POWER AND POWER-FACTOR. 



73 



currents. From this triangle obtain by measurement the 

 value of the angle of lag between current and voltage of 

 the complete circuit (= #), which will be the angle 

 between the lines representing (7 2 (in the non-inductive 

 resistance) and C 3 the total current. 



This is because C 2 is in phase with the voltage of the 

 circuit, and would therefore be parallel to it in the 

 diagram of current and voltage. Similarly the angle of 



C3 



SCALE OF AMPERES 



FIG. 33. DIAGRAM OF CURRENTS. 



lag in the inductive branch circuit r is the angle between 

 (7, and C\. Calculate also the impedance of each branch 

 circuit, and the joint impedance of the two circuits by 

 dividing the voltmeter reading respectively by each 

 branch current and by the main current. These values 

 may be drawn as a triangle of impedance for the part of 

 the circuit between X and Y. 



As an example of the readings taken and of the 

 method of entering up, one out of a series of actual 

 values, together with the corresponding diagram, is given 

 below and on Fig. 33. 



Idle Current. In the discussion previously given of the 

 conditions in a circuit in which a difference of phase 

 exists between current and voltage, it was shown that 

 the total voltage of the circuit might be considered as 



