US2297148A - Railway signaling apparatus - Google Patents

Description

Sept. 29, 1942. c. M. HINES RAILWAY SIGNALING AFPARATUS Original Filed June 23, 1939 1 ENTQR .HZIZQJ.

Cla

HIS A TTQRNE'Y.

PatentedSept. 29, 1942 g 2,297,148 RAILWAY SIGNALING APPARATUS Claude M. Hines, Pittsburgh, Pa., assignorto The Union Switch & Si

gnal Company,

Swissvale,

Pa., a corporation of Pennsylvania Original application June 23, 1939, Serial No.

280,731. Divided and this application April 12, 1940, Serial No. 329,317

Claims.

My invention relates to railway signaling apparatus; and it has particular reference to apparatus of the type employed in railway signaling systems of the class wherein coded trackwa-y energy is utilized to control either or both wayside signals and train-carried cab signals.

This application is a division of my copending application, Serial No. 280,731, filed on June 23, 1939 for Railway signaling apparatus, now Patent No. 2,215,820 granted on September 24, 1940. It has been proposed heretofore to employ saturation type relays, which are characterized by the fact that all the component parts thereof are stationary, as code following relays in connection with railway signaling systems utilizing coded trackway energy consisting of on periods when current flows and on periods when no current flows. I have found that when saturacurrent the alternating energy output of the saturation relay output winding is minimized, and

of the sharp cut-off in the reproand improved forms of railway signaling systems employing code responsive relays of the saturation type.

Another object is the provision of novel and improved forms of saturation type code following relays of the class broadly covered in a copending application, Serial No. 280,997, filed on June 24, 1939 by Bernard E. OHagan, for Railway signaling apparatus, and now Patent No. 2,215,821 granted on September24, 1940.

Other objects and advantages of my invention will appear as the specification progresses.

I shall describe two forms of apparatus embodying my invention, andshall then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view showing one form of apparatus embodying my invention. Fig. 2 is a diagrammatic view illustrating a modified form of the saturation relay shown in Fig. 1.

Similar reference characters refer to similar parts in each of the two views.

Referring first to Fig. 1, the reference characters l and la designate the track rails of a stretch of electrified trackway over which traffic normally moves in the direction indicated in the drawing by an arrow, or from right to left as viewed in Fig. l. The rails I and la are electrically separated by means of the usual insulated rail joints 2 into a plurality of successive adjoining track sections, of which only one section, 34, is shown complete in the drawing. In accordance with the usual practice, impedance bonds 25 are provided sulated joints and which bonds conduct propulsion current flowing through the two track Each track section is provided with a signal, designated by the reference character S with a. distinguishing sufiix, located adjacent the entrance end of the section for governing traffic operating thereover. Signals S may take any one of many suitable forms but in the form herein shown are three indication signals of the color light type, and each signal comprises a red lamp R, a yellow lamp Y and a green lamp G, which lamps when illuminated indicate stop, caution and clear, respectively.

Each section is provided with means, located at the exit end of the section, for supplying to the rails of the associated section coded trackway or signaling energy. This trackway energy preferably is alternating current of a frequency difierent from the fr application I shall assume that the trackway energy is alternating current of a frequency of cycles per second. I shall describe in detail only the means supplying trackway energy to the rails at the exit end of the section lying to the right as viewed in the drawing, or in the rear of section 34, it being understood that the rails of section 3-4 are provided with trackwa energy through the medium of similar apparatus which has been omitted from the drawing since it would be but a duplication of the one for each pair of ina front contacts 6, 38 and 8! of relays H4,

picked up,

at the exit end of the T1 with a suitend; a source of alternating current of suitable frequency connected over one or another of a plurality of circuits to the primary winding of the track transformer T1; a coding device or coder, designated by the, reference character CT with a suitably distinguishing suflix, for coding or interrupting periodically the current supplied to the transformer primary over the plurality of circuits; and control means for selectively rendering active one or another of the plurality of circuits over which the source of current is connected to the primary winding of the track transformer T1.

Each coding device CT is constantly supplied with energizing current from a suitable source of alternating current, not shown in the drawing but having its opposite terminals designated by the reference characters BX and GK, and each device constantly operates a plurality of contacts each at a different preselected rate. As shown in Fig. 1, coder T4 is provided with two contacts 15 and I80, which contacts are periodically opened and closed at the rates of 75 and 180 times per minute, respectively.

Contact I80 of coder 0T6 is interposed in one alternating current is at times circuit over which supplied to the primary winding of track transformer ITS, and this circuit may be traced from terminal BX of the source of 100 cycle alternat-' I80 of coder GT4, BSA and FSA, respectively, which relays will be referred to in more detail presently, and the primary winding of transformer T1! to the other terminal CX of the source of 100 cycle alternating current. The current that is supplied to transformer 'I'IG over the above traced circuit is coded by contact I88 of coder CTl at the 180 code rate, and this 180 code is utilized to provide a "clear" indication in a manner which will be made clear as the ing current, through contact description proceeds.

when both relays BSA and FSA are released, contact 15 of coder C'I'l is interposed in a circuit which extends from terminal BX through back contact 32 of relay BSA, back contact 33 of relay FSA, contact 15 of coder CT, and the primary winding of transformer 1'14 to terminal CK. The current supplied over the above traced circuit is coded at the '75 code rate by contact 15 of coder GT4 and this current is employed to provide a "caution plained presently in detail,

When relay BSA is released and relay FSA is uninterrupted or-non-coded alternating. current is supplied to transformer 'ITl over a circui which passes from terminal back contact 32 of relay BSA, front contact 3| of relay FSA,

former TN to terminal CX. The purpose of this non-coded trackway energy will be made clear as the description proceeds.

Each section is provided at its entrance and with a code responsive relay of what I shall term the saturation relay type, designated by the reference character DR with a suitably distinguishing sufiix. Relay DB5 shown in Fig. 1 located at the entrance end of section 3-4 is an improved indication in a manner to be exand the primary winding of transconnected together at each end 'tegral relay core structure. A primary or no of core 8 of such value form of a saturable transformer type relay, characterized by the fact that all its component parts are stationary. Relay DB5 comprises a magnetizable core 8 having five legs 8, IO, M, ii

to form an inlocal input winding IB is disposed on the central leg I! of the core, and this winding is constantly supplied with alternating current from a suitable source designated by the terminals BX and CK. for setting up a primary flux in core 8. As is readily apparent from an inspection of the drawing, this primary'flux is provided with two parallel magnetic circuits or paths through the relay core, each path including as a common element leg H upon which winding I3 is carried. A'first of the two paths includes, in addition to leg H, the two legs 8 and iii in parallel, and the adjoining top and bottom portions of the core; and the second of the two magnetic circuits includes leg H, the two legs I! and lid in parallel, and the adjoining top and bottom portions of the core.

Relay DB5 also comprises two saturating windings l5 and 44 for controlling the relative reluctances of the two magnetic circuits of core 8. As

herein shown, a. first or biasing winding 48 of these two saturating windings comprises two coils 86a and 44b disposed one coil on each of the two parallel legs of a particular one of the two magnetic circuits of core 8. In the particular relay shown in Fig. l, the two coils a and 84b are disposed on legs I: and I20, respectively, of the second magnetic circuit of the core, and these coils are connected in series in such manner that when supplied with unidirectional current of a preselected magnitude, the coils cooperate in circulating a unidirectional flux through legs I: and as to substantially magnetically saturate these legs. Preferably, the coils a and b are constantly supplied with unidirectional current of the preselected magnitude, and as shown this current maybe supplied from a separate source of unidirectional current, such as a battery not shown buthaving its opposite terminals designated by the reference characters 13 and C, or if desired such current may be supplied from a source of altematins current through the medium of a rectifier. This constant energization of biasing winding 88 of relay DB5 normally causes the second magnetic circuit of core 8 including the two legs I: and Ma. to have a relatively high reluctance with respect to the reluctance of the other or first magnetic circuit, and as a result substantially all of the primary flux set up in the core due to current in winding I8 is caused normally to thread the first magnetic circuit.

The other or control winding ii of the two saturation windings of relay DRS comprises four coils i511, I5b, I5c and l5d disposed one'coil on each of the two parallel legs of the two magnetic circuits of core 8. These coils are connected in series in such manner that winding is supplied with unidirectional current, the two coils of each pair of coils disposed on each of the two magnetic circuits of the core cooperate in circulating a flux through the two parallel legs of the associated circuit. I

The control saturating winding [5 of relay DRS is at times supplied with unidirectional current from the track railsl and Id of its associated section, through the medium of a resonant and I20, respectively,

when the control I rectifier unit RUI, which has its input terminals connected across the rails of section 3-4 adjacent entrance end 4 and which has its output terminals connected across control winding l5 of relay DR5. The details of construction of unit RUI are not shown in the drawing, but this unit usually includes a transformer, a capacitor and a reactor so arranged and proportioned that the 100 cycle trackway signal current is freely passed by the unit. but the propulsion current is blocked and is prevented from reaching the control winding of relay DR5. This unit also includes 9. rec tifier, which functions to convert into unidirectional energy the 100 cycle alternating energy so that winding I5 of relay DR5-is supplied with unidirectional current from the track rails.

The magnitude of current supplied to winding l5 of relay DR5 from the track rails of section 34 ,through the medium of resonant rectifier unit RUI is selected in such manner'that due to the current in the two coils of each pair of coils disposed on each of the two circuits of core 3, there is created flux of a value sufficient to substantially saturate the two legs of each of the two magnetic circuits. The polarity of this current also is selected so that flux due to current in coils I50 and l5d is opposite in polarity to the flux due to current in coils 44a and 44b of the biasing winding, and as a result these fluxes substantially cancel each other. It can be seen, therefore, that when current is supplied to the control winding of relay DRE, legs 9 and III of the first magnetic circuit of the core become magnetically saturated, while a substantially zero resultant flux condition obtains in legs l2 and l2a of the second circuit, and under this condition, substantially all of the primary fiux due to current in winding l3 threads the second magnetic circuit of core 8.

Relay DR5 further includes a plurality of output or secondary windings disposed on relay core 8 in inductive relation with input winding I 3. As shown in Fig. 1, two output windings l4 and 23 are provided one on each magnetic circuit of the core. eludes two coils [4a and Nb disposed respectively on legs l2 and 12a of the second magnetic circuit of the core, and these coils are connected in series in such manner that when electromotive forces are induced therein due to primary flux threading legs I2 and Ho in parallel, such forces are additive. The other output winding 23 of relay DR5 includes two coils 23a and 23b disposed respectively on legs 9 and l of the core and connected in series in such manner that electromotive forces induced therein due to primary flux threading both legs 9 and III in parallel are additive.

With relay DR constructed in the manner just described, it is apparent that when biasing winding 44 of the relay is energized and no current is received from the rails of section 34 by control winding l5, substantially all of the primary flux due to current in winding I3 threads legs 9 and III of core 8. As a result, therefore, an electromotive force of relatively large magnitude is induced in output winding 23 and practically no current is induced in the other output winding I4. When, however, current is supplied from the rails to control winding IS, the flux due to current in winding l5 substantially saturates legs 9 and I0 and substantially all of the primary flux circulates through legs I2 and |2a since the flux due to current in coils I50 and |5d opposes and substantially cancels the flux due One of these output windings H in-- to current in windings 44a and 44b. A relatively high electromotive force accordingly is induced in winding l4 and substantially no current is induced in winding 23 when control winding l5 of relay DR5 is'energized. It follows. therefore, that an electromotive force of relatively large magnitude is induced in output winding l4 or output winding 23 according as control winding i5 of relay DR5 is or is not energized, and that the amplification ratio high. That is to say, the ratio of the magnitude of current that is induced in either output winding when under one condition of the control winding, the primary flux threads the associated magnetic circuit upon which the winding is mounted, to the magnitude of current induced in such winding when under the other condition of the control winding, the primary flux is shunted away from its associated circuit, is relatively large due to the fact that in the latter event substantially no electromotive force is induced in such winding. Relay DR5 accordingly has a relatively high amplification ratio; and windings I 4 and 23 of this relay function as front contact and "back contact windings in that electromotive forces are supplied from such windings when control winding I5 of relay DR5 is respectively energized or deenergized.

Relay DR5 is employed to control, in accordance with the rate at which the trackway energy received by its control winding l5 from the rails of section 3-4 is coded, the associated traffic controlling signal S4 and the supply of trackway energy to the rails of the section next in the rear of section 34. Control of signal S4 is established by relay DR5 through the medium of a decoding transformer DT4, and two signal control relays H4 and AJ4.

Decoding transformer DT4 shown in Fig. l is substantially similar in construction to the splitcore decoding transformer shown in a copending application, Serial No. 213,016, filed on June 10, 1938 by Bernard E. OHagan for Railway traffic controlling apparatus, now Patent No. 2,215,823 granted on September 24, 1940. This transformer comprises two magnetizable cores 45 and 41 provided respectively with primary windings 46 and 48, and two secondary windings 49 and 50 which link both cores 45 and 41. Primary winding 46 is connected through the medium of a rectifier R1 to back contact output winding 23 of relay DR5, and primary winding 48 is connected through a rectifier R3 to front contact output winding M of relay DR5. The primary windings 46 and 48 are so arranged that the unidirectional fluxes which are set up in cores 45 and 41 when current is being supplied 1 to these windings will thread the secondary windings in opposite directions, and in order to cause the flux to decay quickly in the cores 45 and 41 when the associated primary winding becomes deenergized in spite of the short-circuiting action of rectifiers R1 and R3, each core is provided with one or more air gaps 5|, or their equivalent, two such air gaps being shown in the drawing because of the greater ease of assembly of the transformer which is afforded by this arrangement. Secondary winding 49 of transformer DT4 is connected across the input terminals of a rectifier R4, and the output terminals of this rectifier are connected over a front contact 21 of relay BSA to the terminals of signal control relay H4 so that relay H4 is picked up whenever coded current is supplied by relay DR5 to transformer DT4 and relay BSA is picked up.

of the relay is relatively.

medium of a decoding unit DUltIl to relay AJ i.

The details of construction of the decoding unit DUfltfi are not shown in the drawing, but this unit usually comprises a. rectifier and a reactor condenser tuning unit tuned to resonance at a frequency corresponding to the 180 code, whereby relay AJ 4 is effectively energized and is picked up when and only when 180 code is supplied by code following relay DB5 to decodingtransformer DT4. I

The relays AJ 4 and H4 cooperate to selectively control the various aspects displayed by signal S4 in the following manner. When relays H4 and AJ4 are both pic. :ed up; signal S4 is caused to display its clear indication over a circuit which may be traced from terminal B through. front contact I9 of relay H4, front contact of relay AJd and the filament of lamp G of signal S4 to terminal C. When relay H4 is picked up and relay AJQ is released, signal S4 then is caused to display its "caution indication over a circuit passing from terminal B through front contact is of relay H4, back contact 22 of relay AJ4 and filament of lamp Y of signal S4 to terminal C. When, however, both relays H4 and A34 are released, signal S4 then is caused to display its stop indication over a circuit passing from terminal B through back contact 2! of relay H4, and the filament of lamp R of signal S4 to terminal C.

The previously mentioned relays BSA and FSA are slow releasing relays provided to cooperate with relay H4 in controlling the supply of trackway energy to the rails of the section next in the rear of section 3-4, and also to protect against false operation of signal S4 due to a failure of an insulated joint separating the rails of section 3-4 from the rails of the section next in the rear. Relay FSA is connected across the output terminals of rectifier R3 and accordingly is energized in response to current caused to be induced in winding M of relay DB5 when current is received by winding it of this relay from the rails of section 3-4, and the slow releasing characteristics of this relay, effected in part by a resistor 26 connected across its terminals, are selected to maintain its armature in its picked-up condition during the intervals between successive "on periods of the 75 or 180 code. Relay FSA accordingly functions as a front contact repeater. relay for relay DB5. Relay BSA is connected over a front contact 28 of relay FSA across the output terminals of rectifier R1 and it follows that relay BSA is energized in response to current supplied from "back'contacv output winding 23 of relay DB5 if relay FSA also is picked up in response to cur rent induced in front contact output winding 14 of relay DR5. The slow releasing characteristics of. relay BSA which are efi'ected in part by means of a resistor 29 connected across its terminals over front contact 2s of relay FSA, 'are selected to maintain the armature of relay BSA in its picked-up condition during the intervals hetweensuccessive ofi periods of the 75 or 180 trackway code.

The above-mentioned apparatus embodying my invention functions" to control the wayside signal S4 and the supply of coded energy to the rails of the section next in the rear of section 3-4 in the following manner: the rails of section 3-4 are supplied with 180 or with '75 code according as the section next in advance is unoccupied or 00- cupied. When the plied with 180 code and the section is unoccupied, all parts of'the apparatus occupy the positions in rails of section 3-4 are sup-,

, relay BSA to rectifier R4, and this relay is held induced in winding The other winding Ed is connected through the energy received by winding is from the track rails, and with relay FSA picked. up to close its front contact as, relay BSA is held energized in response to the impulses of energy caused to be 23 of relay DB5. Relay H4 accordin ly is connected over front contact 21 of picked up in response to current caused to be in-= duced in winding 49 of transformer UM by the supply of current impulses from windings id and 23 of relay DB5 to-primary windings $8 and dt of transformer DI'd. Also, since these impulses ,or current supplied to primary windings 58 and it of transformer DTd are coded at the rate corresponding to the 18p code rate received by control winding is of relay DB5 from the track rails, the current impulses induced in secondary winding 5d of transformer D'ld are likewise coded at the ratecorresponding to the code rate and relay AJs is energized and picked up. The previously traced circuit for lampG- of signal S 3 accordingly is completed, whereby that signal is caused to display its clear indication; and relays HQ, BSA and FSA complete the previously ,t-raced circuit over which 180 code is supplied to the rails of the section next in the rear of section 3- 3.

When section 3-4 is supplied with 75 code and the section is unoccupied, relays FSA, BSA and Ed are picked up but relay M4 is released. The rails of the section next in the rear of section il-l accordingly are still supplied with 180 code, but signal St is controlled to display its caution indication due to the illumination of lamp Y of this signal over its circuit completed at back contact 22 of relay Md and front contact as of relay Hd.

When a train occupies section 3-Q, the trackway or signaling current is then shunted by the train away from relay DRE so that relays FSA, BSA, H6 and AJd is controlled to display its stop indication due to the energization of lamp R; and 75 code is supplied to the rails of the section next in the rear of section 3-4 over the previously traced circuit including back contact 82 of relay BSA, back contact-33 of relay FSA and contacts T5 of coder GT4. The section next in the rear of section 3-4 is, therefore, supplied with [180 code at all times except when section 3-4 is occupied lows that the supply of current to the rails of a section is controlled by traffic conditions in advance of that section.

In the event that one or both of the insulated joints separating section 3-4 from the section next in the rear breaks down,

clear playing a false aspect. If, for example,

of section 3-4 breaks down due to the passage of a train through the section, the '75 code current that is supplied to the section in the rear of section 3-4 might leak forwardly over the defective joint. This current is provided with a return path around the intact joint 2 in rail I a due to the autotransformer action of impedance bond 25, so that after the train has passed far enough into section 3-4 that a material length of rail is included in the train shunt of relay DB5, control winding l5 of this relay might become sunlciently energized to cause impulses of energy to are all released. Signal S4 and it folthe-relays FSA and BSA function to protect against signal S4 disbe induced in output windings l4 and 23 of relay DRE. However, relay FSA plcl" up on the first impulse of current supplied from relay DRS under the assumed conditions, and with relay FSA picked up and relay BSA released, uninterrupted or non-coded alternating current is supplied to the rear section. 'I'hiscurrent, leaking forwardly over the defective joint, will constantly energize winding l of relay DB5 and cause a relatively large electromotive force to be steadily induced in winding l4, whereupon relay FSA is held energized and all other relays are deenergized. In this condition of the apparatus, signal S4 continues to display its stop" indication. It can be seen, therefore, that there is avoided the possibility that relay H4 might pick up in response to coded current leaking forwardly over a defective joint, and in so doing control signal S4 to an improper aspect. In addition, if relay H4 had been employed to control the suply of 180 or 75 code to the rear section over its front and back contacts, respectively, as is the customary practice, then relay H4 in picking up falsely in response to the '75 code leaking forwardly over, the defective joint would then have caused 180 code to be supplied to the rear section. This 180 code would then leak forwardly over the defective joint and cause relay AJ4 to pick up and thereby falsely control signal S4 to its clear aspect. It can be seen, however, that by utilizing relays FSA and BSA in the manner described, such false indications due to a failure of an insulated joint are prevented.

Referring now to Fig. 2, a modified form of the saturation relay illustrated in Fig. 1 is shown employed as a code re eater at a cut-section location. Relay DR4 shown in Fig. 2 is substantially similar to relay DR5 previously described, except for the fact that only one output winding 23,is employed and this winding is mounted on the two legs I2 and In of the core. In addition, the biasing winding 44 of relay DR5 of Fig. 1 has been replaced by another biasing winding 42 comprising two coils 42a. and 42b mounted respectively on the two legs 9 and III of the core, and this winding is constantly supplied with unidirectional current through the medium of a rectifier R8 having its input terminals connected to a secondary winding 43 mounted on the center leg of the core in inductive relation with winding l3.

It is believed that the operation of relay DR4 will readily be apparent from an inspection of Fig. 2 together with the foregoing description of the operation of relay DR5 shown in Fig. 1, and further detailed description is believed to be unnecessary except to point out that the functions of output winding 23 and biasing winding 42 of relay DB4 are substantially similar to the functions of output winding 23 and biasing winding 44 of relay DR5. That is to say, biasing winding 42 of relay DR4 is constantly energized to create in legs 9 and Ill a biasing flux which normally causes the primary flux due to current in winding I3 to thread legs l2 and l2a and consequently induce in winding 23 a relatively high electromotive force. When, however, current is supplied from the track rails to control winding ii of the relay, the flux due to current in coils l5c and I5d substantially saturates the legs [2 and He while the flux due to current in coils l5a and IN) opposes and substantially cancels the flux due to current in winding 42. The primary flux is shunted away from output winding 23 during the on period of the traclrway code and it follows that winding 23 functions as a back contact" output winding of the relay.

when relay DR4 is employed at a cut section, as shown in Fig. 2, output winding 23 is connected across the track rails of the subsection into which the coded energy is to be cascaded, and control winding I5 of relay DR4 is connected through a resonant rectifier unit RUla to the rails of the other or advance subsection. In this manner the trackway code that is received by the relay from the rails l and la of the advance subsection is repeated or cascaded into the rails of the other or rear subsection.

In addition to repeating the trackway code from one subsection to the next, relay DR4 also functions to supply non-coded or steady clearing out energy to the rails of the rear subsection. This non-coded clearing out energy is supplied by relay DB4 to the rails of a rear subsection whenever the advance subsection is occupied and the coded trackway energy is shunted away from the relay DR4, since under the conditions assumed, winding l5 of relay DB4 is constantly deenergized and as a result there is cohstantly induced in winding 23 of relay DR4 a relatively high electromotive force. This noncoded current is thus supplied from winding 23 to the rails of the rear subsection whenever the advance subsection is occupied, and it may be employed in the usual manner to control apparatus, such as highway crossing signal control apparatus, etc., which it is desired to be responsive only to traflic conditions in the rear of the two adjoining subsections.

Although I have herein shown and described only two forms of railway signaling apparatus embodying my invention, it is to be understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. A relay of the saturation type comprising a five-legged magnetizable core having two magnetic circuits both including a common central leg and two independent legs of said core, a, primary winding disposed on the central leg of said core and normally supplied with alternating current, a saturation winding for controlling the reluctance of said two magnetic circuits and comprising four coils one disposed on each of the four independent legs of said core, said four coils being connected in series in such manner that the resultant voltage normally induced therein in 4 response to said alternating current in said primary winding is substantially zero and being effective when supplied with unidirectional current of a given magnitude to magnetically saturate each of said two'magnetic circuits, a biasing winding for modifying the saturating efiect of said saturating winding on one but not the other of said two magnetic circuits and comprising two coils one disposed on each of the two independent legs of said one magnetic circuit, said two coils of said biasing winding being connected in series in such manner that when said two coils of the biasing winding are supplied withunidirectional current the magnetic flux created thereby opposes the magnetic flux created by the two coils of the saturation winding disposed on the said one magnetic circuit, and a secondary winding comprising two coils disposed on each of the two independent legs of one of said magnetic circuits, said two coils of said secondary winding being connected in series in such manner that any voltages induced therein in response to the alternating current in said primary winding are additive. g

2. A relay of the saturation type comprising" a five-legged magnetizable core having two magnetic circuits both including a common leg and two independent legs oi said core; a primary winding disposed on said common leg and normally supplied with alternating current, a saturation winding for controlling the reluctance of said two magnetic circuits and comprising four coils one disposed on each of the four independentlegs of said core, said four coils being connected in series in such manner that no efiective voltage output winding comprising two coils one disposed on each of the two independent legs of one'of said magnetic circuits, said two' coils of the first.

output winding being connected in series in such manner that any voltages induced therein by the action of said alternating magnetic flux are additive; a biasing winding efiective when supis normally induced therein in response to said alternating current in said primary winding and being efiective when supplied with unidirectional, current of a given magnitude to magnetically saturate each of said two magnetic circuits, a

, biasing winding for opposing the saturating ei-.

saturation winding disposed'on the said one magnetic circuit, a first secondary winding comprising two coils one disposed on each of said two independent legs of said one magnetic circuit and connected in series in such manner that any voltages induced therein are additive, and

a secondary winding comprising two coils one disposed on each of the two independent legs of the other of said magnetic circuits and connected in series in such manner that any voltages induced therein are additive.

3. A saturation relay characterized by the fact that all its component parts are stationary, comprising the combination of a five-legged ma netizable core structure having two magnetic circuits both including a common leg and two independent legs of said core, a primary winding disposed on said common leg for creating an alternating magnetic flux when supplied with current from a source of alternating current, a saturation winding efiective when supplied with unidirectional current to control the reluctances of said two magnetic circuits and comprising four coils one mounted on each of the four independent legs of said core, said coils of the saturation winding being connected in series in such manner that the resultant electromotive force normally induced in said saturation winding by said alternating magnetic flux is substantially zero and being further disposed so that the magnetic flux created by each pair of windings located on either magnetic circuit traverses a closed magnetic path including the associated two independent legs but not 'said common leg, a first plied with direct current to modify the control of said saturation winding on said one but not the other oi said magnetic circuits and comprising' two coils one disposed on each of the two independent legs' oi said one magnetic circuit, said two coils of the biasing winding being connected in series in such manner that any voltages induced therein by the action of said alternatingmagnetic flux will oppose each other and being so arranged that the magnetic flux created rthereby opposes and substantially equals the magnetic flux created by the two coils of the saturation winding mounted On the said two independent legs of said one magnetic circuit whereby a voltage of relatively largemagnitude will be induced in aid first output winding when said saturation winding is energized, and a second output winding comprising two coils one disposed on each of the two independent legs of the other magnetic circuit and connected in series in such manner that any voltages induced therein by the action of said alternating magnetic flux are additive, said second secondary winding being characterized by the fact that a voltage of relatively high, magnitude will be induced therein only when said saturation winding is deenergized. I I, v

a. In combination, a five-legged n'nagnetiitable core having two magnetic circuits each including one common and two independent legs, a primary winding disposed on the common leg of said core and constantly supplied with perio'dically varying current forsetting up a primary flux in said core, a saturation winding disposed on the four independent legs of said core and supplied with unidirectional current for setting up a given condition of reluctance in each of said two magnetic circuits, a biasing winding disposed on a particular one of said magnetic circuits and supplied with unidirectional current for modifying the condition of reluctance set up in said particular one but not the other of said magnetic circuits by said saturation winding, an output winding disposed on said one magnetic circuit, and another independent output winding disposed on said other magnetic circuit,

5. In combination, a magnetizable core having two magnetic circuits both linked by an input winding normally supplied with alternatmg current, two control windings on said core one for varying the reluctances of bothof said circuits andthe other for varying the reluctance of one but not the other of said circuits, and two each of said two magnetic circuits.

CLAUDE M. HINES.

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