STEAM ENGINES 395 



power. This is a custom which originated in the horse 

 power and is to be regretted. 



At the time separators were run with horse power they 

 were smaller than they are now and with fewer acces- 

 sories. At that time 12 horses, by being overworked, 

 would run the separator, but now the separators are 

 larger and are equipped with self-feeders, band cutters, 

 wind stackers, weighers, etc. All of this causes the new 

 separators to run several horse power harder than the 

 old ones. Although the present separators require much 

 more power than the former ones did, competition has 

 kept the rating of the engines down to that of the horse 

 power, while factories are building them much larger. 

 Most traction engines will develop at the brake three 

 times as much power as their rated capacity. 



A better way to judge the capacity than by its com- 

 mercial rating is by the diameter of the cylinder, the 

 length of stroke, and the number of revolutions of the 

 flywheel a minute. 



HANDLING AN ENGINE 



543. Starting the engine. In starting an engine the 

 operator should always see that the cylinder cocks are 

 opened. While the engine has been stopped the steam 

 has condensed and caused considerable water to form in 

 the cylinder, and if there is not some means of letting 

 this out there is danger of injury to the working parts. 

 Even if no water has collected in the cylinder while the 

 engine has been standing, the cylinder walls will be cold 

 and condense the steam as it first enters. It is also well 

 to open the pet cocks from the steam chest and allow the 

 water in there to drain out, and not be carried through 

 the cylinder. The throttle should be only partly opened 

 at first in order to allow the cylinder to hecome warmed 



