US1224139A - Distributing system. - Google Patents

Description

A. CHERNYSHOFF.

DISTRIBUTING SYSTEM. APPLICATION FILED APRfI, 1915. RENEWED SEPT-29, 191s.

Patented May 1, 1917.

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ALEXANDER CHEBNYSHOFF, OF SXVISSVALE, ?EI\T1\TSYLVANIA, ASSIGNOR T0 WEST- INGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN- SYLVANIA.

DISTRIBUTING SYSTEHE.

Application filed April 1, 1915, Serial No. 18,513.

In order to minimize the inductive interference upon intelligence transmission circuits, such as telegraph, telephone systems, etc., which are disposed adjacent to rallway systems, it has been proposed to confine the return flow of trolley currents to the track rails, in preference to ground or earth return in order that the inductive disturbances imposed upon the transmission circuits, may be substantially neutralized. Inasmuch as the rails comprising the tracks of railway systems are more or less in electrical contact with the earth, the latter being equivalent to a conductor of very low impedance, considerable portions of the return trolley currents will ordinarily flow in the earth. As a result, the inductive disturbances set up by the flow of power currents over the trolleys are given free play, because the return currents flowing through the earth are so remotely removed from the trolley currents, that the inductive effects arising from the trolley and earth currents do not neutralize one another to any appreciable extent. However, it is possible to confine the return flow of the trolley currents to the track rails or in regions of the earth which are closely adjacent to the track rails. In this manner, the zones of disturbing inductive influences arising from the flow of the return currents are restricted, and such currents are confined to limited regions close to the trolley conductors, whereby the former may be used effectively to minimize or neutralize the disturbances occasioned by the trolley cur rents.

One method of confining the return trolley currents to track rails is disclosed in the pat ent application of Charles F. Scott, Serial No. 170, filed January 2, 1915, and assigned Specification of Letters Patent.

Renewed September 29, 1916.

Patented May 1, 1917.

Serial No. 122,931.

to the Westinghouse Electric and Mannfacturing Company. In the above-men tioned patent application, series transformers are utilized to inductively interlink the trolley conductors and the rail circuits, the series transformer being disposed in circuit at intervals, the primary windings being connected in series with the trolley conductor, and the secondary windings being connected across insulating joints correspondingly placed in the track circuit. V-Jhen currents flow through the primary windings of the transformers, the electromotire forces induced in the secondary windlngs serve to transfer the impedance drop from the rail circuit to the trolley conductor. In other words,the electromotive forcesimposed at intervals in the rail circuit serve to compensate for the impedance drop in the track circuit. Consequently, the return trolley currents are confined almost entirely to the track circuit.

It is well known that the impedance drop in a railway system varies as the trolley currents are conducted to portions more or less remote from the source of current supply. For instance, the impedance drop to the end of the circuit of a railway system is very much greater than the impedance drop near the source of current supply, because of the greater length of trolley conductor and rail circuit involved in the former instance. Moreover, when a railway circuit is subiected to short circuits occurring near the source of current supply, the values of the short circurt currents are very much greater than is the case when short circuits occur at points on the system more remote from the source of current supply. lVhen the aforementioned series transformers are inserted in the railway circuits to inductively interlink the trolley and the track conductors. the electromotive forces impressed by the secondary windings across the insulating joints inserted in the rail conductors are proportional to the currents flowing through the primary windings of the transformers. Consequently, when abnormally high currents flow through the primary windings, the electromotive forces induced in the secondary windings may be sufiiciently high to disrupt the aforementioned insulating joints.

An object of my invention, therefore, is to provide means whereby the electromotive forces impressed upon the insulating joints in a track conductor may be limited, at all times, to safe values.

For a better understanding of the nature and scope of my invention, reference may be had to the following description and the accompanying drawing in which Figure 1 is a diagrammatic view of a railway system showing an embodiment of my invention,

and Figs. 2 and 3 are diagrammatic views showing methods of connecting the secondary windings of the series transformers to the rail circuit of a railway system.

Referring to Fig. 1, a source of current supply 1, shown as a single phase alternator, is connected through one of its terminals to a trolley conductor 2, and through another of its terminals to a rail 3 of a track. A plurality of series transformers 4: are inserted at intervals along the railway system, as shown, primary windings 5 being connected in series circuit relationship with the trolley conductor 2, and secondary windings 6 being connected to the rail 3 across insulating joints 7. An intelligence transmission conductor 8, shown as a telephone conductor, is disposed adjacent to the trolley conductor 2 and the track 3, and is, there fore, under the inductive influences arising from the currents flowing over the afore mentioned railway circuit. Because of the proximity of the intelligence transmission circuit 8, it is necessary to employ the series transformers 4 in order to substantially minimize the inductive disturbances impressed thereupon, as mentioned above. Under normal conditions, when a moving vehicle 9 receives power from the trolley conductor 2, the return trolley currents are confined to the rail circuit by reason of the electromotive forces impressed across the insulating joints 7 by the secondary windings 6 of the series transformer 4:.

It is essential that the insulating joints 7 at all times be kept intact in order that the signaling systems employed in connection with the railway system may operate satisfactorily and with reliability. Again, the insulating joints 7 can be subjected to comparatively small voltages only by reason of their limited size, the material from which they are made and for other considerations.

It will be noted that the series transfornr ers adjacent to the source of current supply 1 are provided with secondary windings which are composed of a. plurality of separate coil sections 10. For illustration, I have shown a series transformer 11 as being provided with a secondary winding composed of three separate coil sections, and a series transformer 12 as being provided with a secondary winding composed of two sepinsulated rail sections which will correspond.

to the separate coil sections of the secondary windings of the transformers 4. For instance, three insulating joints 1& are arranged in a group and disposed adjacent to the series transformer 11, each secondary coil section thereof being connected across one of the insulating joints It. In a simi lar manner, the secondary coil sections of the other transformers are connected across the insulating joints comprising groups disposed adjacent to their respective transform ers. my invention in no sense contemplates the use of any definite number of separate coll sections for the secondary windings of the series transformers.

\Vhen a short circuit occurs on the railway system in proxii'nity to the series transformer 11, extremely high currents will flow through the primary windings 5 thereof be cause of the very low impedance of this portion of the railway circuit. In other words, the currents flowing from the source of supply 1 will be extremely high because of the proximity of the point at which the short circuit occurs to the source of current supply 1 and the low impedance of the intervening transmission circuit. By reason of separating the secondary winding into a plurality of coil sections. the electromotive force induced in each coil section will be of a sufliciently small value to insure safety to the insulating joints 1st.

V hen a short circuit occurs upon the railway system in proximity to the transformer 12, the current flowing through the primary winding of this transformer will be somewhat lessened because of the greater impedance of the circuit intervening between the short circuit and the source of current supply 1. In consequence thereof, the voltage induced in the secondary winding of the transformer 12 may be safely confined to two separate coil sections which are connected across insulating joints 15 disposed adjacently thereto. In a like manner, a short circuit occurring at a point in proximity to the transformer 13 will cause currents of relatively low value to flow through the primary winding of the transformer 13 because of the high impedance of the transmission circuit intervening between the transformer 18 and the source of current supply 1. In this instance, the electromotive force induced in the secondary winding of the transformer 13 may be of a sufiiciently low value as to be confined to a single coil However, it will be understood that section, which is connected across an insulating joint 16 that is disposed in the track circuit adjacent thereto.

In Figs. 2 and 3, I have illustrated means by which it may be convenient to connect the secondary windings of the series transformer 4 to the rails 3 comprising the track circuit. In Fig. 2, the terminals 1? of a secondary winding 18 are connected to metallic bonds 19 which electrically connect the two rails comprising the track, and which are disposed on each side of the insulating joints 7 In Fig. 8, for the conducting bonds 19 of Fig. 2 are substituted inductive bonds 20 which comprise coils 21 that embrace magnetizable cores 22, the terminals 17 being connected to mid points 22 on the coil windings 21.

Of course it will be understood that in actual installations, the spacing and dispositioning of the transformers and the insulating joints in the track circuit are dependent upon the signaling systems employed, the length of the railway circuit, the character of the intelligence circuit 8, etc. Moreover, it may be advisable to provide the secondary windings of the transformers with adjustable taps as shown in the drawing, in order to compensate for any irregularities that may exist in the relative positions of the intelligence transmission circuit and the railway system. It will also be apparent that the transformers employed may have various ratios between the turns of the primary and secondary windings for the purpose of controlling locally the amount of earth currents and the resulting induction in adjacent intelligence transmission circuits when the latter vary in their position with respect to the railway system.

While I have shown and described in detail an embodiment'of my invention, it will be understood by those skilled in the art that many modifications may be made without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In an electrical system of distribution, the combination with a source of current supply, a conductor connected to one terminal thereof, and a second conductor which comprises a series of insulated conducting sections connected to the other terminal, of a plurality of transformers inserted at spaced intervals to inductively interlink said two conductors, the secondary windings of the transformers adjacent to said source of current supply being composed of a greater number of separate coil sections than those of the transformers more remote from said source of current supply, each secondary coil section being connected to a different pair of insulated conducting sections of said second conductor.

2. In an electrical system of distribution,

the combination with a source of current supply, a conductor connected to one terminal thereof, and a second conductor which comprises series of insulated conducting sections connected to the other terminal, of

plurality of transformers inserted at spaced intervals to inductively interlink said two conductors, the secondary windings of the transformers adjacent to said source of current supply being composed of a plurality of separate coil sections each of which is connected to a difiierent pair of insulated conducting sections of said second conductor, and the secondary windings of those transformers more remote from said source of current supply being composed of single coil sections which are connected to other pairs of insulated conducting sections of said second conductor.

3. In an electrical system of distribution, the combination with a source of current supply, a conductor connected to one terminal thereof, and a second conductor connected to the other terminal, said second conductor comprising a series of insulated conducting sections of unequal lengths, the shorter sections being placed adjacent to the source of current supply, of a plurality of transform ers inserted in the circuit at spaced intervals to inductively interlink said two conductors, the secondary windings of those transformers adjacent to said source of cur rent supply comprising a plurality of separate coil sections which are connected to the shorter conducting sections of said second conductor.

4. A railway system comprising a source of current supply, a trolley conductor connected thereto, a track consisting of a plurality of rail sections comprising a return conductor for the trolley currents, said rail sections being insulated from one another by means of insulating joints, and a plurality of transformers inductively interlinking the trolley conductor and the track, the secondary windings of those transformers adjacent to said source of current supply being composed of a plurality of separate coil sections each of which is connected to a difierent pair of rail sections in order to limit the potentials impressed across the track insulating joints to safe values.

5. A railway system comprising a source of current supply, a trolley conductor connected thereto, a track consisting of a plurality of rail sections comprising a return conductor for the trolley currents, said rail sections being insulated from one another by means of insulating joints, and a plurality of transformers inductively interlinking the trolley conductor and the track, the secondary windings of those transformers more remote from the source of current supply comprising fewer separate coil sections than the secondary windings of those transformers adjacent to said source of current supply, the coil sections of the secondary windings being connected across the insulating joints in the track in order to limit the potentials impressed thereupon to safe values when currents of high value flow through the primary windings of the transformers.

6. A railway system comprising a source of current supply, a trolley conductor connected thereto, a track conductor, insulating joints inserted at unequal intervals in the track conductor, said insulating oints being more frequently placed in the portions of the track adjacent to the source of current supply than in the portions thereof more remote from the said source of current supply, and a plurality of spaced transformers to inductively interlink the trolley conductor and the track conductor, the secondary windings of the transformers adjacent to said source of current supply being composed of a plurality of separate coil sections which are connected across the insulating joints adjacent to said source of current supply, and the secondary windings of those transinsulating joints being arranged in groups,

the groups adjacent to said source of current supply comprising a greater number of insulating joints than the groups more remote therefrom, and a plurality of spaced transformers to inductively interlink the trolley conductor and the track conductor, the secondary windings of the transformers being composed of separate coil sections which are connected across the insulating joints comprising the aforementioned groups.

In testimony whereof, I have hereunto subscribed my name this 27th day of March, 1915. I

ALEXANDER CHERNYSHO FIE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0.

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