US1324152A - Railway signaling - Google Patents

Description

I. S. HULLIDAY.

RAILWAY SIGNALING. APPLICATION FILED DEC. 15. 1917.

1,324, 152, Patented Dec. 9,19I9.

SHEETS-SHEET 1.

N 4 A 7701mm.

J. S. HOLLIDAY.

RAILWAY SIGNALING.

APPLICATION FILED DEC-15,1917.

L3QJ5QQ Patented Dec. 9,1919.

2 SHEETS-SHEET 2.

UNITED STATES PATENT m JOHN S. HOLLIDAY, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OFSWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILWAY SIGNALING.

Specification of Letters Patent.

Patented Dec. 9, 11919.

Application filed December 15, 1917. Serial No. 207,252.

To all whom it may concern;

Be it known that I, JOHN S. HoLLIDAY, a

citizen of the United States, residing at Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Railway Signaling, of which the following is a specification. v

My invention relates to railway signal ing, and particularly 'to signaling of the type embodying alternating current track circuits and alternating current track relays. More specifically, my inventionrelates to systems of this character wherein the relay comprises two windings one of which receives energy from the track circuit and the other directly from thesource independently of the track circuit.

One object of my invention is the provision, in systems of this character, of means for improving the phase relation between the currents in the two relay windings, and for at the same time reducing to the lowest possible degree the amount of current which must be supplied to the track winding of the relay through the track rails.

I will describe one form of signaling system embodying my invention, and will then point out the novel features thereof in claims. I

' In the accompanying drawings, Figure 1 is a diagrammatic view showing one form of signaling system embodying my invention. Fig. 2 is a vector diagram showing the conditions which would obtain in the system shown in Fig. 1 if the condenser C usual, the track rails of the section, a source of alternating signaling current for supplying energy to the rails adjacent one end of the section and a track relay having a winding receiving energy from the ralls ad] acent the other end of the section. The source of signaling current, as here shown, is a generator G of alternating current which is connected with transmission mains P extending along the railway. Current from this source is supplied to the track railsadjacent one end of the section through the medium of a transformer A, whose primary is connected with said transmission mains P and whose secondary is connected with the track rails, a reactance 3 being inserted bet-Ween one rail and the transformer secondary as shown.

The relay, which is designated R, comprises a vane 4 of electro-conduct-ive nonmagnetizable material, such as aluminum, fixed to a shaft 5 which is j ournaled so that the vane may move in air gaps 6 and 7 a in two magnetizable cores 6 and 7. Core 7 is provided with a winding 9 which is connected with the track rails T, and so I will term this winding the track winding of the relay. Core 6 is provided with a winding 8, 8- which is connected with a secondary winding 14 of a transformer A, the primary of which is connected with the transmission mains P. Consequently, this winding 8, 8, which I will term the line winding of the relay, receives energy from the source G independently of the track rails or through the medium of means not including the track rails. The cores 6 and 7 are so located and disposed that the fluxes in the core 6 pass through the vane 4 substantially on opposite sides of the flux in core 7; that is, the air gap 7* is substantially between the two gaps 6*, 6 The principle of operation of a relay of this type is well understood by those versed in the art, hence for the purposes of this specification it is suflicient to say that when the windings 8 and 9 are supplied with alternating currents of the same frequency and of the proper relative phases a torque is exerted on the vane tendingto swin it in counter-clockwise direction to drawing. When winding 9 is denergized, however, the torque disappears and the vane swings downwardly in clockwise direction due to the force of gravity. The shaft 5 on which the vane is mounted controls a contact 12 in such manner that this contact is closed when both windings of the relay are properlyenergized, but is opened when the vane swings downwardly due to denergizathe position in which it is shown in the tion of the track winding 9. It is understood that a car or train in track section CD shuntsall or nearly all of the current from winding 9 so that this winding then becomes denergized. I

The core 7 is provided with a secondary winding 10 to which a condenser 11 is connected. The function of this condenser will be explained hereinafter.

The track section C-D is provided with a signal S for governing traflic therethrough, which signal is controlled by contact 12 of relay R in the usual and well-known manner. 7

The supply of current for this signal is obtained from a secondary winding 13 on transformer A.

When the propulsion energy for the railway is electricity and both track rails are included in the circuit for the propulsion current, means must be provided for conducting such current around the insulated joints 2. plished by the usual inductive bonds, each comprising a magnetizable core 17, and a winding thereon the terminals of which are connected with the two track rails; each winding has a tap at its middle point which is connected by a conductor 16 with the corresponding tap on the adjacent bond of theadjacent track section. As is well understood, these bonds conduct the propulsion current freely from section to section, but maintain the desired difference of potential of the signaling current across the rails of each section.

As is well understood, a relay R of the type herein shown operates most efiiciently when the currents in the two windings 8 and 9 difl'er by 90 in phase, and will not operate at all when these currents are of the same phase. Owing, however, to the low power factors of these windings (about 0.3 for each), it is impossible to secure much phase displacement, even with the use of the reactance 3. The function of the condenser 11 is to enable a considerable phase displacement to be secured. In order to explain how the condenser accomplishes this result, I will first show the conditions which would obtain without the condenser, and then the conditions which obtain when the condenser is employed.

Referring now to Fig. 2, which shows the conditions without the condenser, the line- O-E represents the voltage applied to the track winding 9 of the relay, and the line OI represents the position of the current in this same winding. This current lags behind the applied voltage by a wide angle, because the power factor of the winding is very low-about 0.3. Assuming now that the power factor of the reactance 3 is 0.1, which is about as low as can be obtained, the voltage drop across this reactance is at 0.1 power factor to the current OI and so As here shown, this is accom-' may be represented by the line EX. The total voltage drop across the-reactance 3 and the relay winding 9 is, then, represented by line OX. It is apparent at once that the current O-l does not'lag much farther behind O-X than it does behind O E. Now, the voltage applied to the line winding 8 of the relay is nearly in phase with the line O-X, and since the power factor of this winding is also about 0.3, the cnrrent in the line winding will be in about the position indicated by line OI It is ob vious, then, that thecurrents vin the two windings 8 and 9 are nearly in phase, so that these windings cause very little torque to be exerted on the vane 4.

This difficulty is avoided by the use ofthe multiple with winding 8. The chief reason for using the transformer arrangement shown in Fig. 1 is to step up the volta e applied to the condenser and so ena le a smaller condenser to be used than would be the case werethis condenser connected directly across the winding 9. By placing the secondary 10 directly on the relay core 7,1 avoid the cost of a separate transformer and also the losses due to the exciting current for a separate transformer.

Referring now to Fig. 3, the line O-lE represents the voltage applied to the track winding 9, and the line O-I the current in this winding, exactly as in Fig. 2. The

current taken by the condenser in Fig. 4 is nearly in leading quadrature to the voltage ()E, and so is represented by line O'-'C. The current in the track circuit is the vector sum of O-I and O-C, and may be made of substantially unitypower factor so that it may be represented by line O-S, that is, in phasewith O-E. Although the current in the track circuit is in the position O-S it must be borne in mind that the magnetic -flux in the core 7 is substantially in phase ponent of the current taken by this wind- O-X. Since the voltage applied to the line winding 8 isjsubstantially in phase with the voltage at the secondary of transformer A, it follows that this voltage on the line the magnetic flux in core 6. The phase displacement between the fluxes in the two cores is then represented by angle I O'I hence considerable torque will be exerted on the vane 4. The efliciency of the relay is, consequently, good.

It is a wellknown fact that the transmission of current through track circuits is veryuneconomical, and it 1s very desirable, therefore, to reduce the amount of current which must be applied to the track'winding of a relay to the lowest possible value. By referring to Fig. 2 it is evident that when the condenser 11 is not used, the current which must be transmitted through the rails is considerable, the value being represented by the line O'I but by referring to Fig. 3 it will be seen that when the condenser is used the current which must be transmitted through the track rails is OS, which may be made less than one-half of the current 0-1 Theuse of the condenser, therefore, materially reduces the volt-amperes which must be transmitted through the track rails.

So far as the track winding 9 alone ofthe relay is concerned, what the condenser ac tually does is to supply the wattless coming. That is, the condenser is of such size that the circuit of thesecondary 10 is resonant to current of the signaling frequency.

When the relay is used on an electric rail-- way employingv bonds in the trackway as shown in Fig. 1, the condenser 11 may be ing my invention, it is understood that vamade larger than is necessary to supply the wattless component of the-current for track winding 9, and the extra current taken by the condenser may be made to neutralize the wattless component of the current ,for the.

bond at the relay end of the track section. Although I have shown and described only one form of signaling system embodyrious chan es and modifications may be made thereln within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1.- A railway signaling system comprising, in combination with the rails of a track section, a source of alternatin signaling current connected with said rails, a relay having two magnetizable cores, a'winding on one core receiving energy from said track ralls, "a wlndlng on the other core receiving energy from said source but not through said rails, a secondary winding on said first-mentioned core, and a condenser connected with said secondary winding.

2. A railway signaling system comprising, in combination with the rails of a track section, a source of alternating signaling current connected with said rails, a relay having a trackwinding which receives energy from said track rails and a line winding which receives energy from said source but not through said rails, and means as sociated with the said track winding for increasing the power-factor of the current which flows therein.

3. A railway signaling system comprising, in combination with the rails of a track section, a source of alternating signaling current connected with'said rails, a re lay having a track winding which receives energy from said track rails and a line.

winding which receives energy from said source but not through said ralls, and a coning, in combination with the trails of a track section, a source of alternating signaling current connected with said rails, a relay having a trackwinding which receives en ergy from said track rails and a line winding which receives energy from said source but not through said rails, and means associated with said track winding which takes a wattless current leading the voltage applied to said winding.

5. A railway signaling system comprising, in combination with thetrack rails of a track section, asource of alternating signaling current, a transformer whose primary is connected with said source and whose secondary is connected with said' rails, a reactance included in the connection between one 'of the rails and the transformer secondary, a relay having a track winding receiving energy from said rails and a line winding receiving energy from said source but not throu h said rails, and a condenser associated w1th said track winding and taking a wattless current leading the voltage applied to said track winding.

6. A railway signaling system comprising, in combination with the track rails of a track section, a source of alternating signaling current, a transformer whose primary is connected with said source and whose secondary is connected with said rails, a reactance included in the connection between one of the rails and the transformer secondary, a relay having a track winding be substantially in phase with the voltage across said track winding.

7. A railway signaling system comprising, incombination with the track rails of a track section, a source of alternating signaling current, a transformer whose primary. is connected with saidsource and whose secondary is connected with said rails, a reactance included in the connection between one of the rails and the transformer secondary for causing the current in the rails to lag behind the voltage across said secondary, a relay having a track winding receiving energy from said rails and a line winding receiving energy from said source but not through said rails, the power factors of said windings being low, and a condenser associated with said track winding for causing the current in the track rails to be substantially in phase with the voltage across said rails, whereby the fluxes pro- 1 sec;

duced by the currents in said two relay windings are displaced by a considerable angle.

8. A railway signaling system comprising, in combination with the railsof a track section, a source of alternating signaling current connected with said rails, a relay having a track Winding which receives en ergy from said track rails and a line winding which receives energy from said source but not through said rails, and means associated with one of said windings which takes a wattless current leading the voltage applied to such winding.

In testimony whereof I afiix my signature in presence of two witnesses.

JOHN S. HOLLIDAY.

Witnesses A. HERMAN WEGNER, FAY GLASGOW.

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