US1835608A - Supervisory control system - Google Patents

Description

Dec. 8, 1931.. A. L. MOREAU 1,835,608

SUPERVISORY CONTROL SYSTEM Filed Aug. 9, 1927 5 Sheets-Sheer l WITNESSES: INVENTOR /& 5 M60 A/be/"f L. Moreau Dec.-8, 1931. A. 1.. MOREAU 1,835,608

SUPERVISORY CONTROL SYSTEM Filed Aug. 9, 1927 s Sheets-Shea? 2 WITNESSES A/ber/ A -Mafieau A. MOREAU 1,835,608

SUPERVISORY CONTROL SYSTEM Dec. 8, 1931.

l iled Aug. 9, 1927 5 Sheets-Sheet 5 INVENTOR A/be/f L Mareau ATTORNEY WITNESSES:

Dec. 8, 1931. A. L. MOREAU 1,835,608

SUPERVI SORY CONTROL SYSTEM Filed Aug. 9, 1927 v 5 Sheets-Sheet 4 k m g? g WITNESSES: ENTOR g S W A/ber'l L- Moreau Patented Dec. 8, 1931 wa srArEs PATENT *pFmE j;

. ALBERT L. MOREAUQOF WILKINSBURG, PENNSYLVANIA; ASSIGNOR 'ro WESTINGHOUSE ELECTRIC 8t IVIANUFAGTURING- COMPANY, A CORPORATION OF PENNSYLVANIA SUPERVISORY CONTROL SYSTEM Application filed August 9, 1927. Serial No. 211,681.

My invention relates to selective signalling systems in which apparatus units are selectively controlled and supervised from aremote station.

An object ofmy invention is to providesynchronously operated relay chains located at the two remotely disposed points for synchronously switching signalling lines connecting said pointsto equivalentunits.

Another object of my invention is. to provide circuit arrangements for stepping relay chains, located at two remote points, in synchronism by means of a code. 1

Another object of my. inventionis. to provide means for identifying each selected pos ition before completingthe selection. Another object of my invention is to provide a method ofoperating a synchronous selecting system which includes thesteps of preparation, identification and completion of the selected prepared circuit.

Another object of my invention is to provide circuit arrangements for releasin the selectors when a non-synchronous confition arises (without the use of additional signalling lines).

Another object of my invention is to provide manual means for instantaneously restoring the selecting apparatus to normal, at any time, employing no additional signalline; lines. 7 y 1 Still another object of myinvention is to provide means for employing the same signalling line for control, supervision, drive and reset. I

Another object of my. invention is to provide circuit arrangements for operating relay chains at two remote points in synchronism, employing only uniform fast-type relays. l g

Another object of my invention is to provide a method of selective signalling which includes preparation, identification of the selection, completion of the selection and code operation of the selectedunit.

Still another object of my invention is to provide circuit arrangements whereby the signalling are-maintained open until identification of the selection. c

There are other objects of my invention such control he held by the dispatcher indefinitely. In other signalling systems, a selecwhich, together with the foregoing, will appear in'the specification which follows;

The supervision and control of substation power apparatus .from a dispatchers oflice in-. troduces problems not present in anyothertype of signalling systems. p

In most-of the existing signalling systems, a small-percentage error in selectionis usually considered permissible. No serious consequence results from an occasional error ina telephone, telegraph orother signalling system. On the other. hand, in supervisory control, each operation is important,and the efiectmay be of serious moment. An incorrect operation may result'in damage more costly than the svstemitself. For this reason, it is necessary that the selectingsystem employed be infallibly accurate.

visory-control selecting systems and other selecting systems is found in the fact that,in:

Another vital difference between superthe-former systems, itis desirable to obtain. direct control of theselected unit andthat tion is usually made in order to perform a single operation, such as to ringa called party in a telephone system. In supervisory con:

trol, on the other hand, after having selected,

an apparatus unit, such'as a circuit breaker,

further selective operations, such as opening and closing the circuit breakermay bedesirable, and, since further selections may be performed a number of times, it is important that the selected unit be retainedunder con-.

To accomplish 'trol-of the dispatcher until he restores the:

his latter purpose, that selecting system employs a start-stop synchro-,-

nous operation in which the signalling lines are switched synchronously at the two remote I stations in a step-by -stepfashion and stopped at th e'desired selected point. Direct connections of the selected unit are therefore obtained over the signalling lines. I

In this type of synchronous selection, how

ever, the selected units are subjectedto inductive surges induced on the signalling line.

'Heretofore, this difficulty has been corrected by interposing equipment between the select- 1700 ed units and the line. This equipment, however, is both expensive and renders the system involved.

In order to overcome this difficulty, the present invention employs a code means for stepping the chains synchronously, sothat each position is selected by the accuracy of a code, while the advantage of direct connection is obtained in that the selectors are stopped as in a synchronous start-stop system. 7 Y Y In practicing my invention, I provide circuit arrangements for synchronously stepping relays at two remote points, equivalent relays at each station beingisteppedby an individual code. Signalling lines connecting'the'two remote'points are stepped from point to point by synchronous energization' of the relays mentioned above for sequentially connecting apparatus units at one point to 3 their individual 0 aeratin meansat the other or remote station. Selected units are operated code combinations of impulses.

A checking circuit is provided for identifying the selections made, and a" reset is arranged to operate over the signalling line's.

"Referrin to the drawings, Figs. 1 and 2 are diagrams disclosing the apparatus and circuits at the office, and

Figs. 3 and '4 are diagrams disclosing the apn'aratusand circuits at the substation.

Fig. 5 is a diagram showing the order and relations of the relays as they are energized and deenergized dur'ing'one cycle of operations. 7 In generahmy invention comprises a bank ofselecting relavs'211 tof22'0, located at the ofii c'ehand bank of selecting relays 311 to.

320, located at the'substation for synchronously switching two signalling lines 298'and 299, by means of code impulses from key to key, 150 and 156', and apparatus unit to apparatus unit, 420 and 430. V i

Referring more particularly to Fig. 1,150 and 156 are individual operating ineans. in

this case. twist-type keys. and. associated therewith are individual stop keys 151 and 157; Supervisory lamps 152. 153. 158 and 159 indicate. the condition of their individual remote apparatus unit.

position of the individual twist vkey and associated apparatus unit are not in accord. The position of the selectors is shown by the lamps 1,55 and 161. Key 167 is a master-control key which controls the supply of energy over-the signalling line for performing an operation following a selection. Lamps 168,170 and 171 indicate the condition of thesystem. that is, whether it is at rest or in operation and,

if in'operatiom whether in synchronism or The'relays 104 to 113 p v controlyrelays which functionafter a S na f v Disagreement V lamps 154 and160 are illum nated when the are the operation-- tion has been completed for transmitting an operating code. 7

Referring now more particularly to Fig. 2, the selecting relays 211 to 220 are individual to the keys 150 and 156 and are operated se-' quentially by the switching relays 201 to 210, which function to transfer the drive lineimpulses to successive selecting relays. By novel circuit arrangements, the switching relays deenergize as soon as the necessary switching operationshave been performed. This eliminates the dilficulties encountered when alarge numberofthese relays are simultaneset relay operatively responsive to a nonsynchronous condition for restoring the selectors to normal. I

Referring more particularly to Fig. 3, selecting relays 311 to 320 are energized sequentially in synchronism with the selecting relays 211 to 220 by driving impulses received by'the driving relays 321 to331 and relayed, in turn, to each. succeeding switching relay by relays 301 to 310. Relays 332 and 333 function in response to prolonged opening or deenergization of the drive line to restorethe relays to normal.

Referring more particularly to Fig. 4, circuit breakers 420 and 430 are illustrative of the apparatus units employed at the substation,,although it is to be understood'that any equipments of other types maybe the selected units;

. Relays 412to 41'? are individually 0 981110. ing relays for the circuit breaker 420, and similar relays 422 to 427 are individual to circuit breaker 430. The relays 402 to 409 are the operation-control code-receiving relays which respond to the code transmitted by the relays 104 to 113, following a selection.

Before going into a detailed description of the operation, a general description of the steps which take place in making a selection will be 'given. Normally, a holding circuit is completed over the control line 298. The first operation, either the'closingof a key manually at the ofiice or the automatic operation of a circuit breaker at the substation, opens the holding'circuit. -,A circuit is there- 1 upon completed over the drive circuit 398.

The impulse transmitted over the drive circuit is of a predetermined polarity and is relayed to energize the first selecting relay 211'at the olfice and relay 311 at the substation. The energization of the selecting recheck signalling line. Ii the checking imtwo stations. During this period, although! the selecting relay-s have been energized, the I supervisory and control lines 298 and 299 are open circuitedp Thesupervisory line, as a. matter or :tact, functions at this timeas a pulse is found to be correct, that is, a checking circuit is completed, the relay 230 energizes and completes the circuit of thecontrol and supervisory lines 298 and 29-9 to the selecting relays atthe two stations.

A circuit is now completed from the individual key at the office over the first selecting relay to the apparatus unit over the first selecting relay at the substation and, if the stop key is opened, a closed or tripped code; may be transmitted for operating the circuit breaker.

In order to better understand the invert tion, a more detailed description of the operationwhrch now takes place wi-llbegiven. lhe

operations about to be described will best be understood if theFigure 5 is, studiedat the s closes a circuit for the lamp-170 over a circuit from ground, armature 268 and its back con-. tact, conductor. 198,and, through the lamp 170 same time as the description-is read.

Although the relays are s'lrownconnected to apparently different batteries, it "will be understood that this is used for convenience in illustration and that, in actualpractice, only one battery shown thelower right hand corner of Fig. 2 is used. Thus, the relay 10-1. for example, is connected to the negativel side of the battery shown in the lower .right- 4 for the relay 230 which by-passes the original star-ting key 'at armature 268, the circuit behand corner of 2.; Similarly, the batteries shown in Figs. 3 and 4 are shown for convenience in illustration and it will be 1m:

derstood that a single battery is used ipracr tice, as shown in the lower letthandcorner of Fig. 3. The positive terminals of each'of these batteries are connected to a common re 7 turn circuit which is the return. line for all of the circuits extending between thetwo sta" battery at the ofiicethrough the windingot relay 222, the back contact and armature 286', conductor 298, armature366 and its backcon= tact, through the winding of relay 330 and 7 battery, to ground. This circuit, it will be noted, is completed over the back contacts of relays .230 and 322. If relay .230 is energized by the closing of a start key at the oh'ice,-or

relay 322 is energized as a result-of an automatic operation, this holding circuit Will-be opened to start the selectors into operation be described in more -de-" as will hereinafter tail.

As a resultof the energization of the relay 222 at the oft-ice, an energizing circuit is completed for the lamp 168 from ground over armature 268 and its front contact, conductor 196 and, through the lamp 168 and battery,

to ground.- The illumination of the lamp 168.

indicates to the dispatcher that the set is at rest. The energization of the relay 830 at the substation prepares a start circuit for setting the apparatusinto operation, responsivetoan automatic movement of the circuit breaker.

t will be assumed that the dispatcher desired to close the circuit'breaker 430 at the substation. In order todo .this-he-will momentarily operate the. start key 169 to its closed position. A circuit will thereupon be completedfor. the relay 230 from ground throughbattery, the win ding of the relay 230,

back contact and armature 267, conductorv 198, closed contacts of the key 169, conductor 19?, and, through the back contact and armae ture 266, to ground.

The energizationof the relay 230 at the cfliceopens the original holding circuit over the conductor 298 at armature 286. As a re sult of the opening of the holding circuit, the

.relay 222 at, the office and therelay 330 at the substation are deenergized. The deenergization of the relay 222 atthe ofiice opens the originally traced circuit for the lamp 168 at armature .268 and its back contact and and battery, to ground. The lamp'l68 is exsystemis started into operation.

A? further resultof the deenergization of relay 222 is towco'mpletean energizing circuit ing completed from ground through battery the relay 222 at the olfice, the relay 330' at ingot the holding circuit.

With the armature 385 moved to its back p0- he substation is deenergized upon the open- -=s iticn, an energizingcircuit is completed for g the relay 322 from ground over. armature 385 and its back contact, winding of relay 322 and. battery to ground.

lice functions to switch the control and supervisorylines *to a prepared selecting circuit of the relay at the substation likewise Theenergization of the relay 230 the ofarmature 288 at the oliice. The energization."

switches the control and supervising lines to p selecting-circuits over armatures 366 and 367 and. completes the first drive circuit over Q armature 368. A circuit is thereupon completed from ground through battery back contact and armature 273, through the winding of relay 225, back contact and armature .272, armature 291 and its back contact, front contac and armature 288, back contact and armature 269, armature 290 and its back'contact, the ClllVG line 398, back contact and armature 365, armature 368 and its front con- .327 the substation are energized. The

energization of the drive relay at the officeletes an energizing circuit for the first relay 211 from ground over armand its front contact, conductor 175,

back contact 121, conductor 184, and, through the winding of relay 211, to battery and ground. The circuit, it will be noted, is completedover the back contact of armature 121, controlled by relay 103. -As soon as the selecting relay is energized; it prepares a circuit for the succeeding selecting relay. In

order to prevent the succeeding relay from energizing at thistiinepits energizing circuit is opened at armature 121, as will be described in more detail hereinafter.

The energization of the selecting relay 211 completes locking'circuitfor itself over acircuit from ground through battery, through the winding of relay 211, its first extreme lefthand contact, back contact and armature 236,

back contact and armature238, conductor 17 3, back contact an d armature 265 to ground.

[is a result of the energization of the drive relay 327 at the substation, an energizing circuit 15; completed for-the first selecting relay thereat from ground over armature 379 back contact. conductor 394, back contact and armature 434, conductor 395 and through the winding of relay 320 to battery and ground.

The energization of the first selecting relay 320 completes a locking circuit for itself from ground through battery and through the W1 n ding of relay 320 and its first contact, hack contact and armature 362, back contact and armature 358, conductor 392, conductor contact and armature 385 to 497 and back ground. 7

The first'selecting relay at the oflice and he substation are now energized. It will be noted that the first drive impulse was com pleted from negative battery at the office and over the drive line 398 to positive battery at the substation. Attention is called to this act because the drive impulses, it will be fonndupon further analysis, remain the same for the first four selections and then the polarity is reversed for the next four selections.

Upon the energization of the first selecting 211 at the office and the selecting relay a? its front contact, armature 382 and its 320 at the substation, a checkingcircuit is completed from ground through battery, the winding of relay 228, the third contact of the relay 211, back contact and armature 270 through the winding of relay 227, armature 281 andits back contact, the 4th contact of the relay 211, back contact and armature 284, front contact and armature 287, armature 289 and its back contact, conductor 299, back con tact and armature 364, armature 367 and its front contact, armature 370 and its back contact, the 4th contact of the relay 320, back contact and armature 372 and through the winding of relay 325, and the 3rd contact of the relay 320 to ground. This is the check circuit which will be completed only after the selecting relay 211 at the oflice and the selecting relay 320 at the substation areenergized. If the check circuit above traced is completed, this is an indication that the correct selecting relays have been energized at the ofiice and at the substation and the selection preparedkby the energization of the relays may thereupon be completed. I

-The relay 228 in the check circuit traced above is a low-resistance relay and fails to operate over the circuit traced. It functions to open the check circuit to give an indicatlon at the oflice when two 'succeedlng selecting relays at the same station energize simultaneously, in which case, as will be described in more detail hereinafter, suflic ent current passes through this relay to energize 1t. The

relay 227, energized in the checking circuit 7 traced above, operates to complete an energizing circuit for the relay 226 over the armature 280 and its front contact.

The energiz'ation of the relay 226 co1npletesa locking circuit for itself from *ground through battery, winding of relay 226, front contact-and armature 277, and front contact and armature 275 to ground.

A further result of the energization of relay 226 is to complete an energizing circuit for the relay 229 from ground over the armature 275 and. its front contact, armature 278 and its'front contact, armature 282 and its back contact, through the winding of relay 229 and battery to ground.

The energization of the relay 229 switches the control and supervisory lines 298 and 299from their checking position to their operating position. The above-described operations, it will be noticed, take place only after the position of the selecting relays at the oflice and at the substation have been checked or identified. l

substation is. extended over the backcontact of armature 364-, front contact of armature 367 and 370, conductor 493, armature 437 and its back contact, conductor 490, over the 6th contact of theselecting relay 320 to con ductor 396 and armature 4630f the individual circuit breaker 420,- while at] the 011106, the supervisory line 299 is extended over the armature 289, armature 287 andits' front contact, armature 284 and its front contact,

conductor 192, the armature 124 and its back contact, back contact and'armature 125, armature 131 and its back contact, conductor 186, to the 7 th contact ofthe selecting relay- 211, conductor 179, armature 116 and its back contact, conductor 188 and through the winding of relay 232 to ground. 2 r

The circuit just traced-assumes that the previous supervisory signal for this point was the same, that is, a tripped-circuit-breaker condition. the first circuit breaker will then be defenergized, as will be explained inmore detail hereinafter. The armature 116 will be on its back contact. The relay 232 will not be energized, as there was 110 battery in the circuit traced. 'An energizing" circuit for the lamp 153 is completed from ground over armature 115 and its back contact and through the lamp 153 to battery and ground. Lamp 153 burns green and indicates to the dispatcher that the circuit breaker is open.

If, however, the previous supervisory signal had'been a closed supervisory signal, the

relay 101 would have been energized and locked in a manner to be described in more detail hereinafterf The supervisory signal would then have followed upon the opening of the circuit breaker and would have been completed over armature 116 and its front contact, conductor 187, and through the winding of relay 233 to battery and ground,

the first part of the circuit being the same as that traced above.

The energiz'ation of the relay 233 would have provided a shunt circuit for the locking battery of relay 101 from ground over ,armature 294 and its back contact, front contact and armature 296, the last contact of the selecting relay 211, conductor 178 and through the armature 114 to battery and ground. As a result of this circuit, the lockof relay 323, back contact and The relay 101 individual toingcircuit of relay. would opened and relay 101 would have becoine deenergized; to complete the above-traced circuitforthe lamp 153, indicating to thedis' patcher that the circuitbreaker has opened,

Referring now again tothe selecting operations, a further result ofthe energization of the relay 229, following the correct checkimpulse transmission, is to. complete an en-. 1

vidual to this point has not beenoperated. Not only is this-circuit completed over the contact of the key, but also over the :front contacts of the check relay and selecting relay; The relay,= therefore, must I be 'enere gized, that is, a selection must have been. made before this operation which isprepara tory to the succeeding selection, can be completed. Ifthe stop key has been operated to its open position, the stepping operations tracedthus farwill stop, and no further selecting; relays willbe energizeduntil the stop key is again releasedto close its contact at 151. a

I, The energization of the relay 223' completes a locking;- circuit for itself from ground through battery, winding. of, relay 223, -frontf contact and armature 271, and over the conductorl89-to ground over the circuit traced above.

course, upon the fact that thestop 'keyindi deenergizes and opens the originale'nergizi ing circuit of the relay 226 at armature 280. The energization of the relay 223 also opens the drive circuit at armature 272 andthereby deenergizes the drive relay 225.

Attention is called, at this time, to the fact that control and supervisory operations take place while the drive circuit is energized, and the preparation for the stepping operations takesplace by the opening and furthe-rclosing of the drive circuit during a non-operating control and supervisory period. This is an important feature of this system, since,

maintaining the drive circuit energized during the operating period, it becomeslpossible to detect non-synchronous conditions 7 and restore theapparatus to normal without the needof'further signalling lines.

The above-mentioned detection and restoration become possible by reason of the fact that, at no time, should the drive, line be opened for a very long period of time, since it is only opened momentarily during the stepping periods. If the apparatus is brought .to a stop for any'operating purposes, the drive line is closed. Wherefore, ifthe drive line opens for a period longer than a predetermined reasonable stepping time, it is due to some difficulty or trouble in the system and this extra long open period can then be employed to automatically reset the apparatus to normal.

If, on the other hand,trouble should occurwhen' the driveline is closed, it is only necessary for the dispatcher to open the drive line and kee it open for an interval of time, whereupon the apparatus is restored to normal; This will be described in more detail hereinafter.

The above description of the operation has now been traced through a complete cycle. lVith the drive line opened at armature 272,

the relay 225 at the ofiice and 327 at the sub-' station are deenergized. The deenergization of the relay 225 at the oilice completes an energizing circuit for the first switchover relay 201 from ground through battery, winding of relay 201, thesecond'contact of selecting-relay 211, and back contact and armature 274 to ground.

The'energization of the relay 201 completes a locking circuit for itself from ground through battery, winding of the relay 201, front contact and armature 236, back contact and armature 238, and back contact and armature 265 to ground.

A further result of the energization of relay 201' is to complete an energizing circuit for the relay 103 from ground through bat tery, winding of relay 103, conductor 174,

"' front contact and armature 235, and back contact and armature 265 to ground. 7

The energization of the relay 103 completes a locking circuit for itself from ground through battery, the winding of relay 103,

front contact and armature 120, conductor 7 173 and back contact and armature 265 to ground.

' The energization 'of the relay 103 opens the original energizing circuit for the first selecting relay 211 at armature 121 and completes an energizing circuit for the relay 164 over armature 122 and its front contact.

The energized relay 164 completes a looking circuit for itself over armature 166 and "the key 162 and completes a circuit for the buzzer 163 over armature 165. The dispatcher is thus advised that the set has been started into operation. Should he be away from his desk when the set is started into operation,

due to an automatic movement of a circuit breaker, his attention is thus called to the fact that a change has taken place, and he will immediately return to his desk to find out what operation has taken place. The buzzer "continues until he operates the key 162 in order to open the locking circuit of therelay The energization of the relay 201 switches the selecting relay circuit from the drive recircuit for the switchover relay 310 from 1 ground through battery, winding of relay 310, second contact of the relay 320 and back contact and armature 379 to ground.

The relay 310 locks itself over a circuit from ground through battery, winding of relay 310, front contact and armature 362, back contact and armature 358, conductor 392, conductor 497 and back contact and armature 385 to ground.

The energization of the relay 310 completes an energizing circuit for the relay 401 from ground through battery, winding of relay 401, conductor 393, front contact and armature 361, conductor 392, conductor 497 and back contact and armature 385 to ground. The energization of the relay 401 completes a locking circuit for itself over armature 432 and conductor 497, as traced above.

The energization of the'relay 401 opens the original energizing circuit for the first selecting relay 320 at armature 434 and transfers the starting circuits of all the apparatus units to the reset relay 410 overthe front contact of armature 433, as will be described in more detail hereinafter.

The energization of the relay 310 opens the locking circuit of the selecting relay 320 at armature 362 and its back contact and pre pares an energizing circuit for the next selecting relay 319 at armature 363 and its front contact.

Returning now to the operations at the ofiice, a further result of the deenergization of the drive relay 225 at the office is to open the locking circuit for the relay 226 and the energizing circuit for the relay 229 at armature 275. The signalling lines are now restored to their original positions for first transmitting a check impulse.

Upon the deenergization of the selecting relay 211, the locking circuit of the relay 223 is opened at its fifth contact. The deenergization of the relay 223 again completes an energizing circuit over the drive line for the relay 225 at the ofiice and relay 327 at the substation, the'circuit being completed from battery at the office to ground at the substation.

Upon the energization of the relay 225 at the ofiice, an energizing circuit is completed for the second selecting relay 212 over a circuit from ground through armature 274 and its front contact, the front contact and armature 237 and through the winding of relay 7 contact and armature 241and back contact and armature 265 to ground.

At the substation, the e'nergizationof the drive relay 327 completesan energi'zingcircuit for the second selecting relay 319 over a circuit from ground through armature 379 and its front contact, armature 382 and its back contact, front contact and armature 363 and through thewindingof relay 319 to battery and ground. 7

With the second selecting relay at the ofiice and that at the substation energized, a check circuit will be completed from ground over the third contact of the selecting relay 212, the back contact and armature 270 through the winding of relay 227, armature 281 and its back contact, thefourth contact of the selecting relay 212, back contactand armature 284, front contact and'armat'ure. 287, armature 289 and its back contact, conductor 299 and back contact and armature 864, armature 367 and its'front' Contact, armature 370 and its back contact, fourth contact of'the selecting relay 319, back contact and arma ture 372, through the winding of relay 325,

the third contact of the selecting relay 319 and through the winding of relay 324 to battery and ground. g

It will be noted from the above that each selecting relay, upon energiz'ation, prepares a circuit for its individual switchover m ceeding selecting relay. By this arrange-V ment, a positive opening of the previously completed connection of, the control and supervisory lines over the first selecting relay is accomplished before it is. possible to complete a circuit through thefsucceeding selecting relay. 2

As further protection against possibly making incorrect selections, the control and supervisory line, it will be noted, are maintained disconnected from the selecting relays during each stepping operation and are not again completed until the checlrimpulseim dicates that the selection has been correctly and properly made, i p It will be noted that the second drive impulse was of the samepolarity and over the same line, and, therefore, identical with the first drive impulse.- Therefore, it is quite possible that the wrong selecting relay may be energized. However, the check impulse just traced is completed through the contacts of the two selecting relays at the oflicc and at the substation and is of the opposite polarity fromthe check impulse traced above for the first selecting relay. The combination of the-check and drive impulses areincrating positions. 1(l6IltlCLl to those descrlbed' in connection dividual for each pair of equivalent selecting relays at the oifice and at the substation. That is, for eachselecting position, a drive and check impulse of a predetermined polarity and over a predetermined. line individual to thatiselecting position is completed.

If relay #1 at theofiice and selecting relay #2 at the substation were to be energized,

this check impulse would not be completed. It will be noted that the check impulses are completed over' the third and fourth contacts of thevarious selecting relays. A study offthe disclosure will show that the third contact of the first selecting relay at the oifice is connected to the winding of relay 228 and battery, whereas the th rd contact of thefirst selecting relay at the substation isconnected has energy from battery at the ofiice to employed to distinguish the various check,

impulses, but also achange in the signalling line over which the impulse is to be transmitted. The check impulse traced above not only passesthrough the third contactof the selecting relay but also through the fourth.

While the third contact, as explained above,

determines the polarity which is tobe'transmitted, the fourth contact determines the line over which this impulse shall be transmitted.

In the case of the first two selecting relays, since the polarity is reversed, as indicate, above, there is no needto change-the signalling line, and the fourth contacts of the two selecting relays are multipled and connected over the supervisory line. i

If the check impulse traced above is properly completed by reason Ofthe correct en: 'ergizatlon of theselecting relays at the ofiice and at the substation, the check relay 227 is energized. Theenergization of the relay 227 completes an energizing circuit for the relay 226'over the armature 280.

The energization of the relay 226 completes a locking circuit for itself over armatures 277 and 275 and, at the same time, an energizing circuit is completed for the relay 2279, as described above.

The energization of the relay 229 switches the control and supervisory line to their op- These operations. are

with the-first selecting-relay operation;

Similarly, at the substation, the energization of the relay;825 over the check circuit traced above completes an energizing circuit to, ground. The checkimpulse, therefore,

I CO

tions.

for the relay 326 over the circuit traced above, and the energization of the relay 326, in

turn, completes an energizing circuit for the relay 323, as traced above.

The energization of the relay switches the control and supervisory lines 298 and 299 from their checking to their operating posi- The control and supervisory circuits are now again completed.

If the stop key has not been pulled out at the second selection posit-ion, the drive circuit is again opened, the signalling lines are again switched to their check positions and the drive line thereupon again closed for the third drive impulse; This impulse is identical with that traced for the first two. When, however, the third selecting relay is ener-. gized, the check impulse transmitted is completed from ground through the battery, the winding of relay 228, the third contact of the relay 213, back contact and armature 270, the winding of the relay 227, armature 281 and its back contact, the fourth contact ofthe' relay 213, back contact and armature 283, the

front contact and armature 286, over the con the same polarity. However,'it will be noted that this impulse is transmitted over a different conductor. This particular check cir-' cuit can only be completed if the third selecting relay at the ofiice and the third selecting relay at the substation are energized. Should selecting relay #3 at the office and relay #4 at the substation, or any other non-equivalent combination of selection relays be energized,

this circuit would not be completed. If the check impulse is correct, the energy transmitted will operate the relays at the office and at the substation for switching the signalling lines to their operating positions, as has been described in detail above.

When the fourth stopover relay 205- energizes, an energizing circuit is completed for the relay 224 over a circuit from ground through battery, the winding of the relay 224,front contact and armature 247, and back contact and armature 265 to ground. .The energization of the relay 224 reverses the connection of the winding of the relay 225 from battery to ground at armature 273 and its front contact.

At the substatiom'upon the cnergization of the fourth selecting relay, an energizing circuit is completed for the relay 328 from ground through battery, winding of the relay 328, front contactand armature 352, conductor 392, conductor 497, and back contact and armature 385 to ground. I

fice and relay 328 at the substation, as described above, reverses the polarity of the drive impulse from battery at the oiiice and ground at the substation to battery at the substation and ground at the oflice. It will be noted that the first four selecting relays are energized by drive impulses of the same polarity. Each selection, however, is identified or checked by an impulse, individual to that selection, either by a different polarity or by a different transmission line. Thus it may be said that each selecting relay has been operated by a code, since two impulses, both of which must be of the correct polarity and over the correct line, are transmitted before a selection was completed.

The selecting relays from 5 to 8 are now energized in the manner described above in connection with the first four selecting relays except that the polarity of the drive impulse is reversed. At each energization of a selecting relay, a check impulse is transmitted in exactly the same manner as described in detail above to identify the selection either by polarity or signalling lines over'which the impulse is transmitted.

Upon the energization of the eighth switch over relay 208 at the otfice, the energizing circuit for the switchover relay 224 is opened at armature 256. Similarly, the energization of the eighth switchover relay at the substation opens the energizing circuit of the relay 328.

The deenergization of the relay 224 at the oiiice and relay 328 at the substation restores the drive circuit to its original condition, and the ninth and tenth selecting relays are energized by drive impulses which are like those which energized selecting relays 1 to 4.

A further result of the energization of the eighth selectingrelay is to complete an energizing circuit for the relay 231, from ground through battery, the winding of the relay 231, the front contact and armature 256, the back contact and armature 265 to ground.

At the substation, the energization of the eighth selecting relay 303 completes an energizing circuit for the relay 321 from ground through battery, Winding of the relay 321, the front contact and armature 340, conductor 392, conductor 497, and backcontact and armature 385 to ground.

The energization of the relays 231 and 321functions to transfer or switchover the conductors 299 and 398. The drive impulse, it will be recalled, was transmitted overthe conductor 398. As a result, however, of the above-described switching operation, conductor 398 will now function for the ninth and tenth selection as the supervisory line and conductor 299 which formerly functioned as a supervisory line, now is the drive line.

The next drive impulses, while ofthe same polarity as those which energized the first four selecting relays, will" nowbe transmitted over the conductor 299 and over the front contact of armatures 290 and 365 tothe line drive relays 225 and 327, as traced be fore.

The check impulse for the ninth and tenth selecting relays 'Will be transmitted over the conductor 398. Asis clear from the .above description, no two selecting relays have the same combination. This code canbe con tinned by employing the conductor 398- as the supervisory line and theconductor 299 as the drive 111116 for the next eight selecting relays, whereupon, thecontrol line can be switched withthe d'rlve line nrthesame man- I ner as described 1n detail above, so thatthe:

drive impulses are transmitted over the conductor 298, and the conductor- 398. functions: 7

This codingcan be conkey 150 to position the keyfor closing the circuitbreaker. I

As a result of the" operation of stop key 151, the circuit formerlytraced through the stop key for energizing the relay 223 in,

order to open the drive circuitis not completed at. this time, andthe drive circuit. remains closed, thereby stopping thelrelay T ductor 195,.contact of thefmasterkey167, conchain from further stepping,

. Thedispatcher will now-operate the ter key 167 to its closed position. and main tain it in this position until the correct supervisory signal, indicating that the circuit breaker has closed in accordance with his operations, is received.

Should the dispatcher open the master key before the signal; is received, the apparatus is restored to normal ithout performing the operation, as will be described in more d e;

tail hereinafter.

After the selection has been made, acode of impulses is transmitted over the line+operatingchain of relays, both at the ofiiceand at the substation, for closing the circuit A difierent code is employed for tripping the circuit breaker. This arrangement for operating the circuit breaker as breaker.

a selector by means of a codeis called operation control.

It is an essential part of a supervisorycontrol system inasmuch as it overcomes one of the chief difficulties experienced in employ ing a synchronous relaygsystem, namely, the sensitiveness of such a system to elect-rlcal disturbances from extraneous sources.

It is, of course, possible to so operate synchronous system that-as the line shall be switched synchronously at both ends, di-

rect circuits are completed. at .each position" to apparatus units without. the use of a fur-r 'ther code ofimpulsesxforactual,operation. 1

upon the apparatus units, since it requires. not. I

only that a completeand correct selection, be madefor'opera'ting'the'unit but-also the. transmission of the. proper; code thereafter. In this case=,.fiveiimpulses, three over the control line and two over the supervisory line, for .changingthe polarity are .transmittedfor: closing the selected circuit breakenwvhile three impulses; are transmitted for trippingv the ,circuitbreaker; 1 1 Therelays 104 t0 113, are the operationcontroll relays located; at the office, and the relays. 402 to 409;. the relays located at the substation for receiving operation-control code signals. g i.

The code that is tobe transmitted is determined. by the particular .relay 107 or 105 energizeds 'Energization of the relay 107' causes the transmission of five impulses for closing. the circuit breaker, and the energization of the relay 105 transmit's three impulses;

for .tripping' a circuit, breaker. 7

In this instance, since it isassumed that the circuit breaker is to be closed, theindividual key has been operated to energize the relay; 1'07 over-a. circuitlfrom ground through bat.-

tery, the winding'of1relay.107,fthe closed contact of the key' 150, conductor .180, the sixth. contact of "the selecting relay 211, conductor 194C,"arn1ature,2 76 and itsfront contact,back contact and armature 279 and the In front contact and armature 275t0 ground."

It'will be noted that this circuit. is completed over the'front contact of the line-driverelay 225. The circuit is Ialsocompleted over the front contact of-thecheck relay 226. This LI.

completes an ena V contact andilower armature of relay 113, front contact andarmatu're 132 andover con-v Y ductor 194 to ground as traced above. I

yyTh'e jenergization of the relay'226 -completed the first? operation control impulse over the control line from. positive batteryat thev olfice to negative battery at the substation, the circuit being completedfrom ground over the fifthcontact'of the selectingrelay 1211, conductor 181, the right-hand contact of the stop .key 151, the armature 136 and'xits back contact, back contact. and-arma-. Y

ture 139, the upper contact of the key. 167,. conductor 193,. the front contact and arma-:

ture 283, front contact and armature 286, conductor 298, armature 366, and its front tact and battery to ground.

The energization ofthe relay 406 at thesubs'tation completes an energizing circuit for therelay 404 from ground through battery, windingof the relay 404, front contact and armature 446, conductor 495, armature 374 and its back contact, front contact and arm'a-.

ture 382, front contact and armature 379 to ground The relay 404, which isa slowrelease relay, energizes and remains closed during the succeeding periods of impulses.

A further result of the energization of the V an energizing circuit for itself over the front relay 406 is to complete an energizing circuit for the relays 402 from'ground through battery, winding of the relay 402, back contact and armature-449, front contact and arma-' ture 447, front contact and armature 442, and over conductor 495 to ground, as traced above. I

Theenergization of the relay 402 completes'an energizing circuit over the super visory line from positive battery at the substation to negativebattery at the office. This circuit is completed from ground over the conductor 495, armature 442 and its front cont act, armature 448 and its back contact,

armature 454 audits back contact, front contact and armature 437, conductor 493, front contact and armature 370, front contact'and armature 367, armature 364 and its back contact, supervisory line 299, back contact and armature 289, armature 287 and'its front contact, armature 284 and its front contact, conductor 192, armature 124 and its front contact, through the winding of the. relay 108, armature 140 and its back contact, to battery and ground. a y

The energization of the relay 108'at the office completes an energizing circuit for the relay 109 from ground-through battery, winding of relay 109, back contact and armature 142,- front contact and armature 133,

" front contact and armature 132 to ground oyer'the conductor 194. Y Y

The energization of the relay 109 opens the originally traced impulse circuit over the.

control line at armature 136. The opening of the control line'deenergizes the relay 406 at the substation which, in turn, completes an energizing circuit for the relay 407 from ground through battery, winding of relay 407, back contact and armature 439, front contact and armature 436, back contact and armature 447, front contact and armature 442 to ground over the" conductor 495, as traced above, and also completes an energizing circuit for relay 405 from ground through battery winding of relay 405', front contact and armature of relay'404, back contact and armature 446 to ground over conductori495;

The energizationof the relay 407 at the substation opens the originally traced supervisory impulse at armature 448 and completes a locking circuit for itself over this armature from ground through battery, winding of the relay 407, front contact and armature 448, front contact and armature 442 to ground over the conductor 495. The opening. of the supervisory line deenergizes the relay 108 at the office which, in turn, completes an energizing circuit for the relay 111 from ground through battery, winding of the relay 111, back'contact and armature 146, back contact and armature 134, and front contact and armature 137 to ground as traced above. i

The energization of the relay 111 completes pletes the third operation control impulse over the control line'from negative battery at the ofiice to positive battery at the substation, the circuit being completed from ground through battery, armature 144 and its back contact, front contact and armature 139, upper contact of the master key 167, conductor 193, front contact and armature 283, front contact and armature 286, conductor 298, armature 366 and its front contact, armature 369 and its frontcontact, conductor 494', and through the winding of relay 406, armature 450 and'its front contact to ground over conductor 495.

The energization of the relay 406 co1npletes an energizing circuit for the relay 403 from ground through battery, winding of the relay 403, back contact and armature'453, front contact and armature 449, front contact and armature 447, front contact'and z grgiature 442 to ground over the conductor substation completesa locking circuit for itself from ground through battery, winding'of the relay 403, front contact and armature 438, front contact and armature 442 The energization of the relay 403 at the visory line from negative battery at the substation to positive battery at the office, this circuit being completed from through the battery, armature 443 and its front contact, armature 440 and its front contact, armature 445'and its front contact, armature 451 and its back contact, armature 454 and its back contact, front contact and :J 9

ground a:

tor1 2, the front contact and'armature 124,

and through the winding of the relay 108, armature 140 and its front contact, back contact and armature of the relay 106 to ground over conductor 194. r. I

fThe energization :of the relay 108 com plates an energizing circ uit for the relay 112 from ground through .battery,:-Windingof. the relay 112, front contact and armature 142, front contact and armature 133xto ground, as traced above. 7 1..

The energization ofthe. re'lay1l2 completes and energizing circuit for itself over the front contact and armature 145. The energization of the relay 112 opens the third operating control impulse. over'the control line at ar1nature144.. As aresult, the relay. 406 is doenergized at the substation and completes an energizing circuit for the relay 408 from ground through battery, Winding of the relay 408, front contact and armature 439,

front contact and armature 436, back con tact and armature 447, front contact and armature 442 to ground-over the conductor 49,5.

The energization of the relay 408 completes a locking circuitffor itself over the front contact and armature .452 and over t contact and armature 442lto ground 0'. erthe conductor 49.5. l A further result of the onergization of the relay 408 is to open the fourth operation Icontrol impulse over the SHPGLVlSOLy line at armature 451 and to prepare an energizing circuit for the relay 409 at'armature 453. 7

The opening of the supervisory line at the substation deenergizes the relay 108 at the oliice- The deenergization of the relay 108 at the office coinple es'an energizing circuit forthe, relay 113 over, the circuit from" ground through battery, Winding of the relay 113, front contactand armature 146, back contact and armature 134, and front contact and armature 137 to ground over the circuit traced above.

The energization of the relay .113-com" pletes a locking circuit over the armature 149 and its front contact. A further resultof the energization of the relay 113 is to complete the fifth operation control impulse from negative battery at the office over the control line to round at the substation I a u o b 7 this circuit bein com leted from round A O e through battery, 'thearmature 148 and: its

front Contact, front contact'and armature 139, the upper contact of the master key 167, conductor 193, front contact and armature 283, front contactand armature 286,

conductor 298, armature, 366 and its front contactf-arniature369 and its front contact conductor494, through the Winding of the.

relay 406, arniatl'ire 450 and lts front contact, :to ground overithe conductor 495;

The-energization of the relay 406 at the substation completes an energizing, circuit for the'relay 409 from ground through batt'ery, Winding of the relay: 409, front contact and armature 453,- front contact and armature 449, front contact and armature 447, front contact and armature 442 to ground over thef-conductor-495'. y

A furtherresnlt of the energization of the relay 406-is to. open the energizing circuit of-the relay 405.

.'-After an interval oftiine, the armature of relay, 40 5 :drops to its back position. A circuit is thereuponcompleted for closing the circuit from'ground through battery, armature 443 and its front contact, armature 440 and its front contact, armature 445 and its back contact,armature.455 and its front contact, conductor 491, the seventh contact of the selecting relay 320, conductor 397 and through the Winding of the relay 414 to ground; i g

Theenergizat'ion of the relay 414 completes ane'nergizing circuit for the solenoid 417 from thene ative side of thebattery, front contactand armature .466, winding of the solenoid 417'to, positiviesideof the battery, the

energization of the solenoid 417 completing an obvious energizing circuit for the operatingmagnet 419 over the contacts 472 and 473. The circuit breaker 420 is thereupon operated to itsclosed position. The closing of the circuit breaker completes an obvious energizing circuit for the relay 413 which, upon energization, in, turn, completes an energizing circuit for the relay 412 over arn1ature 485.

- The energization .of'the relay 412 operates its arinature .463 andcompletes an energizing circuit over the supervisory line from ground through battery, front contact and armature 463, conductor 396, sixth contact of selector relay320,-conductor 490, back contact and armature 437, conductor 493, front'contact and armature 370, front contact and armature367, armaturef364 and its back contact,

supervisory line 299, back contact and armat l T 289, armature287 andlits front contact, armature 284 and its front contact, conducrelay211, conductor 17 9, armature. 116 and its back. contact, conductor 188 through the Winding of the relay 232 to ground. 7

The energization of the relay 232.con1plefes i an energizing circuitfor the relay 101 from ground through battery, armature 295 and its front contact, back contact and armature 296, eighth contact of the selecting relay 211,

conductor 17 8 through the Winding of th relay 101toground;v z

fore, happen that he closes the circuit breaker The energization of the relay 101 completes a locking circuit for itself over armature 114 and opens the circuit for the lamp 153 at the back contactof 115 and-at its front contact closes a circuit for the'lamp 154.

The extinguishing of the lamp 153 and the illumination of the lamp 154thusqgives an indication to the dispatcher that the circuit breaker h as closed in accordance with his operation. I

Since the circuit which the dispatcher is to close is, remotely disposed from him, he has no Way of ascertaining the condition of the lineat the time he operates the circuit breaker to the closedposition. Itmay there'- on a short-circuit. In such case,the overload relay on the circuit breaker will immediately operate to'trip the circuit breaker to its open position. This may happen while the control impulse is still completed for the operate winding of the circuit breaker so that the circuit breaker will again start. to close,

' followed, of course, by an immediate opening thereof when it closes upon the short-circuit.

This may happen a number of times, causing what has become known in the art as pumping. consequences, not only to the circuit breaker but to the line which is thusbeing periodically closed. It is essential, therefore, to provide some means whereby, if the circuit breaker once closes and is immediately opened, it may not close again unless the dispatcher goes through the operation of tripping the circuit breaker and then again closingit by the operation of his keys.

This problem becomes difirlcult by "reason of the'fact that the pallet contacts of the circui U breaker are so arranged that the supervisory signals may be completed before the circuit breaker has completed its entire movement and been latched closed. A 7 Means must be provided for maintaining the energy on the line a predeterminedlength of time in order to insure that sufficienten ergy' is suppliedto completely close the circuit breaker. A s-a part of this means, it'is further necessary toprovide an arrangement for disconnecting this source of energy in case the circuit breaker latch isclosed and then tripped.

Iprovide a simple and very accurate antinumping arrangement. It Wlll be assumed that, immediately upon the closing of the cir tion, after a short interval; of time, and-a circuit is completed over the'supervisory line Pumping may result in serious of the back contact the relay 101 being energizedat this time, conductor 187 relay 233 tobattery. v i

The energization of the relay 233 completes a shunt circuit for the relay 101 from ground over the armature 294 and its back contact, front contact and armature 296, eighth contact of the selecting relay 211, conductor 178 over the armature 114 and its front contact and battery toground. The relay 101 isthus deenergizedand permits the armature to drop to its back position,

The lamp 154 is extinguished and the lamp 153 illuminated, thereby indicating to the dispatcher that the circuit breaker has been tripped; A further result of the energizetion of the relay 233 is to open the energizing circuit of the relay 110. It will be re called that this circuit was completed over the conductor 191 and armature 297. 7

Upon the energization of the relay 233, this circuit is opened at armature 297. The deenergization of relay opens the control line at armature 139. The opening'of the control line deenergizes the relay 406 at the substation. The deene 'ization of the relay 406 opens the energizing circuit for the relay 404 at I armature 445.

, 111, 112 and 113 still remain energized so long as the master key is depressed so that no new open tion can be restarted, since the control line is opened at relay 109 at the office.

Under-these conditions, in case the master key is released, the relay 107 will still remain energized over a circuit from ground through battery,;winding of the relay 107, the closed contact of the key 150,-conductor 180, sixth contact of selector relay 211, conductor 195, front contact an d armature 1 0, armature 138 and its back contact, front contact and ari'z'iature 147, conductor 194, armature 276 and its front contact, back contact and armature 279,

and front contact and armature 275 to ground. r 4. 1

In 01 der, therefore, to release the appara tus under, these conditions, it is necessary,

not only to open the master key 167, but also to switch the twist key to its tripped position in order that it may agree with the condition of the circuit breaker.

The circuit for the relay 107 is, thereupon, deenergized which, in turn, opens the circuit for the relays 108, 109, 111 and 113, all of which have been energized over the front contacts ofarmature 132 of the relay 107.

Upon the restoring of the stop Ikey '151'to close its left-handcontact, an energizing circuit is completed for therelay 223, as traced above, which opens the'driveline'at armature 272, and the apparatus is thereupon stepped again-from contact to'contact. I

Upon the energization of the last selecting relay 220, an energizing circuit is completed for the relay 221 from ground through bat tery, winding ofthe relay221, armature 264 and its front contact, and front :contactand armature 274 to'ground. The energization of the relay 221-opens the round circuits of all the locking andenergized relaysat armature265 'and 266: All

' of the relays are-deenergized, and a locking circuit is completed forthe' r'elay221 from the ground to battery, winding of'the relay.

221, front contact and ar1nature- 267, back contact and armature 268".to ground;

At the substation, upon the energization of the last selecting relay, the" energized clrcuit of all the locked relays "is opened and the apparatus is restored to normal-in thesame manner. for the relay 222' at the office and the relay 330 at the substation, as originally "traced.

- The energization of the relay-222at the sub;

station opens'the energizing circuit" of the relay 221 which thereupon is deenergized to its original normal position.

In the foregoing, the. manner in which a circuit breaker is operatedto a closed position by the transmission-of-five'impulses has been described. InQorder to operate the breaker to a trip position'instead of to a closed position, only three impulses are trans,- mitted as stated above; This is accomplished by operating the twist key 150 to the position shown, whereupon a circuit is completed for the relay instead of for the relay 107, the circuit extending from ground throughbats tery to the winding of relay105, through the left hand contact shown closedv in {thekey 150, and thence over; conductor 180 as traced above in connection. with the relay. 107.. It will be noted that relay 106 is connected in multiple with-relay 105 andenergized'simultaneously therewith.

As a result of the energization ofrelay 105,

a circuit is completedfor the relay 104 from tion to energize relay 402 as a result of which second control A circuit is'thereupon completed {1 the secondcontrolimpulse was. transmittedfrom thesubstation tothe oiiice- Thissecond impulse, it willbe recalled, energized relay 7 108, which, in-turn, energized relayil09l 'En-.

ergizationof relay 109 opened the energizing circuit, of the first control impulse, deenergizing relay 406. Relay 406 upon deenergiza's tion energized relays 407 and 405. Energiza tion of relay 407uopened the circuit for the impulse circuit, to deenergize the relay 108. Energization of relay 10.8 onergizes'relay 111. which,.in turn, energizes relay '110'and upon energizationofrelay 110,

the third controlimpulse is transmitted over the lineto energize relay 406.. Relay 406, upon energization, energizes 'relayf 403 which prepares an energizing circuit for the :relay 108-as describ edin full above. This operation is repeated up to this point for'tripping the bl' eiker. L

.It will be noted at this time, however, result of the energization of relay-106, the

circuit. for the fourth control-impulse which energized relay I 108,, is opened atv the back contact of the first armature of energized-remains energized for ailonger period of time than normal-and,- during. this period the relay 405, which as described here, isgenerl gizedover the back contact and armature 446, 15 deenergized after an interval of, time and drops its-armature445 to its back contact,

completing thereover acircuit for, performing. an operation. I

1 In the first described operation for closing he breaker,-following the transmission of the five controlimpulseathe relay 409 was energized before the relay 405 deenergizedand accordingly the operating circuit was completed over .thearmature 455; and its front I 106, softhat-no circuit' can be completed 7 for this: fourth control impulse. Accordingly, "the relay 406Jat: the remote station. re-' Contact which as traced out over conductor 491, 'eXtends to the relay 414.

In the present case, however, inasmuchas only three impulses were transmitted before the pause occurred. permitting the deenergizationof the relayr405, relay 409 has not been energizediandaccordingly the control circuit rendered effective when relay 405 deenergizes, extends over the ar-matures 455 and its back contact and through.thecontactsof the selecting relay to relay 415 which, in

turn, complete an energizing circuit for the solenoid 415 to complete an energizing circuit for the tripping magnet 418.

" Aswill now be clear' from the above de' Y scription, the'closing is performedbyfive impulses'during which periodthe relay405 is maintained energized, it being a' slow-re lease relay whlchremalns energized during the short intervalsbetwe'en the energization V of relay 406. When'the {impulsing stops, however, and the relay406 remains energized for longer than a predetermined interval, a

sufiicient time is provided for permitting deenergization of relay405 and, as a result,the control circuit iscompleted. The control 7 circuit, inturn, dependsupon-whether the relay 409 has or has not been energized; if

only three impulses have been transmitted as described aboVe,.thel-relay409 is. not men gized. 1 In order to. restore the apparatus to normal, it is necessary to. operate the stop key 7 'a resultof the operation of the stop key to its normal-position, therelay406iis deenergized',

whichdeenergizes any of the operation'con trol relays at the substation such as relays 402, 403, 404, 405, 406, "407; In'this manner the eiitire apparatus is restored to normal.

Should a circuit breaker. automatically operate, the-apparatus is set intooperation in substantially the same manneras that de scribed in connection with azkey operation. Inorderto illustrate this, it Will be assumed that the circuitbreaker 420 is automaticallyclosed.- Upon the closing of .the circuit breaker an energizin g circuit is completed for the rel'ay 413 1Vhich, in turn, completes ant-energizing circuit forthe'relay 412...

1 'Following the energization of therelay 413, but before the relay 412 'is completely energized, :a circuit is completed for the relay 410 from ground over armature 464-and this purpose.

its ffront contact,b'ack contact and armature 462, armature433 and its back contact, con;

ductor 497-and through'the Winding of the 1 relay 322 and battery to ground.

The 'energization of the relay 322 opens the normal holding {circuit over the control line 298 and -deene'rgizes the relays 330'atthe substation and 222 at the office. Thereafter, tlie' drive circuit operates in exactly the manner described above in connection Witlian operation from the office until the "circuit breaker which'ha's been operate'd'is'reached, whereupon a supervisory signal is transmitted over'the supervisory line, in am'ane .d scri d bo ee j 7 It may happen that a second circuitbreaker will be operatedautomatically after the ircuitfbreaker 420 has operated but before the apparatus has been restored normal. Means must. be provided for preventing the supervisory signal for this operation from beinglost. A restart circuit is provided for It will be recalled that one of the first re 7 lays Which energized upon' operation of the first selecting relay is the relay 401. .The

energization of the relay 401 transfers the start'operati'on previously traced over the armature. 433 and its'back contacttoarmature 433 and its front contact.

It Willbe assumed that the circuit breaker 430. closes Whilethe selected relays are in operation and the relay 401 is energized and locked over armature 432. As in the case of the circuit breaker 420, upon the closing of the circuit breaker 430, the relay423 is energized and, :in turn, completes an energizing circuit forthe relay 422. Before the and-armature 458 to ground over the con ductor498. -A further resultof the energization of the relay 410 is to prepare an energizing circuit for the relay 411 over the armature 456; This circuit is not completed at thistime because, during the operation of the selecting relay, the relay 330'is deenergize'dzand the armature 385 is: on its back contact. r

.After the selecting relays have completed their cycle of operation and been restored to normal, in the manner described in detail above, the relay 330 is energized. A circuit is-thereupon completed. from ground over armature 385 and its front contact, conductor 496, front contact and armature 456 and through the Winding ofthe relay 411 and batteryto ground.

The energization of the relay 411 completes a locking circuit for itself over armature 459 and its front contact to ground over conductor 496, and the armature 460 completes a circuit for the'relay' 322 over armature 457- anditsback contact. This'momentary circuit energizesthe relay 322, Which, thereupon, again starts the selecting apparatus into operation, in the manner described in detail above. e

A further result of the energization of the relay 411 is to open the. energizing circuit of the relay 410 at armature 461'. The relay 410 is deenergized and, in turn, completes a circuit for the relay 322 over the conductor- 497. The relay 322 isenergized and starts the selected apparatus into operation, in a manner described in detail above.

. As soon as the apparatus is started into operation,-'t he relay 330 is deenergized and opens the lockingcircuit of the relay 411; Therelay 411 is deenergized to open the original energizing circuit of the :relay 322. The selecting apparatus now operates in the manner described above until the circuit breaker which is operated is reached, whereupon a ill) nssaeos supervisory signal is transmitted, in the man-v ner described in detail above. 1 i i This arrangement also provides a repeat circuit which operates everytime anapparatus unit is changed to check the circuitof'the unit for the dispatcher. Thus, should the dis patcher select any circuit breaker foroperation and complete the operation of the breaker, the supervisory signal is received, the selecting apparatus continues through until finally restored to normal, whereupon the cycle of operationsis again repeated andfa second supervisory signal or check ispro vided for the dispatcher. r 2

it will be recalledjthat it was-pointed out, inthe beginning of the specification, that, if the relays fallout of step, so that two non.- synchronous sele'cting'check relays are energized simultaneously, the check circuit will fail to operate. A further arrangement has been provided for immediately restoring the apparatus to normal should such aiconditio'n.

occur. a I, r

In order toillustrate the operation, it will be assumed that the selecting vrelay 211at the oiiice energized.simultaneously ywithfthe selecting relay 319 at the substation. As has been pointed out in detail above, no checking circuit is completed, and the relay 227, therefore, fails to be energized. The lamp 171 which is energized every timelthe relay-227 is energized, fails to illuminate and the .dispatcher is thus apprized of trouble .in his set.

In order to restore the apparatus to normal, it is only. necessary for him toclose'tlie key 172. An obvious energizing circuit is.

thereupon completed for the relay 234i. The energization of relay 234 .efl'ectsthe opening of its armature 291 to open the drive circuit and armature 292 to remove the shunt circuit.

around the highresistance 292a to insertthe resistance in the energizing circuit for the relays 222 and 330 which are energized when the system is in a normal non-operating condition.

At the same time armature 2926 opens the negative side of the station battery circuit for all the normally non-energized relays at the dispatchers office. In other words, the armature 2925 controls or opens a bus conductor which is illustrated simply as a batteryand ground connection at each relay throughout the system. V

Therefore, it is evident that theopening'of armature 292?), of relay-23l, restores allthe relays at the dispatchers oliiceto their normal condition. w y Since the normal operating; condition is attained when the drive lineis ClOSGdytllQ drive line is normally open only forsmall intervals of time duringv the operation of the selecting relays, namely, periods during switching from one selecting relay, to the succeeding selecting relay.- The energization of the relay 2345, however, maintains thedrive circuit for the relay the *relay'333 is normally maintained energized overfthe frontcontact of armature 380 when the system is in operation. Durlng the line open at armature 291 for a period longer than 18 usual during the operating condition.

short interval of time betweenthe stepping operationsywhile the relay 327 is deenergized, relay cannot be'cleenergizedy since it isfa slow-releaserelay.

Upon the opening of thedrive line, however,- and'its benig mai'ntained open for a longperiod'oftime, the relay 333 drops to its back position and completes an energizing over the armature 391.- The energization'of the relay 332' eflects the opening of its-armature 332a toopen the groundcircuit of all the energized relays at the substation which are, thereupon, restored tonormal. E 1 3. As described hereinbefore, the opening of armature 292, of'relay 23 i, inserted the high resistance 292a in the energizing circuit for relays 222 and 3 30. .This causes'relays and 330 to drop out if they are energized or toremain out of deener 'ized, and relay 33O at itsyarmature 385a opens the normal holding circuit for maintaining relay333 closed when the'driverelay 327 is not operating. This permits the: relay 333 to open its-arn'iature 391, when the armature 380 of the drive relay 327v remainsfopen for a prolonged inter val of time in response to the operation of key 172.., I I

f two selecting relays at either'the oliice or stat-ion, are operated simultaneously, the apparatus is restored'to normal in the following manner. It will be assumed that resimultaneouslyl A circuit is thereupon completed for the relay 228 from ground through battery winding of'the'rclay 228, third con? tact of the relay 211, and third contactof the relay 2l2toground.

The energization offthe relay 228 opens the circuit ofthe checlrrelay 227 at armature 281. The dispatcher is thus apprised of trouble in this apparatus. The relay 22S,

. 0 lays 21-1 and 212 at the ofiice areenergized it should'be noted, is so designed that, when energizedin series with the relay .227, asis true during the checking operations, it does not get enough energy .to operate its armature, but,when locally energized, as traced above, it operates its armatures to their front contacts.- Similar y,'the energization of any two selecting relays at the substation will completean energizing circuit for the relay The energization of the relay 324 opens the circuits otthe relays 323 and325 to restore the apparatus to'n'ormal, in the manner described in detail above. False operations of any kind are thus-eliminated..-

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