TRANSFORMER CONSTRUCTION 



103 



possible, the coils are generally made circular, the core being given a 

 rmss-section which is stepped as shown in the figure so as to fit 

 into the coils. In the figure the low-voltage coil is shown next the 

 core, the liigh-voltage coil being outside. Frequently, in order to 

 reduce magnetic leakage, the high-voltage coil is wound in two 

 sections, the low-voltage coil being sandwiched in between them. In 

 other cases, each winding is subdivided into a number of very short 

 coils, the sections of the high- voltage winding alternating with those 

 of the low- voltage one on the core (the sectional coils of both windings 



Fio. 81. Single-phase Transformer. 



FlG. 82. Berry Transformer. 



being of the same size, and placed on the top of each other). Even 

 with the simple arrangement shown in the figure, it is advisable, in 

 the case of very high voltages, to wind the high-voltage coil in a 

 number of equal sections, separated from each other by barriers of 

 insulating material. 



Fig. 82 illustrates the construction of the Berry transformer. The 

 circular coils having been wound, a number of bundles of core-sheets 



(in carrying out repairs), are rather alow processes. By adopting a butt-joint pure and 

 simple between the core and yoke-plates, the transformer may be dismantled and built 

 up again very quickly. 



