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Electricity for the farm. Frederick Irving Anderson
Читать онлайн.Название Electricity for the farm
Год выпуска 0
isbn 4057664625922
Автор произведения Frederick Irving Anderson
Жанр Языкознание
Издательство Bookwire
He had the usual idea, at the start, that a current strong enough to light a 100 candlepower lamp would kick like a mule if a man happened to get behind it. He watched the city man handle bare wires and finally he plucked up courage to do it himself.
It was a 110-volt current, the pressure used in our cities for domestic lighting. The funny part about it was, the farmer could not feel it at all at first. His fingers were calloused and no current could pass through them. Finally he sandpapered his fingers and tried it again. Then he was able to get the "tickle" of 110 volts. It wasn't so deadly after all—about the strength of a weak medical battery, with which every one is familiar. A current of 110 volts cannot do any harm to the human body unless contact is made over a very large surface, which is impossible unless a man goes to a lot of trouble to make such a contact. A current of 220 volts pressure—the pressure used in cities for motors—has a little more "kick" to it, but still is not uncomfortable. When the pressure rises to 500 volts (the pressure used in trolley wires for street cars), it begins to be dangerous. But there is no reason why a farm plant should be over 110 volts, under usual conditions; engineers have decided on this pressure as the best adapted to domestic use, and manufacturers who turn out the numerous electrical devices, such as irons, toasters, massage machines, etc., fit their standard instruments to this voltage.
As to the cost of this co-operative plant—it was in the neighborhood of $200. As we have said, it provided eight electrical horsepower on tap at any hour of the day or night—enough for the two farms, and a surplus for neighbors, if they wished to string lines and make use of it.
The dynamo, a direct-current machine, 110 volts pressure, and what is known in the trade as "compound,"—that is, a machine that maintains a constant pressure automatically and does not require an attendant—was picked up second-hand, through a newspaper "ad" and cost $90. The switchboard, a make-shift affair, not very handsome, but just as serviceable as if it were made of marble, cost less than $25 all told. The transmission wire cost $19 a hundred pounds; it is of copper, and covered with weatherproofed tape. Perkins bought a 50-cent book on house-wiring, and did the wiring himself, the way the book told him to, a simple operation. For fixtures, as we have said, his wife devised fancy shades out of Mexican baskets, tissue paper, and silk, in which are hidden electric globes that glow like fire-flies at the pressing of a button. The lamps themselves are mostly old-style carbon lamps, which can be bought at 16 cents each retail. In his living room and dining room he used the new-style tungsten lamps instead of old-style carbon. These cost 30 cents each. Incandescent lamps are rated for 1,000 hours useful life. The advantage of tungsten lights is that they give three times as much light for the same expenditure of current as carbon lights. This is a big advantage in the city, where current is costly; but it is not so much of an advantage in the country where a farmer has plenty of water-power—because his current costs him practically nothing, and he can afford to be wasteful of it to save money in lamps. Another advantage he has over his city cousin: In town, an incandescent lamp is thrown away after it has been used 1,000 hours because after that it gives only 80% of the light it did when new—quite an item when one is paying for current. The experience of Perkins and his neighbor in their coöperative plant has been that they have excess light anyway, and if a few bulbs fall off a fifth in efficiency, it is not noticeable. As a matter of fact most of their bulbs have been in use without replacing for the two years the plant has been in operation. The lamps are on the wall or the ceiling, out of the way, not liable to be broken; so the actual expense in replacing lamps is less than for lamp chimneys in the old days.
Insurance companies recognize that a large percentage of farm fires comes from the use of kerosene; for this reason, they are willing to make special rates for farm homes lighted by electricity. They prescribe certain rules for wiring a house, and they insist that their agent inspect and pass such wiring before current is turned on. Once the wiring is passed, the advantage is all in favor of the farmer with electricity over the farmer with kerosene. The National Board of Fire Underwriters is sufficiently logical in its demands, and powerful enough, so that manufacturers who turn out the necessary fittings find no sale for devices that do not conform to insurance standards. Therefore it is difficult to go wrong in wiring a house.
Finally, as to the added value a water-power electric plant adds to the selling price of a farm. Let the farmer answer this question for himself. If he can advertise his farm for sale, with a paragraph running: "Hydroelectric plant on the premises, furnishing electricity for light, heat, and power"—what do you suppose a wide-awake purchaser would be willing to pay for that? Perkins and his neighbor believe that $1,000 is a very modest estimate added by their electric plant to both places. And they talk of doing still more. They use only a quarter of the power of the water that is running to waste through the wheel. They are figuring on installing a larger dynamo, of say 30 electrical horse-power, which will provide clean, dry, safe heat for their houses even on the coldest days in winter. When they have done this, they will consider that they are really putting their small river to work.
CHAPTER II
A LITTLE PROSPECTING
Small amount of water required for an electric plant—Exploring, on a dull day—A rough and ready weir—What a little water will do—The water wheel and the dynamo—Electricity consumed the instant it is produced—The price of the average small plant, not counting labor.
The average farmer makes the mistake of considering that one must have a river of some size to develop power of any practical use. On your next free day do a little prospecting. We have already said that 250 cubic feet of water falling 10 feet a minute will provide light, heat and small motor power for the average farm. A single water horsepower will generate enough electricity to provide light for the house and barn. But let us take five horsepower as a desirable minimum in this instance.
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