THE TBANSFOEMER. 



183 



Graphic Representation of Phase- Relations in a Transformer. 



It is important to form a clear idea of the relation 

 existing between the several varying quantities in a trans- 

 former, and this may be best done by representing them 

 ^graphically in vector diagrams. 



Case I. Transformer without load and without magnetic 

 leakage. Let the line E l (see Fig. 85) represent that 



o 



Ce 



FIG. 85. TRANSFORMER ox 

 No LOAD. 



FIG. 86. TRANSFORMER ON 

 NON-INDUCTIVK LOAD. 



' SCALE Of PRIMARY VOLTS 

 Imillllll I 



, SECONDARY 



20 30 

 SCALE Or PRIMARY AMPERES 



I T i va , T o j. , n 



SO 60 70 80 ' S * IO 



SECONDARY 

 MPS - * 10 



SCALE Or LINES 



10 



15 20 THOUSANDS OF UN S 



part of the primary applied voltage which is spent in over- 

 coming the induced back voltage, due to the alternating 

 flux in the core. 



The current taken by the transformer is partially 

 magnetising current which is an idle current, and 



