THE DIKECT-CI'IMIKNT MOTOK 



('II. IX 



gives the current curve obtained by starting up the same 

 car by the series-parallel method. The gradual decrease 

 of the current during the second stage of the first step is 

 clearly marked, the irregularities being due to the uneven 



PARALLEL CONTROLLER shewn thus 

 SERIES -PARALLEL .. 





10 IS 



Seconds 

 FIG. 49 



25 



handling of the controller. The hump in the curve at nine 

 seconds from the start is due to a step in the controller 

 which weakens the magnets, thereby increasing the current 

 momentarily, and slightly increasing the speed. There is 



