PART SIX FARM MOTORS 



CHAPTER XL VIII 

 ELEMENTARY PRINCIPLES AND DEFINITIONS 



Farm Motors. Farm motors as discussed in this text 

 include machines which furnish power for operating farm 

 machinery. In the broadest sense, the term farm machinery 

 includes farm motors. Owing to a lack of space it will be 

 possible to consider only such motors as are in general use for 

 agricultural purposes. 



Energy. Energy may be denned as the power of pro- 

 ducing a change of any kind. It is the function of a motor to 

 utilize and transform energy in such a way that it may be 

 used in operating machinery. There are two general forms 

 of energy: (1) potential or stored energy, like that con- 

 tained in unburned coal; and (2) kinetic, or energy of 

 motion, an example of which is the energy of the wind. 



Sources of Energy. The sources of energy which are 

 made use of by farm motors are feed, fuel, and the wind. 

 The first two of these represent potential energy and the 

 last kinetic. 



The Most Important Farm Motors. The motors which 

 are used generally for operating farm machinery are the horse, 

 the windmill, the gas, gasoline, or oil engine, and the steam 

 engine. Other types of motors, such as the water wheel and 

 the electric motor, are used to a limited extent for agricultural 

 purposes. All of these motors, with the exception of the 

 electric motor, are prime movers; that is, they take the energy 



313 



