REGULATORS 



213 



through a preventive resistance. The resistances con- 

 necting the fingers to the line prevent excessive exchange 

 currents as the fingers pass from contact to contact, 



To 



(7e/je^&/f~ vwwww W^ 



Fig. 75. ER Regulator 



and the line voltage is varied uniformly. The regulator 

 transformer is oil cooled. 



The tests required are: resistances, tap voltages or 

 ratio, core loss, impedance, heat run, insulation, and 

 checking of clutch coil and limit switch circuits. 



