TRANSFORMERS 



305 



reactance is proportional to the square of the number of turns and, 

 therefore, 



= I l } x 2 (approximately) . 



184. Voltage Characteristics. The voltage characteristics of 

 a transformer show the relation between the secondary terminal 



80 Percent Power Factor Lagging 

 50 Percent Power Factor Lagging 



Amperes. Load Current 1 



FIG. 279. Voltage characteristics of a transformer. 



voltage and the secondary load current for a given primary im- 

 pressed e.m.f. and a given load power factor. Typical voltage 

 characteristics are shown in Fig. 279. They can be calculated 

 from equation 291. The change in voltage from no load to full 

 load is very small, even when the power factor is low. 



