74 



POWER AND POWER- FACTOR. 



being composed of two components, viz. : the energy 

 component (= E cos #) in phase with the current, and 

 the idle component ( E sin <) } period out of phase 

 with the current. 



For some purposes it is preferable to treat the total 

 current as if formed of two components respectively in 

 phase and period out of phase with the voltage. It is 

 immaterial from a mathematical standpoint whether the 

 current or voltage is looked upon as consisting of two 

 components, since there is actually one current and one 

 voltage in the circuit, and it is only for purposes of 

 investigation that we consider either of them to be of a 

 composite character. 



FIG. 34. CUKVES OF VOLTAGE AND COMPONENT AND RESULTANT CURKEXTS. 



Following out this idea, Fig. 34 has been drawn to 

 represent the same current, voltage, and angle of lag as 

 shown in Fig. 7, page 17. In this case, however, the 

 current is resolved into two components whose values are 

 C cos in phase with the voltage, and C sin $ % period 

 behind the voltage in phase. These components are 

 usually termed the energy current and the wattless or idle 

 current respectively, and are shown by the dotted lines 

 marked <7 e and C { . It is evident from the curves that 

 at any instant the sum of the instantaneous values of 

 energy and wattless currents is equal to the total current. 



