106 



COMMERCIAL ELECTRICAL TESTING 



KHJO 



2OOO 3OOO 

 Feet per W/?vte 



Fig. 31. Coefficient of Friction of A-C. Brushes 



Fig. 31-b. Efficiency and Losses on a 750 Kw., 600 Volt, 750 R.P.M., 25 Cycle, 

 3-Phase Rotary Converter 



