490 



CURRENT RECTIFIERS 



[Cn. XIII 



683. Mercury arc rectifier. This is a method of securing 

 direct current from alternating. It is a utilization of the mercury 

 arc, and gives an efficiency of about 70%. The current is slightly 



FIG. 259 FIG. 260 



FIG. 259. MERCURY ARC RECTIFIER, FRONT VIEW. 



(Cut loaned by the General Electric Co.). 



This size is designed for 30 amperes. It requires 14.5 amperes alternating 

 current at 220 volts or 29 amperes at 1 10 volts, and delivers 30 amperes direct 

 current at 62 volts. (See tests 754). It consumes 2600 watts alternating 

 current and delivers 1860 watts direct current which gives 8,600 candle-power 

 with the projection arc. 



FIG. 260. MERCURY ARC RECTIFIER, REAR VIEW. 



(Cut loaned by the General Electric Co.). 



This gives a good view of the rectifier bulb and the inductor directly below 

 the rectifier bulb which serves to limit the current in the arc by acting upon the 

 alternating current primary. The iron case on the floor contains a com- 

 pensating reactance which serves to smooth out the fluctuations on the rectified 

 current. 



