US2833883A - Alternating current relay - Google Patents

Description

May 6, 1958 L. D. AUTEN ALTERNATING CURRENT RELAY Filed May 29, 1953 INVENTOR. LLOYD D. AUTEN IMPEDA N Cf United States Patent ALTERNATING CURRENT RELAY Lloyd D. Auten, Fredericktown, Ohio, assignor to The Hartman Electrical Manufacturing Company Application May 29, 1953, Serial No. 358,500

11 Claims. 01. 200-91 The invention relates in general to electromagnetic structures and more particularly to relays operable on alternating current wherein two separate windings are provided on the core and energized at a phase angle preferably ninety degrees and operating on a pivoted armature, which has exerted thereon a substantially constant torque through a complete cycle of the energizing voltage.

The prior art alternating current relays have previously used a core structure wherein there was established in the core two separate fluxes that were out of phase. Generally these two separate fluxes are a main flux and a lagging auxiliary flux caused by a shading coil. Such shading coils do shift the flux phase relationship, however, to be effective they require intimate contact between the armature and pole face, which destroys accurate control of the voltage drop out point, and also they are undesirable and uneconomical in that they cause a power loss in the shading coil and cause increased heating of the core and windings.

An object of the invention is to provide an alternating current relay which is free of chatter or hum without using any shading coils.

Another object of the invention is to provide a relay having a balanced armature construction so that the contacts operated by the relay armature will not be affected by acceleration, vibration, or physical shock.

Still another object of the invention is to provide a relay construction which combines two or more magnetic forces through a common armature.

Still another object of my invention is to provide an electromagnetic structure utilizing two coils to achieve two magnetomotive forces which are to some extent out of phase to establish a unidirectional torque on a rotatable armature.

Another object of the invention is to provide an electromagnetic structure for use on alternating currents which has greater torque and hence permits a small structure for a given magnetic pull.

Still another object of my invention is to provide a magnetic structure which may he applied to very small as well as very large designs.

Another object of my invention is to provide an alternating current relay which has freedom from chatter or hum caused by the alternations of the frame so that the armature need not actually contact the pole pieces and hence inaccurately controlling the voltage drop-out point of the relay contacts, instead, accurate control of the voltage drop-out point of the relay contacts may he obtained.

Another object of my invention is to provide a relay having constant torque on the relay armature and constant pressure on the electrical contacts throughout a 360-degree cycle of the energizing voltage to obtain low contact resistance.

Other objects and a fuller understanding of this invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which:

Figure 4 is a sectional view taken on the line 4-4 of Figure 3;

Figure 5 is a partial view similar to Figure 4 and show; 1 ing the armature in a magnetically energized position;

Figure 6 is an electrical schematic diagram showing energization from three phase;

Figure 7 is a schematic diagram showing an alternative energization method; and

Figure 8 is a schematic diagram showing energization from single phase or direct current.

The Figures 1 to 4 show the preferred form of the in- Y vention which has been embodied in an alternating current relay 11. The relay 11 has frame 12, core 13, windings 1 4, and an armature 15. The frame comprises the first, second, third, and fourth insulating blocks 16, 17, 1

18, and 19. The blocks 16, 17, and 18 are fastened together by rivets 20 with the core therebetween. The Figure 4 best shows the core 13, and it comprises a first core portion 21 and a second core portion 22. Each of these core poitions is generally U-shaped. The first core 1 portion 21 has a long leg 23 and a short leg 24.. Similarly, the core portion 22 has a long leg 25 and a short leg 26.

lel and spaced and extend into magnetic coupling arrangement with the armature 15. The pole faces of all feet A first coil 27 to 30 preferably lie in parallel planes. 31 is disposed on the core portion 21 and a second coil 32 is disposed on the core portion 22.

The armature 15 is generally elongated and magnetic and has first and second fiat faces 35 and 36. The arrnature is fixedly attached to a shaft 37 which is journaled in a bearing 38 in the block 16 and in a bearing 39 in the block 19.

The shaft 37 carries an insulator disk 41 for rotation therewith. A contact spring 42 extends generally radially from one side of the disk 41 and has contacts 43 thereon for cooperation with oppositely disposed fixed contacts 1 44 and 45. These contacts 44 and 45 are adjustable, as shown by the mounting screws 46. An insulator sleeve 33 surrounds the shaft 37 between the disk 41 and the armature 15 to insulate the shaft from a flexible lead 34 assembly is symmetrical and pivoted at the center of' gravity and that this symmetry even includes the disk 41 with the resilient strip 47 and contact spring 42 thereon. This mounting at the center of gravity assures that acceleration, shocks, and vibration will not affect'the position of the armature 15 relative to the frame 12, which is of particular benefit in many applications. The block 19 is fastened to the blocks 16, 17 and 18 by any suitable means such as the bolts 52. The armature 15 has a reduced width at the ends to permit arcuate movement as shown in Figures 4 and 5. Figure 5 shows the position of the armature when the core 12 is magnetized, and in this position, the faces 35 and 36 are generally parallel to the pole faces of the feet 27 and 30. A non-magnetic abutment 53 is adjustably carried on a core bracket 54,

with this abutment 53 preventing actual contact of the The legs 23 to 26 each have inwardly extending I feet 27 to 3%), respectively. All feet are generally paral I bythe residual magnetism.

This preventssticking of the armature tothe pole faces by residual magnetism after de-energization of the windings 14, and thus an accuratecontrol of the voltage dropout pi nt rriflyibe obtaifidt p The Figure 6 shows a method of erirg'izatibn 'of -'the relay-911. Coils- 55; 56- and 57 representthe three phase windings of an alternator or transformer. ing's -31 andSZ f the relay 11 'are energized from such a three phase source with the coil 31 connected across the extremities of the coils -56-'and 57' and the coil 32 connected across the coil 55. This will place a=higher voltage on winding 31," hence preferably the winding 32 w'ill have' jthe"square"root' of three timesthe num"-' ber of turns on' winding "31" so that each winding", will havethe same number of amperetur'ns. The energizatior'i sy'st'errt of Figure6 will-"establishvoltages 9O degrees out of phase on the windings -31 and32 andthese" The magnetornotive'force of each'of the windings" 3iand" 32} operates"by means'of the feet. 27 to' 30', on opposite longitudinal sides of, center of the'arrnature IS and onopposite"lateral sides 'of'the armature.

The flaxrrbm'nie winding 31 will thread "the core 21, passing 'through'the' foot 27, the right half of arma-' tu'r '15 "and"the"foot 28.l Similarly, the flux from the coil-sfwiuhhreadthe core"22 through'the foot 30, the left half of "thef'arni'ature l and the foot 29/ Each oftliese'flilxeswillestablish a'tor'que on the armature which 'i'sklockwis'e as viewed in Figure 4. This clock wise torque is"resisted by the coil spring- 48, which mainfains tharmature in the position shown in Figure when" the relay. is de-en'ergized. Upon energiiatioii'," the forc'of the flux causes rotation of the arriiatu'reto the 'posit'ion shown in Figure 5. Theforce or torque exerted on the armature 15 is proportional to the squ'ar'e of th'ev'fiux, which is proportional to the square of'the applied 'voltage as longas theoperation of thecore is maintained below the knee ofthe saturation curve. This force, being proportional to thesquare of the applied voltage, .is thus a double frcquencycomponentandwith the windings 31 and 32 ninety degrees: out. of p ha'se, thev total force or-torquecnthesarmature is uniform throughout a complete 3.60-degreecycle.

This completely eliminates chattering of hum and maintainsfan even-contact pressure onthe. contacts 43 -and45. Alsowith this uniform and constant torque, the. voltage dr op-out setting of therelay. may be accuratelyestablished withoutthe-necessity of having thearmature-actually con-tact the polefaces to be held in place Since the armature does not? contact the pole faces, thereis. not the chatter and hum generally-associated with alternating current relays;

Another means--of-' obtaining a ninety degreerphase shifit is tofluse one of the; various 'meansifor changing between 'thrcephase and -two' phase, other than thefoneshownini Figure 6': The Scott connection of: transform ers' is one such-methodfor obtainingftwo volt ages ninety geneialiyg'reatei'" than that obtainable-by the use. of

shadin'g ceils and" hence this construction produces an' The' wind alternating current relay which has performance equal to or-better than most prior-forms of 'alternating cnr rent relays.

The Figure 8 shows a circuit for energization of the windings 31 and 32 from a voltage source represented by lines 58 and 59. The lines 58 and 59 may carry alternating current or direct, current. With operation on alternating current, impedances 60 and 61 may be used as phase "shifting ifdevicesn sor -both of these impedances maybe used, and they may be used The relay 11 may be operated on direct current. such...

as by a circuit as in Figure 8 without. the useof lanyseries or parallel impeda'nces. The relay. will operate; quite satisfactorily, on direct current, becausetheswind ings 31"and'32will each produce equal'and clockwise torques on the armature 15.

Although this invention has. been .describedin its, preferred-form witha certain .degreesofiparticularity', it: is understood that the. present disclosure of l pm,

thatnumerous changes in the details of. construction.

and thecombination and arrangement .oflparts-may be resortedto without departing. from-.the spirit aminthef scope of the: invention: .as hereinafter claimed.-

What is claimed is:

1. An electromagnetic. structurewomprising, a tframe n an armature pivoted to said framefi-rstanda second discrete-permeable cores fixedly attached; to saidv frame and each being -magneticaliy. coupled tov said armature at least in one position of said armature fortfir st and. second magnetic circuits, ,means to urge said. armature clockwise; first and second winding means: on slit structure to establish. first and second: varyingj in': time? 1 magnetomotive :forces in said. cores. ofi different phase;

and saidwcores beingphysicallydisposed: relative-to armature, whereby; saidfirst and .second. 'magnetomDtive-r forces each establish. countervclockwise' torques: at the: same time-in said-armature of a value-suflicient come' -said urging} means.

2. An: i electromagnetic structure: comprising; a: fitting a permeable": armature pivotedsubstantili'y: at. 'tha.:ccn-:--

ter of gravity thereof to said frame, permeable m means 'fixedly 2' attached I to said: frame magnatically coupled to' saidarmatureat. least 'in' one positiow of said armature for: first' and: second: magnetic circuits} said armature having two long sidesudefiningm' lengtll dimension, said core -means: extending on opposite longitudina-l sides of said pivot center, means to urgesaicl armature clockwise, first and second winding 'mean's on said structure to establish first 'and second alternating magnetomotive-forcesin saidcore means of diiferent phase,- and "'said=' core" means being ph'ysicaliy disposed" relative td'saidarmature whereby said first and second magnetornotive forces establishcounter=clockwise' torques Z in said armature of a value suflici'e'nt' to" overcome said urging" means and to maintain continuously a counter clockwise torque on said'armature throughout a. three.

hundiedsixty;degreacycle. oflsaid a1iernating,magneto-- motive. forces.

3. An electromagnetic structure comprising aaframeefl netically coupled to said armature, said'armatuumlvimr ferred-form .has beenv made: only by way of example two long sides defining a length dimension, said cores each extending on opposite longitudinal sides of said pivot center, means to urge said armature clockwise, said armature with said cores establishing first and second magnetic circuits, first and second winding means on said first and second magnetic circuits to establish first and second alternating magnetomotive forces in said core substantially ninety degrees out of phase, and said cores being physically disposed relative to said armature whereby said first and second magnetomotive forces establish substantially equal counter-clock- Wise torques in said armature of a value sufficient to overcome said urging means and to maintain a substantially constant counter-clockwise torque on said armature throughout a three hundred sixty degree cycle of said alternating magnetomotive forces.

4. An electromagnetic structure comprising, a frame, an armature pivoted to said frame, first and second discrete permeable cores fixedly attached to said frame and each being magnetically coupled to said armature, said armature in one position thereof completing at the same time substantially closed first and second magnetic circuits in said first and second cores, respectively, first and second winding means on said first and second magnetic circuits to establish first and second alternating magnetomotive forces in said first and second cores, respectively, of different phase, means to urge said armature clockwise, and said cores being physically disposed relative to said armature whereby said first and second magnetomotive forces each establish counter-clockwise torques at the same time in said armature of a value sufiicient to overcome said urging means.

5. An electromagnetic structure comprising, a frame, a permeable armature pivoted to said frame, a permeable core fixedly attached to said frame and having first and second portions magnetically coupled to said armature, said armature in one position thereof completing substantially closed first and second magnetic circuits for said first and second core portions, respectively, first and second winding means on said first and second magnetic circuits to establish first and second alternating magnetomotive forces in said first and second core portions at least sixty degrees out of phase, means to urge said armature in one rotational direction and said core portions being physically disposed relative to said armature whereby said first and second magnetomotive forces establish substantially equal torques in said armature in the same rotational direction and opposite to said one rotational direction of a value sufiicient to overcome said urging means and to maintain a torque on said armature in said opposite rotational direction throughout a three hundred sixty degree cycle of said alternating magnetomotive forces.

6. An electromagnetic structure comprising, a frame, a permeable armature pivoted to said frame, a permeable core fixedly attached to said frame and having first and second portions magnetically coupled to said armature, said armature in one position thereof completing substantially closed first and second magnetic circuits for said first and second core portions, respectively, first and second winding means on said first and second magnetic circuits to establish first and second alternating magnetomotive forces in said first and second core portions substantially ninety degrees out of phase, means to urge said armature clockwise, and said core portions being physically disposed relative to said armature whereby said first and second magnetomotive forces establish substantially equal counter-clockwise torques in said armature of a value sufficient to overcome said urging means and to maintain a substantially constant counter-clockwise torque on said armature throughout a three hundred sixty degree cycle of said alternating magnetomotive forces.

7. An electromagnetic structure comprising, a frame, a permeable armature pivoted substantially at the center of gravity thereof to said frame, a permeable core fixedly attached to said frame and having first and second portions magnetically coupled to said armature, said armature having two long sides defining a length dimension, 1

each of said first and second core portions extending on opposite longitudinal sides of said pivot center and ex tending on opposite lateral sides of said armature, means to urge said armature clockwise, said armature in one position thereof completing substantially closed first and second magnetic circuits for said first and second core portions, respectively, first and second winding means on said first and second magnetic circuits to establish first and second alternating magnetomotive forces in said first and second core portions substantially ninety degrees out of phase, and said core portions being physically disposed relative to said armature whereby said first and second magnetive forces establish substantially equal counter-clockwise torques in said armature of a value sufficient to overcome said urging means and to maintain a substantially constant counter-clockwise torque on said armature throughout a three hundred sixty degree cycle of said alternating magnetomotive forces.

8. An electromagnetic structure comprising, a frame, a generally U-shaped core on said frame, an armature pivotally mounted to said frame, first and second feet on said core extending inwardly toward said armature and spaced different distances from said pivot, said two feet being disposed on opposite sides of said armature, first and second winding means disposed on said structure, andmeans for energizing said two winding means from a varying voltage source with a phase displacement therebetween to establish in said armature two separate fluxes with a phase displacement therebetween in accordance with said energization phase displacement.

9. An electromagnetic structure comprising, a frame, first and second magnetically separate cores on said frame, an armature pivotally mounted to said frame at the center of gravity of said armature, said armature and cores so constructed that said armature in one position thereof completes a magnetic path for both said cores, separate Winding means disposed on said cores, and means for energizing said winding means form an alternating current source for substantially equal ampere turns at a phase displacement of at least sixty degrees therebetween.

10. An electromagnetic structure comprising a frame,

first and second permeable core portions generally U- shaped with first and second legs on said frame, a symmetrical armature pivotally mounted to said frame, first and second permeable feet on said first and second legs, respectively extending inwardly toward said armature, the first foot of said first core portion being adjacent the second foot of said second core portion and on the same .side of said armature, said two feet on each core portion being disposed on opposite sides of said armature, each of said first feet being the same distance from said pivot point, each of said second feet being the same distance from said pivot point, winding means disposed on said first and second core portions, respectively, and means for energizing said winding means from an alternating current source for generally equal ampere turns at a phase displacement of at least forty-five degrees.

11. An electromagnetic structurecomprising a frame, first and second permeable core portions generally U- shaped with first and second legs on said frame, a permeable armature pivotally mounted to said frame substantially at the center of gravity of said armature, first and second permeable feet on said first and second legs, respectively, extending inwardly toward said armature, the first foot of said first core portion being adjacent the second foot of said second core portion and on the same side of said armature, said two feet on each core being disposed on opposite sides of said armature, each of said first feet being the same distance from said pivot point, each of said second feet being the same distance from SBidJQiVDbtPQiD-Ljfil'fiii and second .:coils;tdisposed lcunsaid: firstsandtsecondacores; respectively, and. means. for ener g zingt said. lcoils iroml anralternating curr.entv source for: substantially equal. ampere rturns at. a .phasesdisplacement therebetween, whereby for, .anyand all rotational positions of. saidarma-ture there exists". a generally uniform torque onrsaidsarmature throughouta-complete cycle-of said alternating .current voltage.-.

1-2, electromagnetic .structurezcomprising .a frame first." and. second permeable. core portions. :gener-ally U shaped .with lfirstrand :second .legs onzsaid frame, a permeable symmetricali armature: pivotallymounted to said. frame at:- the center .ofgravity of said .annature,..-first. and second permeable feet :on.;said1 firstand: second. legs respectively,, .extendiugs inwardly toward 'said larmature the. first. foot of said-.first core portion. being adjacent. the seeondfootofsaidsecondccore portion andtontthe same; side .of said armature, said twodieetv on each..core portion.- being, disposed. ou-opposite sides. .of said-armature; each-.:- of;.said.first. feet. being the same. distance from saidpivot. point,..each.,of saidsecondfeet being;the samedistance from said pivot point, saidiarmature in onemotationah. limitadapted tozlie closelyadjacent theends of all; said feet, first .and second coils-disposed. on said firstaand second. core portions, respectively, and; means-.lfor- :ener.--' gizing said.coils from-can. alternatingycurrent. sourcefor. substantially -,equal ampere turns ata. phase displacement of. I substantially ninety. degrees. therebetweem, whereby, for. any and all rotationallpositionsrof said armature there exists.:a..substantially coustantetorque on said armature. throughout.acompletecycle. or said. alternating current voltage;

13. An electromagnetic. structure. comprising a. frame;. first and second discreterpermeable .cores :generally, U- shapedwith long and short legs. on: said. frame,. a permeablelelongated symmetrical armature pivotallymounted to. said frame at. the. center .of gravity of said. armature, first and second-permeable. feet on said:.long and short I legfirrespectively, extending inparallel and. spacedrela. tionship inwardly=towardsaidzarrnature, the firstfootof saidfirst core beingadjacentth second. foot .ofsaid. secondcore and on. the same sideof. said.armature,.and said .twofeet oneach core beingdisposed onopposite sides of saidarmature, each of said firstfeet being the:same distance from..-.said..pivot point,..each...of..said.second feet being thesarne distancefronr said .pivot point,.said-.arma1 turein one rotational limit. adapted .to lie closely adj acent; the. ends .of. 'all said.feet,..fi'rst. and..second..coils...disposed on said. first. andsecond cores, respectively, andrneans.

for energizing said coils" .frjom an alternating current 7' source for substantially equal 'ampereturns at a phase displacement of'substantially ninety degrees therebetween, whereby for any andall. rotational positions. of said armature there exists a substantially constant torque on said armature throughout a complete cycleofi saidCalternating current voltage.

14. An electromagnetic structure comprising aframe,

first and second-discrete permeable coresgenerally U sh'apedwith' long and short legs-on. said frame, allsaid long and short legs; being, parallel,.. a. permeable, elongated. symmetrical...armature pivotallymounted .to said..frame at the physical lcenterandcenter ofgravity ofsaid. armature, first and. secondpermeablel feet. on said long andr short legs, respectively, extendingin paralleland spaced. relationship.inwardlyttowardsaid. armature, the .first foot;- of ;-said; first core being; adjacent.'the second foot. .ofsaid: second. core .andonthmsame rsidetof said armature, said.

two feetoneach core beingdisposedcon laterally oppositesides of.saidarmaturqrthe.two. .feet on each core-being; on longitudinally. opposite sides of. center. ofisaid-garma:

ture, eachof said. first ".feet .beinggthe .samecdistance from. said pivot point,.each. oi said. second -feet being ,the same: distance from: said. pivot point; said. armature-in. one. rotatioualnlimit. adapted to lieclosely adjacent the ends of all.

saidtfeetzzmeansrtoturgesaid. armature away from said onerrotationale limit, .firstr and second 1 coils. disposed. .on first;andlseeondtcores, respectively, and means-for enen. giaing saidi coils-fromaan alternating. current: 'sourcefor.

substantially equal: ampere turns at.-:a phase -displace.-=

mentofsubstantially ninety degrees therebetweemwhereby-,for-. anyandlall. rotational positions. of said armature there exists a;constant torque on said armature through-nv out-.a-complete cycle .of said alternating current voltage; 15..- .An-.- electromagnetic structure comprising, ;av frame,-

a permeable-armature pivoted-substantially at thecenter of gravity thereof: to saidrframe, a permeable core fixedly attached to said-frame and having first and secondpor-i titans-magneticallycoupled .tosaid armature; said arma-l wture having; two long sides defininga length. dimension,

said core extending :on .opposite longitudinal-sides of i said...

pivot center and extending on opposite. lateral sides ofsaid armature, means: to urge said -armature clockwise,- said armature in one-=position thereof completing, substantially closed-.first- -.and secondmagnetic. circuitstthrough: said.- first and. second core port-ions, respectively, first and second. windingsmeans .on said; first andsecond magnetic circuits .to establish first and second alternatingmagneto' motivatorces-in. saidfirst and second core portions'subi *stantiallyqrinety. degrees-out of phase, and said.;coreportions. being.;,physically ;.disp.osed relative 1 tov saidt armaw' hundred sixty degree cycle of said. alternating magnetm motive ,forcesn 16.. An.v electromagnetic structure comprising a frame,

first. and;second jpermeable1core portions. generally- Ur shapedrwith firstand secondlegs on said frame, .a symmets rical.armature'pivotally mounted to said frame, first-ands second.p airsv of permeable feetcooperating. with. said first andzseeondxylegs. andsaid armature toestablish-fir'st: *andsecond substantially closed magnetic circuits. foronearcuate-positiomof-said armature,,two feetbeing disposed on -.one side of. said armature and the other tvvofeet being .disposed Eon 'theopposite side .of said armature;

each-.ofsaid-firstfeet being thesame distance from-said pivot poinn each; of. said second feetbeing thesame dis:

tance. from .saidpivot point, winding means disposedon; saidsfirsttandsccond .core portions, respectively, and means fon energizing said winding means. from. 1 an alternating current-source for -generally equalampere turns at aphasez.

displacementofijat. least forty-five .degrees.

17.. An electromagnetic structure :comprisinga-frame,

a core includingrfimt and secondpermeable core portions: generally U-shaped with first and second legs on said frame; a:: permeable symmetrical armature pivotally armature-in-' one rotational limit adapted to establish sub stantially closed first and second magnetic circuits through saidfirst andsecond core portions of approximately equal.

low. reluctance and for another rotational limit position adaptedto establish approximately equal higher reluctance in said first and second magnetic circuits because .of'fincreased air gaps therein, first and second. coils .di'sposedonsaid .first andjsecond core portions, respectively,

anduneansforenergizing. said coils from an alternating; current source for substantially equal ampere turns at; a:

phaserdisplacement of. substantially ninety degrees. therebetween, whereby-there is established. asubstantiallyconstant torque on said armature throughout a complete cycle of said alternating current voltage.

References Cited in the file of this patent UNITED STATES PATENTS 5 Negbaur July 12, 1898 Poppenhusen July 29, 1902 Hallborg et a1 Aug. 26, 1924 Leake Feb. 25, 1930 10 Keller Dec. 22, 1931 10 Bossart Nov. 8, 1932 Kercher Sept. 13, 1938 Milliken June 13, 1939 Knudsen Dec. 21, 1943 FOREIGN PATENTS Great Britain Dec. 3, 1948 France Dec. 11, 1928 France Feb. 11, 1929 France Apr. 23, 1946

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