100 HZ. PHASE SELECTIVE TRACK CIRCUIT SYSTEM

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May. 1981 C-9/83-150-2141-5

PRINTED IN USA

SERVICE MANUAL 6055

Operation and Maintenance

100 HZ. PHASE SELECTIVE

TRACK CIRCUIT SYSTEM

UNION SWITCH & SIGNAL DIVISION AMERICAN STANDARD INC./ SWISSVALE, PA 15218

m UNION SWITCH & SIGNAL

CAUTION

The following is only mandatory for clear Lexan molded drivers. Deviations from this procedure may result in damage to equipment.

If it is desired to use an aerosol spray for cleaning relay contacts, only virgin Freon TF (available from Miller Stephenson Chemical Co. as MS-180 or MS-230 contact RE-ID FREON '.IF) is approved by U.S. & S for cleaning contacts with the driver attached to the contact spring.s.

4 • 2 .1.1 Gener al

a. Preliminary Information

The cleaning tool should be used to clean no more than 12 front (carbon) and 12 back (silver) contacts, after which they should be washed before re-use. The cleaning tool should be cleaned using a mild soap or detergent and water, rinsing thoroughly and allowing to dry.

4597, p. 14

See Enlarged Area

Figure 3. PN-250 Style Relay

NOTE

In the final cleaning procedures outlined in the following sections, it is recommended that all silver contacts be cleaned first and then all silver impregnated carbon contacts in order not to contaminate the silver tips with residue that might adhere to the cleaning tool from cleaning the silver impregnated carbon contacts.

STOP PIN C;,

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4.1 INTRODUCTION

SECTION IV SHOP MAINTENANCE

UNION SWITCH & SIGNAL m

'!his section provides the information necessary to perform shop level repairs of the PN-250 style relays covered in this manual. In general, relays arriving at the shop for repair have been checked in the field and have been found to perform unacceptably or have been physically damaged.

4.2 CIBANING AND INSPECTION

Before inspecting the relay and initiating repairs, use a soft cloth to clean the exter:i,or carefully to rem::>ve any dirt or dust that may have collected. A safe cleaning solution of alcohol and water may be used for removal of accumulated dirt, grease, etc.

Inspect the relay exterior for signs of physical damage, such as.cracked or broken cover, cracked or damaged housing, and damaged and or missing contact block terminals and indexing pins. If severe damage is found, a careful inspection of the interior canponents should be made for obvious physical damage.

Remove the cover and clean the surface between the armature and the pole faces, ·especially the stop pin area (see Figure 3), using a lint free cloth and alcohol.

Proceed with relay contact cleaning, using the following reconunended cleaning materials:

Reconmended Cleaning Materials

Cleaning Tool Extra sleeving for recovering three metal strips 14/0 Metallographic paper sheet 9" x 14" Burnishing tool

Distilled Water

4.2.l Cleaning Relay Contacts

Order Reference

N378099 J772330 J035215 J397187

'!his section covers reconunended methods for the preparation and cleaning of relay contacts.

After contacts have been dressed and/or after adjustments have been made to meet calibration -requirements, the contacts should be cleaned in accordance with the procedure given in paragraph 4.2.1.l and 4.2.1.2. Due to the possible unavailability of the sleeving (J772330) for the cleaning tool (N378099), an alternate contact cleani~g procedure is presented in Paragraph 4.2.2.

4597 I P• 13

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( Section

I

II

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III

IV

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VI

VII

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CONTENTS

INTRODUCTION

THEORY OF OPERATION

2.1 TRACK CIRCUIT OPERATION 2.2 GENERAL THEORY 2.3 DETAILED THEORY

2.3.1 F70 Inverter Driver 2.3.2 FS0-1 Inverter Follower

Input Stage 2.3.3 FS0-2 Inverter Follower

Output Stage

INSTALLATION

3.1 FREQUENCY 3.2 PHASE RELATIONSHIP 3.3 PILOT LINE 3.4 POWER OFF RELAYS

PHASE SELECTIVE CODED TRACK CIRCUIT SYSTEM

4.1 TRACK FEED

4.1.1 Output Stage Loading

4. 2 LOCAL FEED 4.3 PHASE SELECTIVE UNIT 4.4 PC-250P TRACK RELAY 4.5 CODE FOLLOWING TRACK RELAY

"ON TIME". 4.6 DECODING CIRCUIT 4.7 INSULATED RAIL JOINT BREAKDOWN

DETECTION

SYSTEM POLARITY

GROUNDING AND CROSSBONDING

TRACK CIRCUIT APJUSTMENT

7.1 LOCAL ENERGY 7.2 TRACK ENERGY ADJUSTMENT 7.3 TRACK ENERGY LEVEL ADJUSTMENT 7.4 TRACK ENERGY PHASE ADJUSTMENT

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1 1 3

3

4

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7

7 9 9

11

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13 13 15

16 16

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17

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18 18 19 19


Section

VIII

IX

Figure

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9. 1 ELECTRONIC COMPONENTS 1i~/,~ I

9. 2 ORDERING PARTS :i--·-

ILLUSTRATIONS

System Block Diagram

Inverter Follower Stage Interconnection

Phase Selective Track Circuit with Pilot Line Synchronization

Reserve Driver Applications

Phase Selective Unit {Operation)

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SECTION I

INTRODUCTION


This manual provides a comprehensive look as to the operation of the 100 Hz coded Phase Selective Track Circuit System and its associated components as applied to a 60 Hz AC propulsion territory.

The system provides: 1. A high degree of immunity to interference from the

60 Hz propulsion power and its harmonics. 2. Insulated rail joint breakdown protection. 3. Double-rail propulsion return paths.

SECTION II

THEORY OF OPERATION

2.1 TRACK CIRCUIT OPERATION

The track circuit operates with the application of a coded 100 Hz signal to the track through an AC propulsion bond at the feed end of the track circuit. At the receiving end of the track circuit a phase selective circuit compares the track voltage to a synchronized local voltage and operates a code following relay. When a train enters the track circuit, the track voltage is reduced in amplitude such that the operation of the code following relay ceases and the train is detected. It is the comparison of both phase and amplitude of the track voltage to a local reference signal that assures the superior performance of the phase selective system.

2.2 GENERAL THEORY (Refer to Figure 1)

A 10 volts D.C. battery drives the FS0-1 Inverter Follower Input Stage, the FS0-2 Inverter Follower Output Stage, the F-70 Inverter Driver, and relay loads. The F-70 Inverter Driver, converts the D.C. power into 100 Hz. square wave power of a low power level that is in turn fed into the FS0-1 Inverter Follower Input Stage and is amplified to provide 100 Hz pilot line energy and phase selective local steady energy, and a 100 Hz input signal to the F50-2 Inverter Follower Output Stage which in turn applies power to the track. The FS0-1 also takes the 10 volt battery power and applies it to the F50-2 after passing it through a surgesuppressing reactor. The FS0-2 Inverter Follower Output Stage receives a 100 Hz signal from the Input Stage which provides a switching signal to its power transistors. These in turn amplify the low level voltage supplied by the Input Stage. The F50-2 Inverter Follower Output Stage then codes the signal through external coding contacts, and reamplifies the coded 100 Hz signal to a high power level for application to the track.

6055, p. 1


TRACK \ -----~~~~~~...-~----~\~~f--~~~~~-

100 Hz CODED

r-- 1--, I

F50-2 H-RELAY INVERTER CODING FOLLOWER I CONTACTS OUTPUT STAGE I

I lOVDC 100 Hz I

I F50-l I 100 Hz. INVERTER PILOT LINE

lOVDC -..f FOLLOWER I INPUT

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100 Hz. CODED

---,

F50-2

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10 VDC 100 Hz I . I

I FS0-1

STAGE I lOVDC ....,

100 HZ,

F70

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TRACK ENERGY

PSU

100 Hz. PILOT LINE

LOCAL ENERGY

lOVDC 1M INVERTER DRIVER

I PHASE

I , SELECTIVEi.... I

UNIT

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6055, p. 2

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HEAD BLOCK LOCATION

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6 L _ TRACK ~A.:_ _J

INTERMEDIATE LOCATION

Figure 1. System Block Diagram

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UNION SWITCH & SIGNAL m 2.3 DETAILED THEORY

2.3.1 F-70 Inverter Driver

The F-70 Inverter Driver is essentially a tuned-reed type square wave signal generator. Its primary function is to supply a 100 Hz. square wave low power signal which is used to drive the FS0-1 Inverter Follower Input Stage by supplying the base switching power for its power transistors.

The F-70 Inverter Driver utilizes a contactless resonant reed oscillator which produces a stable 100 Hz. frequency within +0.1 Hz regardless of normal variation in supply voltages.

The 10 Volt D.C. input is applied at terminals +10 and -10 of the F-70 Inverter Driver, through a 3/4 ampere 3AG size normal blow fuze mounted inside the unit.

The output from the F-70 Inverter Driver is in the range of 20 volts peak to peak square wave (minimum 16 volts peak to peak), taken from terminals lZ and 2Z, which is applied to terminals lX and 4X of the FS0-1 Inverter Follower Input Stage when connected.

Two (2) F-70 Inverter Drivers, one primary driver and one reserve, have been installed at each driver location at the end of each interlocking area. The primary driver supplies the 100 Hz reference signal for the system in normal operation, the reserve driver signal being applied to the system only in the event of a failure in the primary driver causing loss of its output signal and dropping of the driver power off relay DPOR. In normal operation, both drivers are wired and energized with 10 volts D.C. but only one of their outputs is connected to the system at any one time.

The output terminals lZ and 2Z of the primary F-70 Inverter Driver are connected to the front contact of the DPOR. The output from the reserve driver is connected to the back contacts of the DPOR. The heels are then connected to lX and 4X of the FS0-1 Inverter Follower Input Stage. The control of the DPOR is connected directly across the output of the primary driver through a full wave rectifier bridge. This arrangement allows replacement of a faulty F-70 Inverter Driver unit without interruption of normal service.

Inverter Driver locations should be checked at regular intervals to determine which (primary or standby) driver is operating the system, so that the primary driver can be replaced if found to be defective.

6055, p. 3


2.3.2 FS0-1 Inverter Follower Input Stage

The FS0-1 Inverter Follower Input Stage is a solid state square wave inverter which supplies three low power steady energy 100 Hz outputs, the pilot line reference signal, phase selective local energy, and base power for the switching transistors in the FS0-2 Inverter Follower Output Stage. The F50-l requires a drive frequency input either from the pilot line reference signal through terminals lX and 2X, or directly from an F70 Inverter Driver through terminals lX and 4X. When driving the input stage from the pilot line through terminals lX and 2X, terminals 3X and 4X must be connected together by means of a jumper in order for the driver signal to be applied to the unit. This 3X and 4X connection must not be used when driving the unit directly from the F70 Inverter Driver through terminals lX and 4X, since the input load resistor and clipper circuit would cause an excessive load on the F70 Inverter Driver output circuit.

The 10 volt D.C. input should be applied to terminals +10 and -10. The unit provides its own ripple and line surge suppression through the use of a 1.8 millihenry reactor and a 10,000 Mfd. capacitor directly inside the 10 volt input.

CAUTION

Caution must be exercised when connecting the 10 volt D.C. feed to the input stage, as incorrect polarity applied to terminals +10 and -10 will blow fuse Fl in the unit. The 10 volt connection wires from the battery or buss should be at least #9 AWG wire size and kept as short as possible, due to the high current likely to pass through these wires. (These wires carry the 10 volt D.C. energy for both the low power input stage and the high power output stage units).

Both the pilot line reference signal and the phase selective local energy should be taken from output terminals lP and 2P. This output winding will supply nominal 22 Volts, 100 Hz square wave steady energy at approximately .5 amperes. This provides sufficient energy for the multiple connection of two FS0-1 Inverter Follower Input Stages to the pilot line at separate remote locations and three phase selective track units in multiple at the local location. This winding is protected against overloading by a 5 ampere fuse Fl located in the 10 Volt D.C. input circuit.

The output voltage level is a function of both battery voltage and unit loading, but should be in the range 18-31 volts RMS under normal loading conditions.

The base drive pow~r outputs are seperate isolated output windings

6055, p. 4

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UNION SWITCH & SIGNAL

on the same transformer from which the pilot local signal is taken. These outputs supply 100 Hz square wave steady energy for switching of the power transistors in the FS0-2 Inverter Follower Output Stage. They are brought out to keyed Cannon plug connectors, through which they are cable connected to the output stage. Each winding delivers nominal 3.5 Volts 100 Hz at O . 2 amperes .

These units maybe used in a cascade configuration essentially indefinitely, with an Inverter Driver location being requirea only at the start of the Phase Selective System.

Each FS0-1 Input.Stage is designed to accommodate two FS0-2 output stages as shown in Figure 2, so that all track feed configurations may be operated wi~h a single input stage and either one or two output stages.

2:3.3 FS0-2 Inverter Follower Output Stage

The FS0-2 Inverter Follower Output Stage is a solid state square wave inverter which supplies coded high power 100 Hz square wave energy for application to the track circuit. The FS0-2 requires a 100 Hz square wave base power drive frequency input from the F50-1 Inverter Follower Input Stage for switching control of its power transistors. The 10 volts D.C. power is applied to the F50-2 through the F50-l for ripple and line surge suppression, to terminals +lOA and -lOA from corresponding terminals (+lOA and -lOA) on the F50-1.

CAUTION

Caution must be observed when connecting the 10 volt D.C. feed to the output stage, as incorrect polarity applied to terminals +lOA and -lOA will blow fuse F2 in the unit. The 10 volt connection wires from the F50-l to the F50-2 should be at least i9 AWG wire size and kept as short as possible, due to the high currents likely to pass through these wires. These wires carry the heavy current required . for the track circuit feeds which could range as high as 30 amperes.

External coding contacts are required to be connected between terminals F and Hin order to produce coding at the track output windings. Although any code rate may be used, 120 code was chosen for this application. This coding contact makes and breaks the 10 volt applied to the first stage of power amplification so that the current broken by the coding contacts is normally in the order of 0.5 amperes or less. Thus, a coded signal drives the final power amplifying stage, so that both track output secondaries supply identical coded 100 Hz high power outlets from two (separate isolated) windings. The coding circuit is protected against overloading by a 2 ampere slow blow fuse (Fl) •

6055, p. 5

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Figure 2. Inverter Follower Stage Interconnection

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UNION SWITCH & SIGNAL ffi Track energy is taken from terminals lA through lE and 2A through 2E, each group being intended to feed one track circuit. Thus, each output stage will support the operation of a double track feed location. If more than two track feeds are necessary at a location, a second output stage may be connected to the same input stage, providing up to four track feeds. The various open circuit voltages obtainable from a track output secondary with 10 volts D.C. input are as follows:

lA - lB lB - lC lC - lD 10 - lE

25 Volt 25 Volt 62 Volt 12 Volt

with 2A through 2E being indentical to lA through lE. These voltages are approximate and will vary depending upon battery voltage fluctuation and unit loading.

When connecting the output to the track circuit, an external resistance (50 ohms) roust be used on the feed end of each track circuit to provide a current limit with a track shunt condition. The track outputs are protected against overloading by a 30 ampere slow blow fuse (F2) in the F50-2 Inverter Follower Output Stage.

Loading of the two track output secondaries combined,should be limited to 300 VA or less to prevent blowing the 30 ampere fuse.

SECTION III

INSTALLATION (Refer to Figure 3)

This section provides the systems wiring polarities and adjustment information necessary for proper installation of the 100 Hz Phase Selective Track Circuit System.

The systems wiring must be arranged such that a standardized order of instantaneous polarities is adhered to throughout the system. The convention is as follows:

3 • 1 FREQUENCY

The 100 Hz pilot frequency was chosen to provide maximum immunity to interference from a 60 Hz propulsion frequency and its harmonics. The 100 Hz system will not vary more than + O. 1 Hz.

6055, p. 7

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FS0-2 INVERTER FOLLOWER OUTPUT STAGE

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SECOND TRACK 20 CIRCUIT

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FOLLOWER 2A ... -OUTPUT

20 ym } SECOND TRACK STAGE CIRCUIT

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lP PILOT FS0-1 .--------. FS0-1

INVERTER FOLLOWER INPUT STAGE

,-- - - - - -~ PILOT LINE 2P l ~·..,,..~~~~~~~~~~~~~~-+~+-~~~~~-=-~ ~810 l~ - - - - ~ 2

2X

C: INVERTER 1-~ l' ..J.J...._J I ~2 FOLLOWER 4X +10 I INPUT 810'- - - - - _ J

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F70 ~BlO INVERTER

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DRIVER ~NlO (RESERVE) r2S

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Figure 3.

(1) (2) (3) (4) (5) (6) (7) (8) (9)

( 10) (11) (12) (13) (14) ( 15) (16) (17)

F70 INVERTER DRIVER, N451034-6803 FS0-1 INVERTER FOLLOWER INPUT STAGE, FS0-2 INVERTER FOLLOWER OUTPUT STAGE, PN150 BE RELAY, NJ22513-002 RECTIFIER (RELAY BASE MT'D), X433718 PC250 TR RELAY, N322S56-003 RESISTOR, SO Q, lSOW, .N4Sll40-0l04 FUSE, l. SA LIGHTNING ARRESTER, N327989 CABLE, .N4510 34-8°701 AC PROPULSION BOND, N4~1003-0501 LINE FILTER, N451036-0403 FUSE, O.SA PHASE SELECTIVE UNIT, N384378-003 PC250 P RELAY, N322559-016 CAPACITOR UNIT, N436274 PN250BE RELAY, N322550-704

N451033-1602 N451033-1502

TPR

Pha·se Selective Track Circuit With Pilot Line Synchronization

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UNION SWITCH & SIGNAL m 3.2 PHASE RELATIONSHIP

Since the ~hase Selective Track Circuit is a two element system requiring track circuit energy and local energy, it is necessary that the 100 Hz power phase relations be carefully observed. Within the F50-1 and F50-2, all 100 Hz outputs are in phase with the 100 Hz input. In addition to maintaining phases within units, a pilot line is used between cases to keep each case in phase with every other case on the installation. Anytime it is necessary to replace any wiring or unit within the case, it is imperative that the wiring be replaced exactly as it was, or the instantaneous polarities may be wrong.

The output polarity of any one Inverter Driver (1Z-2Z) is not important, as this is an individual source of power, but after the driver signal is fed through the first F50-l Inverter Follower Input Stage then every other Inverter Follower Input and Output stage must be kept in phase.

3.3 PILOT LINE

All feeds to a group of phase selective circuits must be from the same power source so that the track circuit feed and the local energy to the Phase Selective Unit of a particular circuit have a constant relationship and the instantaneous polarities of adjacent circuits can be arranged to be opposite. In this application, a nominal 15 volt, low energy pilot signal is cascaded from location to location over a pilot line to synchronize the signals on the F50-l Inverter Follower Input Stage. The 100 Hz pilot frequency for each section between headblocks (interlockings) is initiated in the F-70 Inverter Driver located at one end of each interlocking or siding area, and is fed into an F50-l Inverter Follower Input Stage at the same location. A steady energy signal out of the F50-l Inverter Follower Input Stage is applied to the phase reference pilot line which supplies a phase reference signal for the F50-l Inverter Follower Input Stage at the next signal case. The pilot line then extends the entire length of that section to the next interlocking. The pilot line is connected to terminals lX and 2X of the FS0-1 Inverter Follower and the pilot signal is regenerated to provide an output at terminals lP and 2P at every F50-l Inverter Follower location. The lP and 2P terminals of the F50-l Inverter Follower Input Stage also supplies phase selective local energy to phase selective receiver track units. The pilot line signal is protected against loss of pilot signal due to the F70 Inverter Drivers failure through the use of a reserve driver (shown in Figure 4A) located at each driver location which is wired and energized. In the event of failure of the Primary Driver, F70, the output of the faulty driver is automatically disconnected and the output of the reserve driver is connected into the system through the action of the driver power off

6055, p. 9


BlO +10 PRIMARY F70

NlO -10 INVERTER DRIVER

BIO +10 RESERVE F70

NlO -10 INVERTER DRIVER

100 HH, PILOT LINE

BlO +10

RESERVE F70 INVERTER

lZ

2Z

lH

2H

+T -A ~

+B -B ~

DPOR

u

2H

4A. PRIMARY DRIVER LOCATION

+T -A • •

+B .-B

PPOR

r - - -, I I PILOT I ILINE I I FILTER L __ _J

NlO -10

DRIVER _____ _.

4B. INTERMEDIATE LOCATION

lX

4X

lX

2X

3X

4X

Figure 4. Reserve Driver Applications

6055, p. 10

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FS0-1 INVERTER FOLLOWER INPUT STAGE

FS0-1 INVERTER FOLLOWER INPUT STAGE

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UNION SWITCH & SIGNAL ffi relay (DPOR). The reserve driver then operates the system until the primary driver is replaced. Additional Standby Drivers maybe located at various points in the system to prevent a complete system failure in the event of a pilot line failure midway through the system. (See Figure 4B)

3. 4 POWER OFF RELAYS

These are PN-150BE high efficiency biased relays. They are D.C. relays adapted for 100 Hz. A.C. operation through the use of a relay base - mounted full wave silicon rectifier bridge as shown in Figure 3.

The DPOR relay is connected across the output from the primary F70 Inverter Driver (terminals lZ and 2Z). The output from the primary driver is also applied to the driver pilot input terminals lX and 4X on the F50-l Inverter Follower Input Stage across the front contacts of the DPOR. The output from the reserve driver is connected to the back contacts of the DPOR so that, in the event of a driver failure, a reserve driver pilot signal will be immediately applied to the system. The system will then operate from the reserve driver until the Primary driver is replaced and energized.

When the pilot signal from the primary driver ceases and the DPOR transfers the output from the reserve driver onto the pilot line, the system will experience an instantaneous shift in its reference phase, since the signal from the reserve driver is not likely to be in phase with the previous drive signal. This shift will not affect the operation of the track circuits, since the decoding circuits will easily bridge the contact transfer and phase shift time.

A similar operation is obtained from the DPOR relay at an intermediate standby driver location.

If a DPOR transfers midway through the system due to loss of pilot signal into its location, the portion of the system from the location of the DPOR on-will operate using the standby driver at that DPOR location as a frequency and phase reference.

Since that portion of the system beyond the pilot fault would then be operating from a signal source (intermediate driver) different from the initial system signal source (primary driver), the two portions of.the system would not likely be in phase. . The two ends of the track circuit just ahead of the intermediate driver location·would thus be fed from two different signal sources which may or may not be in phase, or which could "float" in and out of phase due to slight frequency d£fferences between the two drivers. This latter condition could cause a "pumping" of the track relay, causing erratic signal behavior. To avoid this possibility, a contact of the DPOR is inserted in the track circuit(s) just ahead of the

6055, p. 11


intermediate driver location to disable these circuits upon the transfer of the DPOR. These circuits will stay down as long as the DPOR is de-energized.

SECTION IV

PHASE SELECTIVE CODED TRACK CIRCUIT SYSTEM (Refer to Figure 3)

The operation of the coded phase selective track circuit system is based primarily upon maintaining the proper phase relationship between the coded energy received from the track and the local steady energy fed tp the Phase Selective Unit at the proper driver frequency (100 Hz} throughout the system. It provides track circuit immunity to induced foreign currents of any frequency other than the pilot frequency of the system, double rail propulsion return paths, and insulated rail joint breakdown protection.

4. 1 TRACK FEED

The track energy is coded through the action of a 120 code WABCO (US&S) type PC-250TR Code Transmitter relay which applies +10 volts D.C. to the switching transistors in the F50-2 Inverter Follower Output Stage. This coded signal is applied to the track circuit and is detected by a .Phase Selective Unit which controls the response of a WABCO (US&S) type PC-250P track relay.

For a given track circuit configuration, the track feed voltage (magnitude and phase angle) is a function of battery voltage and output stage loading, both are which variable factors. Battery voltage may be anywhere from 14 to 9.2 volts (8 cells of nickel cadmium).

4.1.1 Output Stage Loading

Output stage loading is dependent upon track circuit configuration ballast condition, and occupancy. A given track circuit configuration will establish some basic loading condition for the unit. The track feed signal will then assume a magnitude and phase angle. Variations in ballast condition, however, will cause variations in leakage current, and thus cause variations in the magnitude, phase angle, and waveshape of the signal. These variations in magnitude and phase angle will cause corresponding variations in track relay "On Time" (see section 4.5 for ~ef.} at the relay end of the circuit.

When a track circuit becomes occupied, the impedance of the load on one output winding of the output stage changes. The impedance decreases and changes from resistive - inductive to almost purely resistive. This change has two effects: (1) The

6055 f P• 12

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UNION SWITCH & SIGNAL m decreased impedance of the load on the secondary feeding the shunted track circuit causes an increase in loading which is felt by both output secondaries, so that the other track circuit being fed from the same unit will experience a change in feed energy (magnitude and phase angle) which will cause a small change in track relay On Time at the relay end of the unshunted track circuit, (2) due to the effect of load reflection through a transformer, the change from inductive-resistive to purely resistive loading on the shunted output winding will cause a phase shift in the track feed energy being applied to the unshunted track circuit which will also cause a small change in its track relay ·on Time. The cumulative effect of shunting a track circuit, then, is to cause a change in track relay On Time in the other track circuit which is being fed from the same unit. Variations from 0% to approximately 4% decrease may be expected.

NOTE

The "On Time" refered to here is the track relay On Time at the relay end of the track circuit under discussion, and not the transmitter On Time which is a function of the code transmitter.

4. 2 LOCAL FEED

A steady energy square wave local phase reference signal for the Phase Selective Unit is supplied from the local FS0-1 Inverter Follower Input Stage at the relay end of the track circuit through its pilot.signal output terminals lP and 2P.

4.3 PHASE SELECTIVE UNIT, N384378-003 is shown in Figures 3 and 5.

The coded track signal at the relay end of the circuit, drives the Phase Selective Unit. A tuned filter in the Phase Selective Unit, rejects the intrusion into the unit of 60 Hz propulsion signals, as well as any stray signals of any frequencies other than 100 Hz which may enter the track system. Terminals 2P, 3P, 4P and SP are taps on the tuned filter reactor, which provide for ·adjustment of the filter tuning to compensate for the difference in inductance between long and short track circuits. Factory adjustment of the filter tuning compensates for normal track circuit inductance encountered. The voltage developed across the track winding in the unit is then a sine wave voltage due to the presence of the series tuned filter.

6055, p. 13


TRACK CODE "OFF"

TRACK CODE "ON"

TRACK RECTIFIER

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1, ,., ...... , \.J ... , .... ,

2MFD

II LOCAL

LOCAL RECTIFIER

____ TRACK

+lP

• 2P

TRACK 3P INPUT .--~~~-----4 P (CODED) ------·

1N2980B

= 0

5P

30Q, 25Wl L+

L-

LOCAL INPUT

CODE "OFF" N R-o--1 ____ 0 __ '. _____ TRACK

: CODE "ON" - -- -1, ~ OHMS 20 OHMU

PC-250P RELAY

Figure 5. Phase Selective Unit (Operation) 6055, p. 14

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UNION SWITCH & SIGNAL m The phase of the track signal is then compared with that of the steady energy square wave reference signal on the local winding of the Phase Selective Unit. The local voltage is limited to 16 volts by means of a 16 volt (5% tolerance) Zener diode clipper circuit. Thus, the local reference is held essentially constant, independent of battery voltage variations. If the phase difference between the two signals is excessive, depending on relative voltage magnitude, or if there is no input signal from the track, the local reference energy is sufficient to hold the contacts of the PC-250P relay closed in the reverse position.

During the "Off Time 11 of the coded energy from the track, the local voltage supplies sufficient voltage across the local rectifier to give an output between N and R- to drive the PC-250P reverse.

During the "on" pulse of the code, the track input signal cancels the opposing polarity of the local voltage giving no output out of the local rectifier between N and R-, but applying a pulse of energy across the track rectifier and giving an output between R+ and N to drive the PC-250P to the normal position. ·

This pattern will continue alternately as the coded track signal is received at the relay end of the circuit, providing the code rate pulsed drive for the PC-250P code following relay.

Thus with a constant level local voltage, variations in the· "On Time 11 of the code following relay are caused only by variations in the track feed voltage and the ballast condition for a given track circuit configuration, providing the local energy circuit is intact.

The condition of the local and track input circuits may be determined by terminal measurements as described in Section 8.3.

4.4 PC-250P TRACK RELAY

The PC-250P Track Relay is a m~gnetic stick type relay which must be driven from one position to the other, otherwise it remains in its last energized position. The steady local energy is sufficient to drive the track relay to the reverse position during the absence of signal from the track during an off period of the code or with a train shunt in the track circuit. A 100 Hz signal from the track of sufficient magnitude and of the proper phase during the On Time period of code will cancel out the local energy and drive the PC-250P track relay to the normal position.

6055, p. 15


4.5 CODE FOLLOWING TRACK RELAY "ON TIME"

Relay "On Time" is defined as being that percentage of a full code cycle during which the normal contacts of the relay are closed. This orientation is employed since the normal contacts are driven closed during the coded track signal On Time. On Time is normally measured directly with a low voltage D.C. code meter, and provides an indication of the balance between the duration of alternating pulses being applied to a stick type code following relay to drive it alternately from one position to the other. The code meter is calibrated to indicate the percentage of the full code cycle (or alternating pulse cycle} that the contacts to which it is connected are closed.

Recommended On Time. for proper decoding circuit operation in this application is 30-65% for resistor type feed configurations. "Off Time" correspondingly, should be 35-70%.

NOTE

When measuring relay On Tir.:i.e., use WABCO (US&S) code meter J620754 and make measurement on unused relay contacts.

4.6 DECODING CIRCUIT (Refer to Figure 3}

The Capacitor-Rectifier unit is designed to store sufficient energy so that the TPR relay will remain energized long enough to bridge the Off Time of a normal 120 code {per minute} cycle. When the track energy code pulse turns off, the local energy on the Phase Selective Unit will drive the track relay to the reverse (R} position, recharging the capacitor for the next "on" pulse. The resistor in series with the decoding capacitor limits the charging currents in order to prevent contact welding. The diode snubs the TPR relay to provide slow dropaway. The TPR will thus remain energized so long as the code pulses are received from the track. If steady energy is received from the track, or if the local energy is removed from the PSU, the track relay will stop coding and the TPR will release.

The· On Time of the track relay must be maintained within acceptable limits (30-65%} in order for the decoding circuit to function properly.

4.7 INSULATED RAIL JOINT BREAKDOWN DETECTION

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-Through the assignment of instantaneous polarity to each end ( of the track output secondaries of the F50-2 Inverter Follower

6055, p. 16

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Output Stage, insulated rail joint breakdown protection is established for the system. The 11 A11 end of the track secondaries is defined as the positive (+) end, the 11 E" end as the negative {-) end. The polarities as indicated on the track configurations of each circuit show the system of staggered polarities thus derived. This polarity arrangement is possible since drive signal phasing is synchronized through out the system.

SECTION V

SYSTEM POLARITY

An arrangement of instantaneous polarities, as mentioned in Section 4.7, has been established throughout the system, which must be maintained in order for the track circuits to operate. The convention is as follows:

FS0-1 Input Stage, lX ( +) 2X (-}

lX (+) 4X (-)

lP ( +) 2P (-)

(Output terminal lP is in phase with input terminal lX)

FS0-2 Output Stage, lA ( +} lE (-)

2A (+) 2E {-)

(similarly, B negative with respect to A, C negative with respect to B, etc.)

(output terminals lA & 2A are in phase with input terminal lX on the FS0-1 Input Stage}

F70 Inverter Driver, lZ (+) 2Z (-}

Phase Selective Unit, IP (+} 2P,3P,4P or SP (-)

L+ (+) L- {-)

The impedance bond has terminal Pl in phase with terminal Sl or if {+) is applied to Pl, Sl will be (+).

6055, p. 17


SECTION VI

GROUNDING AND CROSSBONDING

All ground connections to be made within the confines of a double rail track circuit at an impedance bond location must be connected to the center tap of the impedance bond and not to a rail in order to maintain the balanced track circuit condition necessary for proper operation of the two rail track circuits. When structures and/or equipment are to be grounded to the rails at a point where no impedence bond is available, such grounding connections must be made through the center tap of a grounding coil. This method of connection is necessary to maintain a balanced track circuit condition.

On a single track railroad, the propulsion return crossbonding must be spaced at intervals no closer than one mile and no closer than every second impedance bond location if broken rail protection is to be maintained.

SECTION VII

TRACK CIRCUIT l\DJUSTMENT

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The Phase Selective Track Circui 1: is a two element circuit and g as such, both local and track energy must be considered.

7.1 LOCAL ENERGY

The local energy, as mentioned previously, is taken from the 100 Hz steady energy output terminals lP and 2P on the F50-l Inverter Follower Input Stage at nominal 22 volts. This energy is applied to the Phase Selective Unit local input terminals L+ and L-. This signal is reduced to 16 volts inside the Phase Selective Unit by means of a 30 ohm resistor and a close tolerance (5%) Zener Diode for application to the local windings of the unit. The ideal condition is to have sufficient energy into the Phase Selective Unit local terminals, with track energy off,to get sufficient output between terminals N and -R without any output between terminals R+ and N, in order to drive the PC-250P track relay to its reverse position.

7.2 TRACK ENERGY ADJUSTMENT

The track energy input into terminals lP and 2P,3P,4P or SP

6055, p. 18

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UNION SWITCH & SIGNAL EEi of the Phase Selective Unit must be of sufficient magnitude and proper phase angle during the track code on-time to cancel the effect of the steady local energy and to provide sufficient output out of terminals R+ and N of the Phase Selective Unit to drive the PC-250P track relay to its normal position.

7.3 TRACK ENERGY LEVEL ADJUSTMENT (Transmitting End)

The track energy level adjustment is made at the feed end of the track circuit by choosing the correct tap of the F50-2 output. The choice of output connection will depend on the length of the track circuit since a longer track circuit requires more energy for operation than a shorter one. The F50-2 output connections are shown in Table 1.

Track Circuit Length in Feet F50-2 Output Connections

0-2500 lA-lC or 2A-2C 2500-3500 lC-lD or 2C-2D 3500-4500 lC-lE or 2C-2E 4500-5500 lB-lE or 2B-2E 5500 and up lA-lE or 2A-2E

Table 1. Track Energy Level Adjustment

7.4 TRACK ENERGY PHASE ADJUSTMENT (Receiving End)

The track energy phase adjustment is made at the relay end of the track circuit by choosing the correct tap of the track input of the Phase Selective Unit. These taps provide compensation for the phase shift that the track signal undergoes due to ballast leakage and rail inductance. A longer track circuit will require more phase compensation than a shorter one. The Phase Selective Unit track connections are shown in Table 2.

Track Circuit Length Phase Selective Unit In Feet Track Connections

0 - 1500 lP - 5P 1500 - 2500 lP - 4P 2500 - 5500 lP - 3P 5500 and UP lP - 2P

Table 2. Track Energy Phase Adjustment

6055, p. 19


SECTION VIII

MAINTENANCE

8.1 GENERAL

This section provides the maintenance technician with maintenance and troubleshooting information to enable him to rapidly isolate faults within the system using a minimum amount of time and test equipment.

Nominal Operating Voltages

The following voltages are nominal voltage figures and serve only as a guide for the maintainer in pin pointing trouble (comparable with readings obtained using the WABCO (US&S) Code Heter J620754.)

A) D.C. Source

Battery Voltage - 9.2 VDC min. - 14 VDC max.

B) F70 Inverter Driver

1). Unloaded -(terminals lZ to 2Z) - nominal 12 volts, 100 Hz A.C.

2). Loaded -(terminals lZ to 2Z) - nominal 10 volts, minimum 8 volts (100 Hz A.C.)

C) F50-l Inverter Follower Input Stage

Pilot - Local voltage terminals lP to 2P, nominal 22 Volts minimum 18 volts, 100 Hz A.C.

D.C. voltage terminals +lOA to -10A, 9.2 Volts DC minimum 14 volts DC maximum

D) F50-2 Inverter :eollower Output Stage

Track Output secondaries terminals A to E nominal 100-170 V Peak (100 Hz A.C. 120 Code)

8.2 FIELD MAINTENANCE

In the event of a failure in any part of the system, any defective unit encountered should be replaced with a spare which is known to be good, and the defective unit returned to the shop for repair.

The cause of a failure in the system can usually be identified

6055, p. 20

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UNION SWITCH & SIGNAL m and corrected with a minimum service delay with the use of the troubleshooting guide presented below.

8.3. SHOP MAINTENANCE-TROUBLESHOOTING

Relay End

A). Check battery Voltage - if okay then proceed to (B}. If low or high(outside voltages listed above) check charge circuit, battery connections, and/or cell condition.

B). Check TR (PC-250P) relay - if stopped,proceed to (C) If operating - check position of TPR relay.

1. If TPR is up, check circuits to signals and signal controls.

2. If down, check TR (PC-250P) On Time • To do this, connect a code meter across an unused "normal" contact such as 2P-2N, 3P-3N or 4P-4N. On Time should be 30-65%.

3. Check for shorted decoding capacitors by connecting a voltmeter across the capacitor, looking for 0 -10 Volts pulsating D.C. Voltage.

C). Check track input terminals lP and 2P, 3P, 4P or SP on Phase Selective Unit. Voltages should be in the approximate range 7-50 volts peak, coded 100 Hz A.C. when read using a code meter.

If okay then proceed to (D)

1. If low, check for the correct Phase Selective Unit track connections as given in Table 2. Recheck voltage and TR (PC-250P) On Time

2. If zero and track circuit is unoccupied, check the 0.5 amp track fuse - if fuse is okay, go to feed end of track circuit.

If blown, replace fuse, and check for cause of track circuit unbalance (possibly broken rail, loose bond wire, etc.)

3. If steady, go to feed end, check for inoperative 120 code transmitter or foreign material causing a short circuit between terminals F and Hof the F50-2 Inverter Follower Output Stage.

6055, p. 21


D. Check terminals L+ to L- on the Phase Selective Unit. The voltage should be in the appropriate range 15-22V ( (minimum 13.8 volts) steacy energy 100 Hz A.C. If PC-250P relay is stopped and both inputs { lP, 2P, 3P, 4P, SP, L+ and L-)are OK, proceed to check (E). If L+ to L- voltage is low or zero, check the voltage at terminals lP and 2P of FS0-1 Inverter Follower input Stage.

a) If okay, check wiring between units, (If DPOR relay contact is used in the circuit, check DPOR relay. (If down, check for incoming pilot signal from line.)

b) If low or zero, replace ~50-1.

E. Check Phase Selective Unit Output

Remove associated 0.5 ampere track fuse (see Figure 3) on terminal board. With normal local voltage applied to L (+) and L (-), should read approximately 2.25 volts steady A.C. across terminals lP to R (-). This will check zener diode in local input circuit. Low or Zero voltage indicates Zener shorted. Voltage greater than 3 volts indicates zener circuit open. Replace 0.5 amp fuse, connect positive meter lead to R+ and negative lead to R-. On 3 volts D.C. scale, the meter should read pulsating voltage with at least 0.5 volt needle bounce. This checks the tuning of the series tuned filter and continuity in track input circuit.

1. If reading is okay, replace PC-250P relay. 2. If readings are not okay, replace Phase Selective Unit.

Feed End

NOTE

The relay end track fuse is a 0.5 amp normal blow fuse. Time lag fuses should not be used in this application.

A. Check track output terminals A to E and pilot-local output terminals lP to 2P for nominal outputs as listed for the FS0-1 and FS0-2.

Check the track connections for correct feed end output voltage from F50-2 as given in Table 1.

1. If both are okay, proceed to Cm. 2. If track output only is low, check unit fuses in

F50-2 Inverter Follower Output Stage. If either or both are blown, replace unit.

3. If both track and pilot local - voltages are low or zero, check unit fuse in F50-l Inverter Follower Input Stage. If blown, replace unit.

6055, p. 22

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UNION SWITCH & SIGNAL m 4. If F50-l unit fuse is okay, check battery voltage

a. If battery voltage is okay, proceed to (C). b. If battery voltage is low or.high(outside previously

listed limits), check the charge circuit, battery connections, and/or cell condition.

B. Check 1.5 amp track fuse on terminal board. If okay proceed to (C).

If blown, replace fuse, check for cause of track circuit unbalance (possibly, broken rail, loose bond wire, etc.}

NOTE

The feed end track fuse is a 1.5 ampere normal blow Fuse. Time lag fuses should not be used in this application.

C. Check Pilot Voltage into F50-l Inverter Follower Input Stage -(terminals lX and 2X if fed from line, lX and 4X if fed from F70 Inverter Driver) should be:

a. 15 Volts (minimum 13.8 v) 100 Hz A.C. from line. b. 10 Volts {minimum 8 V} 100 Hz A.C. from driver.

1. If pilot voltage into F50-l is low or zero, proceed to (D) •

2. If pilot voltage into F50-l is okay, replace F50-1 with spare unit known to be in good working order.

D. Check pilot voltage into case at terminal board or at output terminals lZ and 2Z of F70 Inverter Driver. Voltages should be listed in check(C) •

1. If voltages are okay, check the wiring betw.een the terminal board and the F50-l or between the F70 and F50-l.

2. If pilot voltage is low or zero at the terminal board, check pilot line circuit. If F70 Inverter Driver output is low, check DC input at terminals +10 and -10 on unit (should be 9.2 to 14 volts DC)

3. If driver input voltage is okay,:replace unit with a spare unit known to be in good working order.

4. If a driver input voltage is low or zero, check D.C. feed wiring to driver.

6055, p. 23 \


SECTION IX

PARTS SELECTION/ORDERING

9.1 ELECTRONIC COMPONENTS

If it becomes necessary to replace components during unit maintenance, replacements for all parts may be obtained through US&S field offices. However, certain of the standard electronic components may be obtained from outside sources.

CAUTION BEFORE REPLACING ANY STANDARD ELECTRONIC COMPONENTS,IU THE VARIOUS TRACK CIRCUIT UHITS,FROM SUPPLIERS OTHER THAN US&S, CHECK THE PARTS LISTS TO OBTAIN THE CORRECT VALUE, TOLERANCE, RATING AND DESCRIPTION FOR THE COMPONENT. ALL REPLACEMENTS SHOULD BE EXACT REPLACEMENTS UNLESS IT IS CLEARLY KNOWN THAT A DIFFERENT COMPONENT WILL NOT ADVERSELY AFFECT SYSTEM PERFORMANCE. THE WRONG COMPONENT MAY CAUSE IMPROPER OPERATION OF THE SYSTEM OR RESULT IN EQUIPMENT DAMAGE.

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It is important to remember that the physical size and shape O of a replacement component must be considered and must be equivalent to the original, otherwise the performance of the replacement may be affected (.particularly at high frequencies).

9.2 ORDERING PARTS

6055 I P• 24

When ordering replacement parts from (US&S) include the following information:

1. Unit nomenclature.

2. Unit serial number.

3. A description of the part.

4. US&S Part Number.

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UNION SWITCH & SIGNAL ffi For additional parts list breakdown of the various components comprizing the Phase Selective Track Circuit System, refer to the following service manuals for further breakdown of that particular unit.

Phase Selective Track Circuit Unit Part Number Service Manual

A) F70 Inverter Driver N451034-6803 SM4589 B) F50-l Inverter

Follower Input Stage N451033-1602 SM4588A C) F50-2 Inverter

Follower Output Stage N451033-1502 SM4588B D) Phase Selective Unit N384378- 003 SM6001 E) PC-250P Track Relay N322559- 016 SM4570A

6055, p.( 25/26

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100 HZ. PHASE SELECTIVE TRACK CIRCUIT SYSTEM

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