DIRECT-CURRENT DYNAMOS AND MOTORS. 
51 
The frequency is the number of revolutions per second 
multiplied by the number of pairs of magnet poles, or 
The mass, M, when allowing 10 per cent. of the core 
length for spaces between the lamina, is given by the 
formula: 
Peet Bi )t XK Be OL oniesevecee so. (31) 
TABLE 19. 
HYSTERESIS FACTOR FOR DIFFERENT FLUX DENSITIES. 
Density, in|Hysteresis ||Density, in|Hysteresis ||Density, in| Hysteresis 
Lines per| Factor. Lines per| Factor. Lines per| Factor. 
Square Watts per|| Square _ Watts per||} Square Watts per 
Inch. Cu Inch.|}| Inch, Cu. Inch.|} Inch. Cu. Inch 
Ba. 7). Ba 7. Ba. q). 
10000 .0007 60000 0128 82000 .0211 
15000 -0014 . 61000 0131 83000 .0215 
20000 .0022 62000 .0135 84000 .0219 
25000 .0031 63000 .0138 85000 .0223 
30000 .0042 64000 0142 86000 0227 
32300 .0048 65000 0145 87000 .0232 
35000 - .0054 66000 0149 88000 .0236 
37500 .0060 67000 0152 89000 .0240 
40000 .0067 68000 -0156 90000 .0245 
42500 .0074 69000 0160 92500 .0253 
45000 .0081L 70000 -0164 95000 0261 
47500 .0088 71000 .0167 97500 0275 
90000 -0095 72000 0171 100000 .0289 
51000 .0098 73000 .0175 105000 .0312 
582000 .0102 74000 -0179 110000 .0337 
53000 .0105 75000 .0183 115000 .0362 
54000 -0108 76000 .0187 120000 .0387 
55000 .O111 77000 .0191 125000 .0414 
56000 .0114 78000 .0195 130000 .0442 
57000 .0117 79000 .0199 135000 .0470 
58000 .0121 $0000 .0203 140000 .0498 
59000 0124 81000 0207 145000 .0527 
