US995588A - Electric-wave transmission. - Google Patents

Description

J; H. GUNTZ.

1 ELEGTRIG WAVE TRANSMISSION.

APPLICATION FILED MAR 11 1905.

995,588. w Patented June 20, 1911.

JOHN H. CUNTZ, or HoBoKEN, NEW JERSEY.

ELECTRIC-WAVE TRANSMISSION.

Specification of Letters Patent. Patented June 20, 1911 Application filed March 11, 1905. Serial No. 249,543.

To all whom it may concern:

Be it known that I, JOHN H. CUNTZ, a citizen of the United Statesyresiding at Hoboken, Hudson county, State of New Jersey, have invented certain new and useful Improvements in Electric-Wave Transmission, of which the following is a Specification.

This invention relatesto systems of elec tric circuits in which inductance is distributed in'such a manner as to suitably counteract the effect of the distributed capacity. V

This invention relates more particularly to complete metallic circuits, having outgoing and returning conductors, and the inductance is produced or increased by disposing the conductors in helical form, with or without a core, and winding the outgoing and returning conductors in opposite senses, so that their inductive effect will be multiplied.

When varying electric currents are transmitted over long circuits they are attenuated in a manner which is indicated by the formula c or that is, at any distance m from the source of current, its strength will have decreased from unity to e or in that proportion, where c is the base of the Napierian system of logarithms, m is the distance, in any convenient units of length, and p, which is termed the attenuation constant, is equal to (R -l-L w )%-Lw} different frequencies, these component waves will be attenuated in different degrees, and

- the resulting current or combined wave will be not only attenuated but distorted. This is notably the case in telephonic transmission. 1

When the inductance of acircuit, L, is

practically zero, the above formula reduces to When, however, the inductance, L, is

made large compared with the resistance, R, the expression for 72 becomes whichis independent of the frequency, so that currents made up of waves of different frequencies will have their components attenuated in the same degree and will not suffer distortion. And also, by increasing L, the attenuation can be minimized.

I have invented a method for increasing the inductance of a circuit without proportionately increasing its resistance and electrostatic capacity, and this I accomplish by winding my conductor in a helical form, and, where desirable, disposing it about a core, which may be of magnetic'or nonmagnetic material. The inductance of the circuitcan be calculated by the formula complete metallic circuit with telephone transmitting and receiving instruments. The-outgoing and returning conductors are Wound 1n opposlte directions about a core or support. The primary and secondary windings of the induction coil of the microphone transmitter are shown wound on the core of the line circuit, but I do not confine myself to this special construction, and, in general, Fig. 1 is intended to be diagrammatic and the transmitting and receiving apparatus may be any telephone, telegraphic or other suitable apparatus. Fig. 2 shows a portion of a complete metallic circuit, with a core composed of finely stranded material, straight or twisted, and with outgoing and return conductors wound about the core in opposite senses. Fig. 3 shows a portion of a cable with a complete metallic circuit. The outgoing and return legs of the circuit consist each of a plurality of conductors, wound in opposite senses about a core of a finely stranded material. The two legs of the circuit are in difi'ereut layers, with insnlation between, and on the outside is more insulation and a protective sheathing and armtuiug. Figs. a and P show forms oi the core in which the individual wires break joints.

In Fig. 1 A and 11' represent the two legs of a circuit, wound in opposite sensesabout the core, or support, B. a repre- I do not wish to confine myself to these, but

my transmitting and my receiving apparatus may be any suitable telephone, telegraph or other apparatus.

In Fig. 2, A and A represent the conductors forming the two sides Of a circuit, wound in opposite senses about the core B which is composed of finely stranded material. 0 represents insulation about each conductor.

In Fig. 3, A and A represent respectively the plurality of conductors forming thetwo sides of a circuit, wound in opposite senses about a core 13 consisting of finely stranded material. 0 represents insulation between the outgoing and return conductors; C represents insulation outside the outer layer of conductors; 0 represents sheathing or jute or other protective material; and D represents armor or similar material for protecting the cable.

To show the benefits secured by my invention, I will take as an example an underground telephone or telegraph circuit between two points 250 miles apart. I will assume a circuit composed of conductors each of which hasa resistance of ll-ohms per mile and the mutual electrostatic capacity between which is .08 microfarads per mile. When constructed in the usual way, with the outgoing and return conductors twisted up together in the same direction so as to avoid inductive effects, such a circuit will have negligible inductance, and the attenuation constant p will equal For a wave frequency of 1000, (a will equal 0280, approximately. C, in the present case, is .08 microfarads per mile, and R is the sum of the resistances of both sidesof the circuit, or 22-ohms per mile. Substituting these avalues in the above forceases mula, we obtain a value for p equal to .074: per mile, approximately. Currents having a frequency oi 1000 per second will therefore be attenuated, on such a circuit, in the proportion of L WW--L i G 107,000,000 10 'That is to say, less than 1 Tobi (W approximately.)

, iron wires, having a total cross-sectional area of 0.125 square centimeter and whose permeability at the magnetizations employed will be about 180. 1 wind my conductors helically, with a pitch of 2 centimeters, so that taking both sides of the circuit together, there will be one turn per centimeter. 'l he value of the inductance per mile of this line will therefore be, by the formula already given for L, 0.04:5 henry. By winding the conductors in the manner described, I have increased their average length, and therefore their resistance, by about 50 per cent., and the capacity will be increased in no greater degree, if as great a one. The mutual capacity of this circuit as now constructed will therefore not be more than 0.12 microfarad per mile, and the sum of the resistances of both sides of the circuit 33-ohms per mile. Substituting all these values in the formula may? z L which is the attenuation constant per mile.

The attenuation for the Whole line, 250 miles long, will therefore be we obtain of the current will arrive at the receiving microfarads per nautical mile. .W'hen constructed in the usual non-inductive manner,,

' the inductance of such a circuit will be practically zero. The attenuation constant, for a frequency of 1000, will therefore, by the formula per mile, and the attenuation e will equal e (100X.o97) e 9.7 1

approximately, for the 100 mile cable. If

this cable is constructed according to my 4 method, using a core of fine iron wires with a permeability of 180 and a cross-sectional area of 0.25 square centimeter, and winding the conductors with a helical pitch of 2 centimeters, the inductance will be 0.10 28 henry per nautical mi-le. I can use a single conductor for each side of the circuit, or a plurality of conductors, and their cross-section may be circular, rectangular, and any other shape. Assuming that I use a single conductor, of circular section, the length of circuit will be about doubled by winding both sides in the manner indicated and the resistance and capacity will be talzen as increased in the same ratio. The value for the attenuation constant per mile, will therefore be R c n 0.6 10- n'm/ 0.1048

The attenuation for the 100-mile cable will then be e (10o .024) e 2 :4 F E,

approximately, and Wavesv of all frequencies will be attenuated in the same degree.

As a third example, let us take another submarine cable 100 miles in length, but

having smaller conductors with. a, resistance,

for each le of the circuit, of 15-ohms pernautical mi e,*and a mutual capacity of 0.1

microfarad pernautical mile. The attenua-, tlon, when constructed in the usual non-m ductive manner, will be the same as before, or

for the 100-mile cable. When constructed according to my method, with the same core pitch, the length of the conductors, owing to their smaller section, willbe increased only about per cent. Taking the resistance and the capacity as increased in the same ratio, the attenuation constant per mile and the attenuation for the 100-mile cable will be by increasing the number of turns, of the conductor, by increasing the cross-sectional area of the core, by using. core material of higher permeability, or by increasing the' permeability in other ways. J

'The electric circuits of the present application may be constructed with or without a core, and the latter, if used, may be of magnetic or non-magnetic material. When composed of conducting material, the core should be finely divided in order to'minimize eddy currents, and if of magnetic ma terial'it should have the qualities of low liysteresis and high permeability.

When used for telegraph and telephone purposes, .the currents are so small and the turns of the conductor are so few, that very feeble magnetic fields are created, and the cyclic changes of magnetism, whether occurring by, themselves, or superposed upon stronger steady currents, are so small as to reduce hysteresis to a minimum, the hysteresis curve becoming practically a straight line, inclosing 110 area.

Longitudinally, the core may be constructed in separate sections in order to diminish malgnetic retentivity and electrostatic effects; but, in order to preserve mechanical continuity and tensile strength, the core, if divided longitudinally, may have its individual wires break joints as'shown in Figsr and 4 y In my circuits, as already stated, I may use conductors havin cross-sections of any suitable shape. Di erent shapes possess various advantages. For the same sectional .area, single circular conductors have the smallest surface, and will have a minimum area of contact on their insulation with each other, and so will have a small mutual capac'ity. On the other hand, circuits composed ofa plurality of small circular conductors, or with flat, ribbon-shaped conductors will have the advantage of compactness,

.will require less outside insulation and will make a smaller and stronger cable. An advantage of increased. surface of the conductors is that for rapidlyalternating currents, which are mainly confined to the surface layers of conductors, conductors With relatively large surface offer less resistance, in proportion to the total cross-section, than conductors with less surface.

Any suitable insulation may be used, it being desirable, of course,to use that which will hate the lowest specific inductive capacity compatible with other requirements. For instance, particularly on land lines, I may use paper insulation with as much air space as possible, and when a plurality of Wires is employed, the two sides of the circuit being wound in layers, 1 may use a perforated or continuous insulating strip between the layers, made of paper or other material, In some cases I may use a strip or a eylinder of paper or of some other insulating material as a core or support to Wind my conductors upon. A plurality of circuits, such as have been described herein, may be made up into one cable.

The electric circuits herein described may be used for telephone, telegraph, power transmission and all other purposes, and I do not limit myself to any special use, nor to the precise apparatus and construction shown herein, but

What I claim and desire to secure by United States Letters Patent is as follows:

1. In a line for the transmission of varying electric currents, a paramagnetic core, and outgoing and returning continuous conductors disposed helically in opposite senses about said core, so as to counteract suitably the electrostatic capacity of the line.

ceases 2. In an electric cable, a core of parama netic material, a conductor wound helically about said core and insulated therefrom, a second conductor Wound in the opposite direetion about said core and insulated therefrom and from the first-named conductor, so as to counteract suitably the electrostatic capacity of the cable.

An electric circuit in which the outgoing and returning parts of the circuit consist of continuous conductors disposed helically in opposite senses about a supporting non-current carrying core, said core conslsting of stranded paramagnetic material, so

as to counteract suitably the electrostatic capacity of the circuit.

4. In an electric circuit, outgoing and returning conductin Wires substantially continuously wound, in opposite senses, to create inductance suflicient in amount to suitably counteract the capacity of the circuit, and a magnetizable core for said Wires ex-- tending substantially throughout the length thereof, the said core being metallically dis-- continuous.

5. In a system of telephone transmission, a complete metallic circuit, a magnetic core extending substantially throughout thecircult, and windings of the induction coil or": the microphone transmitting apparatus disposed about said core.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing Witnesses, this 10th day of lfviarch, 1905.

JOHN H. GUNTZ, Witnesses WM. 0. Genre,

HERMANN F. CUNTZ.

' a Copies of this patent may be obtained for five cents each, by addressing the fiommissloncr o1 Pateml a Washington, D. 93.

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