US1210628A - Loading-coil. - Google Patents

Description

W. FONDELLER.

LGADiNG COM,

APPLICATION man :um 21. 3916.

1 52 1 Patented Jan. 2, 1917.

OKQ/Md UNITED STATES PATENT OFFICE.

WILLIAM FONDILLER, OF NEW YORK, N. Y., AssrGNoR TowRs'rnRN ELECTRIC COMPANY, INCORPORATED, on NEW YORK, N. Y., A CORPORATION OF NEW YORK;

LOADING-COIL Application filed June 21, 1916.

T 0 all whom it'm ag concern State of New York, have invented certain new and useful Improvements in Loading- Coils, of which thefollowing is a full, clear, concise, and exact description.

This invention relates to loaded telephone lines, and more particularly it relates to an improved form of loading coil to be used for loading phantom telephone lines. Its object is the reduction of crosstalk in phantom line systems.

It has hitherto been proposed to load a phantom circuit according to the system described in the Campbell and Shaw Patent No. 980,921, by the use oi? loading coils with discontinuous magnetic cores; that is, cores having small non-magnetic gaps. Such coils have been found effective to minimizeto a large eXtent unbalaneesin line impedance caused by the magnetizing effect of strong foreign currents, such as lightning discharges, to which the telephone lines may be exposed. A description of such so-called air-gap coils and of their adaptation to the use in question will be found in an applica-.

tion for Letters Patent of Shaw and F ondiller, Serial No. 861,421, filed September 12, 1914;.

This invention provides an improved winding arrangement for such air-gap coils, and consists in so proportionin'g the inner and outer windings of each core section that the mutual inductances between the windings which are in series with one physical circuit and those which are in series. with the other physical circuit are balanced, thereby eliminating to a large extent any danger from crosstalk in the coil itself.

The invention will be more clearly under reference to the accompanying drawing. I L

In the drawing, 1 and 2 represent the line conductors oi one physical circuit, and 3 and 4 represent the line conductors of another physical circuit which are combined in the usual manner, not here shown, to produce phantom circuit.

5 is a loading coil with windings connect-- ed in series with each one of the four line conductors in such a manner as to add in ductance t0 the phantom circuit without adding inductance to the component physi- Specification of Letters Patent,

Patented Jan. 2, 1917.

Serial No. 105,035.

cal circuits. The core of the coil 5 is divided into two sections, each comprising two quadrants, (S and 9, and 7 and 8, respectively, the sections being separated at their extremities by non-magnetic gaps 10. Each quadrant is provided with an inner and outer winding; for example, quadrant 6 has an inner winding 11 and an outer winding 12; quadrant 7 has an inner winding 13 and an outer winding 14-; quadrant 8, has an inner winding 15 and an outer winding 16, and quadrant 9 has an inner winding 17 and an outer winding 18. Each line conductor is connected in series with an outer winding of one quadrant and an inner winding of the opposite quadrant; for example, line conductor 1 is connected to one end of the winding 12, the other end of which is connected to one end of the inner winding 15 on the quadrant 8, the other end or said winding being connected to line again. The windings on the diiferent quadrants are connected in such a way that when phantom circuit currents flow therethrough, the magnetizing effect of the windings will be cumulative to cent quadrants, for example, quadrants 6' and 7, it has been iouud, where the inner and outer windings have the same number o'l turns that the mutual. inductance of two outer windings, l2 and 1 1, is greater than the mutual inductance of two inner windings, 11 and 13. It has also been found that the mutual inductance of an inner winding 11 of one quadrant, and an outer winding 14 o l an adjacent quadrant is intermediate betwecr the. mutual inductance of the two inner' windings and the mutual inductance of the two outer windings, but that it is nearer the latter. The same condition obtains with reference to the windings on adjacent quadrants of the same section, such as, quadrants 7 and 8, though in this case the absolute values oi the inutuel inductences are greute than in the case where the quadrants sepers ed by on The unbalance mutual inductunces thus introducco has been 1:, found to be :1 cause crosstalk in sir-gap oepend on runny factors, such as the size, shape and materiel oi the core and the nuinher and dimensions of the air-gaps, in general, however, a gproper balance of the inntuel inductsnces will obtain it the deviation v of the mutual lllClllCtlllCQ between on inner Winding of one quadrant and the outer winding or. an adjacent quadrant from the mean of the mutual indiiictunce of the two outer windin s and the mutual inductance of the two ll'lLol windings oi? said quadrants some, in absolute value, regardless whether these quadrants are separated sir-wipe or not. I A. convenient way of realizing this c0ndition is to, that this deviation shall be zero, 6. 8., considering any two adincent quadrants, the mutual inductance the in ner winding" of one quadrant and the outer winding of other quadrant shall be so i or approximately equal to the mean of 1e mutual inductance of the two inner nd the niutuei inductance of the two outer wind-- ings.

lin e specific case in which this winding arrangement has been applied to u coii for loudii" a phantom circuit, it has been found ratio of 1.03 to 1 has been effective produce the desired degree of mutual inductance balance in the coil, to effectiv y minimize the cross-talk danger.

W is claimed is:

1. loading coil having a magnetic core, i ne windings in a plurality of layers on e. plurality of sections thereof, some of said sections being separated by non-magnetic gens, each line conductor through the coil includi' windings in. different layers on opposite core sections, the ratio of turns in said diii'eren layers being so proportions that the mutual inductance between windot one layer on one section and wind-- ing e. ditterent layer on on tion shell deviate "from the mean of the run tuel inductences between two windings of first layer on said ad acent sections the two windings ct said different coil having a magnetic core,

inner and on wine: 3 on plurality of sections of s: it. core, non magnetic sepu z ting some of said sections, each line condue-tor through the 0011 including an inner winding on one core section and an outer winding on the opposite core section, the rutio of tu 1S in s-iiid i r and outer windings being such that t e deviation of the mutual ilflCllllCllftllCE between an inner windof one section and an outer winding" of L on adjacent section from the mean of the uni inductance of the two inner windings and the mutual inductance of the two outer "windings oi? said sections is the same, in

absolute value, regardless of whether said one section, and the winding of a. ditierent er on on. i gucent section shall be sous-l sdjuce; sections and the two windings of said difierent layer u said sections.

[1. loading" (301i liming a magnetic core with non-niaunetie inner and outer windings on o. plurality of sections of said core, each line conductor through the coil including an inner winding on one core seetion and an outer windi-.. on the oncoz: Li.

' site core section, ratio of turns in 'seid inner and outer windings being so reportioned that the mutual inductance between an inner winding of one section and an outer Winding of an adjacent section 1 way between the mutual inductance ot the two outer windings adjacent sections end windings of said adjacent sections.

line conductors comprising two ph ysicel circuits, u loeding coil for adding inductance to said line conductors when phantom circuit prising annular core, nonmagnetic gens divi core into equal. sections of two i each, on inner and an outer windquadrant, each line conductor coil i eluding an outer windof one quadrant one. inner winding re opposite quot nt, the tour windings one hys i circuit being located on oputs, the four windings of the '"cuit heir locutedon the lrui s, the of turns in posits one l other ph s to the moon of too mutual inductunces he-' tween the two windings oi the first layer on 9 current flows therein, said coil cont;

' unity, 1

cuit current flows therein, said coil comprising an annular core, non-magnetic gaps dividing said core into equal sections of two quadrants each, an inner and an outer winding on each quadrant, each, line conductor through the coil. including an outer winding of one quadrant and an inner winding of the opposite quadrant, the four windings of one physical circuit being located on opposite quadrants, the four windings of the other physical circuit being located on the other two opposite quadrants, the ratio of the 'number of turns in the inner windings to,

the number of turns in the outer windlngs being such that the deviation of the mutual inductance between the inner winding of one quadrant and the outer winding of an adjacent quadrant from the mean of the mutual inductances of the two inner windings and two'ou'ter windings of said adjacent quadrants is the same in absolute value regardless'oi whether said quadrants are on the same or different core sections.

7. In a loaded phantom line system, four line conductors comprising two physical circuits, a loading coil for adding inductance to said line conductors when phantom circuit current flows therein, said coil comprising an annular core, non-magnetic gaps dividing said core into equal sections of two quadrants each, an inner and an outer winding on each quadrant, each line conductor through the coil including an outer winding of one quadrant and an inner winding of the opposite quadrant, the four windings of one physicalvcircuit being located on opposite quadrants, the four windings of the other physical circuit being located on the other two opposite quadrants, the ratio of the number of turns in the inner windings to the number of turns in the outer windings being such that the mutual inductance between an inner windin on one quadrant and an outer winding on an adjacent quadrant is midway between the mutual inductance of the two inner windings and the mutual inductance of the two outer windings of said adjacent quadrants.

In witness whereof, I hereunto subscribe my name this 20th day of June, A. D. 1916.

WILLIAM, FONDILLER.

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