur occasionally; and it also insures smooth running, easy governing, and the highest efficiency. Since the electric current, once the plant is installed, will cost practically nothing, the farmer can afford to ignore the power going to waste, and consider only how to get the best service.
The Two Extremes
The amount of water to be had to be turned into electricity, will vary with location, and with the season. It may be only enough, the greater part of the year, for a "toy" plant—a very practical toy, by the way—one that will keep half a dozen lights burning in the house and barn at one time; under some conditions water may be so scarce that it must be stored for three or four days to get enough power to charge a storage battery for these six or eight lights. A one-quarter, or a one-half kilowatt electrical generator, with a one horsepower (or smaller) wheel, will light a farmstead very satisfactorily—much better than kerosene lamps.
On the other hand, the driving power of your wheel may be sufficient to furnish 50 or 100 lights for the house, barn, and out-buildings, and barn-yard and drives; to provide ample current for irons, toasters, vacuum cleaners, electric fans, etc.; to do all the cooking and baking and keep the kitchen boiler hot; and to heat the house in the coldest weather with a dry clean heat that does not vitiate the air, with no ashes, smoke or dust or woodchopping—nothing but an electric switch to turn on and off; and to provide power for motors ranging from tiny ones to run the sewing machine, to one of 15 horsepower to do the threshing. A plant capable of developing from 30 to 50 kilowatts of electricity, and requiring from 50 to 100 horsepower at the water wheel, would do all this, depending on the size of the farmstead. One hundred horsepower is a very small water project, in a commercial way; and there are thousands of farms possessing streams of this capacity.
Fluctuations in Water Supply