Analytical Study of the Alternating Current Arc. 335 



Table IV. B. 



Observations on the Periodic Variation of the Intensity of the 

 Light of an Alternating Current Arc. 



Light from Crater. Short Arc. 



Frequency . . = 50 ~ 



Length of arc = 0*32 cm. 



Potential-difference of carbons (mean") oc > -, 



t v v 5- = 3b volts, 



square value) j 



Current (mean square value) . . . = 14 amperes. 



Power expended in arc = 532 watts. 



Pressure at alternator terminals . . =93 volts. 



Angle of 

 Phase. 



Current 



through Arc 



(instantaneous 



value). 



Angle of 

 Phase. 



Intensity of 



Light from 



Crater of 



lower Carbon. 













20 



4-13-1 



20 



61 



40 



+ 7-2 



41 



56 



60 



+ 0-8 



63 



45 



80 



- 50 



84 . 



58 



100 





105 



51 



120 





126 



101 



140 

 160 

 180 

 200 





148 

 170 

 191 

 212 



220 



227 

 216 

 111 









220 



- 6-3 



232 



64 



240 



- 04 



253 



73 



260 



4- 4-6 



273 



66 



280 



+ 12-6 



294 



63 



300 



+ 176 



315 



77 



320 



+ 19-0 



335 



60 



340 

 360 





359 



338 



317 



36 



63 



78 

 88 







i 





79 



2 A 2 



