US1966418A - Control system for track switches - Google Patents

Description

y 0, 1934- w. H. REICHARD 1,966,418

CONTROL SYSTEM FOR TRACK SWITCHES Filed June 30, 1930 INVENTOR MMM M ATTORNEY Patented July 10, 1934 1,966,418 CONTROL SYSTEM i on TRACK svvrrcnns Wade H. Reichard, Rochester, N. Y., 'eneral Railway Signal Company,

N. Y. Application June 30,

assignor to Rochester,

1930, serial No. 464,903

4; Claims. (01. 246-1 8 This invention relates to systems employed for the control of railway track switches, and-more particularly pertains to an alternating current system of this type having inherent characteristilesa protecting it from crosses, grounds and the One object of this invention, is to provide a system having the above mentioned cross protection. characteristics which is entirely operable upon alternating current' Other objects, purposes and characteristic fea tures of the present invention will be in. part obvious from ,the accompanying drawing, and in part pointed out as the description of the invention progresses. Y

In describing the invention in detail, reference will be made to the accompanying drawing, in which the apparatus and circuit arrangement employed for the control of a railway track switch in accordance with the present invention has been shown in a diagrammatic manner.

With reference to the accompanying drawing, a main track has been illustrated by the rails 5, and a diverging route has been illustrated by the rails 6, this diverging route being connected to themain track by a track switch TS.

The track switch TS is operated to either a normal locked position, as shown, or to a reverse locked position by a suitable switch machine SM, such for example, as shown in the patent to W. K. Howe, Patent No l 166,903, dated September 4, 1923, with an alternating current motor and control means adapted thereto, as herein described in accordance with the present invention.

Besides the operating mechanism of the switch machine as disclosed in the above mentioned patentjthis switch machine SM includes an alternating current induction motor M of the two phase winding type having a rotor or armature A and two phase windings PH -and EH Asso- 'ciated with the motor Mis a condenserC of suitable capacity to provide the desirable relative phase displacement between the currents in the respective phase windings PH and PH when'the motor M is receiving operating current.

' The switch machine S M also includes a group of pole changer contacts PC and an electromagnetic'brake BEL The pole changer contacts PC include movable contacts "7, 8 and '9. The movable contact "'7 makes contact'between a certain pair'o'f fixed contacts when ina normal extreme position, "and a certain other pair of fixed contacts'when in a reverse extreme position. Thismovable contact '7' is mechanically operated by the switch machine to its respective positions in correspondence with the position'of the track switch TSat the'end of each operation; "or is electrically operated to an opposite" position during the operation" of the switch'machineto'thereby reverse the switch machine in mid-stroke. This electric operation of the movable contact 7 during the operation of the switch'machineis provided for by a'pole changer coil. 12 for operating the' movable contact to a normal extreme position and a pole changer coil 14 for operating the movable contact to a reverse extreme position.

jThe movable contacts 8 and 9 are capable of assuming normal positions, intermediate positions H and reverse p'os'itionsfThese contacts are operated' toint'ermediate positions'as' soon as the track switch TS is unlocked by the switch ma chine SM; and are operated to extreme positions in correspondence with the track switch TS as soon as the track switch is again locked. How- 7 ever, these contactswhen operated to extreme positions 'are preferably caused 'to be actuated slightly prior to the movement of the movable contact 7 for reasons hereinafter pointed out.

The brake BR, may be of any suitable type, such as shown for example, in the patent to W. K.

Howe, Patent No. 1,852,574 dated April 5, 1932,

which is'ope'rably released by the operating current, as it is connected 'in series with the two phase windings-PH and PH When the brake is released, the armature A can then operate the switch'machine. a

A control relay CR is provided at the track switch TS to govern the operation of the switch machine SM. This control'relay CE is of the alternating current induction type, such for example as shown in the patent to W. K. 'Howe, Patent No. 1,710,664, dated April 23, 1929, having a rotor CR and'twophase windings 15 and 16. The rotor CR operates the contacts 18 and19 to either of two extreme positions depending upon the energization of the two phase windings 15 and" 16 as hereinafter explained. The windings 15 and 16 are constructed alike and therefore have substantially the same electrical characteristics. They are mounted on a magnetic structure such as usedin a polyphase induction type relay, as shown in the above mentioned Patent 1,710,664. I 1 T Associated with the relay CR are two asymmetric units R 'and R which are connected in series combinations with their respective'phase windings l5 and 16'. These two asymmetric'units are "oppositely poled in respect to each other. These series combinations are'connected in 111111- iple as illustrated and are controlled ove'r'the line circuit "extending to the tower in amanner hereinafter described. I "The" relayCR' may, in some cases, be provided with atogglearrange'ment or other means for holding its contacts 18 and 19 in their last opercontrol lever L is provided, which is slidable back and forth to operate contact blocks 20 and. 21 to either' of two extreme positions. When these movable contact blocks 20 and 21 are in one ex.-

treme position, they make contact between certain vide both at the tower and at the switch location,

which source is specifically illustrated as a suitable transmision line extending between the two points. In the tower a local transformer T. is

provided to supply alternating current energy from the transmission line at that point through two. fuses 2 and 23, while at the track switch a local transformer T is provided to supply electrical energy from the transmission line. at that point through two fuses 24 and 25.

The asymmetric units R R and R are preferably of either the electrolytic, crystal or copper oxide type in which the direction of rectification is inherent in accordance with the chemical action or physical phenomena inherent in its construction. Also, these rectifying units are preferably of the type which allow a certain amount of leakage or back flow current therethrough for purposes hereinafter explained.

It is believed that the various functions and features of the invention will be best understood by further description being set forth from the standpoint of operation.

Operation With the control lever L in the. normal extreme position shown, two energizing circuits receiving energy from the local transformer T are completed for the relay CR over the line circuits extending from the tower, which causes the con-v tacts 18 and 19 to assume extreme positions, such for example as those shown.

The first energizing circuit is traced from the left-hand terminal of the secondary of transformer T through fuse 22, wires 30 and 31, contacts 32,20, wire 33, rectifying unit RF, wire 34, contacts 35 21, line wire 36, wire 37, rectifying unit R phase winding 15 of relay CR, line wire 38, fuse 23, back to the right-hand terminal of the secondary of transformer T v The second energizing circuit is traced from the left-hand terminal of the secondary of trans-1 former T through fuse 22, wires 3-0 and 31, con tacts 3220, wire 33, rectifying unit R wire 34, contacts 3521, line wire 36, wire 39, rectifying unit R phase winding 16 of relay CR, line wire 38, fuse 23, back to the right-hand terminal of the secondary of transformer T It will be noted, that the first energizing circuit for the relay CR has the rectifier units F} and R3 connected in series therein in. a manner so that their valve actions are in thesame direction in the circuit, thus causing a uni-directional pulsating current of appreciable value toflowtherein. As

this circuit is of comparatively low resistance, this pulsating current will lag appreciablybehind the impressed voltage as applied by the secondary of transformer T by reason of the inductance of the phase winding 15.

In the second energizing circuit of the relay CR, the rectifying units R and R are included therein with their respective valve actions opposing each other, so that the result in the circuit is exactly the same as a comparatively high resiststantially in phase with the: impressed voltage as supplied by the secondary of transformer T From the foregoing description, it is obvious that with the two types or kinds of current in the respective phase windings of the polyphase induction type relay, a torque will be produced in therotor of such relay by reason of the phase dis-- placement between the two kinds of current which will operate the contacts 18: and 19 to the positions as shown.

When the control lever'L is moved to its opposite or reverse extreme position. from that shown, two other energizing circuits are completed for the relay CR. In one of these circuits the valve action of the rectifying units R and R is in the same direction, thereby, in this case causing the unidirectional pulsating current to flow in the phase winding 16. However, in the other one of these circuits, the valve action of the rectifying units R and R oppose each other thereby causing a relatively small alternating current to flow in the phase winding 15. From this it is seen, that the phase windings 15 and 16. are respectively energized with the opposite types of current, thus changing the relative phase displacement of the currents in the two windings. This change in the relative phase relationship causes the contacts 18' and 1-9- to be operated to their opposite extreme positions from those shown in the drawing.

With the control lever L in the normal extreme position, as illustrated, contacts 18 and 19 of relay GR; are moved to extreme positions as shown. However, when the control lever L is moved to its opposite or reverse extreme position, the contacts 18 and 12} are operated to their opposite positions to correspond therewith and the switch machine SM" receives operating current from the secondary of transformer T Assuming such reverse positions of lever L and contacts18 and 19-, the switch machine motor M is energized through a circuit from the left-hand terminal of the secondary of transformer T through fuse 24;, wire do, contact 18 of relay CR in a left-hand position, wires 41, 42 and 43, contacts 44-7, wire 45, phase winding PH wire 46, winding of electro-magnetic and 48, fuse 25, back to the-right-hand terminal of the transformer T This circuit energizes the phase winding EH and the brake BR. Because this circuit is ofcomparatively low resistance and includes the phase winding PH having inductive reactance, the current therein lags itsimpressed voltage from the secondary of transformer T In multiple with the phase winding PH is the condenser C and phase winding PH receiving current at the same time from the secondary of transformer T through a circuit from wire 15, through wire 50, condenser C, wire 51, phase winding PH to wire 46. The condenser C,.included in this latter circuit, counteracts the inductive reactance of winding PH and, therefore,- the current leads in time phase the current passing through winding PH Due to the time phase difference of the currents through PH and PH the motor develops armature torque. rent which flows in this latter circuit combines with the current flowing in the brake BR, wires 4'7 The curcircuit formerly ,to the right-hand operating circuitjat traced through the phase winding PH and flows through the winding of the electro-magnetic brake BR. The resultant current flowing in the brake BB. is effective to actuate its braking element in a manner to release the armature A and allow itto operate the switch machine SM. This operation .of the switch machine unlocks the track switch TS and operates the movable switch points thereof toward the reverse extreme posi- .tions.

Slightlybefore the track switch TS is unlocked, .thezmovable contacts8 and 9 are moved to intermediate positions,-engaging their respective con :tacts 54 and 59, and-with lever ,Landcontacts .18 .and 19 win their reverse positions, the pole changer coil 12 is energized through a circuit from the left-hand terminal of the secondary of transformer T through fuse 24, wire 40, contact :18 of relay CR in itsleft-hand position, wires 41 .and;42,.contacts 54-8, wire'55, pole changer coil .12 wires 56;and 48,.fuse 25, back to the right .handterminalof the secondary of transformer T This energization of thepole changer coil .l-2rcauses the movable contact 7 to be held in the normal position shown, during the time that the switch machine is operating the track switch TS .towardsits reverse position.

.With' the, movable contact 9 in an intermediate position, the pole changer coil 14 is connected to ,the normal operating wire 58 ofthe switch machine in. such a manner that it may be enerrgized if the contacts 18 and 19 of the relay CR are returned'to normal positions shown. This circuitis traced from the left-hand terminalof the secondary of transformer T through fuse .24,-wire 40, contact 18 of relay CR in-a righthand-positiomwire 58, contacts 59-9, wire 60,

pole changercoil 14, wires 61 and 48 fuse 25 back terminal of the secondary of transformer T This energization of the pole changer coil 14 while the track-switch TS is unlocked causes the movable contact? to be operated: to the opposite or reverse extreme position from that shown, thereby closing the normal operating circuit of the switch machine motor M .and .moving the, track switch to its normal posioperated by the switch machine to reverse extreme positions thereby opening the reverse voontacts,44'7. In this connection, it is noted that preferably the movable contacts 8 and Qareoperated from intermediate positions to extreme positions slightly prior to the operation of movable contact '7. This provides that the movablecontact '7 -may be easily operated without undue-mechanical stresses, as prior to its operation, the holding effect of the pole changer coil 12 or 14 is removed by the opening of its respective circuit-at the contacts54-8 or 59-9 respectively.

As soon as the operating circuit of the switch machine is opened at contacts 44-7 the current energizing the brake BR ceases to flow thereby causing-the braking el-ement'to engage the motor armatureA- and immediately bring it to stop. It is to be understood in this connection, that the brake BRiS'lliCllldGd within the embodiment of the present invention more with the object or pro viding means for retaining the switch machine in brake BR. is.omitted,the motor M inherently pro- .vides its .own snubbing action by reason of the circulating currents produced in its own windings after external current supplyis removed. These circulating currents are effective to absorb a part of any kinetic energy stored in the armature,

which causes the armature to be brought to rest without undue over-run thereof.

.One theory concerning this inherent snubbing action will now be briefly stated. With the motor energized as above described, the energizing circuit maybe opened at any time during the time cycle of the alternating current supply, and at that time either the condenser or one of the phase .windings, or the condenser and one or both of the phase windings will have energy stored therein.

Whenthe supply circuit is opened, this stored enan.operated os ti n... han wi a bi cto pr yiding snubbing action which of course occurs when such a brake is provided. However, if-the ergy causes a current to oscillate backand-forth between the condenser and the phase windings armature absorbs a part of the kinetic energy .stored in the armature.

The operation of the switch machine from a reverse position to a normal position will not be described in detail, asit may be readily understood by. analogy to the operation already ,described. However, the normal operating circuit of themotor Mis traced from the left-hand terminal of transformer T throughfuse 2.4,,wire

40, contact 18 of relayv GR in a right-hand position, wires 58 and 62, contacts 637, wire 64, phase winding PH wire 46, winding of brake BR, wires 4'7 and 48, fuse 25, back to the righthand terminal of transformer T During the normal operation, the condenser C is connected in series with phase winding PH and this series combination, connected in multiple with phase winding PH receives current from the same source described for winding PH It is noted, that during the normal operation, the current in the phase winding PH is a lag- ;ging current with respect to current in PH. This relative phase displacement is opposite from the phase displacement for the reverse operation above described, thereby causing the armatureA to rotate in the opposite direption.

Let us now consider the characteristics of cross protection provided by the circuits and devices ofthe present invention,..and the manner in which the application of either director alternating current through the various control .wires is prevented from causing false and undesirable operations.

' Let us first assume that a cross occurs between "wires 3i) and 36. If such a crosswere to occur, the characteristic of current flow in the wind-v ings 15 and 16 0f relay CR would be identical, that is, a pulsating alternating current with onehalf of each cycle of considerably larger amplitude than the other half would be flowingin both windings. This larger amplitude alternates from one phase winding to the other winding but since the half cycles of the larger amplitude are substantially out of phase with each other the resulting torque is substantially zero.

Let us now assume that a cross occurs between 450 wires 30 and 38, the transformer T is thus shortcircuited and no current fiows to the relay CR to thus falsely control it. A similar condition exists when the control wires 36' and 38 are shortedthereby shorting out the control relay CR and leaving only the rectifying unit R3 in series with the transformer T It is seen that, if an external alternating current source is applied to the wires 36 and 38, such for example as from the transformer T no false control of the relay CR can occur, for the same reason given when the wires 30 and 36 were assumed to be connected.

If direct current is applied to the wires 36 and 38, no false control of the relay CR can occur inasmuch as it is an induction motor type relay and cannot respond to direct current.

Considering the operating circuits of the switch machine SM to be in normal conditions as shown, a cross between the normal and reverse control wires 58 and 42 does not result in operation of the switch machine inasmuch as the motor M is shunted out by a circuit including contact 19 of relay CR. If such a cross occurs, a short circuit on the transformer T is traced from the lefthand terminal of the secondary of transformer T through fuse 24, wire 40, contact 18 of relay CR in a right-hand position, wire 58, through the cross to wire 42, contact 19 of relay CR in a right-hand position, wire 65, fuse 25, to the righthand terminal of the secondary of transformer T Such a short circuit on the transformer T causes the fuses 24 and 25 to burn out thereby opening the circuit. If a cross occurs between the wire 58 and wire 48, it is obvious that the same result occurs except that the short circuit on the transformer T does not include the contact of relay CR.

It is noted that the motor M cannot respond to any false application of direct current inasmuch as it is an alternating current induction type motor.

Thus, a control system for a railroad track switch has been shown and described, which is accomplished entirely by the use of alternating current, this system being protected from crosses and being protected from the application of foreign alternating currents and foreign direct currents all in a manner that no false operation of the track switch can occur.

Having thus shown and described one particular embodiment of the present invention and having illustrated this embodiment in a rather conventional manner, it is desired to be understood that the simplified showing adopted for the disclosure of the present invention, has been selected for the purposes of facilitating in the description of the invention rather than for the specific purpose of showing the scope of the invention, and it is to be understood in this connection, that various changes, modifications and adaptations may be made to adapt the invention to the particular use to which it is desired to be put in a practical manner, all without departing from the spirit or scope of the invention except as demanded by the scope of the following claims.

What I claim is:-

1. In a remote control system for railroad track switches, a manually operable control lever, a remote track switch, a source of alternating current at said control lever, a source of alternating current at said track switch, means for operating said track switch from said source local thereto, governing means for said operating means responsive only if uni-directional pulsating current is applied thereto, and means controlling said governing means including said control lever, said source local thereto and means at said lever for changing alternating current to uni-directional pulsating current, whereby said governing means and said operating means are protected from crosses between each other.

2. In a remote control system for railroad track switches, a manually operable control lever, a source of alternating current local to said lever, a remote track switch, a switch machine having a motor, a source of current local to said track switch, a relay for controlling the application of energy from said source local to said switch to said switch machine, said relay being of the induction two phase type having a rectifier connected in series combination with each phase winding, said rectifiers being oppositely poled in respect to each other, said series combinations being connected in multiple-series combination, a line circuit connecting said multiple-series combination of said relay with said control lever and said source local to said lever, and a rectifier in said line circuit at said lever, whereby said track switch may be operated to either of two opposite positions in accordance with said control lever.

3. In a remote control system for railroad track switches; a switch machine for operating the track switch; a manually operable control lever; a source of alternating current local. to said control lever; a two phase induction motor type relay for controlling the operation of said switch machine, said relay having its two phase windings connected in multiple and including a rectifier means connected in series with each winding, and each rectifier means being poled oppositely and provided with a predetermined amount of leakage; a rectifier means associated with said control lever; and circuit means connecting in series said relay, said source, said rectifier means associated with said lever and said lever, whereby said rectifier means associated with said lever may be reversed in said series circuit when said lever is operated to an opposite position; whereby said relay is governable to either of two positions by said control lever resulting in a corresponding operation of said switch machine.

4. In a remote control system for railroad track switches; a switch machine for operating the track switch; a manually operable control lever; a source of alternating current local to said control lever; a two phase induction motor type relay for control ing the operation of said switch machine, said relay having its two phase windings of like inductive characteristics connected in multiple and including a rectifier means connected in series with each winding, and each rectifier means being poled oppositely and provided with a predetermined amount of back leakage; a rectifier means associated with said control lever; and circuit means connecting in series said relay, said source, said rectifier means associated with said lever and said lever, whereby said rectifier means associated with said lever may be reversed in said series circuit when said lever is operated to an opposite position; whereby said relay is governable to either of two positions by said control lever resulting in a corresponding operation of said switch machine.

WADE H. REICHARD.

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