Temperature on the Hysteresis Loss in Iron. 



123 



By this means we can ascertain how nearly equation (5) holds 

 for any particular experiment. 



The results obtained for a specimen of wrought iron, 

 sectional area 1*56 sq. cm., for E = 8, 16, and 24 volts 

 respectively are given in Table I., and are shown also in 

 fig. 2, the curve giving the values of the hysteresis loss being- 

 marked A. 



The resistance of the portion of the primary circuit between 

 a, b (fig. 1) containing the battery and ammeter was very small 

 compared with that of the rest of the circuit, so that no 

 appreciable error was introduced by not varying R 2 in any 

 definite manner. The values of W obtained by this means 

 were found to agree within 5 per cent, with the values 

 obtained by calculating from the areas of the cyclic B-H 

 curves. 











Table 



I. 









H. 

 0.34 



B. 



E=8 volts. 



E = 16volts. 



U,. 



E= 24 volts. 



2U,-U 2 



3U 2 -2U, 



(Mean) 

 W. 



U 3 -W 



Eddy-Current 



Loss. 



X. 



194 



5-9 



7'3 



8-8 



4-5 



43 



4-4 



4-4 



0-G8 



540 



32-3 



38-2 



44-1 



26-4 



26-4 



26-4 



17-7 



1-02 



1205 



154 



169 



185 



139 



137 



138 



47-0 



1-36 



2657 



585 . 



655-4 



721 



5146 



524 



519-3 



201-8 



1-70 



4629 



1528 



1640 



1736 



1416 



1448 



1432 



304 



2-04 



6107 



2471 



2702 



2919 



2240 



2268 



2254 



665 



2-38 



7139 



3396 



3714 



4017 



3078 



3108 



3093 



924 



2-72 



8077 



4242 



4683 



5124 



3801 



3801 



3801 



1323 



3-06 



8749 



5159 



5702 



6211 



4616 



4684 



4650 



1561 



3-40 



9332 



5940 



6551 



7161 



5329 



5331 



5330 



1831 



4-01 



10148 



7297 



8145 



8960 



6449 



6515 



6482 



2478 



We have seen (equation 5) that in these experiments 

 U — W measures the eddy-current loss ; in this specimen the 

 eddy-current loss when E = 24 volts amounts to more than 

 30 per cent, of the hysteresis loss. The values of the eddy- 

 current loss for different inductions for E = 24 volts are given 

 in the last column of Table I., and are shown graphically in 

 fig. 2 (Curve X.) (p. 124). 



The values of U, W, and X are given in ergs per cub. 

 cent, per cycle, X being the space-average of the eddy- 

 current loss. 



Experiments on a Wrouglit-iron Ring, 



Mr. W. M. Mordey* has shown that the increase in the 

 magnetic hysteresis which had been noticed in the iron cores 

 * Proc. Roy. Soc. vol. lvii. Jan. 1895, pp. 224-242. 



