Encyclopaedia Britannica, 11th Edition, 'Ehud' to 'Electroscope' / Volume 9, Slice 2 - Various

H	B	μ	H	B	μ	H	B	μ
.19	27	139	8.84	4030	456	44.65	8,071	181
.41	62	150	10.60	4491	424	56.57	8,548	151
1.11	206	176	12.33	4884	396	71.98	9,097	126
2.53	768	303	13.95	5276	378	88.99	9,600	108
3.41	1251	367	15.61	5504	353	106.35	10,066	95
4.45	1898	427	18.21	5829	320	120.60	10,375	86
5.67	2589	456	26.37	6814	258	140.37	10,725	76
7.16	3350	468	36.54	7580	207	152.73	10,985	72

The metal of which the tests are given in Table IV. contained 2% of silicon, 2.85% of total carbon, and 0.5% of manganese. It will be seen that a magnetizing force of about 5 C.G.S. units is sufficient to impart to a wrought-iron ring a flux density of 18,000 C.G.S. units, but the same force hardly produces more than one-tenth of this flux density in cast iron.

The testing of sheet iron and steel for magnetic hysteresis loss has developed into an important factory process, giving as it does a means of ascertaining the suitability of the metal for use in the manufacture of transformers and cores of alternating-current electromagnets.

In Table V. are given the results of hysteresis tests by Ewing on samples of commercial sheet iron and steel. The numbers VII., VIII., IX. and X. refer to the same samples as those for which permeability results are given in Table III.

Table V.—Hysteresis Loss in Transformer-iron.

Maximum Flux Density B.	Ergs per Cubic Centimetre per Cycle.				Watts per ℔ at a Frequency of 100.
Maximum Flux Density B.	VII. Swedish Iron.	VIII. Forged Scrap- iron.	IX. Ingot- steel.	X. Soft Iron Wire.	VII.	VIII.	IX.	X.
2000	240	400	215	600	0.141	0.236	0.127	0.356
3000	520	790	430	1150	0.306	0.465	0.253	0.630
4000	830	1220	700	1780	0.490	0.720	0.410	1.050
5000	1190	1710	1000	2640	0.700	1.010	0.590	1.550
6000	1600	2260	1350	3360	0.940	1.330	0.790	1.980
7000	2020	2940	1730	4300	1.200	1.730	1.020	2.530
8000	2510	3710	2150	5300	1.480	2.180	1.270	3.120
9000	3050	4560	2620	6380	1.800	2.680	1.540	3.750

In Table VI. are given the results of a magnetic test of some exceedingly good transformer-sheet rolled from Swedish iron.

Table VI.—Hysteresis Loss in Strip of Transformer-plate rolled Swedish Iron.

Maximum Flux Density B.	Ergs per Cubic Centimetre per Cycle.	Watts per ℔ at a Frequency of 100.
2000	220	0.129
3000	410	0.242
4000	640	0.376
5000	910	0.535
6000	1200	0.710
7000	1520	0.890
8000	1900	1.120
9000	2310	1.360

In Table VII. are given some values obtained by Fleming for the hysteresis loss in the sample of cast iron, the permeability test of which is recorded in Table IV.