US2475662A - Electrical relay - Google Patents

Description

July 12, 1949 A. E. DODD ELECTRICAL RELAY Filed Feb. 5, 1945 5 F Pg 551 5 U J 313% a 1 0 9 L I la il is" 17a 185 26 ""ME. 17429 O INVENTOR B2 v APzhaPE,D0dd

HIS A TTORNE Y Patented July 12, 1949 ELECTRICAL RELAY Arthur E. Dodd, Union Switch Edgewood, Pa., assignor to The & Signal Company, Swissvale,

Pa, a corporation of Pennsylvania Application February 3, 1945, Serial No. 576,072

6 Claims. 1

My invention relates to electrical relays, and particularly to electrical relays f the direct current type having both a neutral and a polar armature. More particularly, my present invention relates to a relay of the type described suitable for use in railway signaling systems,

In certain applications of relays of the type described in railway signaling systems it is highly desirable in the interest of safety that the relay be provided with means to insure that the neutral armature will not pick up when the relay becomes energized until the polar armature agrees in position with the polarity of the energizing current, and one means for accomplishing this result is disclosed in Letters Patent of the United States No. 1,822,496, granted to Branko Lazich on September 8, 1931. Briefly described, this means comprises a pair of bucking windings mounted on extensions provided on the pole pieces of the main electromagnet. The extensions are so disposed that when the neutral armature swings away from the pole pieces of the main electromagnet, it will swing toward these extensions, whereby unless the bucking windings are energized by current of the proper polarity when the main electromagnet of the relay becomes energized, these pole piece extensions will cause the flux from the main electromagnet to exert a force on the neutral armature which holds it against the pole piece extensions. The bucking windings are arranged to be supplied with current usually from a local circuit over pole changing contacts controlled by the polar armature, and the parts are so proportioned that these windings will be energized by current of the proper polarity to cause the neutral armature to pick up when and only when the polar armature agrees in position with the polarity of the energizing current.

With a polar relay constructed in the manner outlined above, the voltages applied to the main and bucking windings must be maintained within certain limits with respect to each other, or the neutral armature will fail to pick up even though the polar armature agrees in position with the polarity of the energizing current. This is not objectionable for applications where the amount of line resistance is small because in these applications there is usually no difficulty in holding the voltages within the necessary limits. However, for applications where the line resistance is likely to be large, such for example, as is the case in signal control service, the limited operating range of the relay tends to limit its usefullness.

One object of my present invention is to provide an improved relay of the general type dis- 2 closed in the said Lazich Patent No. 1,822,496, which relay may be operated over wider limits of voltages and in a larger number of difierent circuit arrangements.

According to my invention, I accomplish this result, either by providing the relay with an auxiliary neutral armature and including in the energizing circuit for the bucking windings a contact controlled by this armature and closed only when this armature is picked up, or by including in the energizing circuit for the bucking windings a front contact of an auxiliary relay which is connected in series with the windings of the main electromagnet of the relay.

Other objects and characteristic features of my invention will become apparent as the description proceeds.

I shall described two forms of relays embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a view, partly diagrammatic, showing one form of relay embodying my invention. Fig. 2 is a diagrammatie view showing another form of relay embodying my inventio Similar reference characters refer to similar parts in both views.

Referring first to Fig. 1, the relay in the form here shown comprises a core A consisting of three parallel legs I, 2 and 3 connected together at one end by a backstrap 4, and provided at the other end with pole pieces 5, 6 and 1, respectively. The middle leg 2 is a permanent magnet, but might, of course, equally well be a constantly energized electromagnet; while the two outer legs I and 3 and the backstrap 4 are of ordinary magnetizable material.

The leg I is provided with a coil la and the leg 3 is provided with a coil 3a. The two coils la and 3a together comprise the operating winding of the relay and this winding is included in circuit with a battery BI and a pole changer P comprising two contacts 8 and 9.

The pole piece 5 is provided with two extensions 5a and 5b, and the pole piece I is likewise provided with two extensions 1a and lb. The extensions 5a and la, as shown in the drawings, extend laterally toward each other, but in actual practice these extensions project rearwardly from the pole pieces to a point opposite the middle leg 2, which latter leg is offset rearwardly from the legs I and 3. The extensions 5b and lb are made U-shaped for a purpose which will appear presently, and are provided with coils l0 and II, the purpose of which will also appear presently.

The relay also comprises a main neutral armature I2, an auxiliary neutral armature I3 and a polar armature I4. The main neutral armature I2 is biased b gravity to a released position in which it rests on non-magnetizable stops c and secured to the extensions 5?) and 1b, respectively, but is-adapted to be at times moved against the action of gravity to an attracted position in which the armature then engages non-magnetizable stops 5d and Id provided on the underside of the pole pieces 5 and I, respectively. The

neutral armature I2 controls a contact I5 which is closed or open according aslthis armature occupies its released or its attractedposition.

The auxiliary neutral armature I3 is biasedby gravity to a released position in which it is separated from the pole piece extensions 5a' and Ta by means of air gaps, but is adapted to bemoved, when the relay becomes energized, to a position in; which it -engages .,non-magnetie stops 5e and 1e secured to the pole pieceextensions 5a and 1a, respectively. This armature controls a contact t6- which 'is open or closed according as it occupies its ,released orits attractedposition.

The polar armature Idis pivotally supported intermediateitsends bymeans of a pivot pin II between bifurcations whichare formed in the pole piece-6, and is arranged to swing toward one or the other of. the pole piece extensions Eaand Ia; non-magnetic stops Mabeing attached to the armature. to prevent the armature from coming into actual contact with. the pole piece extensions. The polar armature I4 actuates two contact fingers I1 and IB toclose normal contacts II'I'Ia and, I8"I8a or reverse contacts Il-I'Ib and I8|8b according as the armature is ,swung toward thepole piece extension Error the pole, piece extension Ia.

The two coils Illand II are connected in series in ansener gizingl circuit which is'supplied with current of normal or reverse polarity from a suitable source here shown as a battery B2; according as the normal contacts I'I--I'Ia and I8'I8a" or the reverse contacts I'II'Ib and- IB- IBZJ are closed. This'energizing circuit includes the contacts I5 and I6 controlled by the armaturesj 2 and I3, and it willbe' obvious therefore that this circuit will become closed when and only when the polar'armature occupies one or the .other of its extreme positions, the main neutralarmature I2 is released, and the auxiliary armature I3 is picked up. The two coils l0 and I I function under certain conditions which will be made clear hereinafter to neutralize the flux which threads the pole piece extensions 5b'and 'Ib'due' tothe energization of the main eoils'Ia' and 3a, and the coils,.l0 and Il may, therefore, be collectivelyreferred to as a bucking winding.

As shown in the drawing, polechanger. P is in its normal position, so that current of what I shall term normalpolarity is being supplied to the coils Ia and 3a. Under these, conditions, the

polar armature I I will occupy its normal positionin which it is shown in the drawing, and the main and neutral armatures, I2 and I3 willboth belpicked up. With the neutral armature. I2 in its'lpicked up position, the circuit for the bucking coi1s;,I0,and His open at contact I5, and these coilsflaretherefore deenergized.

I will now assumethat pole changer P is reversed, therebyreversing the polarity of the current supplied tothe,mainoperating coils Ia, and 3a JjThe reversal of, the current inthese coils will cause the flux threa dingtthe armature ,I 2 to de-.,,

crease to zero, and when this happens this armature will release due to its gravity bias. As soon as armature I2 releases, the reluctance of the flux path from the pole pieces 5 and I to the armature by way of extensions 5b and 1b will become less than the reluctance of the flux path from the pole pieces 5 and 1 to the armature by way of the air, gaps between the pole pieces and the armature and, consequently, as the flux builds up in the reverse direction in the legs I and 3, it will exert a hold-down torque on the armature I2 until such time as the coils I0 and II become energized to neutralize the flux in the extensions Eband lb. The reversal of the flux in the cores I and 3 will alsocause the polar armature I 4 to reverse, and the armature I3 to release and again pick up. The reversal of the polar armature I4 will open the normal polar contacts II-I'Ia and I8?I8aand close the reverse polar contacts III'Ib and I 8-I8b and, consequently, when the armature, I3 picks up and closes the front contact Ill,- the coils I0 and I] will become energized by current of reverse polarity. The coils IIIand II are, disposed on the extensions fib'andflb'in such nanner'that when these coils are energized by current of the same relative polarity as that which is being supplied to the coils laand 3athe fluxes set up in the extensions 5band 'Ibby the two sets of coils ,willneutralize each other; and the parts are so proportioned that the armature I3 will notpick up until the flux induced in the legs I and 3 by the energization of coils'Ia and 3a has built up to the value necessary to cause thearrnature S2 to pickup-with the flux in theextensionstbfland 'I'b'neutralized-- Itwill be seen; therefore; that thepicking up of the armature- I2 under the conditions just described is delayed until after theauxiliaryzarmature l3 picks'up. When the-armature I2 picks up the resultant opening of the contact I5 deenergizes-the-coils I0 and I I to therebysave energy.

When the pole changer P is restored to its noi mal position,-the mainenergizing coils-Ia-and 3a will "again receive current of reverse polarity.

This will cause-both neutral armatures l2'and II-I'Iaand I8-I3a, and as a result, as soon as the neutral armature- I 3 again picksup; the bucking winding will receive current-of normal polarity- Since the'ma-in anclbuckingwindings will then both be-receiving current-0f normal polarity',-the-flu-xes induced in the extensions Strand 'Ib 'by these-windings will again neutralize each other, and the main armature will therefore pickup and will open the contact I5therebydeenergizingthe bucking'winding.

I will-now assume that withthe parts injthe position shown in the drawing pole'changer P is reversed, but that the polar armature Miails'to reverse in response to the reversal inthe' polarity of the current supplied to the operating coils la and 3a. Under these conditions when'the neutral armature I3 picks up, the bucking winding will' be supplied with current of normalpolarity, and since this ,current is of the opposite relative po larity to that suppliedto the main winding, the effect of the bucking windingwillbe to induce in, the extensions 5b. and 1b, a, flux which assists that duetothe current in the mainwinding; As

a result, the neutral armature I2 willn0w beheld in its released position a ainst thenon-rnagnetic stops 50' and TOT Thesame result willoccur if the .polar armature P fails to move to its normal position when it occupies its reverse position and the pole changer P is operated to cause the coils Ia and 3a to be supplied with current of normal polarity.

Referring now to Fig. 2, in the modified form of my invention here shown, I employ, in place of the front contact l6 controlled by the auxiliary neutral armature l3 for delaying the application of energy to the bucking winding until the flux in the main winding has built up to the value at which it is desired to have the armature l2 pick up, the front contact 26 of an auxiliary relay C the energizing winding of which is connected in series in the energizing circuit for the coils la and 3a. This relay is so adjusted that it will close its front contact 2 6 when the current in the coils la and 3a has increased to approximately the same value at which the armature I3 picks up and closes the contact [6 in the form of the relay shown in Fig. 1, and it follows, therefore, that the relay combination shown in Fig. 2 will operate in essentially the same manner as the relay shown in Fig. 1.

It will be seen from the foregoing that in both forms of relays embodying my invention I have provided means for delaying the application of energy to the bucking winding until the flux in the main winding has built up to approximately the value at which it is desired to have the main neutral armature l2 picked up. As a result, when energy is applied to the bucking winding, the main neutral armature I! will pick up as soon as the flux induced in the bucking winding has built up to the value at which it neutralizes the main coil flux in the extensions 5b and lb. This causes the pick-up value of the main neutral armature [2 to become practically independent of the voltage applied to the bucking winding so long as sufficient energy is supplied to this winding to always insure that the flux due to the bucking coils will be able to neutralize the main coil flux which threads the polar extensions 5b and lb.

It will also be seen that the use of the auxiliary armature or the series relay serves to delay the application of energy to the bucking winding in the desired manner under direct pick-up conditions as well as when the energizing circuit is pole changed, and in addition provides a means for deenergizing the bucking winding when the main winding is deenergized. The fact that the bucking winding is deenergized when the main winding is deenergized results in a savings in power over the form of relay described in the Lazich Patent No. 1,822,496, referred to hereinbefore.

One advantage of a relay constructed in accordance with my invention is that it permits the relay to be operated over a wider range of voltages and in a larger number of difierent circuit arrangements than has heretofore been possible with polar relays which are provided with a means for positively checking that the position of the polar armature corresponds to the polarity of the energizing current supplied to the main coils before it is possible for the neutral armature to pick up.

Although I have herein shown and described but two forms of electrical relays embodying my invention, it is 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 y invention.

Having thus described my invention, what I claim is:

1. A relay comprising an operating winding and a bucking winding, a polar armature responsive to the polarity of the current in said operating winding, a neutral armature, means for picking up said neutral armature when and only when said operating and bucking windings are both supplied with current and the current in said bucking winding is of the same relative polarity as the current in said operating winding, means controlled by said polar armature for controlling the polarity of the current supplied to said bucking winding, and means for delaying the energization of said bucking winding when said operating winding becomes energized until the current in the operating Winding has built up to the desired pick-up value for the neutral armature.

2. A relay comprising an operating winding, a polar armature responsive to the polarity of the current in said operating winding, a main and an auxiliary neutral armature both responsive to the presence and absence of current in said Winding, and means for preventing said main neutral armature from picking up unless said polar armature occupies a position corresponding to the polarity of the current being supplied to said winding and said auxiliary neutral armature has picked up.

3. A relay comprising an operating winding, a polar armature responsive to the polarity of the current in said operating winding, a neutral armature responsive to the presence or absence of current in said operating winding, a contact, means for closing said contact when and only when said operating winding is energized to a predetermined extent suflicient to pick up said neutral armature, and means controlled in part by said contact for preventing said neutral armature from closing unless said polarized armature occupies a position corresponding to the polarity of the current being supplied to said winding.

4. A relay comprising a core provided with pole pieces, an operating winding on said core, a polarized armature cooperating with said pole pieces and responsive to the polarity of the current in said winding, pole piece extensions secured to said pole pieces, a first neutral armature movable between said pole pieces and said pole piece extensions and biased toward said pole piece extensions, a bucking winding on said pole piece extensions, a second neutral armature cooperating with said pole pieces and responsive to the presence or absence of current in said operating winding, and means for supplying current of normal or reverse relative polarity to said bucking winding when and only when said second neutral armature is picked up according as said polarized armature is in its normal or its reverse position, the parts being so arranged that unless said polarized armature occupies the position corresponding to the polarity of the current being supplied to said operating winding said bucking winding will assist the operating winding in holding said first neutral armature against the pole piece extensions but that when the polarized armature occupies the position corresponding to the polarity of the current being supplied to the operating winding the bucking winding will oppose the flow of flux through said extensions so that said first neutral armature will move toward said pole pieces.

5. A polar relay comprising an operating winding adapted to be reversibly supplied with ourrent, a polarized armature responsive to the po- 7 larityi-of the current in said ope'rating' winding, a neutnai armature responsiveto -the -presence and" absence- 0f current in I said winding, an aux iliary relay connected in series with said: operat ingx-Winding; andqrieans effectivewhen the polar ity'of the current supplied to said Operating Winding is reversed-f or preventing -said neutral' armature: from closing I unless said p01mized ar-' mature occupies the position *correspondingto the polarity-of the current being "supplied-to said winding and said auxiliary relay energized-to a' predetermined extent.

6. A polarrelay comprisingan'operating' wind ing, -a polarizefiarmatur'e responsiveto them Iaritymf the current in said" operating Winding; a neutral ermature-'--responsive to the presence" and absence of current in said windingyan'aux iliary relay connected in series with" said operating 1 windingand provided with a contactwhich' becomes closed w'hen-and*oi11y"wheri"said auxin" 15 Number ary rela'yis energized to azpredetermin'ed extent,

and'means =for preventing said neutrail fa'rmature from-closing -unless said polarized armature occupies'th position corresponding :to *the ipo1ar-' ity of the current being supplied-t0 said winding andsaid cbntact is closed;

E DODD. 1

REFERENCES: GITEDQ;

The'folldwing' refereni'ces are of record in the' file of this patent:

UNITED '1S'IATES r PATENTS i Name Date" Lazich Sept; 8, Allen" De;"8,

Eckha'rdt Dec. 14, 1943 Aylsworth Nov; 21,

I 1931* Willing Oct: 26,1937-

Images