. The Bell System technical journal . \ \\ \\ \\\ iv\ I m \ \\ V ^ k ^ ^ , UJ _lO o ct UJ °- LiJ 2 (T ^ O Fig. 2—Imaginary component of mutual impedance gradientfor conditions of Fig. 1. limiting curves so that for a given frequency a properly chosen homo-geneous ground conductivity leads to equivalent results. The equiva-lent conductivity varies with the frequency, increasing or decreasingwith increasing frequency according as Xi is greater or less than X2;this variation of apparent homogeneous conductivity with frequencyhas been frequent
. The Bell System technical journal . \ \\ \\ \\\ iv\ I m \ \\ V ^ k ^ ^ , UJ _lO o ct UJ °- LiJ 2 (T ^ O Fig. 2—Imaginary component of mutual impedance gradientfor conditions of Fig. 1. limiting curves so that for a given frequency a properly chosen homo-geneous ground conductivity leads to equivalent results. The equiva-lent conductivity varies with the frequency, increasing or decreasingwith increasing frequency according as Xi is greater or less than X2;this variation of apparent homogeneous conductivity with frequencyhas been frequently observed in results obtained from mutual im- 168 BELL SYSTEM TECHNICAL JOURNAL 00014 ~>. ^, y /^ o a 00012 -^^ 4>o- / ^ ^ — —■ ---:.. Q- u ■^ 4 . - / / 1 ^ ~^ 2 ^ .... y 00006 10-2 ^ in 5 00004 ,y I 00002 ? JiH^ 0 5 10 Fig. 3—Two-layer earth X2 = lOXi; real component of mutualimpedance gradient. 50. 5 yl/Xs^ X 1000 Fig. 4—Imaginary component of mutual impedance gradientfor conditions of Fig. 3. MUTUAL IMPEDANCE OF GROUNDED WIRES 169 pedance measurements.^ For a given frequency the complete groupof curves of which Figs. 2 and 4 are examples may be put in more con-venient form by plotting the equivalent conductivity as dependent onthe other parameters of the problem. The mutual inductance of wires 6 and s, as given at the headof the corresponding column in Table I, is: L^ss = N°s, + N°{Aa) - N°(Ab) - N°iBa) + N°(Bb), where i\°ss is the mutual Neumann integral of the wires and is themain term in the formula.■* The small contribution arising from theremaining terms is as shown on Fig. 5 always less than A = — Aa ~ - ~ ■-^ -\2f\2 ^^ ■^ ^^ ^ S s ^, 0 ^ ^^ ^ ;^::^ - — b ^^::::S ^ s s S _i 0 ■—■ - -■ ::i^^ 1—_——-^ S -q ::: ; ^^^^^::r~-—» ^ -0-50 i:::::^^^^^ r- ^ 5 1 .^^^^ T ~1 r k z| 0
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
