US 2100498 A
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Description (OCR text may contain errors)
Nov. 30, 1937. T. u. WHITE SIGNAL CONTROL C RCUITS Filed OCb. 10, 1932 3 SheecS-Sheeb l Nov. 30, 1937. 'r u. WHITE SIGNAI CONTROL cRcUITs Filed 001;. 10, 1932 3 SheebS-Sheet 2 rrr.
Nov. 30, 1937. T. u. WHITE SIGNAL CONTROL CIRCUITS Filed oct* lO, 1932 3 Sheets-Sheet 3 Patented Nov. 30, 1937 PATENT OFFICE SIGNAL CONTROL CIRCUITS Thomas U. White, Chicago, Ill., assignor to Associated Electric Laboratories, Inc., Chicago,
Ill., a corporation of Delaware Application October 10, 1932, Serial No. 636,984
The present invention relates in general to signal control circuits, but is particularly concerned with the provision of circuits and apparatus for protecting equipment of a low voltage signalling system in which the signalling circuits are of such a character as to require the frequent interruption of such circuits. Such circuits often include a number of multiple paths and carry a load which is great enough to produce excessive arcing at contact springs, employed frequently to interrupt points in the circuit which are common to they combined load of a number or all multiples of the circuit. In such circuit arrangements lamps are sometimes lighted over conductors extending a substantial distance from the source of current employed, causing a quite noticeable voltage drop. Certain of the protecting equipment of the present invention inherently, to a certain extent, overcomes this undesirable feature, incidental to its use for protecting purposes, but which may also be employed at strategic locations to assure uniform brilliancy of all the lamps of the system. In a chain circuit including a great number of switching contacts serving as a common feed conductor for a large number of lamps, sectionalizing relays are used to break up the chain circuit into smaller sections. The application of potential to one end of a section causes a relay at the other end of the section to apply potential to the adjacent section, and so on. With this arrangement small Wire can be used onY each section because of the smaller number of lamps in each section reducing the amperes in such sections. In addition, auxiliary circuits are established for the lamps while the switching contacts in the series circuit are being opened. These auxiliary circuits also shunt the switching contacts to temporarily carry the load so as to prevent injurious arcing at 40 the operated contacts during their operation.
An object of the present invention is to provide sectionalizing means for such circuits to limit the loads carried by them., thus in eiiect enabling an unlimited number of multiple oircuits to be controlled as one.
Another object is to provide sectionalizing means which will function to apply potential from either section to the other,
Another object is to provide a line sectionalizing equipment which may be employed in line loops without danger of the equipment being improperly locked up over such loops.
Another object is to provide circuit sectionalizing means which may also be employed as a current booster.
(Cl. 177-3l1) A further object is to provide load shunting circuits and apparatus which permits the safe and satisfactory use of contacts for controlling circuit loads which would not otherwise be satisfactory for the control of such loads.
The invention has been shown and described as a part of the circuits and apparatus of a` power supervisory board. Fig. 1 of the drawings constitutes a map representing the apparatus and interconnections of a power net-work. This map may be built along the lines of the map shown in the co-pending White Patent No. 2,010,338, granted August 6, 1935. Fig. 2 diagrammatically illustrates the selecting equipment employed by the power supervisor in controlling the display signals and the symbols of the map shown in Fig. 1. Fig. 3, which should be placed to the right of Fig. 2, diagrammatically illustrates the circuits and apparatus directly and indirectly controlled by the supervisor to maintain the display condition of the map, shown in Fig. l, in a display condition representing the condition of the actual equipment represented or a proposed change in the condition of the actual equipment.
Referring now particularly to Fig. 1, the manner of reading the map will be briey explained. In the network illustrated in this figure, the source of current normally supplying the network is supplied from a generator, which, when active, is represented by the lighted condition of the symbol labeled Gen tell-tale which is lighted by the lamps similarly labeled in Fig. 3. In an emergency, current from another network may be supplied to the present network at the point labeled Interconnection. The various tell-tale symbols representing buses, lines, and transformer banks, have been labeled and can therefore be readily identified. These tell-tale symbols are provided with lamps, which, with their controlling circuits, are shown in Fig. 3. In Fig. l one each of the bus disconnect, line disconnect, by-path, and oil switches have been appropriately labeled so that any of such switches may be readily identified.
These various switch symbols are equipped with mechanical indicators of the type disclosed in the copending Obergfell Patent No. 1,966,042, granted July 10, 1934. Two of these indicators, 20B and 260, are diagrammatically shown in Fig. 2. The contacts on these indicators, as well as those not shown in Fig. 2, are shown in Fig. 3, and by their closed or open condition control the various tell-tale circuits at the same time that ,their semaphore cylinder causes their associated symbol toindicate to the supervisor the open or closed condition of the apparatus represented.
The equipment shown in Fig. 2 comprises a Strowger switch SS of the wellV known vertical and rotary type, which responds to dial impulses to rst select one of ten groups of contacts and which is then rotated to select a desired Contact of such group. VOnly two mechanical indicators are shown connected to the bank of the switch shown in Fig. 2, but it should be understood that w there is actually one of these devices for each of the switches represented in Fig. 1 and that each of these devices is equipped with contacts as shown in Fig. 3. The supervisor exercises full control over the selectionand operation of the Y mechanical indicators, such as 260 and 200, by the use of the calling device CD', and keys KV and KI, respectively. In the operation, the key Klis rst operated followed by the operationof the calling device to appropriately position wiper 2 l0 of switch SS,-after which the key K is operated enabling the subsequent operation of the calling device to operate the selected indicator, as will'be subsequently more fully explained.
As previously mentioned, the equipment of Fig. 3 includes the tell-tale circuits and lamps used to light up certain symbols of the map shown in Fig.
' land the tell-tale circuit controlling contacts of the mechanical indicators employed in conjunction with the symbols representing the switching devices. `VThis gure, in addition, includes protective equipment including a pair of load shuntingY relays 30| and 302 which, through the medium of their contacts, provide individual circuits for the various tell-tale lamps of the board and which serve to carry the load required to light these lamps, while circuits, normally including a plurality of the indicator contacts in series, ordinarily carrying the load of these-lamps are being opened and closed by the supervisor. The load shuntingrelays are Valso employed to cause any lamp otherwise'deprived of current to intermittently ash-so that the associated symbol will signify-to the power supervisor the loss oi current at such point in the system. Fig. 3 also contains a pair of line sectionalizing relays 303 and 304 employed to break up a long line into sections so as to limit the line load, thus enabling the use of relatively small line wires, which are much more readily employed in making the required connections to indicator and relay contacts. VIn arranging the. circuits Vin this manner long lines are avoided and the relays 303 and 304 therefore serve as boosters maintaining an even brilliancyY of the lamps of all line sections even when distributed over aV comparatively large area Von theV board.
' Itwill be. noted from an inspection of Fig. 3 that the contacts 300 ofthe mechanical indicator,associatedwiththe oil switch 00, are open and that, likewise, jthe contacts 390 of the rnechanical indicator associated with the oil switch 90 at the interconnection with another'system are likewise open. Therefore, the only current supplied to theboard under these circumstances is that supplied through-the contacts of relays 30| and 302V under control of the interrupter I. Accordingly, while this condition remains the telltale symbols of the board so equipped will intermittentlyflash Vand thus indicateV to the supervisorthe representation of a no current condif tion. Y
- Y The supervisor changes the display condition of the board to agree with changes occurring in the field as he is advised of them, or for the purpose of setting up a proposed change which he believes necessary to the proper maintenance of service. It will be assumed that the supervisor has been advised from the eld that the generator has been cut into service. The supervisor, accordingly operates his key Ki to its alternate position and dials the digits 00 required to position the wipers 2 I 0 of the Strowger switch SS into connection with the mechanical indicator 200 associated with the' oil switch 00.
The off-normal contacts 2H of the calling de.- Vice CD are closed during all stages of operation of the calling device and during such period positive potential is supplied through the left contacts of keys KI and K to the conductors 2l2 and 2i3, respectively. The relay 2&5 accordingly becomes energized and removes negative potential from the windings of relays 303 and 304 to unlock either of these relays if they happen to be energized. at Vthis time. The applicationof positive potential to conductor Z Vcauses the relays 30l and 302Y to maintain the various lamp signals of the board lighted steadily during the operation of vthe calling device.
When the first digit 0 is dialled the impulse springs 2&0. are closed ten times and accordingly ten impulses are transmitted from positive potential, suppliedV through the left contacts of key Kl, through the impulse springs 2 l0, through the right break contacts of key K, and the winding of relay 20| to negative potential. The relay 20l follows these impulses and repeats positive impulses to the vertical magnet 205 by way or" slow release relay 202 and the upper break contacts ofY relay 203. The stepping mechanism driven by the vertical magnet 205, accordingly, elevates the wiper 2| 0 opposite the tenth level of bank con-v tacts. VThe slow release relay 202 remains energized during transmission of the impulse series and'at its contacts completes the circuit of relay 204. This latter relay at its contacts prepares an operating circuitfor relay 2.03 and a holding circuit for itself, which, however, is not effective until relay Y202 `restores following the complete transmission of therst digit. VThe relay 203, upon operating, transfers the operating circuitY of the switch from the .vertical magnet 205 to theV rotary magnet 206 Vso that the second series of impulses transmitted by the calling device is transmitted to the rotary magnet which, through the medium ofV its associated mechanism, moves the wiper 2H) into engagement with the tenth contact Yof the selected level. Y
The wiper 2I0 now being connected Ywithrthe mechanical indicator 200, associated with the oil switch symbol 00, is available for operation by the supervisor. Thersupervisor now operates key K to its alternate position, which substitutes the conductor extending to wiper 210 for the conductor extending toI the impulsing relay 20L It will be appreciated therefore that any subsequent operations of the calling device CD will cause positive potential impulses to be transmitted tol the wiper 2|0 and to the winding of the indicator 200. The supervisor under the circumstances assumed, transmits the required impulses to bring the cam of the indicator into the proper position to close the contacts 000V in which position the drum of the indicator appropriately displays a color representing the closed position of theV represented switch. As a result of the closure of contacts 300, tell-tale relay 305 becomes energized andat one pair of its contacts closes the circuit of the lamp labeled Gen. tell-tale, associated with the generator tell-tale symbol, thus indicating on the map that the generator is now connected tothe network. The relay 305 also applies positive potential to the line 306, and since all of the bus disconnect, line disconnect, and oil switches in the left section of the network are shown as being closed, this positive potential is applied directly t the transformer bank No. 1 tell-tale lamp, the line tell-tale #l lamp, the customers bank tell-tale lamp and to the winding of relay 30:4. This relay upon operating, since all of the mechanical indicators in the right hand section of the network are illustrated as being closed, excluding the one at the interconnection, supplies positive potential to the lamps included in this section of the network. It will be seen, therefore, that, although the positive potential is being intermittently applied through the interrupter to the relays 3M and 302, the operation of these relays will be without effect so long as current is steadily applied from other sources direct to the lamps.
The described operations would have been substantially the same had the supervisor decided to close the contacts of the oil switch 93 at the interconnection instead of employing current from the generator of the network.
It will now be assumed that the supervisor has been advised that the oil switch 63 has been tripped and that he desires to ascertain the effect of this change on the service. He accordingly operates key KI, transmits the digit 60, by operating the calling device as before, and in so doing, connects the wiper 2|0 with the mechanical indicator 260 associated with the oil switch symbol 30. He then operates key K and the calling device :as required to open the contacts 360 of the mechanical indicator, and to position such indicator as required to represent the open condition of the represented oil switch 60 on the display map. It should be noted that, in the network shown, current is being supplied from the generator source to the line conductor 307 by two paths, namely, by way of the line conductor 306 and conductor 308, comprising the path interrupted by the opening of the oil switch 63; and by the second path including the conductor 309 and a series of oil and disconnect switches which are still closed. Therefore, the opening of the oil switch 60 is without effect except that there may be a deciency of current supplied to the line conductor 301 under some circumstances. Therefore, in a system as shown, no change in the condition of the tell-tale symbols occurs at this time.
It will .now be assumed that the generator is disconnected from the system and that the supervisor, being so advised, selects and operates the mechanical indicator 200 to again open the contacts 300. Upon opening the contacts 300 the tell-tale relay 305 becomes deenergized and the generator symbol lamp is accordingly extinguished. It will be seen that when positive potential was applied to the line conductor 306 when the relay 305 was energized and with the consequent energizaticn of the sectionalizing relay 304, as previously described, positive potential was supplied from this relay over the right section of conductor 309 to the line 301, back over line 308 and through the switching apparatus to the line 306. Therefore, unless some special arrangements are provided the deenergization of relay 305 will not result in the removal of positive potential from this loop circuit which now includes the winding of relay 304. It will be noted, however, that upon each operation of the calling device to perform theV selection vof a mechanical indicator the relay 2I5 removes negative potential from the sectionalizing relays 303 and 304 and in this manner insures their deenergization occurring each time a selection is made. These relays therefore can never remain locked up in a loop circuit such as described.
If special provisions are not provided, the opening of right-hand contacts of relay 305, which at times may carry the load of a large number of lamps, will result in excessive arcing, resulting in damage to these contacts. The same holds true as regards. the Various contacts of the mechanical indicators. This is especially true of more elaborate systems than the one disclosed, as such systems involve the use of a large number of lamps. The prevention of arcing of contacts included in circuits carrying loads too large to safely break, is taken care of by the relays 30| and 302. These relays, as previously explained, are maintained energized during the operation of the calling device CD and establish individual circuits for the various lamps of the system during the time any of the chain circuits are being broken. In other words, the relays 30| and 302 may be termed load-shunting relays for the reason that they shunt the load from the contacts normally carrying it while such contacts are being opened.
The selecting switch SS of Fig. 2, after each operation, is released consequent to the restoration of key KI which closes a circuit for the release magnet 201 by way of the off normal springs ON. These off normal springs are automatically opened consequent to the restoration of the switch wipers to their normal position.
What is claimed is:
l. In a signalling system, a plurality of signals, circuits for said signals including a circuit connected to all of said signals, signal control contact sets interspersed throughout the length of said circuit, means for operating any set of said contacts to interrupt the circuits of one or a plurality of said signals depending upon the contact set operated, auxiliary circuits for all signals, and means for closing said auxiliary circuits consequent to the actuation of said first means and until the desired set of said contact sets has been opened, each auxiliary circuit including only suflicient current flow to operate one signal.
2. In a signalling system, a plurality of contact sets connected in series relation in a current feed conductor, a plurality of indicating devices energized over circuits including parts of said conductor and one or a plurality of the contact sets depending upon their point of connection with said conductor and the feed point or points of the conductor, means for operating any desired set of said plurality of contact sets to interrupt the circuits of those devices included in the interrupted portion of the common circuit, auxiliary circuits for said indicating devices, and means for completing said auxiliary circuits to maintain such devices energized until after the interruption of the series circuit, each auxiliary circuit carrying less current than said conduct-ors.
3. In a signalling system, a multi-branch signalling circuit, contacts connecting the branches in said circuit, signals included in said branches, means for energizing said signals over said bran'ches, shunting circuits for shunting said branches, each shunting circuit carrying less current than the branch circuit which it shunts,
means for operating any of said contacts to disconnect one or a plurality of said branches from said circuit, and means operated responsive to the operation of said means for completing said shunting circuits to shunt said branches and to maintain said signals energized during the actuation of said first means. Y
4. In a signalling system, a signallingV circuit including a plurality'of branches, contacts connecting said branches in said circuit, signals connected to said branches, means for connecting a potential to said circuit to energize said signals over said branches, means for operating any of said contacts to disconnect one or a plurality of said branches from said circuit dependent upon Y the contact'operated, and meansoperated re-v sponsive thereto for connecting said potential directly to each branch to maintain said signals energized and to thereby preventV the opening of anyV circuit' carrying as much current as the branches and thus prevent arcing at the operated contacts during the operation 'oi any of said contacts.
5. In a signalling system, a plurality of signals, Y
6. A signalling system as claimed in claim 5Y in which there is means for intermittently operating said relay While said impulse sender is not operating to ash the lamps not otherwise lighted. Y
THOMAS U. WHITE.