198 SUCCESSFUL FARMING 



every machine and pulley is stationary, because the length may change 

 slightly with use. For outdoor work where machines may be moved, it 

 gives excellent service. 



Oil of any kind is detrimental to almost every kind of belt, and 

 care should be exercised to keep rubber belts free from it. Rubber belting 

 is resistant to steam and is, therefore, used to a great extent in creameries. 



Belt Slipping. All manner of belt dressings should be avoided because 

 they often contain some material which shortens the life and hardens the 

 surface of a belt. The hardening of a belt finally causes it to crack. Any 

 sticky material put upon a belt will cause a loss in power due to an excess 

 adherence to the pulley. If a large pulley drives a small one, it is best to 

 pull with the lower side which is kept horizontal and allows the upper 

 side to sag. This brings a greater surface of the belt in contact with the 

 pulley. 



To twist a belt, as in pulleys to run in opposite directions, often pre- 

 vents slipping by a greater exposure of the belt to the pulley. 



WATER MOTORS 



Overshot Wheels. The overshot wheel receives its power from the 

 weight of water carried by buckets which are fastened to the circum- 

 ference of the wheel. The water enters the buckets at the top of the 

 wheel and is discharged near the bottom. A wheel of this character is 

 made by placing between two wooden disks a number of buckets or 

 V-shaped troughs. The wheel may be supported upon a wood or steel 

 shaft supported on concrete piers. Motors of this type can be built to 

 operate under falls as low as four feet and may be expected to supply 

 anywhere from 3 to 40 horse power, depending on the head of the fall 

 and the water available. 



Undershot Wheels. The undershot wheel is propelled by water 

 passing beneath it in a horizontal direction, which strikes veins carried 

 by the wheel. Such wheels are often used for irrigation purposes where 

 the fall is too slight for other types of wheels. Most of the undershot 

 wheels have straight, flat projections for veins, but the most efficient 

 wheels are built with curved projections. This form of water motor 

 operates satisfactorily where the water current is rather swift and in 

 places where the volume of water is kept constant. They will not operate 

 in streams that are ever flooded. 



Breast Wheels. Under conditions where little fall may be procured, 

 a breast wheel may be employed to develop power from running water. 

 This type of wheel receives the water near the level of its axis, but in 

 most features it is similar in its action to the overshot wheel. The veins 

 may be straight or slightly curved backward near the circumference. 



The wheels mentioned above are very awkward and cumbersome 

 for the amount of power that they are capable of developing. In other 

 words, they are not what is known as efficient; however, they are cheap 



