ANIMAL MOTORS 



297 



Often horses are overworked in tread powers without the 

 owner intending to do so, or even knowing it. 



FIG. 201 



420. Sweep powers. In the sweep power the horses 

 travel in a circle, and the power is transmitted from the 

 master wheel through suitable gearing to the tumbling 

 rod, which transmits the power to the machinery. Sweep 

 powers vary in size from those for one horse to those 

 for 14 horses. Attention is often called to the fact that a 

 considerable part of the draft is lost because the line of 

 draft cannot be at right angles to a radius of the circle 

 in which the horse walks. For this reason a considerable 

 portion of the draft is lost in producing pressure toward 

 the center of the power, often adding to the friction. The 

 larger the circle in which the horse travels, the more 

 nearly the line of draft will be at right angles to a radius 

 to the center of the circle. 



