130 



TIIK TRANS FORMER. 



If there were no loss of voltage e., would be -r, consequently 



K 



the drop of voltage in the transformation is given by 

 C 2 [ pr + r 2 L which is directly proportional to the secon- 

 dary current. 



The result of the resistance of the windings is thus to 

 produce a variation in the ratio of transformation, the 

 secondary voltage being less with increased loads. It is 

 usual to take account of this in designing the number of 

 turns of the windings, and to make this ratio such that the 

 secondary voltage will be slightly too high at light loads, 

 and slightly too low at the maximum load. In this way 

 the exact voltage required is approximated to at average 

 outputs. 



The current given out by the secondary winding is 

 usually called the " load current," or sometimes simply 

 the "load." 



EXPERIMENT XXII. DETERMINATION or REGULATION 

 OF A TRANSFORMER. 



DIAGRAM OF CONNECTIONS. 



I.. II. 



R 



V v F 2 



A 



8,8 



FIG. 60. 



Source of alternating current. 



Primary and secondary windings of transformer. 



Variable non-inductive resistance for varying 



transformer load. 

 Voltmeters for reading primary and secondary 



voltage. 



Ammeter for reading output of secondary. 

 Switches for breaking primary and secondary 



circuits. 



