Rules for widths of belting d = diameter of either driving or driven pulley in inches. n = number of revolutions per minute of pulley considered. w4 = width in inches of single leather belting or of 4-ply canvas or 4-ply rubber belting. w5 = width in inches of 5-ply canvas or of 5-ply rubber belting. w6 = width in inches of double leather belting or 6-ply canvas or 6-ply rubber belting. H.P. = Horse-power to be transmitted by belt.

Rule:— w4 = 3000 H.P./DN w6 = 6/10 w4

Rules for determining size and speed of pulleys or gears

The driving pulley is called the Driver, and the driven pulley the Driven. To determine the diameter of Driver, the diameter of the Driven and its revolutions, and also revolutions of Driver, being given.

Machinery and Motors 188

To determine the diameter of Driven, the revolutions of the Driven and diameter and revolutions of the Driver being given.

Machinery and Motors 189

To determine the revolutions of the Driver, the diameter and revolutions of the Driven and diameter of the Driver being given.

Machinery and Motors 190

To determine the revolutions of the Driven, the diameter and revolutions of the Driver, and diameter of the Driven being given.

Machinery and Motors 191

If the number of teeth in gears is used instead of diameter, in these calculations, number of teeth must be substituted wherever diameter occurs.

Machinery and Motors 192

Table of power required to operate high-grade triplex pumps

The estimates given in the table are made with a liberal allowance of power. The power for other capacities and heights is, approximately, in proportion to that tabulated. By " head " is meant the vertical distance from surface of water supply to point of delivery. One foot head is equivalent to .43 pound pressure. The head is increased by the friction of the water in pipes and elbows.

General service pumps

Machinery and Motors 193

Table of theoretical horse-power required to raise water to different heights

Allowance should be made for friction; for ordinary pumps, allow twice the power given in table.

Machinery and Motors 194

Horse-power of steel shafting For line-shaft service

Machinery and Motors 195

Electric appliances on the farm.

Many electrically-operated machines and devices are now on the market. The list is being added to rapidly. The following tabulation will give some idea of the development along these lines, aside from electric lighting and house wiring : —

Device                                                                                                                Horse-power

Required

Cream separator..................    1/2 to 4

Milking machine..................      3 to 5

Grindstone....................    1/2

Bottle-washer...................    1/2

Water-pump...................      1 to 10

Shredder.....................    10 to 15

Silage-grinder...................    10 to 20

Feed-grinder...................      5 to 10

Threshing....................    10 to 20

Wood-saw....................      3 to 5

Corn-sheller....................      1 to 4

Hay-press....................      4 to 25