US1674127A - Remote control system - Google Patents

Description

June 19,1928.

J, l. BELLAMY I'IEMOTE CONTROL SYSTEM Oiginal Fiied May 17,' 1923 5 Sheets-Sheet 1` Jahn T.EEZZEmy Y J. l. BELLAMY REMOTE CONTROLA SYSTEM June 19, 192s. l O 1,674,127

Original Filed May 17, 1925 5 Sheetseet f\ N Y w Lx N MSMQQM UQ g www@ Q l @s Jahn B15225111 J. l. BELLAMY REMOTE GoNTRoL SYSTEM June 19, 1928.- 1,674,1 2 7 led May 17,` 1&23 5 Sheets-Sheet 4 Irzuen cfr- Jahn I. E'ellsmy June 19,1928. 1,614,127

J. l. BELLAMY l REMOTE coNTRoL 'SYSTEM 'original Filed May 17, `192s '5 sheets-sheet 5; l

Pill l/l Patented June 19, 192s.

UNITED STATES' PATENT OFFICE.

JOHN I. BELLAIY, 0F CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO

AUTOMATIC ELECTRIC INC., OF CHICAGO, ILLINOIS, A CORPORATION OF DELA- WARE.

REMOTE CONTROL SYSTIEBVI.

Application led May 17, 1923, Serial tion; and the principal object is the production of new and improved circuit arrangements whereby the operation of the system as a whole is improved and rendered less susceptible to error.

In order that the full utility of the present invent-ion can be readily grasped, it may be pointed out that it has been' proposed to control the circuit breakers, starters, etc., of a number of ,substations of,rfor example, a street Vrailway vpower distributing system, from a single point, atxvhich oint a compotent despatcher is located. cans are provided for keeping this despatcher informed at all times of the load requirements at each of the substations under his control. These means are not disclosed in this application, but are shown inthe co-pending application of Nelson, Serial No. 515,664, filed Nov. 16, 1921, corresponding to .F rench Patent 560,- 020, on which this case may be considered an improvement. The despatcher is, there- Y fore, in a position to decide intelligently as [all to whetherV any particular machine in vany one of the substations under his control should be in service or not. He is able to calculate this, not only from his knowledge of the total instant load at the substation inA question, but also, from his general knowledge 0f the instant load at each ofthe other in any substation as he sees fit, either starting or stopping a spare machine or' connect,- ing up or disconnecting one or more intersubstation tie feeders.

VThere are two circuits between the despatchers oilice and each associated substa` tion. One of these circuits is used by the No. 639,628.` Renewed April-13, 1928.

despatcher for the purpose of controlling the substation switching apparatus, and the other is used to control the lighting and extinguishing of indicating lamps in the despatchers ollice in accordance with the positions assumed bythe various pieces of substation switching apparatus.

In a system of the above character, a piece of switching apparatus, a circuit breaker, for example, is thrown in or out by the des- 'patcher through the medium of an automatic switch in the substation. causes this switch to be positioned for the desired circuit breaker by means of his outgoing control'circuit extending to the substation in which thecircuit breaker in question is located, and when a circuit breaker is thrown in or out by the despatcher, or when cuit breaker oesin the-out7 lam is ext-inguished and the` in lamp is lit, and when the circuit breaker goes out, the in lamp is extinguished and the out lamp is lit. These lamps are controlled automatically by an automatic switch, which, in turn, is cont-rolled from the substation overthe despatchers incoming control circuit.

It is obvious that in actual practice an automatic switch, such as the substation switch referred to above, ca-nnotalways be depended upon to arrive `on the desired contact. The switch may fail to operate at all; it may fail to operate correctly; or the despatcher may set the switch on the wrong contact through ari-errori, uch asis likely to occur from time to time. Since the above is true, it-.is desirable to provide meansfor informing the despatcher of the actual position of the substation switch before he per- The despatcher `forms the final act which is to operate the disclosed in the prior case of Richardson et al, Serial No. 628,723, tiled March 30, 1923, corresponding to British Patent 213,537, on which this case may be considered an 1mprovement.

It is desirable that the correctness of the setting of the switch in the despatchers oliice be verified before the connections of the in and out lamps are switched. Otherwise, the lamp indication cannot be always depended upon. Accordingly, an object of the invention is the provision of new and improved circuit arrangements for accomplishing this result. If. a particular circuit breaker at the switching station is in, the in lamp corresponding to that breaker will be lighted. Should that breaker automatically go out the checking switch will select the out lamp corresponding to that breaker and start it flashing. The dispatcher upon seeing the flashing lamp notes its number and operates his callinGr device to set his control switch on that num er. If the signal is correct the out lamp will be automatically lighted steadily and the in lamp extinguished. If, however, the signal is erroneous, that is, the supervisory switch selected the lamp which did not correspond to the circuit breaker, when the dispatcher lands upon the number of the flashing lamp it will not. be lighted steadily. He will then release his control switch and the supervisory switch will be released automatically and will again be operated in an eiort to send in the correct signal. This reoperation of the supervisory switch will continue until the 'correct signal is received at the control station.

A further feature of this invention relates to a mechanically locked polarized relay for the control of the in and out lamps of the indicating device. In the previous mentioned applications these lamps were controlled by a relay which was locked up by electro-magnetic means. In the event. that the battery to the indicating panel was momentarily cut off, these relays, which were locked up,`would unlock themselves and fall back. It would then be necessary for .the dispatcher to check the indication of every device in the substation after he had restored battery to the indicating device. In the present invention the polarized relay which controls these lamps is locked mechanically into the position last set, and should the battery to the indicating device be momentarily interrupted there would be no serious consequences for the mechanical lock would hold the indicating device as last set, and when the battery was restored thereto the indications would be correct.

There are various other features having to do with the detailed workings of the s ystem which will appear fully hereinafter. Other improvements, disclosed in this application in connection with the above ob- ]ects, are shown merely to enable a clearer understanding of the invention. These improvements are claimed in the co-pend1ng application of Rithardson and Bellamy, Serial No. 635,454, tiled April 30, 1923, corresponding to British Patent 215,321. D

Referring no w to the drawings which show 'a sufficient amount of equipment cmploycd in a system of the character set forth above to enable the invention to be understood and its utility appreciated, Flg. 1 shows certain apparatus in the despatchers otiice which is connected with one of the substations under his control by the two pairs of conductors 16 and 17 and 18 and 19; Figs. 2, 3, and 4 show controlling apparatus in the substation; and Fig. 5 shows a part of the power'switching equipment in the substation.

Specifically, Fig. 1 shows the calling device (D by means of which the despatcher operates the control switch in the distant substation. This drawinV shows also the lamp control switch D wiich is controlled from the substation to effect the lighting and extinguishing of the Aassociated signal lamps, such as the lamps L and L2.

Figure 2 shows the relay group RG which is used for such purposes as will be described hereinafter.

Figure 3 shows the control switch E which is located in the substation and which is controlled by the despatcher over the conductors 16 and 17 by means of the calling device CD and the key K, Fig. 1.

Figure 4 shows the call sending equipment comprising the relay group RG and the sending switch S. This drawing shows also four sending control relay sets SC-ll, SC- 12, SiC-19, and SC-10, of which two are provided for each starter, circuit break er, etc., in the substations. The sending control circuits SC-ll and SC-12 are associated with` the circuit breaker CB, Fig. 5. whose in and out numbers are 11 and 12` respectively, and the sending control circuits SC19 and SC-10 are associated with the starter ST, whose in and out numbers are 19 and 10, respectively. These sending control rela-ys control the operation of the switch D, Fig. 1, through the medium of the relay group RG and the sender S.

Figure 5 shows the motor enerator Mtl which is operated from the tirce-phas al ternating current supply through the starter ST and which supplies direct current to the substation bus-bar 401 by way of the circuit breaker CB.

The signal operating switch D, Fig. l, and the switching equipment controlling switch E, Fig. 3, are mechanically identical with each other and are of the step-by-step vertical and rotary movement type of automatic switch disclosed in Automatic Telephony,

second edition, a book written by Smith and Campbell and published by McGraw-Hill Book Company. A photograph of this type' oi' switch is shown on page 55 ot this publication and `a skeleton drawing is shown on page 58. A description accompanies the photograph and sets forth how this type of switch operates. The circuit-s of the switches D and E, while similar to each other in certain respects, are somewhat diiterent from each other and each will beV described fully hereinafter.

-Thecalling device CD, Fig. 1, maybe of any one. of several well-known types, but for the purpose of this application is assumed to be of the type shown on pages 40 and 410i Automatic Telephony above reterred to. Thefunction of this calling device, as stated hereinbefore. is to control the switch E in the substation over the conduc tors 16 and 17.

The sending switch S., Fig. 4, comprises two semi-circular rows of contacts which are wiped over by the wipers 361 and 362 under the control of the stepping magnet v363.

These wipers are operated step by step as the stepping magnet 363 is alternately ener'- gized and deenergized, being advanced upon the deenergization of stepping magnet 368 rather than upon its energization. .One vmechanical embodiment of such a switch is shown on page 51 of Automatic Telephony referred to above.

In 'view of the factthat substations and their equipment areV well-known in the art, no attempt has been made to show the substation layout in any great detail, only so much being shown as will be needed to describe and explain the vvarious features of the present invention. It is to be understood, however, that, although the starter ST and the circuit breaker CB, Fig. 5, are the only'v pieces of substation switching equipment shown, in actual practice a great many more similar devices willbe found in each substation. It is, therefore, assumed that there are several other switching dcvices in the substation. That being the case, each of the switching units has'l its own sending control relays, such as the send-vv ing control relays SC-11 and SC- -12, Fig. 4. These sending control relays are interconnected with the ones shown by the band of conductors terminating in arrowheads at the right-hand edge of Fig. 4, and by the locking chain circuit extending through contacts on the relays 802, 304, 306, and 308 and which is dotted to the right of relay 308 and extended to the conductor 252 which is assuined to be connected at the end of the chain.v y

It is to be understood, of course, vthat in practice it is only necessary to have one battery in the substation and one battery in the despatchers oifice to supply current for the remote control system, and that the. sev eral batteries are shown only for thc sake ot simplicity.

The apparatus having been described in a more or less general manner,` its operation will now be taken up in detail. For this purpose it will be assumed that the despatcher decides to put the motor generator MG in the substation into operation. In order to do so thc despatcher must iirst bring about the operation of the starter ST. Accordingly, the despatcher operates the circuit closing key K associated with the calling device CD, Fig. 1, thereby closing a eir-A cuit vfor the slow to pull up relay 6 at the contacts 4.` This relay is made slow to pull up in the addition to being slow to fall back by placing the copper collar on the armature end of the core rather than on the opposite end. This is denoted by the position of the copper collar on the upper end of relay ,6 which is assumed to be the armature end. To proceed with the description of the operation, relay 6, being slow to pull up, does not pull up forthetime being, and relay 7 energizes in multiple with relay 6 through the resting Contact ot armature 12 and said armature. Upon energizing, relay 7 closes a bridge across conductors 16 and 17 at armature 14. This bridge, it will bc noted, includes the interrupter contacts 2 of the calling device CD. A moment later the relay 6 energizes and places ashunt around armature 14 and its working contact at armature 11 and at armature 12 disconnects relay 7, whereupon replay 7 dcenergizes.

In the substation line relay 201 of the switch E energizes over conductors 16 and 17 in response to the above mentioned bridge being placed across these conductors in the despatchers oice, and at armature 213 closes a circuit for the slow-acting release relay 202, whereupon relay 202 energizes; prepares a circuit for vertical magnet 208 at armature 215; and at armature 214 opens a point in the circuit ot rclease'anagnet 210 and places ground on the locking conductor 155, thereby closing a circuit for release relay 108, Fig. 2. Relay 108 now energizes;

places ground on the locking conductor 156 at armature 131; and removes battery from the pick-up conductor 164 at armature' 132 so as to remove the sending control relays SC-11, etc., fromv the control of the associated devices, such as the circuit breaker CB, Fig. 5,until after the despatchei completed the desired operation.

'The despatcher now operates the callingdevice CD in accordance with the first digit 1 of the in number 19 assigned to the starter ST, thereby producing one interruption in the bridge' across conductors 16 and 17 at the interrupter contacts 2. Vhen this occurs, line relay 201 deenergizes once motraced circuit and raises the wipers 233 andl ing release relay 202 at amature 213, and closes a circuit for vertical magnet 208 as follows: from ground by way of armature 213 and .its resting contact, armature 215 and its working contact, contact of off-normal spring 212 and said spring, slow-acting series relay 203, and vertical magnet 208 to battery. Release relayl 202, being slow-acting, does not deenergize at this timeand vertical magnet 208 energizes over the above 234 opposite the first level of their associated bank contacts.. The slow-actinv series Vrelay 203 is energized in series wlth the vertical magnet 208 and isl made slow-acting in-order to enable it to retain its armature attracted throughout a series of several impulses in case the wipers 233 and 234 are to be raised to some level other than the first. Upon energizing, relay 203 opens a point in the circuit of rotary magnet 209 at the resting contact of armature 217, and at the working contact of armature 217 closes av circuit for itself and for vertical magnet 208 which is effective after the off-normal .springs 211 and 212 have shifted as they do on the first vertical step. Amoment after the ilnpulse of current has died away, the slow-acting relay 203 deenergizes and shifts the operating circuit fromthe vertical to the rotary magnet.

The despatcher now manipulates the calling device CD in accordance with the second digit 9 in the in number 19, thereby producing nine interruptions in the circuit of line relay 201 of the switch E. Each time line relay 201 deenergizes in response to one of these interruptions, it closes a vcircuit for rotary magnet 209 as follows: from ground by way of armat'ure 213 and its resting contact, armature 215 and its working contact, normally open cont-acts controlled by olf-normal spring 212, armature 217 and its resting contact, resting contact of armature 226 and said armature, and rotary magnet 209 to battery. By the operation of Iotary magnet 209 the wipers 233 andv 234 are rotated step by step into engagement with the ninth set of bank contacts 239 and 240 in the first level. Relay 204 -is`enerefized in multiple with rotary magnet 209 and, being slow-acting, retains its armatures attracte throughout the rotary movement, thereby maintaining the upper winding of switching relay 205 disconnected at armature 218. As a further result of the euergization of relay1 204, it closes a circuit for the discriminating Irelay 103 of the relay group RG, Fig. 2, as

follows: from ground by Way of the'upper,J

winding of relay 103, conductor 153, working contact of armature 229 and said armature, armature 220 of relay 204 and its working contact, conductor 252, the chain of contacts carried by relays 308, 306, etc., Fig. 4, conductor 157, armature 127 and its resting contact, and resistance 126 to battery. Upon energizing, rela 103 locks its lower winding to the grounded locking conductor 156 at armature 117; places battery on conductor. 163 at armature 125; disconnects the lower winding of relay 102 from conductor 161 at armature 118; and at armature 127 disconnects the locking chain conductor 157 from the resistance 126 and connects it to the lower Winding of relay 102 for a reason which will be seen subsequently.

v At the end of the rotary movement, slowacting relay 204 deenergizes; opens the circuit of the upper winding of discriminating relay 103 at armature 220, leaving rela, 103 locked up by means of its lower win ing; and at armature 218 connects up the upper wading of switching relay 205, thereby completing the circuit of the upper winding of relay 205 as follows: from ground by way of the grounded locking conductor 155, resting contact of armature 218 and said armature, upper winding of relay 205, normally closed contacts controlled by armature 224, wiper 234, bankcontact 240, conductor 248, resting contact of armature 381 and said armature, left-hand winding of relay 306, conductor 163, armature 125 and its working contact, and resistance 126 to battery. Relays 205 and 306 energize in series over the above traced circuit and relay 205, upon energizing, closes a locking circuit for its lowcr winding at armature 223, connects the grounded locking 'conductor 156 directly to the wiper 234 and disconnects its own upper winding at armature 224, prepares a circuit for relay 206 at armature 225, disconnects the rotary magnet 209 at armature 226 so as to prevent the rotary magnet from energizing again when the despatcher releases the control circuit, and at armature 227 opens another point in the circuit of relay 107.

Relay 306 in the sending control circuit SC-19, upon energizing over the above traced circuit, shifts the circuit of its righthand Winding at armatures 383 and 384 circuit for cut-of relay 305 at armature 386;

connects the first and ninth impulse stopl conductors 371 and 379, respectively, of the. sender S to the first and second digit stop conductors 314 and 315 at armatures 388 and 389, respectively; and at armature 385 places ground on start conductor 158, thereby closmg a circuit for relay 107 in the relay group RG'. Relay 107, upon energizing, places a multiple ground on the local locking conductor 156 at armature 130, and at armature 128 prepares a circuit for relay 102. Relay 335 inthe relay group RG is also energized over start conductor 158 and closes a circuit for relay 336 at armature 350, which relay, in turn, energizes and closes a circuit for relay 337 at armature 351. Relay 337, upoll energizing, at armature 353 opens a further nected with the despatchers incoming con# trol conductor 18 throughV the resting contact of armature 123 and said armature of' the relay group RG, Fig. 2, and through the resting contact of armature 114 and said y armature, a bridge is now complete across conductors 18 and 19, and line relay 26 oi' the switch D in the despatchers oflice accordingly energizes and closes a circuit'for release relay 27 at armature 37. Release relay 27, upon energizing, places ground on the locking conductor 63 at armatu1e'39, andi at armature opens a point in theicircuit of release magnet 33 and prepares a circuit for vertical magnet 32. The switch D is now ready to be operated'to check the position of the switch E before the despatcher performs thev final act to operate the starter ST.

ln the substation, as a further result of the ground potential being placed on start conductor 158, a circuit is closed for sending relay 338, Fig. 4, as follows: from ground by uay of start conductor 158, armature 122 of relay 106, Fig, 2, and its resting contact,

y conductor 162, armature 4348 and its resting Contact, resting contact of armature 358 and said armature, sending relay 338, interrupter 342, and4 the resistance 341 to battery. As a result, relay 338 commences to vibrate under the control of the interrupter 342.

' Upon the first effective energization of re- ,lay 338, a circuitis closed at armature 354w for stepping magnet 363 of the sender S. Upon energizing, magnet 363 attracts its armature, thereby moving the associated pawl into engagement with the next notch in the wiper driving ratchet wheel 365. The wipers 361 and 362, however, are not moved at this time. Upon the subsequent deenergization of sending relay 338, magnet 363 deenergizes and the wipers 361 and 362 are accordingly advanced-into engagement with the first set of associated bank contacts. Upon wiper 362 engaging the first bank contact, a circuit is close-d :for pick-up relay 339.

Upon energizing, pick-up relay 339 prepares a locking circuit for stop relay 340 at armature 356, and at armature 357 Vremovesthe shunt from around armature 355 and its resting contact. As a further result ofwiper 362 engaging the first bank contact, a circuit is closed for relay 331 in multiple with relay 339. Relay 331, upon energizing, closes a locking circuit for itself including relay 332 at armature 343. Relay 332 does not energize at this time'on account of the fact that it i's shortcircuited. Y

With the shunt removed'from around ar- 357 the nextenergization of stepping relay 338 results in the circuit of line relay 26 of the switch D being opened at armature 355, in Vaddition to the circuit of stepping magnet 363 being closed. g

When stepping relay 338 deenergizes again, the circuit of line relay 26 of the switch D is again closed and the wipers 361 and 362 are advanced into engagement with the second set of associated bank contacts.

Vhen wiper 361 comes. into engagement with its second bank contact, a circuit is closed for stop relay 340 as follows: from ground by way of armature 345 of relay 332 and its resting contact, first digit stop conductor 314, armature 388 and its Working contact, first impulse stop conductor 371, Wiper 361, and stop relay 340 to battery. Upon energizing, stop relayr340 disconnects the sending relay 338 at armature 358, While the lsaid relay 338 is still deenergized; completes its locking circuit at armature 359; and .at armature 360 connects the Wiper 362 with stepping magnet 363 through its local interruptor contacts 364. The first digit l1 in the desired number' has now been transmitted and the Wipers 361 and 362 of the sender S are advanced step by step in a forward direction by a buzzer-like action of stepping magnet 363 which interrupts its own circuit at contacts 364 until their move-` ment is arrested in response to the wiper 362 passing off the last grounded bank contact. The passing of wiper 362 off the last grounded bank contact results also in the circuit of relay 339 and the initial circuit of relay 331 being opened. Whenth'is occurs, relay 332 is no longerI short circuited and immediately energizes in series with relay 14331 from ground supplied over :the

grounded conductor 162. Upon energizing,

relay 332 opens a further point in the initial circuit of relay 331 and prepares acircuit` for relay 333 at armature 346, and at arma ture 345 removes ground from the flrstldigit stop conductor 314 and places ground on the second digit stop conductor 315.

After an interval, the slow-acting pick-up relay 339 deenefrgizes; replaces the shunt around Varmature 355 and its resting contact at armature 357; and at armature 356 opens brateagain, the above operations are reA peated by the sender S under the control of the sending relay 338. The'piek-up relay 339 energizes on the first'movement of the mature 355 of sending relay 338'at armature switchv wipers andveach energization of relay 338 thereafter results in the circuit of fthe relay 26 being opened at armature 355. This continues until Wiper 361 arrives upon the bank contact in which the ninth lmpulse stop conductor 379 terminates, at which time the nine impulses in the second digit 9 of the desired number have been transmitted. When this occurs, stop relay 340 energizes over the second digit stop conductor 315 which is connected to the ninth impulse stop conductor 379 at armature 389 and its working contact.. The energization of relay 340 at this time 'results in the wipers 361 and 362 being again restored to normal.

As mentioned above, a circuit is prepared at armature 346 Yfor relay 333 at the end of the first digit and, consequently, upon the energization of pick-up relay 339 at the beginnmg of the second digit 9, which was sent out as described above, relay 333 energizes and closes a circuit for relay 334. Then, when wiper 362 is returned to its normal position, the short-circuit is removed from around relay 334, whereupon relay 334 energizes in series with relay 333 and disconnects relay from in multiple with relay 339 at armature 349, and at armature 348 opens a further point in the circuit of'sending relay 338 so as to prevent the said relay 338 from operating again when it is c onnected up at armature 3,58 upon the deenergization of stop relay 340 which occurs su sequently.

In the despatchers ofiice, line relay 26, upon deenergizing in response to the one interruption representing the first digit 1, produced in its circuit as described above, closes a eircuit for vertical magnet 32 as follows: from ground by Way of armature 37 and its resting contact, armature 40 and its working contact, contact of ofi1 normal spring 36 and Said spring, slow-acting series relay 28, and vertical magnet 32 to battery. By the operation of vertical magnet 32, the `wipers 53 and 54 of the switch D are raised opposite the first level of 'bank contacts and, by the combined operation of slow-acting relay 28 and the make before break oft1 normal combination controlled by oi normal spring 36, the operating circuit is shifted from the vertical magnet 32 to the rotary magnet 34 upon the deenergization ofthe slow-acting relay 28 after the termination of the single impulse delivered to vertical magnet 32.

In response to each' of the nine interruptions produced in its circuit for the second digit 9 in the desired number, line relay 26 deenergizes and closes a circuit for rotary magnet 34 as follows: from ground by wayV of armature 37 and its resting contact, armature 40 and its working contact, normally open contacts controlled by ofl normal spring 36, armature 41 and its resting contact, armature 48 and its resting Contact, and rotary magnet 34 to battery. By the operation of rotary magnet 34 in response to the nine impulses of current received over thc above circuit, the wipers 53 and 54 are rotated into engagement with the ninth set of bank contacts 57 and 58 in the first level. The slowacting relay 29 is energized in multiple with rotary magnet 34 and maintains the upper winding of switching relay 30 discon nccted during the rotary movement. Upon the termination of the rotary movement, slow-acting relay 29 deenergizes and completes a circuit for the lamp L and the u er winding of switching relay 30 as fo ows: from ground by way of the booster f battery 60, resistance 61, the flasher F, working contact of armature 38 and said armature, resting contact of armature 42 and said armature, upper winding of switchin r relay 30, normally closed contacts contro led by armature 45, resting contact of armature 5() and said armature, wiper 53, bank contact 57, and the lamp L to battery. The booster battery 60 is poled in such a way as to assist the exchange battery. The lamp L does not receive too much current, however, owing to the limiting effect of the resistance 61. The reason the booster battery is included in the circuit of the flasher F is to provide a circuit for relay 30 when the wiper 53 lands on a grounded bank contact as will be pointed out hereinafter. Upon energizing over this circuit, relay 30 opens a further point in the circuitof the lower winding of relay 5 asso ciatcd with the callingA device CD, and closes a locking circuit for its own winding at armature 46; disconnects the rotary magnet 34 at armature 48 so as to prevent its further operation; first short circuits and then disconnects its own upper winding at armature 45; and at armature 47 prepares a circuit for relay 31. The lamp L now flashes on and and off under the control of the flasher F and `informs the depatcher of the position of the switch E in the substation.

The despatcher having noted the position ot' the switch E as indicated by the flashing tiple with release relay 202 at armature 219 through the working contact of armature 225 and said armature. Then, when relay 201 cnergizes again, relay 206 is energized in multiple with release relay 202 and places ground on wiper 233, thereby sending an impulse of currentthrough bank contact 239 and conductor 247 to relay 425 of the starter ST. Relay 204 of the switch E soon falls back and disconnects relay 206 at armature 1,674,121 n Y f' 1219. Relay 206 then falls back after the interval for which it is adjusted and terminates the impulse being delivered to relay 425. Relay 425, upon energizing, closes a locking circuit for itself at armature 430, and at armature 431 closes a circuit for the slow to pull up relay 426 by way of the resting contact of armature 434 and said armature. Relay 426 is slow to pull up on account of its highly inductive winding, which has many turns, and its still adjustment, and for this reasondoes not operate inmediately. As a further resultof the energization of relay 425, it closes at armature 429 a circuit for the solenoid 415. Solenoid 415, upon becoming' energized, attracts the associated` plunger, with the result that the switch levers of the starter arerswung tothe right and the auto-transformer 420 is connected up, and the lea-ds extending to the motor -411`are connected to the low voltage taps Vhen the motorv of the auto-transformer. 411is first connected up, the initial lnrush ,of current is suilicient to operate the relay lat this time that he does the latter.

After the motor 411 has reached a speed which approximates its running speed, the current intake falls to such a value that`the relay 428 is -no longer able to maintain'its armature 434 attracted and, accordingly, falls back and closes a circuit for relay 426.

'Relay 426, upon energizing, opens the circuit ot solenoid 415 and closes a circuit for solenoid 414. lVhen this occurs, the switch levers of the starter are swung to the left and the leads of the motor 411 are connected to the supply leads 422-424, inclusive. The holding magnet` 416 is now energized in multiple with the resistance 419 and at tracts the armature 418 so as to retain the switch levers in their operated position. Ar-

7. mature 418, upon becoming attracted, opensv the locking circuit of relay 425, whereupon i.

relay 425 deenergizes and opens the circuit of 4relay 426 at armature 431. Relay 426 thereupon deenergizes and opens the circuit of solenoid 414, leaving the switch levers under; the control of the locking' armature 418. I

As a further result ofthe switch levers of the starter ST being thrown into running position, the lever 417 is moved to the left and shifts theground connection from conductor 312 to conductor 311. In response to ground being removed from conductor 312, the cut-off relay 307 of the sendlng control circuit SC-lO deenergizes, and 1n response to ground being placed on conductor 311,l a circuit is closed through the righthand winding of the already energized relay7 306 of the sendingl control circuit SC-li) asv follows: from ground by way of the lever 417 of the starter ST, conductor 311, armature 382 and its resting contact, right-hand winding of relay 306, working contact ot' armature 383 and said armature, normally closed contacts controlled by relays 304 and 302, conductor 157, armature 127 and its working contact, armature 128 and its work-V ing contact, and the lower winding of relay 102 to battery. Since relay 306 of the sendying control circuit SC-l is already energized, the closing of this circuit does not produce any eii'ect on that relay. Relay 102, however, energizes over this circuit and closes at armature 112 alocking circuit for its upper winding from the grounded locking conductor 156. As a further result of the energization of relay 102, it opens the circuit ot' line relay 26 of the switch D at armature 114, and at armature 113 closes a circuit for the slow to pull up relay 101. This relay is similar to relay 426 of the starter ST and is so designed and adjusted that it does not pull up immediately.

Af moment later, the slow to pull up relay .101 energizes; prepares ay locking circuit for its upper winding at armature 109; places ground on conductor 160 at armature 115; and at arma-ture 110 terminates the interruption being lproduced in the circuit of line relay 26 of the switch D.

In the despatchers oiiice line relay 26is deenergized momentarily in response tothe above mentioned momentary interruption produced in its circuit bythe conjoined acv tio-n of relays 102 and 101 of the relay group 110 RG, and closes at armature 37 a. circuit for the slow-acting relay 29. Relayv 29, upon energizing, prepares a circuit for the wiper switching relay 31 ataUna-ture 43. When relay 26energizcs lafter its momen- ,115 tary deenergization, the circuit of slow-act ing relay 29 isopened, but before the slowacting relay- 29 has had time to`deei1ergize,

a circuit is completed for relay 31 as follows: from ground by way of armature 37 and 120 its Working contact, working contact of armature 43 and said armature, working con- .tact oi armature 47 and said armature, normally closed contacts controlled by armature 51, and relay 31 to battery. Relay 31, upon 125 energizing, clooes a lockingcircuit for. itselt traceable from ground through armature 39 in its make contact, conductor 62, arma'- ture 51 in its make contact, throughfrela'y 31 to battery and opens its4 initial circuit at 130 armature 51; disconnects the wiper 53 at armature 50, thereby stopping the 1am L from flashing; and at armature 52 p aces ground on wiper 54, thereby closing a circuit for the right-hand coil of the polarized relay 60, which coil is wound in such a direction asvtofcause the armature 62 to be tilted to the position opposite tothat shown in the drawing, thereby opening the circuit of the lamp L2 and closinr a circuit for the lamp L. The lamp L'- now lbecomes extin uished and the lamp L is lighted steadily, t ius informing the despatcher that the starter ST has finally been thrown into running position.

In the substation as a still further result of the energization of relay 101` F ig. 2, it places ground on cut-off conductor 160, thereby closing a circuit for cut-ofi' relay 305 of the sending control circuit SC-19by way of armature 386 of relay 306 and its working contact.l Cut-off relay 305 thereupon energizes and opens the circuit of both windings of relay306 atarmatures 381 and 382, and at armature 382 locks itself to conremoves ground from startconductor 158 at armature 385, whereupon relay 107 in the` relay group RG, Fig. 2, and relays 331-334, inclusive, of the relay group RG', Fig. 4, deenergize. Relay 107,.upon dcenergizing,

' removes ground at one point from the locking conductor 156, leaving said conductor grounded b rela -108 at armature 131. As a sti l furt ier result of the ground potential being removed from start conductor 158, the circuit ofthe Aslow-acting relay 335 of the relay group RG is opened and, after an interval, relay 335 deenergizes and opens the circuit of relay 336 at armature 350. After another slight interval, relay 336 also dcenergizes and opens the circuit of relay 33T at armature 351, and at armature 352 opens the bridge' across thev` release, the slow-acting relay 33T dcenergizes and closes at armature 353 a. point in the chain circuit which includes conductors 162 and 313.

The release of the switch D will now be described. When line relay 26 dcenergizes in response to its circuit being opened by relay 336 of the relay group RG', it falls back and closes a circuit for the slow-acting relay 29, which relay accordingly ener izes, but for no useful purpose at this time.

fter

aninterval the slow-acting release rela 27.

deenergizes; disconnects the flasher at armature 38; removes ground from the locking conductor 63 at armature 39, thereby opening the circuit of the relays 30 and 31 which accordingly deenergize. The removal of ground from wiper 54 results in the cir the wipers 53 and 54 to their normal position, whereupon the circuit of release magnet 33 is opened at off normal contacts 35 by the switch shaft.

The despatcher after noting that the starter ST has finally been thrown into running position, restores the key K to normal, thereby opening the circuit of the slow-acting relay 6. Relay 6, upon dcenergizing after an interval, opens the circuit of line relay 201 of the switch E at armature 11, whereupon line relay 201 deenergizes and opens the circuit of release relay 202. The release relay 202 deenergizes after an interval and removes ground from the locking conductor 155 and closes a circuit for release magnet 210 at armature 214. Switching relay 205 ot' the switch E-and relay, 108 of the relay group RG both deenergize in response to the removal of the ground potential from conductor 155. lease magnet 210 now energizes and restores the shaft and wipers of the switch E to normal, whereupon the circuit of release magnet 210 is opened at oll normal contacts 211. Relay 108, upon dcenergizing, removes ground from locking conductor 156 atarmature 131, thereby permitting relays 102 and 103 to deenergize. Relay 102, upon deenergizing, opens the circuit of the lower winding of relay 101, whereupon relay 101 deenergizes and replaces battery on the pickup lead 164 at armature 116.

It was assumed before .that the despatcher held the circuit of line relay 201 closedat the key K and waited with the connection of the switch set up for the starter ST to operate, so as 'to receive the check signal as soon as possible. It will now be assumed that the despatcher has operated the switch E, as hereinbcfore described, up to and including the last turn of the calling device CD, which resulted in the starter ST being operated, and that the despatcher does not wait for the starter ST to be thrown in, but releasesn the key K immediately after having operated the calling device GD. .ln this case, when the despatcher releases the switch E, the switch D is still in its operated position and ground is still on the start con- '6 remains closed at the oli normal contacts 3 of the dial until the latter returns to its normal position and, when this occurs, the

circuit of the slow-acting relay 6 is opened', y

and after an intervalwhich is sutliciently long to permit the switch E to function and thereby place ground on the wiper 233, as described hereinbefore, the relay 6 deenergizes and opens the circuit of line relay 201. Line relay 201` upon deenergizing, opens the circuit of release relay 202. Releasel relay 202 now denergizes and at armature 214 disconnects ground romthe locking con-4 ductor 155 and closes a circuit for release `magnet 210 through the off normal contacts 211. The wipers `233 and 234 are now restored to their normal-position by release magnet 210, whereupon the circiut of release magnet 210 is opened at 0H normal contacts 21.1 by the switch shaft when it reaches its normal position. In response to the ground potential being removed from conductor 155, switching relay 205 of the switch E 'and relay 108 of the relay group RG deenergize. Relay 108, upon deenergizing, removes ground at one point from conductor 156, leaving said conductor 156 grounded by relay 107 at armature 130.

As a further result of the removal of ground from conductor 155 by release relay 202 of the switch E, the circuit of relay 306 is opened and it 'deenergizes Upon deenergizing,relay 306 removes ground from start conductor 158 at armature 385, whereupon the various associated relays fall back and the connection set up through the switch D in the dcspatchers oflice is released in the hereinbefore .described Vmanner. Discriminating relay 103 deenergizes at thistirne in response to the removal of ground from conductor 156 by relay 107 at armature 130.

l The circuits associated with. the switch E and the sender arenow at normal and the sender circuits are ready to respondas soon asthe starter ST has completed its operaof armature 353 and said armature, pick-up conductor 164, resting contact of armature 132 and said armature, armature 116 and its resting contact, and resistance 133. Relay 306 accordingly energizes and places ground in its right-hand windingrat armature 384. This ground potential is supplied through the resting contact ofarIna-ture 111 of relay 101, Figure 2, and said armature, resting contact of armature 119 and said armature, and the locking conductor 159. As a further result of its energization, relay 306 opens-'the locking chain circuit at armature 383 and at the samearmature connects the locking chain circuit to its right-hand windingand opens its initial energizing circuit.

As a still further result of the energ'izationV of relay 306, it places ground on start conductor 158 at armature 385, with the result that the sending equipment is set in operation and the switch D is operated, as herein- ,before described, to start lthe-lamp L ilashing.

Since an interval of time has elapsed during which the sending equipmenthas been free to respond to its normal control in the substation, and during which anyone of the several circuit breakers or other devices in the substation might have operated auto` matically, the despatcher cannot be certam that the flashing of the lamp L has been brought about as a result of the starter 'ST 'loA being thrown in, on account of the fact that,

since the switch D and the sending equipment are not and cannot be infallible, the

switch D, as far as the despatcher knows, might have been set on the contacts Aasso- Y ciated with the lamp L by mistake and in response to the operation of some device other than the starter ST. Accordingly, 1t

is necessary for the despatcher to check the setting of theswitch D. In order to do'this, the despatcher closes the line circuitv by means of the key K' and operates the switc E through the'medium of the calling device CD and in accordance with thein7 'number 19 indicated by the flashing llamp L.'

The operation of' the switch Eis the' same as has been described hereinbefore and, for that reason, will not be described again. It

locking chain circuit has been opened at armature 383 of relay306, Fig; 4, the discriminating relay 103 of the relay. group RG, Fig. 4, is not energized at this time. a result, there is no battery on the conductor 163 and no circuit is closed through the wiper 2.3.4 or the left-hand winding of re-` lay 306. Also', since relay `306 is at this time energized, and since discriminating relay 103 is not pulled up, a circuit for the lower winding of relay 102 is completed upon the deenergization of slow-acting relay 204 at the end of the rotary movementv odi the switch E as follows: from ground by way of 115 may be pointed out, however, that :since the the grounded locking conductor 155, resting contact of armature 218 and said armature, upper winding of relay 205, normally closed contacts controlled by armature 224, wiper 234, bank -contact 240, conductor 248, working contact of armature 387 and said armature, conductor 161, resting contact of armature 118 and said armature, and the lower winding of relay 102 to battery. Relay 102 is accordingly energized over this circuit. It may be pointed out, however, that in case the wipers ot' the switch E had landed on some set of contacts other thanthc bank contacts 230 and 240 no circuit would have been closed for relay 102 on account of the fact that the remaining relays cozrrsponding to 306, such as the relay 304, for example, are deencrgized.

To continue with the description, relay 102 energizes and opens the circuit of line relay 26 of the switch D at armature 114, and at armature 113 closes a circuit for the slow to pull up relay 101, with the result that a momentary interruption is produced in the circuit of line relay 26 and is terminated when relay 101 energizes.

In the despatchers office the momentary interruption in the circuit of line relay 26A results in the energization of relay 31 and the consequent operation of the polarized relay 60 to connect up the lamp L and extinguish the lamp L2, thereby notifying the despatcher that the signal has been correctly received. l

In the substation, as a further result-ot the energization of relay 101, ground is placed on the cut-off conductor 160 at armature 115, with the result that a circuit is completed for the cut-olf relay 305 through armature 386 and its working Contact. Re; lay 305 accordingly energizes and performs the usual operations. As a still further re sult of the energization of relay 101, it opens the locking circuit of relay 306 at armature 111, whereuponurelay 306 deenergizes and permits the relays associated with the sending equipment to deenergize, with the result that the switch D is released in the-hereinbefore described manner. The switch E and associated circuits are restored to normal in the manner described above when the despatcher releases the key K.

The next remainingg step in the placing of the motor generator MG,Fig. 5, into service is the throwing in of the circuit breaker CB. Accordingly, the despatcher again closes his line circuit at the key K and then dials the in number 11 assigned to the circuit breaker CB. This results in the wipers 233 and 234 of the switch E being set on the bank contacts 235 and 236. As a result of this, the switching relay 205 of the switch E pulls up in series with the left-hand winding ot the sending relay 302 of the sending control circuit SC-ll over a circuit similar to the one traced hereinbefore through the left-hand winding of relay 306. Relay 302 accordingly energizes with results similar to those described in connection with relay 306, with the exception that it prepares the circuits for the sending out of the number 11 instcadof the number 19. This is apparent since the second digit stop conductor 315 is connected to the first impulse stop conductor 371 at the extreme right-hand armature of relay 302 at this time instead of to the ninth impulse stop conductor 379, as is the case when relay 306 isenergized.

In thedespatchers oflice, the switch D is now operated over conductors 18 and 19 in accordance with the number 11 received from the substation and is set upon the first set of contacts in the first level, whereupon the associated lamp not shown) starts flashing to inform the despateher ot' the position of the switch E. The despatcher accordingly gives the calling device CD a further turn,with the result. that ground at armature 228 is momentarily placed on bank contact 235 through wiper `When this occurs, acircuit is closed over conductor 243 for the operating solenoid 402 of the circuit breaker CB. The solenoid 402 accordingly attracts the plunger 409, with the result that the circuit breaker is thrown in. The switch lever 413 makes contact with the conductor extending to the bus-bar 401, thereby finally putting the 'motor generator MG- into operation. The member 407 is engaged by the notch in the upper portion of armature 408 of trip' magnet 404.and the circuit breaker is thereby retained in its operatedposition after the momentary impulse of current dies away. The low resistance overload winding of the trip relay 404 is shunted around the resistance 403 in the main generator lead in order that the circuit breaker may be tripped in case of overload. The polarized relay 405 is also shunted around the resistance 403 and is provided to give reversed current protection for the motor generator MG. Accordingly, the relay 405 is poled in such a manner that it does not operate with the current flowing in the normal direction as it is now.

As a further result of the operation of the circuit breaker CB, the switch lever 412 removes ground frein conductor 310, thus permitting the lockedsup cut-off relay 303 to deenergize, and also places ground on conductor 309, thereby closing a circuit through the ri ht-hand armature of cut-off relay 301, rightand winding of the already energized relay 302, working contact 'of the lefthand armature of relay 302 and said armature, conductor 157, armature 12T and its working contact, armature 128 and its working Contact, and the lower winding of relay 102 to battery. Relay 102 now energizes 'with the result that -a momentarv interruption is produced in the circuit of line relay 26 of the switch D in the hereinbefore described manner, and the wiper 53 is disconnected and the wiper 54 connected up, with the result that the polarized relay associated with the contacts on which the wipers are now standing is loperated to extinguish the associated out lampv and light the associated in lamp. y

In the substationr as a further result of the energization of relay 102, Fig. 2, ground is placed on the cut-off conductor 160 through armature 115, with the result that a circuit is closed through contacts on the relay 302 for cut-off relay 301. 4Cut-off relay 301 thereupon energizes and closes a locking circuit for itself, at the same timedisconnecting the two windings of relay 302, whereupon relay 302 deenergizes and the sending circuits restore to normal as described hereinbefore in response to 'the ground being removedfrom start conductor 158 ,by relay 302.

The despatcher now releases the key K, thereby opening the circuit of the line relay 201 of the switchA E and permitting the switch E and the associated circuits to be restored to normal in the hereinbefore described manner. Y l l Referring now particularly to Fig. 5, it will be noted that the starter ST can be restored automatically in case the supply of alternatingcurrent fails. This is brought about upon the deenergization of the holding magnet 416, which, as before pointed out, is maintained4 energized -in multiple with the, resistance 419.' It will also be noted that the circuit breaker CB can lbe restored to normal in ease the load on the enerator 410 becomes too great or in case the current is reversed through the generator 410, one example of which is when the alternating current supply fails, leaving the generator 410 connected with the bus-bar` 401, from` which it draws current as a motor. In order to further explain thel operation of the remote control system, it will be assumed that the alternating current .supply is interrupted long enough to permit the holding magnet 416 to deenergize. When this occurs, the armature 418' is retracted and the starter returns to its normal position, thereby disconnecting ground rom the conductor 311 Aand permittingthe locked up cut-off relay 305 to deenerglze, and -causing the energiz'ation of relay 308 over the following circuit:

from ground by way of the lever 417 of the f starter ST, conductor 312, right-hand armaturev of cut-oit' relay 307 and its resting contact, right-hand winding of relay 308, normally closed contacts controlled by the lefthand armature of relay 308, pick-up conductor 313, resting Contact ofv armature 353 and said armature, conductor 164, resting.

contact of armature 132 and said armature,

armature 116 and its resting Contact, and re-v sistance-133 to battery. Relay 308, upon energizing, shifts the circuit of its own righthand winding. from the pick-up conductor 313 to the locking chainconductor at its left-hand armature, and at its inner righth'and armature closes a locking circuit for itself independent pf' the initial energizing ground potential supplied over conduc-V tor 312. This locking circuit includes the common Alocking conductor 159 and armatures 111 and 119 and their resting contacts of the relays 101 and 103, respectively, ,of the relay `group RG.. A further resultv of the energization of relair 308 is that it-prepares the necessary circuits for sending in the correct number to the substation and also places ground on the start conductor f 158. The sending equipment now operates in the herein'before'describedmanner to send in the out number 10 assigned to the starter ST to the substation.

In the substation the wipers 53 and 54 of the switch D are set on the bank contacts 55 and 56 which are the tenth set of bank contacts in the first level, anda lashing'eircuit is closed through Wiper 53 for the out lamp Vthe result that the wipers 233 and 234 of the switch E arel set on the bank contacts 241 and 242. Then, when the wiper 234 is connected up through the upper Winding of the switch- In order to` ing relay 205 at armature 218 upon the de- 'energization of the `slow-acting relay 204 at the end of the rotary movement, a circuit is closed through wiper 234 and bank contact 242 for operating the relay 102 of the -re-4 lay group RG. This circuit starts from the grounded locking conductor 155 and includes the conductor 250, a pair of contacts of relay-308, conductor 161, resting contact of armature 118 and said armature, and the lower winding of relay 102. y The energization of relay 102 in this case resultsin a mo mentary interruption being produced in the circuit of line relay`.26 as described hereinbefore. RelayY 101 in this case, in addition to terminating the interruption produced in the circuit of line relay 26, removes ground from the locking conductor 159 at armature i les closes a locking circuit for itself and dis' connects relay 308, Relay 308 now deenergizes with the hereinbefore described results.

case, as before, the despatcher responds bvl dialling the number indicated by the tiash* ing lamp but, since the flashing lamp is not the one corresponding to the starter ST but is some other lamp, the switch E is not set on the contacts 2&1 and associated with the starter ST and, therefore, there is no circuit cloed over conductor 250 to operate relay 102, as hereinbe'lore described. In

that ease the relays 101 and 102 are not en ergized and the i'lashinglamp continues to flash after the despatcher has completed dialling` the number. Then, when the des patcher releases the key K, thereby opening the 'control circuit ot the switch E and allowing the switch E to be restored as here- `inbefore described, a circuit is clofed for the slow-aeting relay 105 in multiple with release magnet 210 of the switch E through armature 109 and its resting contact of relay 101, armature 120 and its resting contact, and armature 129 and its working contact. Relay 105, upon energizing in response to the momentary impulse of current delivered to it, which impulse is terminated upon the opening of the olf normal contacts 211 of the switch E, closes a circuit for the slowacting relay 106 at armature 121. Relay 10G, upon energizing, disconnects ground from conductor 162 at armature 122, thereby opening the circuit of the relays 331-334, inclusive. These relays deenergize andrestore their associated circuits to normal and relay 331 connects up the sending relay 338 again to conductor 162. As a further result 0l the energization of relay 10G, it opens the circuit of the line relay 26 of the switch D at armature 123, thereby causing the switch D. to be restored to normal position in the usual manner.

Soon after the termination of the momentary ilnpulse of current delivered to it, relay 105 deenergizes and opens the circuit of the slow'acting relay 106, which relay soon deenergizes also and again closes the circuit of line relay 2G of the switch D at armature 123, and at armature 122 again places ground on the conductor 10i.v whereupon the sending relay 338 commences to operate, with the result that the switch D is reoperated.

Assuming that the switch D operates eor- `lowing cnt-oil" relay 301 to deencrglze and rectly this time, thel despatcher receives the correct lamp'indication and the associated@ relay is operated to switch the lamp circuits in response to the subsequent operation ot the switch E brought. about by the despatcher. as described above.

1t is evident thatv in ease the wipers 53 and 54 are set on the wrongset of contacts in response to a t'alse operation either ot thtl sending equipment or of the switch l) itself and the lamp asf'ociated with the setr ot' contaets on which the wipers are set is already lighted, that lalnp cannot be flashed, and in that case the circuit of the upper winding ot the switching relay 30 is closed to ground instead of to battery through the associated lamp. The switching relay 30 energizes over 'Athis circuit on account ot the fact that the booster battery is included in .series with the flasher F. The cnergization ol switching relay 30 results in the buzzer l5 being connected up at armature il in the usual manner and the dcspatchers attention is attracted. Since the despatcner cannot observe a flashing lamp, he does not know in which position the switch D is set, .so he merely closes the line circuit by means ot' his key K and then opens it. This causes the line and release relays 201 and 202 of the switch E to energize when the circuit is closed and then when line relay 201 falls back when its circuit is opened, a circuit is closed through armature 21o and its resting contact and armature 215 and its working contact for the vertical magnet 208 which accordingly raises the shaft of the switch E one step and closes the oft' normal contacts 211. Then, when release relay 202 deenergizes, a circuit is closed through off normal contacts 211 for the release magnet 2l() to restore the switch to normal. A branch of this circuit extends as previously traced to the slow-acting relay 105 of the relay group RG, which energizes with the tinalV result that the switch D is released and reoperated as described above.

It. is obvious that, since the motor 111 is no longer operating, due to the failure of the supply current and to the consequent operation of the starter CT, the motor generator MG slows down and the generator 410 starts to operate as a motor` drawing its current from the bus-bar L3101, assuming, of course, that the bus-bar 401 is supplied with direct current from some other source. In this case the direction of the current flow through the polarized relay 405 isreversed and the armature l1100 is consequently tilted in the opposite direction, thereby closing a circuit through the lett-hand windingr of the trip magnet 404. lVhen this occurs` the trip magnet 401 energizes and attracts the armature 408, allowing the circuit breaker Gli to restore to normal. lVhen this occurs, arm l1:12 removes ground from conductor 300, al-

ground is placed on conductor 310, resultingr in the energizatin of relay 304. The out llo `-` number 12 assigned to the circuit breaker `CB is now sent in in the manner described above in response to the energization of relay 304.

It will be understood, nf course, that the despatcher himself can restore either the ning position, they will not be described in any great detail. It is thought that it will suiiice to point out that the starter ST may be restored to normal in response to a ground potential being placed on'conductor 249 at bank contact 241, which results in the ener'- gization of relay 427 and the opening of the circuit ofholding magnet 416 at armature 33. It is' obvious that the circuit breaker CB may be thrown out by the despatcher in case he sets the switch 'E on the contacts 237 and 238 and bringsabout the energization of relay 206 to place gro-und on conductor 245 throughlwiper 233 and bank vcontact 237 thereby energizing the left-hand winding of trip magnet 404. A

A certain point in connection with the operation of the relays 5-7, inclusive, associated with the calling device CD will now be considered. The relay 5 is a cut-oif relay and isl provided for the purpose of opening the line circuit and closing a circuit for the lamp L in case the despatcher starts to operate the switch E at a time when a call is being sent in from the substation. It' will be noted that when the release relay 27 of the switch D energizes with the relay 6 associated withl the calling device CD deenergized, a' circuit 1s closed for cut-oif relay 5 as follows: from ground by way of the working contact of armature 39 and said armature, armature 46 and its resting contact, resting contact of armature 13'and said armature, and the lower winding of relay 5 to battery. Relay 5,

upon energizing, disconnects relays 6 and- 7 and prepares a locking circuit for itself at armature 10; opens a point in the line circuit at armature 9; and at armature 8 prepares a circuit for the lamp L. Now, in case the despatcher starts to make a call at this time, the lamp L is lighted as soon as he operates the key K-to inform him that the incomingy control circuit is in use. It will be noted, however, that the circuit of the lower winding of the cut-off relay 5 is opened at armature 46 upon the energization of switchlng relay 30 which occurs at the end of the rotary movement. This is done so as to free the outgoing control circuit to permit the despatcher to use it as a check circuit in checking the correctness of the new lamp indication.

In a system of the character set forth'hereinbefore, it is desirable to make arrangements to avoid confusion in case the d es- J patcher starts to operate the substation f switch at thewsame time (or a little later) that a circuit'ibireak'er or other device operates automatically, with the consequent result thatA the despatchers switchis operated to start the correspondinglamp to flashing. If said arrangements were not provided, 'the operation of both switches would occursimultaneously andi the despatcher might mistake the iashing lamp resulting from the' automatic operation of the device in the subremoved from the common pick-upconductor 164 by relay 108 of the relay` group RG,

which relay is controlled' by release relay 202 ofthe switch D. This effectively prevents any of the relays, such' as 306 and 308,

Fig. 4, from energizing in case one of them has not already energlzed prior to the removal of battery from the pick-up conductor l164. However, there is always a possibility that a call has already originated `and that the despatcher takes the outgoing cuit for use before the Vcall has proceed far enough to operate the ybuzzer4 associate, with the switch D. VIn case, however, the call has proceeded far enough to energize the releaseirelay 27, a circuit is closed atl armature 39 through armature 46 and its resting contact and the resting contact of armature 13 and said armature for the lower winding of cut-off relay 5,'which pulls up and opensthe line circuit at armature 9, thereby preventing the despatcher from clos ing the line circuit at'this time. In case the despatcher operates his key `K during this interval, a circuit is closed at the contacts 4 and through the working contact of armature 8 and said armature of the lamp' L, whlch is lighted to inform theV despatcher that a call is on thepway. It may so happen, however, that the call has proceeded far enough to have removed itself from under the control of the common pick-up conductor in the substation and at the same time has not yet proceeded far enough to cause the energization of release relay 27 of the switch D at the time when the despatcher operates his key K. Inl this case the operation of the relays 6 and 7 is as described hereinbefore, and the line circuit is closed and the despatcher can proceed with the call. The crcit of the lower winding of relay 5, however, -is such that it is not disconnected from the switch D until after the slow-acting relay 7 has pulledv up and been disconnected at armature12 by relay 6 and has then fallen back, at which time it finally disconnects the lower Winding of relay 5 at armature 15. rl`his interval during which the lower winding of relay 5 remains connected after the key K is operated is sulliciently long to permit of any call which is already started to proceed far enough to operate the cut-o tf relay 5, with the result that the line clrcult is opened and the busy lamp L is lighted.

I'Vhen such a coincidence as this occurs, the incoming callis interrupted before it is finished, owing to the fact that the cir :uits are arranged in such a manner that in order to break down a connection set up through the switch D and cause it to be set again, it is only necessary -for the despatcher to close his line circuit and then open it. rl`his is in effect what happens at this time on account of the fact that the despatcher closes the line circuit which is then opened automatically, as pointed out above. The switch D is released at this time in response to the operation of relays 105` and 106 of the relay group RG which occurs as hereinbefore'described. The despatcher is informed by the busy lamp L, however, of whathas happened and he merely waits a few seconds for the switch D to be reoperated after the relay 106 of the relay group RG has again deenergized.

What is claimed is:

1. In a remote control system, a control station and a distant substation, a plurality of power switching devices operable automatically independent of the control station, a signalling device at the control station for each switching device to indicate the position thereof, control apparatus by which the indication of the signalling device associated with any switching device may be altered responsive to a change in position of such switching device, means included 'in said control apparatus for operating said .signalling device to notify the despatcher at the control station that a switching device has changed its position and means operative by the despatcher for initiating a checking operation to ascertain if the signalling' device which is to be changed actually corresponds to the switching device which has changed its position.

2. In a remote control system, a control station and a distant substation, a plurality of power switching devices operable automatically independent of the control station, a signalling device at the control station for each switching device to indicate the position thereof, control apparatus by which the indication of the signalling device associated with any switching device may be altered responsive to a change in position of Such switching device, means included in said contl'ol apparatus for operating said signalling device to notify the despatcher at the control station'that a switching device has changed its position, means operable by the despatcher for initiating a checking operation to ascertain if the signalling device which is to be changed actually corresponds to the switching device which has changed its position, and means automatically responsive to the checking operation, provided the signalling device is found to correspoml, for causing the indication of such signalling device to be changed.

3. In a remote control system, a control station and a distant substation, a plurality of power switchingdeviccs operable automatically independent of the control station, a signalling device at the control station for each switching device to indicate the position thereof, control apparatus by which the indication of the signalling device associated with any switching device may be altered responsive to a change in position of such switching device, means included in said control apparatus for' operating said signalling device to notify the despatcher at the control station that a switching device has changed its position, means operable by the despatcher to initiate a checking operation to ascertain if the signalling device which is to be changed actually corresponds to the'switching device which has changed its position, and means automatically responsive to the checking operation, provided the. signalling device is found not to correspond, for causing the reoperation of said control apparatus.

4. In a remote control system, a control station and a distant substation, a power switching device at the substation operating automatically independent of the control station, two lamps at the control station, one of which is always lighted to indicate the positions of said switching device, means operative in response to a change in position of said switching device for notifying the despatchcr of said change b v flashing the dark lamp, other switching devices at the substation and corresponding signal lamps at the control station, and n `ans operable by the despatchcr at the control station for initiating a checking operation whenever a flashing lamp is-obscrvcd to ascertain if such lamp actually corresponds to the switching device which has changed its' position.

5. In a remote control system. a control station and a distant substation, a power switching device at the substation operating automaticallyindependent ot tht` control station, two lamps at the control stat ion. one of which is always lighted to indicate the positions of said switching device. means responsive to a change in position of said switching device for notifying the despatchllt) er by fiashing the dark lamp` other switching devices at the substation and corresponding signal lamps at the control station, means operable by the despatcher at the control station'for initiating a checking operation whenever. a iiashing lampis observed to as- .certain if such lamp actually corresponds to `manently and for causing the associated lamp to be extinguished.

6. In a. remote control system, a control station and a distant substation, apower lswitching device at thesubstation operating automatically independent of the control station, two lamps at the control station, one

of .which is always lighted to indicate the positions of said switching device, means responsive to a change in position` of said switching device for notifying the despatcher by flashing the dark lamp, other switching devices at the substation and corresponding signal lamps at the control station, means operable by the despatcher at the control station for initiating a checking operation whenever a flashing lamp is observed to ascertain' if suoli lamp actually -correspon'ds to the switchingdevice which has changed itsposition, and meanspautomatically `responsive to the checking nperation provided the signal is found to be wrong for vcausing said first mentioned means to reoperate. Y

7. In a remote control system, a control -station and al distant substation, a signal 'circuit between said stations, switching devices at the substation operating automatically independent of the control station, signals at the control station corresponding to said switching devices, a selective switch at the` .control station, means operable 1n response to the operation of one of said. switching' devices for operating said selective switch to cause an intermittent operation of the corre= spending signal, means operable by the dpspatcher at the control station for 'initiating a checking operation to ascertain if'the operated vsignal actualy corresponds to tli'eoperated switching device, and means responsive to the checking operation provided the correct signal has been operated for causing a steady operation of saidsignal.

8. In a remote control system, acontrol station and a distant substation, a signal circuit between said stations, switching devices at thesubstation operating automatically independent of theicontrol station, signals at the control station corresponding -to said switching devices, means operable over said circuit in response to the operation of one of said switching devices for changing said signals to notify the despatcher at the control station as to which switching 'device has operated, means operable by the despatcher for initiating a checking operation to check the accuracy of the notice, and means operated in response to the checking operation,

in case the 'notice is found to be accurate, foragain changing the proper signal to indicate 'the new position oftheioperated switching device. Y A

9. In a remote control system'fa control station and a distant substation, switching devices at the substation operating' automatically independent of the control station, signals at the control station coresponding to switching devices, means operable in' response to the operation of one of said switching devices for notifying the despatcher at the. control station as to which switching de vice llas operated, vmeans operable by .the

despatcher for checkingthe accuracy of the notice, and means actuated automatically at the end of the checkingoperation, incase the vices for operating said selective switch over said circuit to change said signals to notify the dispatcheras towhich switching device has operated, means operable by the dispatcher for `initiating a checking operation to check the accuracy of the notice, means operated through sai-d selective switch in response to Asaid checking operation,in case -the notice is found to be accurate, for; changing the proper signal to indicate the new tposition of the switching device, and circuit means included in the first said means arl ranged so that tlie'dispatcher is compelled to perform the checking operation in order to cause the second changel in signal indication and to restore the signal circuit in readiness for operation by another switching device.-

' 11. In a remote control system, a control station and a distant substation, switching devices in the substation operating automaticallyindependent of the control station, sigf nals Vat the control station corresponding to said switching devices, means operable in response to an operation of one of said switching devices for changing sai-d signals to notify the dispatcher as to which switching device has changed its position, means for locking said first named means in operated,4

position, means operable vby the dispatcher for initiating a 'checking operation to check said notification and if found accurate for automatically unlocking said iirst means, and means for again changingsaid signals in accordance with the new position of the switching device.

12. In a remote control system, a plurality

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