None
In figure 1, start- ing at the upper commutator bar, the wire is wound into the first half of the first section, thence back through one of the opposite half sec- tions b, c, d, e, or /, and thence to the next commutator bar,com- pleting one coil. By winding into the dia- metrically opposite half sections a and d, it will be the Siemens winding, shown com- pleted in figure 2. By winding into a and e it will be the Froehlich winding, figure 3 ; a and c will be the Breguet winding; a and 6, or a and /will both give such irregular windings that they should not be used. The accompanying diagrams show the completed windings, and the five principal modifications of the same. * Abstract from an article on Cylinder- Armatures in the Electrician and Electrical Engineer, Vol. 4, 1885, p. 423, and Vol. 5, 1886, p. 84. (261) Fig. 1. 262 Systems of Cylinder- Armature Windings. In these figures the windings are shown diagrammatically as seen from the commutator end of the armature, the dotted lines representing the winding across the other (pulley) end of the armature. The two halves of the armature being in multiple arc, those sets of coils which form one half are shown by white coil spaces, and will be termed light coils, while those forming the other half are shown by section lined coil spaces, and will be termed dark coils. The coil spaces which are marked with crossed Hues represent the coils which are short-circuited by the brushes. The arrow heads on the lines show the direction in which the current will flow in those wires when the armature revolves to the left, as shown by the arrow on the outside, and when the polarity and the position of the pole-pieces is as shown by the letters N and S. The commutator connections of the dead coils which are short- circuited by the brushes are indicated by the letters 0 0 and have no arrow heads. To avoid too many lines the brushes are drawn outside of the armature, their proper place on the commutator being shown by a small dot. The diagrams thus show at a glance whether the winding is symmetrical, whether the light and dark coils of the two halves of the armature are symmetrically situated in the fields, in what part of the field the dead coils lie, the position and polarity of the brushes, etc. The windings have all been started alike by connecting the beginning of the first coil to the nearest commutator bar, this being the usual way. They may, however, be started from any other commutator bar, without changing the system of winding, by merely shifting the brush line or the relative position of the commutator bars (and brushes) with their respective coils. The Siemens or Hefner-Alteneck winding, figure 2, is irreg- ular after one half of the armature is wound (between the two lower white sections). The coils have not symmetrical positions in the fields. At least one of the short-circuited coils, being in opposite fields, is not dead. All the coils cross each other on the ends of the armature, making a bulky " head." It appears to be no longer used, presumably owing to these objections. The Froehlich winding, figure 3, is quite regular. The dark and light coils have symmetrical positions in the fields. Each Systems of Cylinder- Armature Windings. 263 short-circuited coil lies in one field and is therefore more nearly dead ; the injurious currents in them will therefore be less than in the Siemens. Every two coils being parallel there will be much fewer crossings of wires at the ends, which is an additional advantage. In this system special care should be taken that the coils are wound in their proper spaces, as there are always two, for instance i and A, which are opposite to one, g, i is the right one and h the wrong one. The Breguet winding, figure 4, is practically identical with the Froehlich ; the only difference is in the relative positions of the commutator bars (brush line) and their respective coils. The Edison system, figure 5, is the Siemens applied to an odd number of coils. It is quite regular and the light and dark coils are symmetrically situated. Only one coil is short- circuited, instead of two, as in the other systems. All the coils cross each other as in the Siemens. It is simpler to wind than either of the others. Using an odd number of coils, and wind- ing from a to c, figure 5, instead of a to b, will give a very irregular winding, while from a to d will give a regular one. Instead of winding two neighboring coils next to one an- other, as in figures 2 and 3, they may be wound over each other, thus giving the double Siemens and double Froehlich windings shown in figures 6 and 7. The advantage is that they are easier to wind. They have the same characteristics as in the first forms, with the additional disadvantage that the outer and inner coils have different mean lengths and speeds. The Edison system may also be wound double, but it then appears to lose its characteristic regularity. In the Weston winding, figure 8, and the Hering winding, figure 9, each coil is split into two halves, one half being wound in the lower layers and one half in the upper layers. This makes the mean length and speed of the coils the same, and therefore overcomes the objection to the double windings. They are somewhat more troublesome to wind. The Weston is based on the Siemens, and has all the characteristics of that system, the objectionable effect of the irregularity being, how- ever, greatly reduced. The Hering winding is based on the Froehlich, and has all the characteristics of that system. 264 Systems of Cylinder- Armature Windings. Systems of Cylinder- Armature Windings. 265 266 /Systems of Cylinder- Armature Windings. Systems of Cylinder- Armature Windings. 267 APPENDIX V. Equivalents of Units of Measurement. THE numbers in these tables have all been calculated from the following set of fundamental standard equivalents, viz. : The values of — the meter in inches, the gram in grains, the avoirdupois pound in grains,. the troy (apothecary) pound in grains, the gallon in cubic inches, the atmospheric pressure in millimeters of mercury, the specific gravity of mercury, Joules equivalent 772, acceleration of gravity 981, legal ohm in mercury units, B. A. unit of resistance in legal ohms. The numerical values which were used for this set of funda- mental equivalents are those given in their respective places in the tables. For any subsequent, more accurate, determination of these fundamental values the corresponding corrections of their derived equivalents in these tables can readily be made by simple proportion. For this reason the derived equiva- lents have in many cases been carried to more decimals than would otherwise be reasonable. The values for the weights and volumes of water are based on the metric system. In almost all cases the reciprocal of each equivalent is also given (in its proper place), thus enabling all calculations to be made by multiplication instead of division. The "Approximate Values" have been given in the smallest number of digits, generally only one or two besides the digits 0 and 1. Almost all of these approximate values are within 3% of the correct value, and many of them within 2%. All the equivalents have been calculated by two independent methods, and it is believed that there are no errors 269 EQUIVALENTS OF UNITS OF MEASUREMENT. CARL BERING. UNITS. (In order of size.) EQUIVALENTS. APPROXIMATE VALUES) WITHIN A FEW PER CENT. LOGARITHMS. i Lengths. 1 mil = .025400 = .001 millimeter inch TTfoTI a.404 8259 ,.0000000 1 millimeter = 39.3708 mils 40 1.595 1741 = .039371 inch Js ,.595 1741 1 centimeter = .393708 inch ft T.595 1741 1 inch = 2.53995 centimeters V 0.404 8259 Ifoot = .30479 meter 3 T.484 0071 1 yard = .91438 meter If ,.961 1284 1 meter = 39.370790 inches 40 1.595 1741 = 3.280899 feet ¥ 0.515 9929 " = 1.09363 yards H 0 038 8716 1 kilometer = 3280.899 feet 3.515 9929 ** = 1093.633 yards 3.038 8716 M = .62138 mile i ,.793 3590 1 mile = 5280. feet 3.722 6339 = 1760. yards 3.245 5126 M = 1609.31 meters 3.206 6410 •• = 1.60931 kilometers § 0.206 6410 " = .86838 geog. or naut. mile I T.938 7098 1 geog. or naut. mile = 6080.27 feet 3.783 9229 Surfaces 1 sq. mil = .00064514 sq. millimeter j.809 6518 " = .000001 sq. inch 000 0000 1 sq. millimeter = 1550.1 sq. mils 3^190 3482 1 sq. centimeter 1 sq. inch. 1 sq. decimeter = .001550 = .15501 = 6.4514 = 15.501 sq. inch sq. inch sq. centimeters sq. inches 1 -.190 3482 T.190 8482 0.809 6518 1.190 3482 u = .10764 sq. foot X T.031 9858 1 sq. foot = 929.00 sq. centimeters 2.968 0142 " = 9.2900 sq. decimeters V 0.968 0142 1 sq. yard = .&3610 sq. meter T.922 2568 1 sq. meter = 10.764 sq. feet 4.3. 1.031 9858 = 1.1960 sq. yards 8 0.077 7432 1 are 1 acre = 100. = .40467 sq. meters hectare A 2.000 0000 T.607 1020 " = .0040467 sq. kilometer 3.607 1020 1 hectare = 10000. sq. meters 4.000 OtiOO 4i = 2.4711 acres B 0.392 8980 1 sq. kilometer = 247.11 acres 2.392 8980 1 sq. mile = .38612 = 640. sq. mile acres 5g T-586 7180 2.806 1800 " = 2.5899 sq. kilometers ?g 10.413 2820 270 Equivalents of Units of Measurement. 271 Volun :ies. 1 cub. centimeter = .061027 cub. inch A 5.785 5223 " = .0-33816 fluid ounce 3S 5.529 1203 44 = .0021135 pint 3.325 0003 1 fluid drachm = 3.6965 cub. centimeters V 0.567 7897 44 = .22559 cub. inch 2 T.353 3120 1 cub. inch = 16.386 cub. centimeters -325 1.214 4777 ' = .55411 fluid ounce * T.743 5980 4 = .034632 Eint 2?tf 5.539 4780 4 = .016386 ter ft 5.214 4777 1 fluid ounce = 29.572 cub. centimeters 30 1.470 8797 4 = 8. fluid drachms 0.903 0900 ' = 1.8047 cub. inches § 0.256 4020 1 pint = 473.15 cub. centimeters 2.674 9997 Si = 28.875 cub inches 20Q 1.460 5220 44 = 16. fluid ounces 1.204 1200 44 = .47315 liter u 1.674 9997 1 quart = 946.30 = 57.7500 cub. centimeters cub. inches 2.976 0297 1.761 5520 " = .94630 = .033420 liter cub. foot g T.976 0297 5.524 0084 1 liter = 1000. cub. centimeters 3.000 0000 44 = 61.027 cub. inches 1.785 5223 44 = 2.1135 pints « 0.325 0003 44 = 1.0567 quarts 0.023 9703 41 = .26419 gallon K T.421 9103 44 = .035317 cub. foot T7ff ,.5479787 1 gallon = 3785.2 cub. centimeters 3.578 0897 44 = 231.0000 cub. inches zga 2.363 6120 44 = 3.7852 liters jyi 0.578 0897 44 = .13368 cub. foot A T.126 0683 44 = .037852 hectoliter A 5.578 0897 1 cub. foot = 28815.3 cub. centimeters 4.452 0213 4 = 29.922 quarts 30. 1 .475 9916 4 = 28.3153 liters 1.452 0213 4 = 7.4805 gallons If. 0.873 9317 4 = .28315 hectoliter 2 T.452 0213 4 = .028315 cub. meter A 5-452 0213 1 hectoliter = 105.67 quarts 2.023 9703 4 = 100. liters 2.000 0000 i = 26.419 = 3.5317 gallons cub. feet 1 1.421 9108 0.547 9787 1 cub.^yard = 201.97 = .76451 gallons cub. meter. {3 2.305 2955 T.883 3852 1 cub. meter = 264.19 gallons 2.421 9103 44 = 35.317 cub. feet ¥ 1.547 9787 44 = 1.3080 cub. yards H 0.116 6148 1 stere = 1. cub. meter 0.000 0000 272 Equivalents of Units of Measurement, Weight. 1 milligram = .015432 grain tin ,.188 4320 1 grain = 64.7'99 milligrams 1.811 5680 1 gram = 15.43235 grains 15 1.188 432 J 44 = .035274 ounce avdp. 3?U j.547 4539 44 = .032151 ounce troy 8 5. 507 1908 1 ounce avdp. = 437.50 grains 2.640 97«1 (4 = 28.3495 = .91146 grams ounce troy 11 1.452 5461 T.959 7369 1 ounce troy = 480. grains 2.681 2412 44 = 31.1035 grams 31. 1.492 8092 1 pound troy = 1.0971 = 5760. ounces avdp. grains ti 0.040 2631 3.760 4225 44 = 12. ounces troy 1.079 1812 44 = .82286 pound avdp. § T.915 3245 41 = .37324 kilogram i T.571 9905 1 pound avdp. = 7000. grains 3.845 0980 *c = 16. ounces avdp. 1.204 1200 „ = 1.2153 = .45359 pounds troy kilogram if 0.084 6755 T.656 6660 1 kilogram = 35.274 ounces avdp. 754 1.547 4539 44 = 2.2046 pounds avdp. H 0.343 3340 1 net or short ton = 2000. pounds avdp. 3.301 0300 44 = .90719 metric ton i? T.957 6960 44 = .89286 long ton ft T.950 7820 1 metric ton = 2204.62 pounds avdp. 3.343 3340 44 = 1.1023 short tons H 0.042 3040 44 = .98421 long ton H T.993 0860 1 gross or long ton = 2240. pounds avdp. 3.350 2480 fc* = 1.1200 short tons y 0.049 2180 " = 1.01605 metric tons ft 0.006 9140 Weights and Lengths. 1 Ib. per mile = .28185 klgr. per kilometer ? T.450 0250 44 = .11048 grain per inch I r.043 2829 44 = .0028185 grain per centimeter vil ,.450 0250 1 klgr. per kilomet. = 3.5479 Ibs. per mile £ 5.5499750 41 = .39197 grain per inch TO T.593 2579 44 = .01000 gram per centimeter 3.000 0000 1 grain per inch = 9.0514 Ibs. per mile 9. 0.956 7171 u M U = 2.5512 = .02.5512 = .00255-12 = .0017143 klgs. per kilometer gram per centimeter klg. per meter Ib. per foot i & 0.406 7421 5.406 7421 3.406 7421 -.234 0832 1 gram per centimet. = 354.79 = 100.000 Ibs. per mile klgs. per kilometer 70Q 2.549 9750 2.000 0000 44 = 39.197 grains per inch 40 1.593 2579 K = .10000 klg. per meter T.OOO 0000 44 - .067196 Ib. per foot A ,.827,3411 1 klg. per meter = 391.97 = 10. grains per inch grams per centimeter 400 2.593 2579 1.000 OMXJ i* 1 Ib. p^er foot = .67196 = 583.33 = 14.882 Ib. per foot grains per inch grams per centimeter 1 !.827 3411 2.765 9168 1.1726589 H = 1.4882 klgs. per meter * 0.172 658G Equivalents of Units of Measurement. 273 Weights and Surfaces (Pressures). 1 Ib. per sq. inch =.068044 atmosphere ft 5.832 7894 = .070310 klgr. per sq. centimeter 7 "1 7JTJ 5.847 0142 1 klgr. per sq. centim. =14.223 Ibs. per sq. inch ill 1.152 9858 = . 96778 atmospl i ere i? r 985 7752 1 atmosphere =760. millimeters of mercury col. = 33 . 901 feet water column 34 2 '.880 8136 1.530 2177 = 29.922 inches of mercury column 30. 1.475 9877 = 14.(>% Ibs. per sq. inch ^^ 1.167 2106 = 10.333 meters water column 31 1.014 2248 = 1 .0333 klgs. per sq. centimeter 31 0 014 2248 sp. gr. of mercury = 13.596 9 T. 133 4112 Weights and Volumes. 1 grain per cub. inch = .24686 Ib. per cub. foot i T.392 4457 = .0039545 gram per cub. centimeter 1 Ib. per cub. foot = 4.0509 grains per cub. inch I04Z5<J 4 3.597 0903 0.607 5543 = .016019 gram per cub. centimeter *§* 5.204 6447 = .016019 kilgr. per liter 1 gram per cub. c. m. = 252.88 grains per cub. inch. 1 gram per cub. c. m. = 62.425 Ibs. per cub. foot IS. BOP 5.204 6447 2.402 1097 1.795 3553 1 klgr. per liter = 62.425 Ibs. per cub. foot 1.795 3553 = 2.0862 Ibs per quart 0.319 3637 lib. per quart =.47933 klgr. per liter j.680 6363 1 Ib. per cub. inch = .027681 klgr. per cub. c. m. 5.442 1883 1 klgr. per cub. c. m. = 36.125 Ibs. per cub. inch 36. 1.557 8117 Weight of Water. K. 1 cub. c. m. water weighs 15.432 grains 15. 1.188 4320 1 . gram 1 0.000 0000 1 cub. inch weighs 252.88 grains 2.402 9097 16.386 grams 1.214 4777 .036125 pound 5.557 8117 1 quart weighs 2.0862 pounds 0.319 3637 .94630 kilogram 1 litre weighs 2.2046 pounds 1 1.976 0297 0.343 3840 1 cub. foot weighs 62.425 pounds 1.795 3553 28.3153 kilograms ITO 1.452 0213 1 cub. yard weighs 1685.5 pounds 3.226 7192 764.51 kilograms 2.8P3 3852 1 cub. metre weighs 2204.6 pounds 3.343 3340 M. 1 pound water measures 453. 59 cub. centimeters 2 656 6660 27.681 cub. inches _B5 1 442 1883 " .47933 quarts If T.680 6363 .45359 liter ?o j.656 6600 .016019 cub. foot 81 5 5 204 6447 1 klgr. water measures 61 .027 cub. inches 1.785 5223 1.0567 quarts 15 0.023 970.5 " 1. liter 0.000 0000 " .035317 cub. foot rf* 5.547 9787 The weight of a given volume of any other material, whether solid or liquid, is its specific gravity multiplied by the factor K. The volume of a given weight of any other material, is the fac- tor M divided by its specific gravity. 274 Equivalents of Units of Measurement. Velocities. 1 foot per second = .30479 meter per second = .018288 klmet. per minute * T.484 0071 -.262 1583 1 meter per second = .011364 mile per minute = 3.280899 feet per second = .0600 klmet. per minute l > vr.055 5173 0.515 9929 j.778 1513 = .037283 mile per minute 1 kilometer per minute = 54.682 feet per second = 16.667 meters per second 5. 1 0 ».ft71 5102 1.737 8417 1.221 84S? " = .62138 mile per minute 1.793 3~){K) 1 mile per minute = 88.00 feet per second = 26.822 meters i >er second 27 1.944 4827 1.428 489H " = 1.60931 klmet. per minute 1 0.206 6110 Gravity. ArPPiPrntinn nf Ov / 981-000 centimeters per second leration of gravity = j 32 186 feet per second 1000. H* 2.991 6690 1.507 6619 Forces (see also Weights). 1 dyne = 1.0194 milligrams i. 0.008 3310 " = .015731 grain 5B5 5.196 7630 " = .0010194 gram i nvv 3.008 3310 « = .00003596 ounce avoirdupois 5.555 7849 1 milligram 1 grain Igram = .981 dyne — 63.568 dynes - 981. 1. A.12 1000 T.991 6690 1.803 2370 2.991 6690 1 ounce avdp. = 27811. 4.444 2151 1 pound avdp. 1 kilogram = 444976. " = 981000. 5.648 3351 5.991 6690 Work. lerg = 1. dyne-centimeter 1 0.000 0000 11 = .0000001 joule 7.000 oooo 1 gram-centimeter = 981.00 ergs 1000 2.991 6690 1 foot-grain = .00001 kilogram-meter = 1937.5 ergs y.OOO 0000 3.287 2441 1 joule, or = 10,000,000. 7.000 0000 1 volt-coulomb, or = .737324 foot-pound J T.867 6580 1 watt during every second, or 1 volt-ampere during = .101937 kilogram-meter = .0013592 metric horse-power for one second 1 T.008 3310 3.133 2698 every second = .0013406 horse-power for one second TIT5%CT 3.127 2954 " = .0009551 pound-Fall., heat unit j.980 0407 " = .0005306 pound-Centig., heat unit TT§tJ5 x.724 7682 " = .0002407 kilogr.-Ccntig., 12 3.381 '4342 M = .0002778 watt-hour a 3.443 6975 1 foot-pound = 13562600. ergs. 7.132 3420 <i = 1.35626 joules 4 0.132 3420 " = .13825 kilogram-meter 1 T.140 6730 H = .0018434 metric horse-power for one second TT<TU 3.265 6117 " = .00181818 horse-power for one second ,.259 6373 Equivalents of Units of Measurement. 275 Work.— (Continued.) f 1 foot-pound = .0012953 pound-Fah. , heat unit sifoTj 3.112 3827 ,',' = .0007196 = .0003264 pound-Centig., heat unit kilogr.-Centig., 7cW 3~510"<J ¥.857 1102 ,.513 7762 " = .0003707 watt-hour j.576 0395 1 kilogram-meter = 98100000. ergs 7.991 6690 = 9.81000 joules 10. 0.991 6690 = 7.23314 foot-pounds ¥ 0.859 3270 = .01333 metric horse-power for one second SSO- 5.124 9387 = .013151 horse-power for one second 300 Uuo* 5.118 9643 = .009369 pound-Fah., heat unit •]• -.971 7097 = .005205 pound-Centig., heat unit rife 3.716 4372 = .002: '.61 kilogr.-Centig., sftv 3.373 1032 = .00272f> watt-hour T&iJ 3.435 3670 1 watt-hour = 3600. joules 3.556 3025 = 2654.4 foot-pounds uyia 3.423 9605 = 366.97 kilogram-meters 2.564 6335 = 3.4383 pound-Fah., heat units 0.536 3433 = 1.9102 == .8664 pound-Centig., heat units kilogr.-Centig., " 0.281 0708 T.937 7368 = .0013592 metric horse-power-hour 3.133 2698 ' = .0013406 horse-power-hour 30%ff 3.127 2954 1 metric horse-po\v er- hour = 2648700. joules 6.423 0327 = 1952940. foot-pounds 6.290 6908 = 270000. kilogram-meters 5.431 3638 = 2529.7 pound-Fah., heat units JLQOfiQ 3.403 0735 = 1405.4 pound-Centig. , heat units IJLQQ 3.147 8010 = 637.5 kilogr.-Centig., " 600fi 2.804 4670 = 735.75 watt-hours 3i)00 2.866 7302 1 horse-power-hour = .98634 = 2685400. = 1980000. horse-power-hour joules foot-pounds 1? T.994 0256 6.429 0071 6.296 6652 = 273740. kilogram-meters 5.437 3382 = 2564.8 = 1424.9 pound-Fah., heat units pound-Centig., heat units 10000 JOOOO 3.409 0479 3.153 7754 = 646.31 kilogr.-Centig., 2000 2.810 4414 = 745.941 watt-hours SfiLftO 2.872 7046 K = 1.01385 metric horse-power-hours « 0.005 9744 Heat. 1 gram-Centigrade 1 pound-Fahrenheit -.001 = 1047.03 = 772. k ilogram-Centigrade joules foot-pounds T«Vn ^IQO 3.0J12 3.000 0000 3.019 9593 2.887 6173 = 106.731 = .55556 = .25200 kilogram-meters pound-Centigrade kilogram-Centigrade 3|Q 2.028 2903 T.744 7275 T.401 3935 = .29084 watt-hour 2 T.463 6567 = .0003953 metric horse-power-hour Tffo^TI 1UUUU ?.596 9265 = .0003899 horse-power-hour TTTOTT7T ,.590 9521 1 pound-Centigrade = 1884.66 = 1389.6 joules foot-pounds Iiooo 70QO 3.275 2318 3.142 8898 = 192.116 = 1.8000 kilogram-meters pound-Fahrenheit f 2.283 5628 0.255 2725 276 Equivalents of Units of Measurement. Heat — (Continued.) 1 pound-Centigrade = .4536 kilogram-Centigrade A T.656 6660 * = .52352 watt-hour il T.718 9292 1 kilogram Centigrade = .0007115 = .0007018 = 4154.95 metric horse-power-hour horse-power-hour joules 5 700 5 TooTiTT GOOOO .f..sr)2 It »90 3! 618 5658 * - 3063.5 foot-pounds 3000. 3.486 2238 i = 423.54 kilogram-meters soao 2.626 8968 ' = 3.9683 pound-Fahrenheit I .598 6065 « = 2.2046 pound-Centigrade 0.343 3340 < = 1.1542 watt-hours 0.062 2632 1 = .001569 metric horse-powrer-hour 3.195 5330 = .0015472 horse-power-hour 2THJ5 ,.189 5586 Power. 1 erg per second = .0000001 watt -.000 0000 1 watt, or = 10000000. ergs per second 7.000 0000 1 volt-ampere, or 1 joule per second, or = 44.2394 - 6.11622 foot-pounds per min. kilogram-meters per min. 1 1.645 8093 0.786 4823 1 volt-coulomb per second = .0573048 - .0318360 Ib.-Fah., heat unit per min. Ib.-Cent, & ,.758 1920 5.502 9195 " = .0144402 klgr.-Cent., *1_ ,.159 5855 " - .0013592 metric horse-power 3THT5 -.133 2698 1 foot-pound per min. = .0013406 = 226043. horse-power ergs per second nw* 7.127 2954 5.354 1907 ** = .0226043 watt A 7T.:'..">4 1907 « = .13825 = .00003072 = .000030303 kilogram-meter per min. metric horse-power horse-power .00003 .00003 T.140 6730 -.487 4605 P. 481 4861 1 kilogram-meter per minute = 1635000. ergs per second 6.213 5177 ** = .163500 watt i T.213 5177 \\ = 7.23314 = .0002222 foot-pounds per minute metric horse-p<n\rr ).xf>9 3270 1.346 7874 1 metric horse-power, ' = .0002192 = 735.75 xlO7 horse-power ergs per second rare ,.340 8130 9.866 7302 or = 735.750 watts son.o 2.S66 73(12 1 French horse-power, = 32549.0 foot-pounds per minute Ifloooo 4.512 5395 or 1 cheval-vapeur, or 1 force de cheval, or -4500. = 42.162 = 23.423 kilogram-meters per min. Ib.-Fah., heat units per min. Ib.-Cent., 3.653 2125 1.624 9222 1.369 '6497 1 Fferd kraft = 10.625 klg.-Cent., 1.026 3157 ' = .98634 horse-power T.994 0256 1 horse power = 745.94 xlO7 ergs per second J.S72 T046 = 745.941 watts 3000 2.872 7046. = 33000. - 4562.33 foot-pounds per minute kilogram-meters per min. 1Q{M)J)Q- 900_Q 4.518 5139 3.659 1869 = 42.746 Ib.-Fah., heat units per min. soa 1.630 8960 - 23.748 Ib.-Cent., 7_Q 1.375 6241 = 10.772 klg.-Cent., 11. 1.032 2901 = 1.01385 metric horse-powers fi 0.005 9744 Equivalents of Units of Measurement. 277 Power.— (Continued.) 1 Ib.-Fah., heat unit per min. = 17.45xl07 ergs per second 8.241 8080 = 17.4505 watts 7-Q 1.241 8080 = .023718 metric horse-power SOtJ 5.375 0778 = .023394 horse-power "soiy 5.369 1034 1 Ib.-Cent,, heat unit per min. =31.41x10* ergs per second 8.497 aS05 = 31 .4109 watts 10O0 1.497 0805 = .04269 metric horse-power 7J 5.630 3503 = .042109 horse-power 5.624 3759 1 klgr.-Cent,, heat unit per min. = 69.25xl07 ergs per second 8.840 4145 = 69.24!) watts 70. 1.840 4145 = .09412 metric horse-power = .092835 horse-power s 5.973 6843 5.967 7099 Circular (Cross-section) Units.* 1 circular mil = .78540 square mil = .00064514 circular millimeter 5'fiW T.895 0899 ,.809 6518 = .00050669 square millimeter j.704 7417 1 square mil =1.2732 circular mils 'jU) 0.104 9101 = .00082141 circular millimeter 1 x.914 5619 1 circular millimeter = 1550.1 circular mils afijlfl 3.190 3482 = 1217.4 square mils eooQ 3.085 4381 = .78540 square millimeter 1 square millimeter = 1973.6 circular mils 2$b. T.895 0899 3.295 2583 = 1.2732 circular millimeters V 0.104 9101 If <l is the diameter of a circle, the area in other units is : If d is in mils, area in sq. millimeters = d~x. 00050669 ^nrffff 5.704 7417 d in millimeters, area in sq. mils = d2x!217.4 0<M)Q 3.085 4381 d in centimeters, area in sq. inches = d2x. 12174 6 T.085 4381 d. in inches, area in sq. centimeters = cZ2x5.0669 5 0.704 7417 * A circular unit is the area of a circle whose diameter is one unit, Electrical Resistance. 1 Siemens or mercury unit = .9540 B. A. unit if T.979 5312 = .9134 legal ohm §f T.974 6941 1 B. A. unit = 1.0483 Siemens units 0.020 4688 = .9889 legal ohm j T.995 1629 1 legal ohm = 1 .0600 Siemens units 14 0.025 3059 = 1.0112 B. A. units i: 0.004 8371 278 Equivalents of Units of Measurement. Specific Electrical Resistance. 1 ohm per foot per circ. mil or per mil diam. = .78540 ohm per foot per sq. mil = .16624 microhm per cubic centi- ft T.895 0899 meter i r.220 7346 = .0021166 ohm per meter per m. m. diam. __21 3.325 6447 = .0016624 ohm per meter per sq. m. m. BO(J 3.220 7346 1 ohm per foot per sq. mil = 1.2732 ohms per foot per mil diam. — .21166 microhm per cubic centi- V 0.104 9101 meter J!lff T.325 6447 = .0026950 ohm per meter per m. m. diam. noffti 3.430 5548 = .0021166 ohm per meter per sq. m. m. TcToTJIT g.325 6447 1 microhm per cubic centimeter = 6.0154 ohms per foot per mil diam. = 4.7245 ohms per foot per sq. mil 6 0.779 2654 0.674 3553 = .012732 ohm per meter per m. m. diam. & ^.104 9101 = .01 ohm per meter per sq. m. m. 1 ohm per meter per cir- cular millimeter or per .01 5.000 0000 millimeter diam. = 472.45 ohms per foot per mil diam. U^OQQ 2.674 3553 = 371.06 ohms per foot per sq. mil = 78.540 microhms per cubic centi- 2.569 4452 meter 80 1.895 0899 = .78540 ohm per meter per sq. m. m. 1 ohm per meter per sq. 15 1.895 0899 millimeter = 601.54 ohms per foot per mil diam. = 472.45 ohms per foot per sq. mil 600. uypa 2.779 2654 2.G74 3553 = 100. microhms per cubic centi- meter 100. 2.000 0000 = 1.2732 ohms per meter per m. m. diam. V 0.104 9101 Electrical Quantity. 1 coulomb = .0002778 ampere-hour TTOOTJ 3.443 6975 1 ampere-hour = 3600. coulombs 3.556 3025 Absolute Electrical Units. 1 coulomb = 10"1 electromagnetic units of quantity 1 ampere = 10"1 " " current 1 volt = 108 " " e. m. f. 1 ohm = 109 " " resistance 1 farad = 10~9 " " capacity 1 joule = 107 absolute units of work (ergs) 1 watt = 107 absolute units of power (ergs per second) * 1 micro = 1 millionth 1 mega = 1 million 1 foot-pound I = f 1 kilogram-meter 1=1 See ergs and ergs per second in tables 1 metric horse-power | = 1 of Work and Power. 1 horse-power Equivalents of Units of Measurement. 279 " Dimensions " of Mechanical, Electrical and Magnetic Units. m = mass, I — length, t = time. Surface I* Volume (capacity) ? Velocity It'1 Acceleration It * Force mlt * Weight mlf* Work or heat (joule, foot-lbs. or heat units) mfC* Power (rate of work, watt, horse-power) m I t 3 I \ Electrical quantity * ml Current* mlt'1 Electromotive force * m I T* Resistance * If" Capacity * I 1 1 Magnetic quantity (magnetic lines of force) mlt Magnetic intensity ml t~l *In the electromagnetic system. 464518 UNIVERSITY OF CALIFORNIA LIBRARY. 