1 nnCED-COOLED TRANSFORMERS 



173 



the oil when entering and when leaving tlie transformer i> 

 usually only allowed to be some 10. The specific gravity of 

 transfonin-r oil is about 0,9 and its specific heat is about 0/75. 1 

 . .j.Riitly (l,H> X 0,75 X 0,9 =) 0,78 kelvin is absorbed 

 by 1 cu in of oil when its temperature is raised 1. In our 

 transformer the temperature of the oil is raised 10 D , absorbing 

 7,8 kelvins per cu m. Thus the quantity requiring to be 



circulated is (y^ =\ 1,80 cu m, or (1,80 X 220 =) 400 

 gallons per hour, or 6,7 gallons per minute. 



1"1. Poroed-oil-COOlad tran-fnnjuT anl accessory plant. 



In forced-oil-cooled transformers there arises tin 1 important 

 \\lirtlirr each transformer shall br provid. d \\itli n^ 

 iwii c..iiipl-ti- oil-rhvulsitiiiL.' and cooling plant, or whether all 

 thr : nt-rs in the installation shnll he siipplird from a 



r.uiiiiion oil main. Although the lattrr plan h-ads to the 

 -t tir-t 0001, tin- t'..nn.-r i> t- ! inOO, in thr 



it of a breakdown anywh. f. . it LI imp. .riant that the entire 

 plant shall imt l.e in< -aparit at. -d. O\\ is greatly alVi--tel by tin- 

 admixture of impurity or moisture, and it' any ^m-jle ti 

 former of a bank !' ti-aii>tormers goes wrong, with the con- 



it-lice of impairing the .jualit\ of iOjf --il - nl. i ni" it. then it 



Hoary 

 : ical Kngin 



