292 ELECTRICAL MACHINERY 



from its case is shown in Fig. 183. The water piping is 

 made very carefully to protect against leaks because the 

 least trace of water in the oil would spoil its insulating 

 power. 



FIG. 183. A Water-cooled Transformer, Out of its Case. The water- 

 pipes are placed near the top of the transformer case where the 

 oil is hottest. 



72. Losses in a Transformer. The two sources of 

 energy loss in a transformer are the core loss and copper 

 loss. These two losses are generally about equal at full 



