Nikola Tesla: Colorado Springs Notes, 1899-1900 Page 356

in movement in the excited system would be 2 x 129,500 x $! {{P^{2} \times 75.2} \over {2 \times 9 \times 10^{11}}} $! watts.

If we assume that, as before, 1% of the total energy of the system is frittered down in the lamp we would have, in conformity with what was stated before for determining P, the equation

$! {2 \times 129,500 \times {{P^{2} \times 75.2} \over {2 \times 9 \times 10^{11}}}} $! = 1000 or P² = $! {{18 \times 10^{11}} \over 259} $!

or

P = $! {10^{5} \sqrt{180 \over 259}} $! = $! {10^{5} \sqrt{0.695}} $! = $! {10^{5} \times 0.834} $!

or 83,400 V nearly, which is a small e.m.f. The length of wire in excited circuit was as before stated 2198 feet; the wire being No. 10, with a resistance of 1 ohm per one thousand feet, the resistance of the circuit was about 2.2 ohm. From above p = 2πn was = 6.28 x 129,500 = 813,260 or, say, 813,000 = p. The inductance being, as shown, $! {185 \over 10^{4}} $! henry, the magnifying factor in the coil was $! {{{185 \over 10^{4}} \times 813 \times 10^{3}} \over 2.2} $! = 6840 nearly. The lamp was one with a very short filament and its resistance may have been possibly 6 ohms. Thus with the lamp comprised the magnifying factor was still very considerable, that is, $! {{185 \times 813} \over 82} $! = 1830 or nearly so. Taking it at 1800 we see that it was necessary, under the conditions assumed, to impress upon the ground plate, or near portions of the ground an electromotive force of only $! {83,400 \over 1800} $! = $! {834 \over 18} $! = 52 volts or nearly so! This seems very little indeed, it can be scarcely believed, but the figures seem to be not far from truth. These remarks refer particularly to the experiment illustrated on the plate marked XXIV. in which the connections were the same as in the diagram shown when discussing Plate XXII., the lamp or lamps being in series with the excited coil or system.

In the experiments illustrated in the Plates marked XXV. and XXVI., the connections were schematically the same as in diagram shown a propos Plate XXIII. and the vibrations and other particulars were practically the same as in experiment shown in Plate XXIV. Just described. It is to be stated that when a secondary circuit is used, as in experiments described under XXIII., XXV. and XXVI., in connection with the excited coil, this secondary should for maximum effect be placed near the lower end of the coil; the exact position may be determined by experiment or approximately calculated. Namely, if the coil which is excited were devoid of capacity and the necessary capacity were all on the upper or free end of the coil, then the secondary circuit should, for maximum effect, be just at the center of the coil. But in the experiment as shown, the capacity is distributed and the current is strongest in the first or lowest turn, diminishing towards the top of the coil in each turn. The resultant maximum effect is thus always found near the lower end of the coil, but not quite at the end, since the upper turns also effect the secondary circuit, though proportionately less than the lower ones. The calculation of the maximum position of the secondary is complicated by the fact that generally neither the capacity nor the potential is uniformly distributed, the distribution being greatly varied by very slight irregularities in the dimension of the individual turns or their position, or the position

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