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Nikola Tesla Books

Books written by or about Nikola Tesla

Nikola Tesla: Colorado Springs Notes, 1899-1900 Page 289

November 17, 1899

Approximate estimates from the above readings:

The inductance of coil 344 turns is assumed to be 6 x 106 cm. which is still to be confirmed by close measurement. The inductance of primary when no wire was attached was 7 3/8 turns + conn. = 23,157 cm. With 3 meters wire attached it was 10 1/2 + conn. = 34,642 cm. Hence calling Cs1 and Cs2 the capacities of the excited system, in the two cases respectively we have:

Tp1 = $! {{2 \pi \over 10^{3}} \sqrt{0.0099 \times {23157 \over 10^{9}}}} $!

Ts1 = $! {{2 \pi \over 10^{3}} \sqrt{{{6 \times 10^{6}} \over 10^{9}} {C_{s}}_{1}}} $!

Tp2 = $! {{2 \pi \over 10^{3}} \sqrt{0.0099 \times {34,642 \over 10^{9}}}} $!

Ts2 = $! {{2 \pi \over 10^{3}} \sqrt{{{6 \times 10^{6}} \over 10^{9}} {C_{s}}_{2}}} $!

 

Cs1 = $! {{0.0099 \times 23,157} \over {6 \times 10^{6}}} $! mfd, or in centimeters:

Cs1 = $! {{9 \times 0.0099 \times 23,157} \over 60} $! = 34.386 cm

and since the capacity in the primary circuit was the same in both cases:

Cs2 = $! {34,642 \over 23,157} $! Cs1 = $! {34,642 \over 23,157} $! x 34.386 = 51.44 cm.

The value of effective capacity of the first 3 meters of wire was therefore Cs2 - Cs1 = 51,44 - 34,386 = 17.054 cm.

Calling now Cs3 the capacity of the excited system when 6 meters of wire connected to it we have, since in this case the inductance of the primary was 13 3/4 turns + conn. = 47,154 cm.

Cs3 = $! {47,154 \over 23,157} $!   Cs1 = $! {47,154 \over 23,157} $! x 34.386 = 70.02 cm.

Hence the value of effective capacity of the second piece of wire 3 meters long was

Cs3 - Cs2 = 70.02 - 51.44 = 18.58 cm.

Now in the case when 9 meters of wire were attached the inductance of the primary was 16 1/4 turns + conn. = 56,779 cm. Calling Cs4 the corresponding capacity of the excited system we have:

Cs4 = $! {56,779 \over 23,157} $! x 34 386 = 84.307 cm.

Hence effective value of the 3rd piece of 3 meters length was

Cs4 - Cs3 = 84.307 - 70.02 = 14.287 cm.

Note* In another series of readings for 9 meters the inductance of primary was found to be 17 turns + conn. = 59,665 cm, and on this basis I find:

19

289

19

Fleming, J.A. THE PRINCIPLE OF ELECTRIC WAVE TELEGRAPHY AND TELEPHONY, Third ed. 1916, Longmans Green & Co. London (from now on: Fleming), p. 877.

Contents

Introduction
June 1 - 30
July 1 - 31
August 1 - 31
September 1 - 30
October 1 - 31
November 1 - 30
December 1 - 31
January 1 - 7
Commentaries

Appendices: I, II

Images

Glossary

Lowercase tau - an irrational constant defined as the ratio of the circumference of a circle to its radius, equal to the radian measure of a full turn; approximately 6.283185307 (equal to 2π, or twice the value of π).
A natural rubber material obtained from Palaquium trees, native to South-east Asia. Gutta-percha made possible practical submarine telegraph cables because it was both waterproof and resistant to seawater as well as being thermoplastic. Gutta-percha's use as an electrical insulator was first suggested by Michael Faraday.
The Habirshaw Electric Cable Company, founded in 1886 by William M. Habirshaw in New York City, New York.
The Brown & Sharpe (B & S) Gauge, also known as the American Wire Gauge (AWG), is the American standard for making/ordering metal sheet and wire sizes.
A traditional general-purpose dry cell battery. Invented by the French engineer Georges Leclanché in 1866.
Refers to Manitou Springs, a small town just six miles west of Colorado Springs, and during Tesla's time there, producer of world-renown bottled water from its natural springs.
A French mineral water bottler.
Lowercase delta letter - used to denote: A change in the value of a variable in calculus. A functional derivative in functional calculus. An auxiliary function in calculus, used to rigorously define the limit or continuity of a given function.
America's oldest existing independent manufacturer of wire and cable, founded in 1878.
Lowercase lambda letter which, in physics and engineering, normally represents wavelength.
The lowercase omega letter, which represents angular velocity in physics.