To make this plant ideal, (for, being an actual affair, it has developed some short-comings, with the extension of the use of electricity) it would require a dynamo whose capacity can be figured, from the following:
| Watts | |
| 15 carbon lamps, 16 candlepower, @60 watts each | 900 |
| 10 tungsten lamps, 20 candlepower, @25 watts each | 250 |
| 2 tungsten lamps, 92 candlepower, @100 watts each | 200 |
| Water heater, continuous service | 800 |
| Toaster, occasional service | 600 |
| Iron, occasional service | 400 |
| Oven-baking, roasting, etc | 2,000 |
| 2 stove plates @1,000 watts each | 2,000 |
| 1 stove plate | 400 |
| Vacuum cleaner, occasional service | 200 |
| Vibrator, occasional service | 100 |
| Small water heater, quart capacity | 400 |
| Small motor, ¼ horsepower, occasional | 250 |
| Motor, ½ hp, pumping water, etc | 500 |
| Electric fan, occasional service | 100 |
| ——— | |
| Total current, one house | 9,100 |
| 30 carbon lamps, 16 candlepower, @60 | 1,800 |
| 2 lamps, 100 watt tungsten | 200 |
| Electric iron | 400 |
| Small water or milk heater | 600 |
| ——— | |
| Total current, 2nd house | 3,000 |
| 1st house | 9,100 |
| ——— | |
| 12,100 |
Thus, in this plant, if every electrical device were turned on at once, the demand on the dynamo would be for 12.1 kilowatts, or an overload of over 100 per cent. The main-switch fuse, being for 60 amperes, would "blow" or melt, and cut off all current for the moment. To repair the damage would be merely the work of a second—and at a cost of a few cents—simply insert a new fuse, of which there must be a supply on hand at all times. Or, if either owner exceeded his capacity, the line fuses (one for 20 amperes, and the other for 40 amperes) would instantly cut off all current from the greedy one.
25 and 40 watt Mazda tungsten lamps (¼ scale)
Lessons From This Plant
The story of this plant illustrates two things which the farmer and his wife must take into account when they are figuring how much electricity they require. First, it illustrates how one uses more and more current, as he finds it so serviceable and labor-saving, and at the same time free. The electric range and the water boiler, in the above instance, were later acquisitions not counted on in figuring the original installation. Second, it illustrates, that while the normal load of this generator is 5.75 kilowatts, one does not have to limit the electrical conveniences in the home to this amount. True, he cannot use more electricity than his plant will produce at any one time,—but it is only by a stretch of the imagination that one may conceive the necessity of using them all at once. Ironing, baking, and the use of small power are usually limited to daylight hours when no lights are burning.
As a matter of fact, this plant has proved satisfactory in every way; and only on one or two occasions have fuses been "blown", and then it was due to carelessness. A modern dynamo is rated liberally. It will stand an overload of as much as 100 per cent for a short time—half an hour or so. The danger from overloading is from heating. When the machine grows too hot for the hand, it is beginning to char its insulation, to continue which, of course would ruin it. The best plant is that which works under one-half or three-quarters load, under normal demands.