US1755766A - Direct-current relay - Google Patents

Description

April 22, 1930. J. v. BREISKY 1,755,766

DIRECT CURRENTI RELAY Original Filed Aug. 25, 1925 2 Sheets-Sheet l AT'TORNEY April 22, 1930. J. v. BREISKY DIRECT CURRENT RELAY original Filed Aug. 25,

2 Sheets-Sheet 2 ATTRNEY Patented Apr. 22, 1930 UNITED STATES PATENT OFFICE JOHN V. BREISKY, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGI-IOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF FENNSYLVANIA DIRECT-CURRENT RELAY y Application filed August 25, 1925, Serial No. 52,454. Renewed September 11, 1929.

My invention relates to relays and particularly to direct-current relays. sf-

One object of my invention is to provide an improved diiferential relay.

Another object of my invention is t-o provide a sensitive differential relay having an adjustable operating-time characterist-ic.

A further object of my invention is to provide a relay having a field-magnet structure comprising a polarized magnet, soft-iron pole pieces secured to said magnet and differential windings on said pole pieces for controlling an armature member.

Other objects and advantages `of my invention will appear from the following detailed description of a relay constructed in accordance therewith.

In the accompanying drawings, Figure l is a plan view of a relay embodying the invention, parts of the casing and the frame being broken away in order to show the construction of the armature member and field magnet more clearly.

Fig. 2 is a front view 0f the relay shown in Fig. l.

Fig. 3 is a side view, partially in section, of the relay shown in Figs. 1 and 2, and

Fig. 4 is a diagrammatic view of an automatic reclosing circuit-interrupter system 3c employing the relay shown in Figs. l to 3.

The relay shown in the drawing comprises a frame member l upon which a vertical spindle or shaft 2 is pivoted in bearings 3 and 4.

An armature member 5 and a disc member 6 are mounted upon the shaft 2. A fieldmagnet structure 7 co-operates with the armature member 5. A permanent magnet 8 cooperates with the disc member 6 to damp the movements thereof. The damping magnet 8 may be omitted if it is desired that the relay shall have an instantaneous operatingtime characteristic.

The armature member 5 comprises a mag- .netizable segment 10 of iron disposed eccentrically with respect to the shaft 2 in an aperture in a substantially circular disc member 11 of non-magnetizable metal. The thickness and configuration of the magnetizable armature member lO depend upon the desired operating characteristics of the relay.

The thickness of the disc member 11 is preferably such that the weight per unit area is the same as that of the armature member 10.

. Since the armature member is mounted in an aperture in the disc member 11, and the two members are of equal weight per unit area, the composite armature member comprising the magnetizable and non-magnetizable portions 10 and 11 is balanced upon the shaft 2. Accordingly the bearings 3 and 4 may `be delicate and substantially frictionless, and no error is introduced by an unbalance of the moving element.

As shown in Fig. 3, the upper bearing 3 may be of the pin type, because the lateral thrust against the bearing vis slight on account of the fact that the entire moving element, comprising the shaft 2 4and the members supported thereon, is substantially balanced. The bearing comprises the pin 12 in theV upper end of the shaft 2 engaging the stationary bearing member 13on the frame. The lower bearing 4 comprises a steel ball 15 disposed between sapphire or other jewel bearings 16 and 17 onthe shaft and frame, respectively. The provision of a balanced moving element and frictionless bearings in the relay reduces the errors from Y friction or unbalanced masses.

The field-magnet structure 7 comprises a l polarized magnet 20 having soft- iron pole pieces 21 and 22 secured to the upper and lower ends thereof (see Figs. 1 and 3). The lower pole piece 22 is splitinto two parallel portions 23 and 24 on which are disposed differentially-related windings 25 and 26. The tips of the lower pole piece are separated by a considerable air-gap as indicated at 27, (see Fig. l) to reduce the leakage flux and to increase the torque on the armature member 5.

As shown in Figs. 3 and 4,L the parallel portions 23 and 24 of the lower pole piece 22 terminate adjacent to the armature member 1() on the opposite side thereof from the upper pole piece 21'. The winding 25 is wound in opposite directions upon the portions 23 and 24 of the split pole piece 22. The winding is shown on the drawing as comprising upper and lower sections, the reason for this is Wound in suclrdirection as to oppose the winding 25. Inzorder to secure a more perrect balance between the two opposing w1ndings, the winding 26 upon each portion of4 the split pole piece also comprises an upper and a lower .section adjacent to, and concentric with, the sections of the winding 25.

The polarized magnet 2() polarizes the pole pieces 2l and 22 when the windings 25 and 26 are de-energized or are equally energized;

The magnetic -flux divides equally between the portions 23 and 24 ot the split pole pieces 22 under theseceiiditions. lV'lien one-ofv windings 25Y-or 26 i's'energized more strongly,A

than theother, one of theparalle'l portions , Y 23 or 24 of the split pole piece 22 is strengthened and ,theother is weakened 'depending upon which winding predominates. There is" no tendency to de-magnetize the polarizedA magnet 20, the windings'l and 2G-operating simply tovunbalance the distributionfof the Aflux from thelsplit pole piece 22.L

A movable contact member 29 is secured to the spindle 2 and is adapted to co-operatey with stationary contact members 3()r and .31/

depending I upon the energizationof the windings 25 and 26.- Since no control spring is provided, when the relay is cle-energized or the two diii'erential windings are equally-- energized, the armature member `10 v'does not assume any definite positionbut-remains 1nits initial position until the flux .distribution between the-upper and lowerupole pieces, 21

and 22 becomes unbalanced.;v It .the energi- Zation of the windings 252 and 26-.is .suchv as to concentrate thei'luxuuponthetip ofithe pole piece 23, the armature member 10 is attracted tothe position shown in Fig. 1. It the conditions are reversed and the iux is concentratedv uponthe tip of the pole Vpiece 24, the armature member 10 is attracted to a position corresponding to that shown in Fig. 1 adjacent to thepole tip -24. A control spring maybe provided if desired to co-eperate with the field :magnet structure 7 for controlling the armature member fof the relay in certain applications thereof.;V

The fixed contact members 31 are supported on a pivoted arm 32 (see Figs. V1 and 2) which may be turned about the axis of the shaftv 2.v Adjustmentof thevarm 32 changes the spacing ofthe contact members 29 and 31 and thereby changes the operating time of the relay since lthe movement of the armature member is damped by the damping magnet 8. A scale 33 may beprovided for trolled bythe contact members 29,130 and 31jl of vthe controlrelay.

Inthe system shown in Fig. 4, if a shortcircuit-occursupon the load circuit 36, the circuit-interrupter 3? is opened through the instrumentality of an overload relay 38. The operationof relay 38 opens the holding cir-` cuit ot the circuit-interrupter .37.5 The hold!v lng circuit of the interruptor may ,betracedt from one .conductor of the` supply circuit' through the normally closed contacts 39fot' the transfer switch associated with the cire cuit-interrupter 37, thel closngcoil 4Q of the Circuit-,interrupter and the contacts of relay` 38 'to the other side of the supply4 circuit.

V'Vhen the circuit-interrupter 37 opens, a.

circuit is completed from the point 41 on one side of the circuit-interrupter 37 throughfthe` winding 25 'of 'the control relayv and a :re-,c sistor 42 tothe point 43 on the opposite side.

of the circuit-interrupter. If the short-circuit .'stil-l exists upon the load Alcircuit 36 or if any load is' connected to `this, circuit,4,the winding 25 of the relay is traversed by a current lwhich depends uponthemagnitude of the .resistance of the short-circuit or load on' theload circuit 36.

The energization of the windilig25, actuates the armature member 10 to the control relaydinsuch direction as to effect engageA ment of the movable contact member 29witl1- the back contacts30, since the Awinding 26g` of the yrelay is open-circuited. Upon the closure Aof the circuitincluding the contact! members V3O,a circuit is closed iromoneside of thesupply-circuit through.' theE contact.,- members 29 ,and 30, thel windingjoiVv anmauxil-E y iary `relay 44the, normally open contacts45 of they transferxswitch associated/ with the .I crcuit-interrupter 37, the resistor46, andthe contactmembers of ,theoverload relay. 38 tQ is the oppositeisideof the, supply =cir c uit ..`-4 The. auxiliary relay 44 `.becomes energized. and closes AailockingcircuitI foryits own winding through,itsuppermostcontact members .that

is independent-of the contact members of the control relay.,V

The operation of relay 44 closesacircuit. fromthe point 41 through its lowermost consVY tact members and aresistoril tothe point 43, thereby .establishinga vcircuit in shunt to.A 2;

the ycontact Amembers of Vthe circuit-inter-- rupter 37. v A1 circuitk is alsoclOSeClrom the` point 41 through thev windingz26 of the coinv trol relay,lan adjusting-,resistor 48 and the.

second` Vcontactimelnbers of the` auxiliary. re

lay 44 to the opposite side of the supply circuit. The winding 26 of the control rela)7 is connected, therefore, across the generator 35.

The winding of the control relay is energized directly in proportion to the current traversing the load circuit and, as long as the short-circuit exists, the current traversing the winding 25 is sufficient to maintain the Contact member 29 of the control relay in engagementwith the back contact members 30 of said relay. When the resistance of the load circuit increases to a predetermined value, the winding 26 predominates over the winding 25, and the movable contact member 29 is actuated into engagement with the front contact members 3l of the control relay.

Upon the engagement of the contact members 29 and 3l, a circuit is closed from one side of the supply circuit through said contact members, the third contact members of the control relay 44, the closing coil of the circuit-interrupter 37 and the Contact members of the overload relay 38 to the opposite side of the supply circuit. The `closing coil 40 becomes energized and the circuit-interrupter 37 is reclosed.

The described automatic reclosing system recloses the interrupter 37 at a definite load resistance irrespective of variations in the voltage of the generator 35 since the windings 25 and 26 are both equally affected by variations in the supply voltage. Since the control relay does not embody a restraining spring, the operation of the relay is exactly in accordance with the load resistance throughout the entire travel of the armature member. lVhile the errors introduced by the use of a restraining spring may be reduced by using a very light spring, the use of a delicate spring is not desirable. Furthermore, an appreciable error is always introduced by the use of a spring, whereas there is no theoretical error in the operation of the relay shown in the drawing. The restoration of the movable contact member 29 to a retracted position before the control relay is operative to eect reclosureof the circuitinterrupter insures a definite time delay in the reclosing of the interrupter after the load resistance drops to normal.

I do not consider that my invention is limited to the details of construction shown and described herein, nor that the relay is limited to the specific application illustrated in Fig.

4. Accordingly, I do not desire to be limited in scope except as may be indicated in the appended claims.

I claim as my invention l. A relay comprising a movable magnetizable armature member, a polarized field magnet having a split pole piece co-operating with said armature member and differentially-related windings on the respective portions of said split pole the armature member.

2. A relay comprising a pivoted magnetizable armature member, ay polarized field magnet having pole pieces on opposite sides of the armature member along the axis thereof and diEerentially-related windings on ysaid field magnet for controlling the armature member.

3. A relay comprising a pivoted magnetizable armature member, a Vpolarized field magnet having pole pieces on opposite sides of the armature member along the axis thereof, differentially-related windings on said field magnet for controlling the armature member and means for damping the movements of said armature member.

4. A relay comprising a pivoted magnetizable armature member, a polarized field magnet having pole pieces on opposite sides of the armature member along the axis thereof, differentially-related windings on said field magnet for controlling the armature member and means whereby said armature member is restrained only in accordance with the rate of movement thereof.

5. A relay comprising a vertical shaft, a magnetizable armature member supported thereby for movement in a horizontal plane, a polarized field magnet, upper and lower pole pieces secured to said field magnet and disposed above and below said armature member and differentially-related windings so disposed with respect to the field magnet structure as to control said armature member.

6. A relay comprising a vertical shaft, a magnetizable armature member supported thereby for movement in a horizontal plane, a polarized field magnet, a pole piece secured to one end of said field magnet and extending adjacent to said armature member, a split pole piece secured to the other end of said field magnet and disposed on the opposite side of said armature member and differentiallyrelated windings on each element of said split pole piece for controlling said armature mem- 7. A differential relay comprising a movable magnetizable armature member, a polarized field magnet therefor having a split softiron pole piece disposed adjacent to the armature member and diEerentially-related windings on each element of said split pole piece, each winding on one element being connected in series with a winding of opposite polarity on the other element.

8. A differential relay comprising a magnetizable armature member, means for establishing parallel magnetic fluxes traversing said member and normally-balanced windings so arranged as to alter the relative strengthsv of said magnetic fluxes when the currents traversing said windings vary from a predetermined ratio.

9. A differential relay comprising a magpiece for controlling 1,715 aus netizablearmature member, means. ,for .establishing parallel magnetic Yfluxes y,trzwersing Said-member, normallybalanced windings so arranged as to alter the relative. A.strenggths of ysaid magnetic fluxes when .the currents traversing .said windings vary from a predetermined ratio and means for introducing a time interval vinto the operation of the armature member in its movement in either direc tion. Y

In testimony whereof, I have hereninto subscribed my name this 7th day of August, ,1925.

JOHN V. BREISKY.

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