US1740403A - Electrical conductor - Google Patents

Description

Dec. 17, 1929. H. J'DAN I 1,740,403

ELECTRICAL CONDUCTOR Filed Nov. 14, 1927 iwf-MTM A l s INVENTOR. ims Jamin/f@ 4 TTORNEY Patented Dec. 17, 1929 UNrrEa stares; PATENT' oFF-rca HANS JORDAN, OF KARLSHOIRST, BERLIN; G-ERIIVIKNTI",` SSIGNORI T0' GENEEI ELEC;

. TRIO COMPANY; A CORPORJYTION` OF,E NEW" YORK ELECTEIGAL CONDUCTOR'- Epplicat-ion-1od November 14,1927; SerialNo.-232,992 and invGenmany'March 30,1927..

This invention relates to; electrical' conL ductors` and:y isy particularly applicableto cables for use-1 in telephony.

One forni' of: cablek construction. consists in assigning four Wires to each of a plurality of.A quads. 'lheV four Wires comprising each quad? are insulated andi arel twistedl about a commonyaX-is, various quads being assembled toffor'ni acable; TWozWires lvvhichvlie diametrically opposite to yeachother in the quad. are used for one'sidee circuit, the remaining-'two Wires beingf used for vthe otherside circuit. The Wires of thetvvov side circuits comprise. the conductors of al. plant'oni circuit.4 rhe Wires o of any quad maybe offtl'ie-sain'e diameter; .yet diferent' quads may have wires ofi different diameters, ii' desired. The` capacity' per unit lengthl ofthe ph'znitorn.` circuit in this type of construction is so' great when compared with the; capacity of thel side circuits, that even when* these circuits are I loaded toprovid'ek the same transmission loss the cutoi. frequency or thephantom i'svl'owerthan that ofthe side circuits, which, or course, is und'esirable'i- The conductors of anyf pair mayy if deL sired, be` transposed vtol secures equal and? op posite exposure to; for example', any: ex'- ternalt inductive' influenceor other forms of interference. By increasing the` distance'between they conductors of" a pair,k it isi possible to'reduce the electro-staticcapacity and. at the samel time' increaseathe inductance ofi` these conductors-relatively to each other. Asiswfell lnown inthe' art, decrease in the capacity, 35 and Within certain limits,v increase ot the mutual inductionL are greatly beneficial? to transmission. l

It is one of" the objects or" thisi invention to provide1 a transpositi'onI scheine forv use in 4'0 theconstructionof cableY quads. which` will eiect the elimination ot any undesirable ca;L paciti'es, not only theoretically` but alsoxpra'cL tically. It is a Welllelcnown fact'that an' electrically efficient cable quad:v may, in@V practice,

45 result in considerable crosstall disturbances becausey ofL unavoidablemanufacturing diile culties encountered' in. its, construction.. The chief disadvantage brought; about by these manufacturing difficulties result inr the;v accuniulation ot capacitative effects which, thoughz individually smallY in asparticul'ar section ofthe, quad are,v nevertheless,v or, like nature and'. therefore additive throughout" a long section ot the cable-quadi By providing aY transposition. scheme, it4 is; possible to adequately overcome the: resultant capacita.- tive eiects tending to introducey cross-talk, the transposition1 scheine introducing dissimilar relations as. muchi as. possible throughout bothzsid'ei circuits,comprising,v the quad.

Y This; invention. Will. be betten understood fromfthe,detailedidescription hereinafter following-When read ins connection with the acccrnpanying`-` drawing, showing` one ferm oi embodimentot the,v insrentiomin which Figune, 1i show-s a. transposition scheme e1nployingj the principles ot this; invention, and Figure-2 showsa cross-section or they conductors oat` the quad! provided in Figure 1.

Referringtc-Figurel ofthe drawing, th er-e are showns 4toun conduct-craft, Bu@ and! D, conductors A` andB representing one side -circuitr and conductors. G.; and; D representing thesother side circuit. Conductors A and) B, fon example, may run parallel to each other over af, section a Upon reaching section 5% thesefvvfires mayv be transposed. in order that' the1 upper. conductor A may assume the lowen'position, Whilel conductor B may assume the upper position. Upon reaching section c, these conductors may again be transposed so that conductors-A, andl B may assume; the same nelativekpositions as in sections dZ., At sectiond, another transposition is eifectied, thefconductorsA` and B assumingy the positions present in section These: conductors mayy remain in: this-relative positionthroughout along;section'.` or the cable andare thentranspcsedagain at section e. These: Wiresi may' be transposed periodically throughout the cable as shown in the drawing. The second side circuit comprising conductors C and B may be similarly transposed throughout its length, transpositions occuring at regular intervals, substantially the same as is the case of the upper side circuit of conductors A and B.

It is apparent that the transposition sections within each of the side circuits are not .ot the same length throughout. There is a succession of a number of short transposition sections interrupted at regular intervals by a longer transposition section. The transposition scheme ot' this arrangement is such that a number oi" short sections are provided, which are interrupted periodically by a longer section, these conditions existing in both side circuits to the same extent. However, the conductors oi the quad are so arranged that the series of the short transposition sections in one side circuit are adjacent to one of the longer transposition sections in the other side circuit, and vice versa. The length of the long transposition section may be determined from the expression VJ (vt-t2), Where W is the length of each small transposition section and n, represents the number of serial short sections. In such an arrangement, the couplings introduced in two successive sections, which may be in the same or in different side circuits, substantially balance each other.

In accordance with this invention, the number of short successive transposition sections is to be selected so that the component conductors may assume as many combinations o'f dili'erent positions as possible in both side circuits. In the arrangement shown in Figure l, three transpositions occur in each side circuit in regular succession and then another occurs after a long interval. Moreover, in the arrangement shown, the conductors of each side circuit are uncrossed, then transposed 180 degrees in a clockwise direction and then transposed 180 degrees in a counterclockwise direction, and so on. Assuming each interval to be composed of two short sections and one long section, O representing an uncrossed section, R a section transposed in a clockwise direction and L a section transposed in counterclockwise direction, then the following positions will be present throughout a definite length of one of the side circuits, these positions being repeated in regular order:

O short R short O long L short O short R long O short L short O long R short O short L long The same positions will be present in the second side circuit and similarly repeated in that circuit. Such an arrangement exhibits positive and negative effects in the individual sections resulting in a multiplicity of mutual positions of the conductors.

- Figure 2 shows a cross-sectional view of the conductors. I-Iere A and B represent the insulated conductors of one side circuit and C and D represent the insulated conductors of the other side circuit. It is to be noted that the conductors of each side circuit are adjacent to each other in the quad. Such an arrangement is distinctly different from the arrangement of conductors in the well-known form ot star quadded cable in which diago nally opposite conductors form the respective side circuits.

It is to be noted that it is one o'f the 'features of this invention to employ point-like transpositions, a point-like transposition being one in which the wires are transposed throughout an extremely small distance as compared to the distance between two successive transpositions. Thus, the slope of the wires at each transposition is very steep.

l/Vhile this invention has been shown and described in a certain particular embodiment merely for the purpose of illustration, it will be clearly understood that the general principles of this invention may be applied to other and widely varied organizations without departing from the spirit of the invention and the scope of the appended claims.

l/Vhat I claim as new and desire to secure by Letters Patent of the United States, is:

l. In a cable for telephone systems and the like, the combination of two pairs of suitably insulated conductors the conductors of each section of one pair being sharply crossed a predetermined number ot' times at substantially equal intervals and sharply crossed alternately at one longer interval, the one longer interval of each section of one pair being opposite to the serial intervals of each section of the other pair, and conversely, the shorter serial intervals of each section of the first pair being opposite to the one longer interval ot each section of the second pair, the conductors ot said pairs being twisted uniformly about a common axis, each pair of conductors being employed for the transmission of a telephone conversation.

2. In a cable for telephone systems and the like, the combination of one pair ot conductors covered with suitable insulation, the conductors of each pair being divided into sectiens in each of which said conductors are sharply crossed serially a definite number of times at equal distances and sharply crossed alternately once over a different distance longer than the distance between the serial crossings, a second pair of conductors similarly insulated and similarly crossed, all of said conductors being twisted about a common axis, the longer interval of each section ot one pair being placed opposite to the short serial intervals of each section of the other pair, and vice versa.

8. In a cable for telephone and like systems, the combination of four conductors twisted in common about an axis, each section of tWo adjacent conductors being sharply crossed successively a definite number of times at equal intervals and sharply crossed alternately at one longer and predetermined interval, the short successive intervals of each section of one pair of conductors being adjacent to the one longer interval of each section of the other pair of conductors.

In Witness whereof, I have hereunto set my hand this 25th day of October, 1927.

HANS JORDAN.

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