IKON UNDER PERIODIC MAGNETIZING FORCES. 97 



111 addition it was possible to insert a mpch larger inductance in 

 the magnetizing circuit when the generator was used and so keep down 

 the reactions explained in section 2. 



The procedure in any one experiment has also been described.* 

 In every case a lull wave was taken, the ordinates being 12° in phase 

 apart. The wave forms having been analysed, the results were reduced 

 to absolute measure by applying to them the proper factorsf to reduce 

 thetn to magnetic intensity and induction respectively, in the form — 



H = Hi {sin wt -\- 7i, sin 3 {wt — <f>,) -^ h. sin 5 (wi' — </>,) + &e.,}. 

 B = B, {sin (uit — ^) + h^ sin 3 (w# — 0.) -[- h sin 5 (o^t — ^J + &c.}. 



From these the value of I, the total iron loss per c.c. per cycle, 

 was calculated by the formula — 



I = ^' I" sin 0, + Ufi, sin 3 (6^ - <^,) + 5h,b. sin 5 {$- c/>, + &c. | 

 which can be shown to be- 



ifndB. 



The eddy current loss E, which is part of I, was calculated, as in 

 the paper already quoted from the formula — 



E = (VT ®" 



where a; = thickness, p = specific resistance, T = period, and '3, which 

 has been called the effective induction, is given by — 



v:b= =B,= { 1 + 9J; + 25V + i9V + &c.,}. 

 U the statical hysteresis having been determined for each experi- 

 ment as explained in section 4, the difference I — (E + U), which 

 Fleming has called the kinetic hysteresis, was also obtained for each 

 experiment, and is given in the tables that are to follow. 



6. Tables I., II., III., which follow, embody the results, completely 

 reduced, which were obtained when the magnetizing current was taken 

 from the rotary converter, while tables IV., V., YL, those when the 

 alternator was used. 



Frequencies up to 200 per sec. could be obtained with the 

 generator, while about GO per sec. was the highest frequency at which 

 the rotary would work satisfactorily. 



The meanings of the different symbols in the tables are given by — 

 T = period 

 H = H, {sin Mt + A, sin 3 (ojf — (f>^) + h^ sin 5 {^t — <f).) + &c.} 

 B=B,{sin (wf—0)^b^ sin 3 (ojt — 0- ip,) + h. sin 5 (oj^ -0- ./.j)^- &c.} 



B, B max. , /-T^^ro /^BX 



'^' H, H max. ^ \ dt / 



I = total iron loss per c.c. per cycle. 



E = calculated eddy current loss per c.c. per cycle. 



XJ = statical hysteresis for B max. of experiment. 



* Loc. cit. 



IT. R. Lyle. Pliil. Mug. [t!] vol. VI., p. 549 (1903). 



