POWER AND POWER-FACTOR, 



63 



taken with the same instruments employed for ascertaining 

 the power-factor of an inductive circuit whenever possible. 



The results of the test should be plotted in a curve, with 

 current measured horizontally and power-factor vertically. 

 This is illustrated by the curve in Fig. 28, which was taken 

 on a circuit composed of a choking coil and non-inductive 

 resistance in series. In this case the non-inductive portion of 

 the circuit was varied for each reading. 



i-o 



95 



85 



75 



1 23 4 5 67 8 9 10 11 12 13 14 5 



Amperes, Current. 

 PIG. 28. CUKVE SHOWING VARIATION OF POWER FACTOR WITH CURRENT. 



A resistance of about 100 ohms was put in series with the 

 coil, giving a power factor for the whole circuit of nearly 

 unity. This resistance was then gradually cut out, enabling 

 an increased current to pass, and at the same time reducing 

 the power-factor of the circuit. 



The curve shows the power-factor for the whole circuit, 

 including both inductive and non-inductive portions. Three 

 of the readings actually taken are shown in the table above 

 as an example. 



