US1796957A - Remote control system - Google Patents

Description

March 17, 1931. M. L. NELsoN REMOTE CONTROL SYSTEM Original Filed Nov. 16, 1921 `6 Sheets-Sheet l WH: l?"

- M. L. NELSON REMOTE CNTROL SYSTEM original Filed Nov. 16. y1921 March 17, 1931..

e sheets-sheet '2 March 17, 1931. M. l.. NELSON 1,796,957

REMOTE CTROL SYSTEM original Filed Nov. 1e, 1921 l sweets-sheety s March 17, 1931. M. L. NELSON REMOTE CONTROL SYSTEM Original Filed Nov. 16, 1921 6 `Sheets-Sheet 4 O mo www EN Fl'ar' m L Nel-snn @W 4March 17,1931. M LNELSQN i .'1',A7.`96,957

l REMOTE CONTROL SYSTEM v 'Original Filed Nov. 16, 1921- 6 Sheets-Sheet 5 March 17,-1931.v

M. L. NELSON REMOTE CONTROL SYSTEM Original Filed Nov. 16. 1921 6 Sheets-Sheef 6 Patented Mar. 17, 1931 UNITED STATES- PATENT OFFICE MARTIN L; NELSON, OF PARK RIDGE, ILLINOIS, ASSIGNOR, BY'MESNE ASSIGNMENTS,

TO AUTOMATIC ELECTRIC INC., OF CHICAGO, ILLINOIS, A CORPORATION OF DELA- WARE REMOTE CONTROL SYSTEM Original application filed November 16, 1921, Serial No. 515,664. Divided and this application. filed February 3, 1928. Serial No. 251,512. v

The present invention which is a division` of my co-pending application Serial No. 515,664, filed November 16, 1921, relates to remote' control systems in general, but is l more. particularly concerned with remote control systems that may be used in connection with electric substations; and the principal object, brieiiy stated, is the provision of suchcircuit arrangements as are 1o necessary in order to putsuch a remote control system into effective operation.`

Other objects have to do with the refinement of thev various circuits used so as to make them more eiicient and desirable.

Still another object is to eifect the desired control with the use of the smallest possible number of circuits between the apparatus to be controlled'and the point from which it is controlled.

These objects, together with others which will not be specifically mentioned now, will be pointed out and explained fully hereinafter in connection with the accompanying drawings comprising Figs. 1-10, inclusive. In order to enable the system to be readily understood, Figs. 1, 3 and 5 should be arranged in order, with Fig. 2 over Fig. 3 and with Fig. 4 over Fig. 5, and with the. corresponding lines in alignment. s0 The apparatus shown in Fig'. 1 and in the left hand side of Fig. 2 is located in the controlling station which will be referred to hereinafter as the despatchers oiiice. The remaining equipment shown in Fig. 2 together with all the e'qui ment shownin Figs. 3, 4 and 5, is located 1n the substation, which is connected with the despatchers ofce by two pairs of conductors 60 and 61,' and 83 and 84, as shown. The necessary control overthe apparatus in the substation is exercised over the ,circuit composed of the pair of conductors shown in Fig. 2, and the signals indicative of the condition of the apparatus at the substation are received over'the other pair of conductors, Figs. 1 and 3. The despatchers'oice is assumed to contain duplicate equipment for every other substation in the system." i

The substation shown 'is assumed :to be pro- 50 vided for the purpose of supplying current to a trolley wire of an interurban electric line and may be located at some point along the line between two main stations, two similar substations, or a lmain station and another substation. As shown, the motor generator MG', Fig. 4, is in operation and the grounded generator of the unit is supplying current to the bus bar 238 by Way of the circuit breaker CB2. The bus bar 238 is connected with the trolle wire 235 by way of the circuit breaker C. The motor of the motor generator MG is supplied with three phase alternating current from the high tension mains comprising conductors 350-352, inclusive, Fig. 5, by way of the associated transformer bank, lowA tension mains 347- 349, inclusive, circuit breaker CB, and the starter SI.

The motor generator MG may be placedin service by closing the circuit breaker CB, Fig. 5operating the starter S so as to bring the un tl up-.to speed; andthen closing the circuit breaker CB2 which connects the generator of the motor generator MG to the bus bar 238.

The controlling switch D', Fig. 2, and the signal operating switch D, Fig. 1, are mechanically of the type of automatic switch disclosed in Automatic Telephony by Smith and Cam bell, a book published by McGraw- Hill'Boo Company, 370 Seventh Avenue, New York, N. Y., second edition. A photograph of such a switch lis shown on page of this publication 4and a skeleton drawing is shown on page 58. A description will be found accompanying the photograph. The circuits of these switches are shown complete vand will be described fully hereinafter.

The circuit interrupter Il, Fig. 2, associated with the relay group RG maybe mechanically similar to the automatic sender or calling device shown on pages 40 and 41 of Automatic Telephony above referred to. The function of this interrupter is to control the switch D', with which it is connected by means of. he two conductors 83 and 84 through the medium of the relay group RG. The circuits and functions of the relay group RG will be pointed out and explained more fully hereinafter.

The. apparatus shown in Fig. 3 is actuated by the various devices shown in Figs. 4 and 5 through the medium of a plurality of conductors of which the conductors 301-304, in-

` elusive, are shown. Each of these conductors extends to. and terminates in one of the controlling relay sets'as shown, such as the set comprising the relays 203, 201 and 205. These relay sets are designed so that they differently control the signal operating switch D to which they are connected through the medium of the relay group RG.

The contact making switch C, Fig. 3, comprises two-semi-circular rows of contacts which are wiped over by the wipers 167 and y168 as shown. These` two wipers are rigidly secured to a common spindlefand are operated by the stepping magnet 165 by means of which they are stepped from contact to contact as the magnet is alternately energized and deenergized. One mechanical embodiment of such a switch is shown on page 51 of Automatic Telephony, hereinbefore referred to.

For each different piece of apparatus in the substation such as starters, circuit breakers, etc., there appearsin the despatchers office three indicating lamps, such as the lamps L, L2 and L3, together with a controlling key and relay, as shown, Fig. 1 in the case of a circuit breaker,r one 'of the three lamps is lighted as long as it is thrown in and another lamp is lighted as long as it is tripped.

When the circuit breaker changes position the lamp that is lighted goes out and the other lamp lights. At the same time the third lamp of the group becomes lighted to attract the attention of the despatcher to the fact thaat a change has occurred in that particular group of lamps. Each time a signal comes in, a common buzzer is operated to attract the attention of the despatcher, and in order lto direct the attention of the despatcher to the signals of the substation from which the signal has come, a pilot lamp common to the signals pertaining to the substation in question is lighted. The despatcher isA provided with a push button to shut off the buzzer and extinguish the pilot lamp and other'push buttons one of which is used to extin uish the third lamp of the group of three amps in which the change has taken place. 1

The overload control system comprising the relay group RG2 and the motor M, Fig. 4, is provided for the purpose of giving emergency service by cutting the motor generator MG into service when the'load becomes too much for the other unit and for cutting the unit MG out of service again when they load becomes small enough for the motor generator MG to carry'alone. The overload control system, however, is normally inoperative and isplaced in service automatically in'case either of the two'circuits between the despatchers oiice and the subcuits between the despatchers ofiice and the -substation goes open accidentally.

Figs. 6, 7, and 8 show three modifications of the arrangement shown in Fig. 1 for receiving signals from the substation.

Fig. 9 shows a remote controlled ammeter which is located in the despatchers office and'controlled'by the contact making ammeter A, Fi 4. The manner in which this con'- trol is eflected will be explained more fully hereinafter.

F ig. 10 shows certain signalling and recording mechanism thatmay be installed in a substation that differs from the one shown only in that the operations performed by the the despatcher do not affect the devices at the substation directly but inform an attendant what to do.

It is to be understood that, while there are shown a pluralit of batteries in the drawings, there need only one battery in the substation and one in the despatchers office, the several batteries being shown for the sake of simplicity only.

The apparatus, having been described in general, will now be described in connection with a detailed description of its operation. For this purpose, it will be assumed that the 'despatchen having been informed by the ammeter shown in Fig. 9 that the load in the substation is high enough to warrant the starting of another machine, decides to put the motor generator MG, Fig. 4, into operation so as to supply current for the trolley wire 235 in multiple with the motor generator MG. In order for the despatcher to do this he must first operate the circuit breaker CB4 so as to connect up the leads 347-349, inclusive,to the starter S. In order to throw in the circuit -breaker CB* the despatch- 'er must cause the control switch D', Fig. 2, to place ground momentarily on its bank contactl in which conductor 116 terminates. This is done by manipulating the dial of the interrupter I associated with the relay group G; first in accordance with the level of bank contacts of the switch D in which conductor 116 terminates, the fifth level for example; and then in accordance with the particular contact in that level, which is the contact 111. When the dial of the interrupter I is moved from its normal position, the spring 65 is allowed to come into engagement with its associated contact, thereby closing a circuit for slow releasing relay 69, includv ing armature 79 and its resting contact. Re- -lay 69, u on energizing, prepares a circuit for relay 0 at armature 78, and at armature 77 closes a circuit for slow releasing relay 68. Relay 68, upon energizing, removes the ground potential from armature 73 and prepares a circuit for relay 72 at armature 76, and at armature 73 places a shunt 'around the high woundz normally energized relay 67.1, Relay 67, upon deenergizing, allows armature 73 to come into engagement with its asso- -ciated contact but since the ground potential Y the despatchers oliice and closes a circuit for the slow releasing release relay 92 at armature 99. Release relay 92, u on energizing, opens a point in the circuit o release magnet 95 and prepares a circuit for vertical magnet 96 at `armature 105; places ground upon' wiper -98 at armature 103; and at armature 104 removes ground from the resting contact of armature 100v and places a shunt around the normally energized relay 91. This is done so as to afford a better clrcuit for relay '90. Relay 91 deenergizes but does not perform any function at this time.

As the vdial of the vinterrupter I in the despatchers oice returns to normal position', the circuit of line relay 90 of the switch D is interrupted at the contacts 66 a number of times corresponding to the number for which the dial was operated which in this case is assumed to be ve. Each time line re? lay 90 deenergizes, it opens the circuit of slow releasing release relay 92 but the said relay does not have time to fall back before its circuit `is closed. again upon the next ener'giza-v tion of relay90. As a further result of each deenergization of relay 90 it closes a circuit for vertical magnet 96 as follows: from ground by way of armature 99 and its resting contact, armature 105 and its workingN contact, the contact of off normal spring 102 and said spring, series relay 93, and vertical magnet 96 to battery. By the operation of vertical magnet 96, the shaft and wiper of the switch D are 4,raised step by step until the latter stands opposite the iifth level of contacts. Relay 93 is energized in series with the vertical magnet 96 and being slow releasing -retains its armature 106v attracted through the vertical movement, thereby maintaining its own circuit and that of'vertical magnet 96 intact after the off normal springs 101-102 have shifted as they do upon the `first vertical step. At the end of the series of interruptions, line relay 90 comes to rest in an energized condition and slow releasing relay 93 upon'deenergizing, transfers the operating circuit from verticalmagnet 96 to the rotary magnet 97. l

In the despatchers office, the dial of the interrupter I, upon reaching normal position opens the initial circuit of relay 69 at spring 65,whereupon relay energizes in series with relay 69` over a circuit which extends from there ground by way of the resting contact of armature 82 and said armature, relay 70, workin contact of armature 78 and said armature angd relay 69 vto battery. Relay 69 is maintained energized in series with relay 70 and the latter upon energizing, opens lstill another point in the initial circuit of relay 69 and prepares a circuit for relay 71 at armature 79.

The despatcher now turns the dial of the interrupter I in accordance with theposition of the contact in the fifth level of the switch D' in which the conductor 116 terminates and since the said contact, which is the contact 111, is the third contact in the level,l the number for which the despatcher turns the said dial is 3. As soon as the dial of the interrupter I is moved fromV its normal position,

spring 65. completes a circuit for slow releasing relay 71, which circuit includes armature 79 and its working contact. Relay 71 upon energizing, disconnects armature 73 of relay 67 at armature 81 and at armature 80 pre:

pares a circuit for relay 72. The dial of the interrupter I in returning to normal position causes thecontacts 66 to be separated three,

times, thereby producing three interruptions in the circuit of linerelay 90 in the'switch D. Each time line relay 90 deenergizes in response to one o-f'these interruptions, it closes a circuit for rotary magnet 97 as follows: from ground by way of armature 99 and-its resting contact, armature 105 and its 'working contact, normally open contacts controlled disconnected. At theend of the rotary movement, slow acting relay 94 deenergizes and connects up the wiper 98 at armature 107,

' thereby closin the following circuit for'the solenoid 341 o the circuit breaker C134: from ground by way of. the working contact of armature 103, resting contact of armature 107 and said armature, wi er 98, bank contact ,111, conductor 116, andp solenoid 341 to battery. Solenoid 341, upon energizing, draws down -the associated plunger, thereby rotating the member 343 in a lclockwise direction, whereupon the heavy armature 360 of the trip magnet 340 falls 'into place locking thel member 343 in its operated position. As a ioo result of the operation of the member 343, the

oontactors344-346, inclusive, are forced into engagement with their associated contacts,

y connectingupthe leads 347-349, inclusive, with thestarter S.

In the despatchers oflice the dial of the interrupter I, upon returningto normal position after its second operation, opens the initial circuit of slow releasing relay 71, whereupon relay 72 energizes in series with relay 71 over a circuit which extends from ground, by way of armature 76 and its working contact, relay 72, armature 80 and its working contact, and relay 71 to battery. Relay 71' is maintained energized in series with relay 72 and the latter, lupon energizing, opens the circuit of relays. 69 and 70 atarmature 82.

Relay 70 deenergizes immediately but does.

not perform any particular function at-tliis time. Relay 69, being slow releasing, is maintained energized for an interval and, upon finally falling back, opens the circuit 0f slow releasing relay 68 at armature 77. Re.- lay 68 also is maintained energized for an interval after itslcircuit is opened and, upon finally falling back, removes the shunt from around the high Wound relay 67 at armature 75 and at armature 76 opens the circuit of relay 72 and places ground upon armature 8l. Relay 72 deenergizes immediately but does not perform any function at this time. Relay 71, being slow releasing, holds its arma ture attracted long enough to permit the high wound relay 67 to energize before it replaces ground upon armature 7 3 at armature 81.

In the substation, line relay 90 of the Switch D, .being marginally adjusted, retracts its armature responsive to the removal of the shunt from around the high wound relay 67 of the relay group RG, thereby opening the circuit of release relay 92 and closing the previously traced operating circuit for rotary magnet 97. Rotary magnet 97 and relay 94 energize simultaneously. The energization of relay 94 serves to disconnect the wiper 98 at armature 107 and also to disconnect the resting contact of armature 100 at armature 108. The rotary magnet 97, upon energizing, advances the wiper 98 into engagement 4with bank contact 112. This however, does not have any particular function at this time, being merely an incidental operation. Slow releasing relay 92, upon deenergizing, removes the shunt from around relay 91 at armature 104; disconnects ground from the resting contactof armature 107 at armature103; and at armature 105 opens the operating circuit whereupon rotary magnet 97 deenergizes. As a further result of the deenergization of lrelease relay 92, it closes a i lcircuit for release magnet 95 at armature 1 05 including oil' normal contacts 101 a-nd armature 99 and its resting contact. By the operation of release magnet 95, the shaft and wiper of the switch D are restored to normal position,the circuit of release magnet 95 being opened at off-normal contacts 101 by the switch shaft when it reaches norma-l position. Relay 94 which, as before stated, is slow releasing maintains the resting contact of armature 100 disconnected at armature 108 until after relay 91 has energized in -will be explained. Either of the relay groups, which comprise three relays each, such as the one shown in the upper left-hand corner of the sheet and comprising relays 203, 201, and 205, when actuated by a ground potential on the associated control conductor, such as the conductor 301, causes the switch D in the despatchers office to be prepared for operation in a manner to be explained fully hereinafter, after which two series .of interruptions are produced in the circuit of the line relay of the said switch D. This operation is identically the saine no matter which relay group is actuated, inasmuch as the production of two series of interruptions in the circuit of the line relay of the switch D is con.- cerii'ed, but differs in the number of interruptions produced. The minimum number of interruptions produced in any one series is one and the maximum number is ten. There are 100 suoli relay groups but, toavoid complicating the drawings unnecessarily, only four of them have been shown.l The relay group in the upper left-hand corner of Fig. 3, when actuated, sends in the number 11, which means that each of the two series of interruptions produced comprises only a single interruption. The second relay group sends in the number 12 which comprises one interruption in the first series and two in the second. The following groups of relays that send in the numbers 13-68, inclusive, have been omitted in the drawings and the third group shown sends in the number 69. The fourth relay group shown sends in the number 60 which comprises six interruptions in the first series and ten in the second series. The following relay groups which send in the numbers 71-00, inclusive, have been omitted in the drawings.. The number 00, it may be said, comprises ten interruptions in each series.

It will be understood that the dotted portions of the conductors extending between the second number sending group of relays and the third indicates that they pass through chain contacts on the intermediate' relay sets that are not shown, which chain contacts are identical with those on the relay groups shown. These chain contacts are provided for the purpose of preventing two relay groups from being actuated simultaneously, giving first choice to the ones on the left.

Returning now to the circuit breaker CB* which was operatedas previously explained, responsive to it being operated, certain operations take place with the inal result that the energizing,

' 4 ductor 199 with the second despatcher is notified that the circuit breaker has been successfully thrown in. The manner 1n which this is donefwill now be explained.

I As a further result of the operation of memon conductor 303, a circuit is closed for relay 1 17 4. Relay 17 4, upon energizing, closes the4 following circuit for relay 175: from ground by Way of armature 148 of relay 132, which relay is located in the relay group RG', and

the restmg contact of the said armature, conductor 186, armature 183 and its resting con.

tact, armature 184 and its resting contact, similar armatures and contacts on interme diate relays, (not shown) armature 177 and its workin contact, normally closed contacts controlled battery. Relay 17 5, upon energizing, closes a locking circuit for .itself and opens itsl initial circuit at armature 178, the'said locking cir. cuit being as follows: from ground by way of the'normally closed contacts controlled by armature, 146 of relay 131, which relay is located `in the relay group RG', conductor 187, -armature 212, and its resting contact, armature 213 and its resting contact, armature 178 and its' working Contact, and relay 175 to battery. As a further result of the energization of relay 175 it closes a circuit for relay 173 at armature 180, whereupon relay 173 attracts armature 176, thereby opening the circuit of relay 174 and closing alocking circuit for itself. Relay 17 4, upon decloses the chain contacts again at armature 177. Asa still further result of the^energization of relay 175 it connects the sixth impulse stop conductor 196 with the first digit stop conductor 188 at armature 181; connects the ninth impulse stop condigit stop conductor 189 at armature 182; and at` armature 179 laces ground upon the start conductor 190, thereby closing a circuit for'the slow releasing relay 132. Relay 132, upon energizing, disconnects ground at armature .148 from conductor 186 and consequently from the chain of armatures and contacts including armatures 183, 184, etc. This is done -to render `ineffective the energization of .any of the relays 201, 202, etc., until after the operations necessary to inform the despatcher that the circuit breaker CB4 has been successfully thrown in have been completed.

` As a further result of 'placing ground upon start conductor 190 a circuit is closed for slow releasing relay 130, including armature 140 4and its resting contact. Slow releasing relay 130, upon energizing, places ground y armature 177, and relay 175 to upon armature 146 of relay 131 at armature 143,. and places a shunt around the high wound normally energized relay 129 at armature 144. Thel said relay 129 holds its armature 142 attracted for a slight interval thereafter owing to the slow releasing effect caused by its self induction. As a further result of the energization of relay 130, it closes a circuit for slow releasing relay 131 at armature 145. Relay 131, upon energizing, disconnects ground from armature 142 of relay 129 at armature 147 beforethe latter relay has had time to fall back, and-at the same armature 147 places a multiple ground upon the starting conductor 190 for a purpose that will be more apparent later. As a further result of the energization of slow releasing relay 131 it shiftsthe conductor 187 from ground, by

way of the normally closed contacts con-l armature 146, to ground, by way of the working contact of armature 146 and said armature, and armature 143 and its working contact. v

' AIn the despatchers oiiice, the Vmarginally adjusted line relay 39 of the switch D energizes in response to the placing of the previously mentioned shunt around the high resistance normally energized relay 129 of the relay group RG', and closes a circuit for release relay 37 at armature 57. Release relay 37, upon-energizing, opens a point in the circuit of release magnet 42 and prepares a circuit for vertical magnet 40 at armature 55; 'places ground on wiper 58 atl armature trolled by 54; and at armature 53 removes ground from armature 56, at the same time placing a shunt 'the placing of ground upon start conductor following circuit is closedsufrom ground by way of conductor 190, armature 140 and its resting contact, resting of armature 153 andsaid armature, relay 133, the contact of spring 190 the impulse spring, and resistance v158 to battery.. The spring 156 is alternately moved out of engagement with and brought into engagement with its associated contact by the motor driven cam 157, and consequently after the above traced circuit is closed for relay 133 the said relay is energized and deenergized once during each revolution of the cam 157.

contact 156 and said Each time relay 133 energizes it closes the circuit of stepping magnet of the impulse counting switch C at armature 159. Stepping magnet 165, upon energizing the' first time, attracts its the associated pawl to on the ratchet wheel. energizes, itopens the circuit of stepping engage another notch When relay 133 de-v armature, thereby causingY magnet 165 at armature 159, whereupon the said stepping magnet deenergizes, thereby rotating the wipers 167 and 168 in a clockwise direction and into engagement with the first set of associated bank contacts. The fotation of wiper 168 does not produce any result as yet but wiper 167, upon coming into engagement with the first associated bank Contact, closes the following circuit: from groundby way of the first contact in the bank of wiper 167, the said wiper 167, and pick up relay 134 to battery. Pick up relay 134, upon energizing, removes the shunt from around armature 149 and its resting contact of impulse relay 133 atarmature 150. This does not havel any immediate effect, however, owingto the fact that impulse relay 133 has just fallen back and consequently armature 149 is-in engagement with its resting contact. The next time relay 133 energizes, in response to the closure of its circuit by the revolving cam 157, it opens the bridge across conductors 60 and 61 at armature 149 and consequently interrupts the circuit of line relay 39 of the switch D in the despatchers office. As a further result of the energization of relay 133 it closes a. circuit for stepping magnet 165 of the switch C and the said stepping magnet, upon energizing, causes the associated pawl to engage another notch on the ratchet wheel. When the circuit of impulse relay 133 is opened again, it, upon deenergizing, closes the bridge across conductors 60 and 61 at armature 149, and at armature 159 opens the circuit of stepping magnet 165 of the switch C, whereupon the wipers 167 and 168 are advanced into engagement with the second set of bank contacts. Since the second Contact over which the wiper 167 passes is grounded also as well as all of the following ones with che exception of the last contact, no effect 1s produced by the passing of this wiper to the next contact. Wiper 168, upon coming into engagement with its second lassociated ban contact, extends thc circuit of the impulse stop relay 135 to the first stop conductor 191. Thisghowever, does not produce any effect at this time for the reason that the stop con-` ductor 191 is point.

Impulse relay 133 continues to operate; the bridge across conductors-60 and 61 continues to be opened upon each energization thereof; and the wipers 167 and 168 continue to be advanced step by step in the manner described until the wiper 168 arrives upon the contact in; which the sixth stop conductor 196 terminates, which is the first stop conductor that is connected u at any other point, at which time the bri ge across'the conductors 60 and 61 will `have been opened six times at armature 49 of the impulse rela 133. When wiper 168 arrives upon the .ban contact in which stop -conductor 196 terminates, the tollowfng circuit is closed: from ground by way armanot connected up at any other ture 137 of relay 126 and its restin contact, first digit stop conductor 188, wor ing contact of armature 181 of relay 175 and said armature, sixth impulse stop conductor 196, wiper 168, and stop relay 135 to battery. Relay 135, upon energizing,'closes a locking circuit for itself at armature 154, including armature 151 and its working contact. It will be noted that a circuit is closed for relay 125 in multiple with relay 135 by way of armature 164 and its resting contact, and armature 138 and its resting contact. Relay 125, upon energizing, closes a circuit for relay 126 at armaturel 136, but the said relay 12,6 does not energize for the time being owing to being short circuited by the ground potential which causes the energization of relay 135.

As a further result of the energization of relay 135, it disconnects the impulse relay 133, while it is yet in a deenergized condition, at armature 153; and at armature 155 closes a circuit for stepping magnet 165, which circuit includes armature 166 and its resting contact, and wiper 167 and the bank contact with which it is in engagement. In response to the closure of this circuit the wipers 167 and 168 are rapidly advanced by the buzzer-like action of stepping magnet 165, which opens its own circuit at armature 166. `This 'action continues until the said wipers 167 and 168 are advanced into engagement with the last set of contacts when it is stopped because the last contact in the bank of wiper 167 is not grounded. As soon as the wiper 167 passes ofi' the last grounded contact, the circuit of relay 134 is opened but the said relay, being slow releasing maintained energized for an interval. Upon deenergizing, relay 134 replaces the shunt around armature 149 and its resting contact at armature 150, and at armature 151 removes direct ground from the relays 135 and 125, whereupon relay 126, which heretofore has been shortcircuited, and which is connected with the grounded start conductor 190, energizes in series with relays 125 and 135. Upon energizing, relay 126 disconnects relay 135 from in multiple with relay 125 and connects it in multiple w1th relay `127. Relay 135, however, being slow acting,

holds its armature attracted for an interval. As a further result of the energization of relay 126, it disconnects groundfrom the first Vdigit stop conductor 188 and connects it to the second digit stop conductor 189 at armature 137. At length relay 135 deen'ergizes; disconects stepping magnet 165 from wiper 167 at armature 155; and at armature 153 connects up impulse relay 133.

The circuits are now in readiness for th second digit 9 -to be transmitted', the netrresult so far accomplished being the openin of the bridge across the conductors 60 an 61 six times and the transferring of the ground potential from the first digit stop conductor 188 to the second digit stop conthe bridge across the conductors 60 and 61 a pause has occurred which is determined by the length of time required by the two slow releasing relays 134 and 135 to fall back one after the other. This is done so as to allow time for the change over operation from the vertical tothe rotary movement to take place in the switchD.

Before describing how the second series of interruptions is produced, the effect of the rst series of interruptions on the switch D in the despatchers office will be considered. Each time line relayv 39 of the switch D deenergizes in response to one of the interruptions produced in its circuit, it closes a circuit for vertical magnet 40 including armature 57 and its rest-ing contact, armature 55 and its working contact, the contact of 01T normal spring 44 and said spring, series relay 36, and vertical magnet` 40. By the operation of the vertical magnet 40, which receives six impulses at this time, the switch shaft and wiper are raised step by step until the latter stands opposite the sixth level of bank contacts which we shall assume is the level shown in the drawing. Relay 36 is energized in series with vertical magnet 40 and being slow releasing retains its armature 52 attracted throughout' the vertical movement, thereby maintaining its own circuit and that of vertical magnet 40 intact after the olif normal springs have shifted as they do upon the first vertical step. At the end of the vertical movement, the series relay 36, upon falling back, shifts the operating circuit from vertical magnet 40 to rotary magnet 41. 4

Returning now to the equipment at the substation, when relay 133 energizes again after having been connected up at armature 153 of relay 135 it closes the circuit of stepping magnet 165 at armature 159, whereupon the associated pawl is caused to engage another notch on the ratchet wheel. When impulse relay 133 deenergizes again, the wipers 167 and 168 are advanced into engagement with the first set of contacts, whereupon pick up relay -134 energizes in response' to wiper 167 coming into engagement with the grounded contact, and upon so doing, prepares a locking circuit for relay 135 at armature 151, and at armature150 removes the shunt'from around armature 149 and its resting contact. Relay 133 continues to energize and deenergize in the manner hereinbefore described and at armature 149 opens the bridge across conductors and 61 each time it energizes,

at the same time operating stepping magnet V165 in the usual manner at armature 159. This operation continues uninterrupted until the wiper 168 comes into engagement with f the bank contact in which the ninth impulse stoprconductor 199 terminates, at which time the bridge across the conductors 60 and 61 will have been opened'nine times. Whenv lwith the last set of bank contacts.

resting contact at wiper 168 comes into engagementwith the bank contact in which the ninth impulse stop conductor 199 terminates, the following circuit is closed: from ground by way of armabranch of this circuit extends by way of ar`A mature 164 and its resting contact, armature 138 and its working contact,'and relay 127 to battery. Relay 127, upon energizing, prepares a circuit for relay v128at armature 139 but the said relay 128 does not energize for the time being owing to the fact that it is grounded at both terminals. Stop relay 135, upon energizing, disconnects impulse relay 133 at armature 153; closes :a locking circuit for itself and for relay 127 at armature 15.4; and at armature 155 connects the stepping magnet 165 to wiper 167 through armature 166 and its resting contact. As a result, the wipers 167 and 168 are Ixo'w,.ad vanced step by step by the buzzer-like action of stepping magnet 165 until they come into engagement wiper 167 passes oil the last grounded contact, the stepping magnet circuit is opened and the c1rcu1t of slow releasing relay 134 is` opened. Relayv134, ,upon deenergizing, replaces the shunt around armature 149 and its mature 151 removes directground from the circuit of relays 135 and 127, whereupon relay 128 energizes in series with relay127, ground being supplied by way of vstart conductor 190, and upon so doing, disconnects relay 135 from in multiple with relay 127 at armature 164. Relay 135, however, being slow acting, retains its armature attracted for an interval. energization of relay 128, it disconnects the grounded conductor 190 from the circuit of impulse relay 133 (the said circuit being open at this time at armature 153) and opens the circuit of relay 130 at armature 140. Relay 130, being slow releasing, retains its armatures attracted for an interval. Returning now to slow releasing relay 135, the said relay, upon deenergizing, closes a point in the circuit of impulse relay 133 at armature 153 but this does not have anyeect at this time owing to the fact that the circuit has previously been opened at armature 140 as pointed out. Slow releasing relay 130, upon deenerarmature 150, and at ar- As a further result of When y As a further result of the circuit which includes conductor 303 and ar mature 176 and its working Contact. As .a still further result of the deenergization of relay 175 it disconnects start conductor 190v from ground at armature 179 butthe said conductor is still grounded at armature 147 of relay 131. After an interval slow releasing relay 131 falls back; replaces the ground potential upon locking conductor 187 at the normally closed contacts controlled by armature 146; and at armature 147 removes ground from conductor 190. When the ground potential is removed from conductor 190, the circuit of relays 125-128, inclusive, and 132 is opened. Relays 125-128 inclu- 4sive, denergize immediately. Relay 132,

however, being slow releasing, retains its armature attracted for an interval. Relay 132, upon deenergizing after an interval, places ground upon conductor 186 again, thereby completing the entire cycle of operations. The circuits are now in readiness v to be used over again to transmit another combination of impulses to the switch D.

In the switch D each time line relay 39 deenergizes in response to one of the interruptions of the second series produced in its circuit, it completes the following circuit: from ground by way of armature 57 and its resting contact, armature 55 and its w0rking contact, normally open contacts controlled by oil' normal spring 44, armature 52 and its resting contact and rotary magnet 41 to battery. By the operation of rotary magnet 41 which receives nine impulses at this time, the wiper 58 is rotated step by step until it comes into engagement with the ninth contact in the sixth level which is the contact 11. Relay-35 is energized in multiple with rotary magnet 41 and, being slow releasing, retains its armatures attracted through the rotary movement, thereby maintaining the wiper 58 disconnected and at the same time completing the following circuit for pilot relay 4 at armature 51; from ground by way of the working contact ofl armature 54 and said armature, armature 51'and its working contact, shaft operated spring 62 and its resting contact, conductor 59, and pilot relay 4 to battery. Relay 4, upon energizing, closes a locking circuit for itself at armature 17; closes a, circuit for the pilot lamp L at armature 16; and at armature 15 closes a circuit, for the buzzer B. At the end of the rotary movement, relay 35 deenergizes and at armature 51 connects up the wiper 58, there'by completing the following circuit: from ground by way of the working contact of armature 54 and the said armature, armature 51 and its resting contact, wiper 58, bank' contact 11, relay 5, and resistance 7 to battery. Relay 5, upon energizing, closes a locking circuit for itself at armature 22, opens the circuit of the lamp L2 and closes the circuit of the lamp L3 at armature 21; and at armature 20 closes a circuitfor the lamp L', the said circuit including the resting contact of spriner 19 of the push button P and said spring. s a result of these circuit changes caused by the energization of relay 5 the signal lamp L2 becomes extinguished and the signal lamp L3 becomes lighted, and the individual pilot lamp L becomes lighted to inform the despatcher in which set of lamps the change has occured.

After a slight interval, line relay 39 falls back -in response to the removal of the shunt from around the high wound relay 129 in the relay group RG', as previously described. Upon falling back, armature 57 of line relay 39 opens the circuit of release relay 37 and closes the previously traced circuit for rotary magnet 41. Rotary magnet 41, upon energizing, rotates the wiper 58 into engagement with bank contact 12. This, however, does not have any particular utility and is merely an incidental occurrence. Relay 35, upon energizing, in multiple with rotary magnet 41 disconnects the wiper 58 before it is moved out of engagement with contact 11 and places ground upon conductor 59 again at armature 51. The placing of ground upon conductor 58 does not produce any effect at this time because relay 4 is already energized. As a further result of the energization of relay 35, it disconnects armature 56 of relay 38 at armature 50. After a time, release relay 37 deenergizes and at armature 53 removes f the shunt from around relay 38 and places ground on armature 50, whereupon relay 38 energizes, thereby bringing armature 56 out l of engagement with its resting contact.y As a further result of the deenergization of release relay 37 it opens the circuit of rotary magnet 41 and slow releasing relay 35 at armature 53, at the same time closing a circuit for release magnet 42 including olf normal contacts 43. By the operation of release magnet 42, the shaft and wiper of the switch D are restored to normal position in the usual manner, the circuit of release magnet 42 being opened at olf normal contacts 43 by the` -switch shaft whenit .reaches normal posi-1' tion. Slow releasing relay 36, upon deenergizing, connects up armature 56 at armature i position of the switch D are now both at which only the pilot lamp L is shown, to

ascertain from which substation the signal has come and, upon finding out from which substation the signal has come in, he operates the pilot release push button, such as the push button P, momentarily, thereby opening the locking circuit of the associated pilot relay, such as the said relay fleenergizes; the lamp L becomesextinguished; and the buzzer B ceases to operate. In the present case, however, the despatcher is waiting for the signal and the operation of the pilot relay 4 is merely incidental. The despatcher now knows from the fact that the lamp L2 is extinguished and the lamp L3 is lighted that the circuit breaker CB* in the substation has been successfully 'thrown in. ln order to extinguish the individual pilot lamp L` and to prepare a circuit for it which will be closed when the next signal comes in from the circuit breaker C134, the despatcher operates the locking push button P', thereby shifting the spring 19 from engagement with its resting contact into engagement with its working contact, whereupon the pilot lamp L becomes extinguished.

To continue with the explanation it may be said that the despatcher, having received the signal that the circuit breaker CB4 has been thrown in successfully now performs the operations necessary in order to operate the starter S, which consists in manipulating the dial of the interrupter I so as to send out two series of interruptions to the controlling switch D. The number of interruptions in the first series will correspond to the level of bank .contacts in which the starting lead from the starter S terminates, and the number of interruptions in the second series will correspond-to the particular contact in that level in which the said starting lead terminates. The starting lead fory the starter S vis the conductor 114 and terminates in the bank contact 109 of the switch D',d which is the first contact in the fifth level. Accordingly the first series of interruptions will comprise five interruptions and the second series will comprise only one.

When the despatcher turns thedial of the interrupter I in accordance with the first di it 5, thevarious relaysof the relay group RG operate in the manner described herein- I before with the result that the high wound relay 67 is short circuited and the line and release relays 90 and 92 of the swltch D are energized, thereby preparing the switch for the pilot relay 4, whereupon operation in the manner described hereinbefore. As the dial of the interrupter Ii returns to its normal position the circuit of line relay 90 of the switch D is interrupted five times with the result that the vertical magnet 96 is operated five times, thereby raising the wiper 98 opposite the fifth level of bank contacts.

In response to' the second vmanipulation of the interrupter I, the circuit of linev relay 90 is interrupted once, whereupon the rotary magnet 97 operates to step the wiper 98 into engagement with in the fifth level, after which ground is placed upon wiper 98 and lconsequently upon bank contact 109. Assoon as the various relays of the relay group RG have had time' to functlon the high wound relay 67 is aga-in inserted in the circuit of line relay 90, where-4 upon the said line relay deenergizes with the result tliatithe switclrD is restored to normal position in the previously described manner.

As a result of placing the groundipotential upon bank contact 109, a circuit is closed by way of conductor 114 for relay 310 associated with the starter S. Relay 310, upon the first bank contact 109 energizing, closes a circuit for relay 311 at armature 317. Relay 311, however, -is inductively wound and stiiiiy adjusted so as to make it relatively slow to energize after its circuit is closed and conse uently it does not operate for an interval. s a further result of the energization of relay 310, it closes a locking circuit for itself at armature 316, and at arm ture 315 closes the following circuit: from g ound by way of armature 318 and its resting contact, working contact of armature 315 and said armature, and solenoid 334 to battery. Solenoid 334, upon becoming energized, attracts the associated plunger, thereby rotating the member 325-in a counter clockwise direction, which through the medium of the connecting rod shown brings the contactors 326-331, inclusive, into engagement with their right hand contacts. The contat-tors 329-331, inclusive, upon being operated, connect up the associated auto transformer, andthe contactors 326-328, inclusive, connect the secondary taps from the auto transformer to the motor unit'of the motor generator MG, whereupon/ the motor generator begins to gather yspeed When the initial vinrush of current'occurs, the marginally adjusted relay 3'13, which is shunted around the low resistance 314, is o-peratedand at its armature 3,20 opens the circuit of relay 311 before the said relay 311 has had time to energize. ,y

After the speed of the motor generator unit MG has been brought to a point which approximates its running speedthe current flow decreases sufiiciently to allow the mar nally adjusted relay 313 to fall back, there y closing the circuit of relay 311. Relay 311,

upon energizing, opens the circuit of solenoid 334 and closes the circuit of solenoid 333 at armature 318, whereupon the member 325 is rotated in a clockwise direction, thereby swinging the contactors 326-331, inclusive, to the left. The contactors 329-331, inclusive, dis-connect the and the contactors 326-328, inclusive, `disconnect the motor leads from .the secondary windings of the auto transformer and throw them direct onto the line. lVhen this is done, the magnet 323, which is shunted around the low resistance 332, attracts the armature 321, thereby locking the member 325 in its operated position. As a further result of the' operation of armature 321, the circuit of relay 310 is opened. Relay 310, is made slightly that the member 325 is properly locked before it deenergizes. ,Relay 310, upon deenergizing, opens the circuit of relay 311 at armature 317. Relay 311, upon deenergizing, opens the circuit of solenoid 333 at armature 318. The starter S is now completely voperated and the motor generator MG is running and accordingly it remains4 only to throw in the circuit breaker CB2 so as to connect the generator unit in multiple with the generator unit of the motor generator MG. y

The despatcher is now informed of the fact that the starting of the motor generatorl MG has been completed in a mannerthat will be described` now. In the starter S, when the member 325 is rotated in the clockwise direction, as described, the spring 324is moved out of engagement with its resting contact and into engagement with its working contact, thereby removing the ground potential from conductor 302 and placing a ground potential on conductor 301. When the ground potenytial is removed from conductor 302 relay 169 f ldigit stop conductor 188 with the-first deenergizes and connects up relay 202. This, however, does not produce any result at this time. When the ground potential is .laced upon conductor 301 a circuit is closed or relay 201.v Relay 201, Vupon energizing, re-

moves ground from the armatures 184, 177, etc., and closes a circuit for relay 205 at armature 183. Relay 205, upon energizing, closes a locking circuit for itself and opens its initial circuit at armature 212, and lat armature 208 closes a circuit for relay 203. Relay 203, upon energizing, o ens the circuit of relay 201 and closes a loc ing circuit for itself at armature 204. As a further result of the energization of realy 205, it connects the first impulse stop conductor 191 at armature 209 and at armature 210'connects the second digit'stop conductor 181 with the first impulse stop conductor 191 also. Thus it will be'seen that the first series of impulses to be sent to the switch D as well as the second series will comprise a,

single impulse. As a still further result of slow releasing so as to insure auto (transformer,

the energization of relay 205 it places ground hereinbefore described results in the rela group RG one of whichis that the high7 resistance relay 129 is short circuited, whereupon the switch D is prepared for operation in the manner described hereinbefore. As another result of the placing of round upon start conductor 190 the wipers 16 and 168 are rotated into engagement with the first set of bank contacts, whereupon ick up relay 134 energizes andremoves the sliunt from around armature 149 and its resting contact of impulse relay 133, at armature 150. Upon the next energization of impulse relay 133, the circuit of line relay 39 of the switch D is inter rupted and, upon the subsequent deenergization of the said relay 1 33, the circuit of line relay 39 of the switch the wipers 167 and 168 are advanced` into entacts, whereupon the following circuit is closed: from ground by way of the first digit stop conductor 188, working contact of advanced in the previously described manner to their normal position after which relay 126 energizes and transfers ground from the' firstl digit stop conductor 188 to the second ydigit stop conductor 189.

After the pause, caused by the slow releasing relays 134 and 135 impulse relay 133 is connected up again and the shunt is removed from around armature 149 with the result that another interruption is produced in the circuit of line relay 39 of the switch D after which the wipers 167 and 168 are again advanced into engagement with their second set of contacts, whereupon stop relay 135 energizes over the followingv circuit: from ground by way of the second digit stop conductor 189, working contact of armature 210, and said armature, and from thence to battery by which includes stop relay 135.,l Stop relay 135, upon energizing, again disconnects impulse relay 133 and connects the operating with the result that the Wipers 167 and 168 are rotated into normal position. .After an intervaLthe various relays of the .relay group RG operate in the manner described hereinbefore to remove the shunt from around high wound relay 129 and to finally restore circuit conditions of all the relays of the relay group RG to normal. i'

magnet to wiper 167 In the switch D, line relay 39, upon de energizing, in response to the first interruption produced in viously traced circuit for vertical magnet 40 D is closed again and 4gagement with the second set of bank conway of the previously traced circuit its circuit closes the Y .pre-

whereupon the wiper'58 is raised opposite the first level of bank contacts. I

In response to the next interruption produced in its circuit, line relay 39, upon (le-- tration that the bank contact 10, even though it is not `the first contact in the first level but is the second contact in the sixth level, is the one with which the wiper 58 is in engagement,

relay 6 is short circuited by the ground poten- ',tial which is placed upon bank contact 10 and,

upon deenergizing, opens its locking circuit at armature 26; opens the circuit of the lamp L6 Aand closesthe circuit of the la-mp L5 at armature and at armature 24 closes a circuit for the individual pilot lamp L4, the said circuit including the working contact of spring 23 and said spring.

Inres onse to the permanent deenergization of line relay 39, which occurs when the high wound relay 129 of the relay group RG is inserted into its circuit, the switch D is restored to the normal position in the hereinbefore described manner.

The despatcher, upon being attracted by the buzzer B, observes the pilot lamp L, thereby ascertaining from which substation the signal has come in and, by observing the individual pilot lamp L, aseertains in which group of lamps the change has occurred.

The despatcher now operates the push buttony P momentarily, whereupon relay 4 deenergizes; the lamp L6 becomes extinguished; and the buzzer B ceases to buzz. In order to extinguish the individual pilot lamp L? and to prepare another circuit for it, the

. despatcher pulls out the push button P2,

thereby freeing the spring 23 and allowing it to come into enga ement with its resting contact, whereupon t e lamp L4 becomes eX- tinguished. r

In order to operate the circuit breaker CB the despatcher manipulates the interrupter I first in accordance withthe level of contacts in the bank of the switch Din which the conductor 241 terminates, and thenin accordance with the particular contact in the level. As a result, the wiper 98 is brought into engagement with -the desired contact in a manner described hereinbefore, whereupon ground is placed upon' conductor 240, thereby closing a circuit for solenoid 240. Solenoid 240, upon energizing, attracts the associated plunger, thereby causing the member 246 to be rotated in a clockwise direction. When vented from returning by the notch in the arit mature of trip magnet 248. As a result of the rotation of the member 246 the contactor 247 is forced into engagement with its associated contact, thereby connecting the generatorl unit of the motor generator MG with the bus bar 238. The motor generator MG is now in service.

The despatcher is informed that the circuit breaker CB has been successfully thrown in in a manner that will be pointed out briefly now. As a still further result of the rotation of the member 246, ground is removed from conductor 244 and isplaced upon conductor 243. These conductors (243 and 244) correspond tothe conductors 303v and 304 of -the circuit breaker CB i and they accordingly extend to two similar groups of relays the difference being that they are arranged to operate the line relay of the switch D a different number of times when ground is removed from one and placed upon the other. That being the case the switch D is again operated at this time and through the medium of signals (not shown) which may be like the ones shown the despatcher is notified of the fact that the circuit breaker CB2 has been successfully thrown in.

In case the despatcher decides that the current which must be supplied to the trolley. wire 235 at some particular time, for example when there are a great many cars running close together and drawing current from this section, is more than the units MG and MG can furnish Without being damaged, he mayconnected up thel feeder 239 at the other substation, the despatcher operates the interrupter I in accordance with the correct number, thereby causing the wiper 98 of the switch D to be brought into engagement with the bank contact in which the conductor 249 of the circuit breaker CB terminates, Whereupon the circuit breaker is thrown in, in a manner described hereinbefore.

After the current demand has disappeared somewhat, the despatcher may disconnect the lead 239 by operating the interrupter I in accordance with the correct number, thereby grounding conductor 250 by causing the wiper 98 of the switch D to be brought into engagement with the bank contact in which the said conductor 250' terminates. When the ground potential is placedy upon conductor 250, a circuit-is closed for trip magnet 253, whereupon the associated armature is attracted allowing the circuitbreaker CB to return to normal position, thereby disconnecting the lead 239 from the bus bar 238. lIt is to be understood that the conductors 251 and 252 correspond to the conductors 303 and 304 and to the placing'of the of the circuit breaker CB4 and consequently the despatcher is informed of each change of position of the circuit breaker CB.

Assuming that the current demand from this substation decreases still further until the load can be carrled by one machine, the

despatcher may disconnect the generator unit ofthe motor generator MG from the bus bar 238 by tripping the circuit breaker CB2. This operation is performed by suitably manipulating the interrupter I so as to cause the wiper 98 of the switch D to be brought into engagement with the bank contact in which conductor 242 ofthe circuit breaker CB2 terminates. When this is done a circuit is closed for trip magnet 248, whereupon the associated armature is withdrawn from the member 246 and the circuit breaker returns to normal position. The despatchcris informed that the circuit breaker has been successfully the placing of ground in the despatchersv ofiice scribed manner.

In order to trip the circuit breaker CB, the despatcher causes the wiper 98 of the con trolling switch D to be brought into engagein the previously dement with bank contact 112, thereby placing a ground potential upon conductor 117-. When this is done trip magnet 340 energizes disengaging armature 360 from the-member 343, whereupon' the circuit breaker returns to normal position. In response to the removal of the ground potential from conductor 303 ground potential -upon conductor 304, relay 173 deenergizes and relay 172 energizes, thereby closing a circuit for relay 160. Relay 160, upon energizing, in addition to placing ground upon start conductor 190 and closing a circuit for relay 170, connects the first digit stop conductor 188 -to the sixth impulse stop conductor 196 and connects the second digit sto conductor 189 to the tenth impulse stop con uctor 200. The relays of the relay group nowfunction in the usual manner and the Wipers 167 and 168 are rotated over the associated bank contacts twice, thereby closing the circuit of the line relayI of the switch D, and then producing two series of interruptions in the said circuit, the first of which colnprises six interruptions and the second of which comprises ten interruptions. As a result, the wiper 58 of the switch D is brought into engagement with the tenth contact in the sixth level of bank contacts, which is the contact 12. When the ground potential is placed upon bank contact 12, subsequent to the wiper 58 being brought into engagementwith it, relay 5 is short circuited and accordingly deenergizes. When this occurs the lamp La is extinguished and the lamps'L and L2 are lighted. The pilot lamp L is lighted and the buzzer B is operated in the usual manner. The despatcher after bein ginforme'd that the circuit breaker CB4 has motor generator MG and In the substation, when the circuit breakerv CB* is tripped the motor generator unit MG stops and the magnet 323 of the starter S be comes deenergized, whereupon the armature 321 is drawn out of engagement with member 325. When this occurs the starter S returns to normal position and the ground potential is removed from conductor 301 and placed upon conductor 302. Relay 303 now deenergizes and relay 202y energizes. Upon energizing, relayJ 202 closes a circuit for relay 163 at armature 184. Relay 163, upon energizing, in addition to closing thelocking circuit for itself and placing ground upon start conductor 190 closes a circuit for relay 169 and at'the two remaining armatures connects the first digit stop conductor 188 with the first impulse stop conductor 191 and connects the second dlgit stop conductor 189 with the second impulse stop conductor 192. As a result, the associated mechanism operates in the hereinbefore described manner first to close a circuit for the lineA relay 39 of the switch D and then to produce two series'of interruptions in the said circuit the first of which comprises only one interruption and the second of which comprises two interruptions. As a result the wiper 58 is brought into engagement with the second bank contact in the first level and the associated signals are operated in the usual manner.V

If the despatcher desires to leave the circuit breaker CB* thrown in he may still disconnect the motor unit of the motor generator MG by causing the wiper of the controlenergizmg, in response to the ground potential being placed upon conductor 115 opens the circuit of magnet 323 at armature 312,' whereupon the'starter S is restored to normal position.

In regard tothe motor generator MG it may be said that the associated apparatus comprising the circuit breakers CB.s and CBl5 and the 'starter S are controlled in the same manner as the apparatus associated with the comprising the circuit breakers CB and CB4 and the starte-r S, respectively. It may be said alsothat the main circuit breaker CB is controlled in the same manner as any of the others.

Itl may happen at some time that one of the control circuits between the despatchers ofiice andthe substation is opened bythe breaking of one of the conductors for example, and in order to take emergency the over load control system comprising the relay group RG?, Fig. 4,'and the motor Mis provided. This over load concare of such an trol system is automatically cut into service and the despatcher is notified when one of the control circuits is opened, in a-manner which will be explained now. Assuming thatone of the two circuits between the despatchers oflice and the substation is opened, the control circuit shown in 2 and comprising conductors 83 and 84 for example, the normally energized relays 67 and 91, associated with the relay group RG and the switch 1)',

- respectively, deencrgizc. Relay (37, upon de.-

i lighted condition of the lamp L1, is informed that the circuit between the relay group RG and the switch D is open and, in order to disconnect the buzzer B and prepare a circuit for it which will be'closcd upon the subsequent deenergization of relay 2, he operates the push button P3, whereupon the circuit of the buzzer B is opened at spring 29.

In the substation, relay 91 of the switch D', upon deenergizing, places ground upon conductor 113 at armature 100 by way of a circuit which includes armatures 104 and 108 and their resting contacts. When ground is placed upon conductor 113, it is extended to the armature 223 of the marginally adjusted control relay 220 of the relay group RGr2 and, assuming that the load'is below the maximim that can be carried safely by the motor lgenerator MG', in which case armature 223 is retracted as shown, a circuit is closed for slow releasing relay 218 by way of armature 233 and its resting contact, armature 2 23 and its Working contact, and the resting contact of armature 226 and said armature. A circuit is closed also for relay 219 by way of ar- Y has energized fully.

G5 armature mature 230 land its restmg contact. Relayv 218, upon energizing, opens the circuit of relay 219 at armature 230 before the said relay As a further result of the energization of relay 218, it disconnects ground from armature 221 at armature 228 ,and at armature 229 opens a point in the circuit of relay 217. Assuming now that the load becomes more than can besafely carried by the motor generator MG for more than a short length of time, the marginally adjusted relay 220 attracts its armature 233, thereby opening the' circuit of slow releasing relay 218 and preparing a circuit for slow releasing relay 217 As soon as slow releasing relay 218 deenergizes it completes a circuit for relay 217 at 229, and at armature 230 completes ergizing, connects the trip conductor 242 of the circuit breaker CB2 and the trip conductor 117 of the circuit breaker CB4 to the working contact of armature 230 at armatures 231 and 232. This however, does not produce any result for the time being. Relay 217, upon energizing, opensanother point in the circuit of relay 218 at armature 226 and at armature 227 completes the following circuit for the motor M: from ground by way of the resting contact of armature 222 and said ar-. mature, Working contact of armature 227 and said armature, armature 225 and its working contact, and the motor M to battery. The motor now begins to drive the contactor 234 in a clockwise direction. As soon as the contactor 234 is moved out of engagement vwith the contact on which it normally rests and to which the .winding of relay 216 is connected,

the said relay 216 deenergizes, thereby opening still another point in the circuit of relay 218 at armature 223. This is done to prevent the operations now' under way from being stopped in a partly finished condition in case t the load should decrease before they are completed. As a further result of the deenergization of relay 216, armature 225, upon being retracted, moves out of engagement with its working contact, thereby opening the in-v itial circuit of the motor M. Just before this occurs, however, a new circuit for the motor M is completed which includes the grounded contact 254 and the working contact of armature 225. As a still further result of the dement with the contact with which the conductor 116 is connected, a circuit is closed for solenoid 341 of the circuitbreaker CB2y whereupon the said circuit breaker is thrown in the usual manner. As soon as 'the con-A 234 rotates a little further, it comes into engagement with the arcuate contact strip 255, thereby closing a circuit for the starting solenoid 334 of the starter S, where-- upon the said starter is operated in the herein, tactor inbefore described manner to connectup the associated auto transformer and to connect the secondary taps thereof with the motor unit of the motor generator MG. The con-4 tactor 234 continues to be rotated and remains` in4 engagement with the contact strip 255 long enough to allowv the motor generator MGto be brought 'up to its running speed.

After a time the contactor 234 passes olf the contact strip 255 and comes into engagement with the contact which is connected with the solenoid 333 of the starter S. The solenoid 334 now becomes deenergized and the solenoid 333, upon energizing, throws the starter S into running position. The contactor 234', upon coming into engagement with the next contact, closes a circuit for the solenoid 240 of the circuit breaker CB2, whereupon the said circuit breaker 'is thrown in, in the usual manner. When this occurs the motor generator MG takes its share of the load.

Upon reaching the starting point, the contactor 234 again closes the circuit of relay 216. Upon energizing, relay 21Gprepares a circuit for relay 218 at armature 223 and at armature 224 opens the initial circuit of relay 215 but the said relay is maintained energized over its locking circuit which includes armatures 221 and 228. As a still further result of the energization of relay 216, it'opens the circuit ol' the motor M at arn'laturey 225, armature 222 being` operated at thisl time. WV hen the circuit of the motor M is opened the said motor stops leaving the contacter 234 in engagement with the contact to which relay 216 is connected.

Assuming nov7 that the load decreases until it can be carried by the motor generator MG the marginally adjusted relay 220 retracts its armature 223, thereby opening the circuit of relay 217 and reparing a circuit for relay 218. IRelay 21%, upon deenergizing, opens another point in the circuit of the motor M at armature 227, and at armature 226 closes the previously traced circuit for relay 218. Relay 218, upon energizing, opens another point in the circuit of relay 217 at armature 229; opens the locking circuit of relay 215 at armature 228, whereupon the said relay 215 deenergizes and prepares a circuit for the motor M at armature 222. As a further rc` sult of the energization of relay 218, it opens the circuit of relay 219 at armature 230 and closes a circuit for the trip magnets 248 and 340 of the circuit breakers CB2 and CB", respectively. Relay 219, being slow releasing, maintains the armatures 321 and 232 attracted for an interval. In response to the closing of thecircuits of trip magnets 248 and 340 the circuit breakers CB2 and CB* are tripped in .the usual manner. Relay 219.

upon deenergizing, opens the circuit of' trip magnets 248 and 340 at armatures 231 and 232. The circuits of the relay group RG2 are now in condition for the motor generator unit MG to be put into service again in case the loadv becomes too much for the motor generator MG to carry alone.

It may be stated that the reason for making' relays 217 and 218 slow releasing is to keep them from responding to momentary changes in the load. "f,

When the circuit comprising conductors 83 and 84, Fig. 2, is Ifinally re aired, relays 67 i and 91 of the relay group R and the switch gized eld winding,

D, respectively, energize again. Relay 67, upon energizing, opens'the circuit of relay 2, Fig. 1, whereupon the s aid relay 2 deenergizes; extinguishes the lamp L7 at armature 27 and at armature 28 closes a circuit for the buzzer B, by way of spring 29 of the push button P3 and its working contact. The despatcher, upon hearing the buzzer B, notes that the circuit is repaired as indicated by the unlighted condition of the lamp L7 and restores the push button P3 to normal position, thereby opening the circuit of the said buzzer.

In the substation, relay 91 of the switch D', upon deenergizing removes ground from the conductor 113 whereupon the relay gro-up RG is rendered inoperative again and relays 218 and 219 deenergize.

Referring now particularly to Figs. 9 and 4, the operation of the ammeters A and A will now be described. The ammeter A, Fig. 4, which is connected so as to indicate the amount of current fed to the trolley wire 235, comprises essentially a pointer 256 anda plu rality of contacts over which the pointer travels, together with the necessary element for moving the pointer in accordance with the load. As shown, the pointer 256 is grounded and a conductor is connected to each of the contacts over which it is adapted to pass. Each of these conductors is assumed to extend to individual relay groups similar to the individual relay groups shown in Fig. 3, to -which the conductors 301-304, inclusive, extend. The first of these conductors associated? with the ammeter A is assumed to extend to a relay group which when actuated in the previously described manner causes the wiper 58 of the controlling switch D in the despatchers ofiice to be raised to the tenth level of bank contacts and rotated into engagement with the first bank contact in that level. In the same way each of the other groups to which the conductors from the am meter A extend, are connected so as to cause the wiper of the controlling switch D in the despatchers office to be raised to the tenth level of bank conta-cts, the actuation of thc group of relays to which the second conduc tor is connected causing the wiper of the switch D to be brought into engagement with the second contact in the tenth level, and so on up to the tenth group which causes the wiper to be brought linto engagement with the tenth contact in the tenth level.

The tenth level of bank contacts of the switch D is shown in Fig. 9 and comprises the Abank contacts 401-410, inclusive, contact 401 being assumed to be the first contact in the tenth level and 410 the tenth.

4 The ammeter A lis assumed to be provided with a graphic record arrangement which may be of any well known type and is driven by the motor M which has a normally eneras shown. The armature of the motor M occupies the position of

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