28 



CONSTANT-VOLTAGE TRANSMISSION 



is increased much more when a synchronous motor is 

 used with continual adjustments in the excitation from 

 leading at heavy load to lagging at light load, than when 

 the synchronous motor is used with fixed rheostat posi- 

 tion. Using the same limits for the power capacity of a 

 line as were used for Figs. 5 and 6, a little calculation will 



No. 000 No. 0000 250000 300000 350000 



Copper, B. & S. Gauge and Circular Mils. 



FIG. 6. 25 Cycle Lines. 



show that by installing synchronous motors, with fixed 

 rheostat position, of a rating equal to 42 per cent of the 

 load kilowatts, the power-factor can be raised from 80 

 up to 95 per cent, and the kilowatt capacity of the line 

 will be increased 54 per cent. Now if the motors are 

 used for adjustable power-factor, and a somewhat larger 



