﻿458 Prof. Lyle and Mr. Baldwin on Propagation of 



current which generates a flux down the cylinder that lags 

 behind FE in phase, and hence may be represented by some 

 such vector as FM or IF, where IF = FM. Hence the 

 vector 01 will represent in amplitude and phase. the flux that 

 would have passed down the cylinder if the eddy current 

 had not been present. Thus we see that the effects of eddy 

 currents at any point of one of our specimens are (a) an 

 increase in the phase retardation, i. e. in X —0 O ; (b) a dimi- 

 nution in the amplitude of the flux there, which manifests 

 itself as an increase in X the leakage coefficient. 



A further set of experiments was undertaken in which 

 these eddy-current effects were much reduced by replacing 

 the solid rod by a cylindrical bundle of soft iron wires, called 

 specimen D, of which the details are as follows: — 



Details of Specimen D. 



A cylindrical bundle of soft iron wires. 



Number of wires = 185. 



Length of each wire = 3G8 cms. 



Diameter „ = '0791 cm. 



Area of iron section of specimen = *909 cm. 



Diameter of bundle = 1*5 cm. 



Specific resistance of iron = 1*3G6 x 10 4 . 



No. of turns on magnetizing coil = 366. 





ii ii 



search coil central = 



= 5. 









ii ii ii ii a = J-"* 







„ ,, „ ,, (> = 50. 







,, ,, ,, ,, c = 1UU. 





Statical Permeability for different inductions. 



B 



100 1000 



2000 



4000 



5000 



6000 



8000 



10000 



12000 



* 



202 ! 475 



750 



1140 



1240 



1260 



1125 



875 



575 



In Tables XVIII., XIX., and XX. are given the results 

 of three series of experiments with this specimen at one 

 frequency (T = *0255) ? but with different initial fluxes, and 

 in Table XXI. those of one series at the frequency for which 

 T=*0515, the initial flux being approximately the same as 

 in one of the preceding series, while in Table XXII. are 

 given the results for continuous magnetizing force also with 

 approximately the same central flux. 



