US2414583A - Polarized electromagnet - Google Patents

Polarized electromagnet Download PDF

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Publication number
US2414583A
US2414583A US542203A US54220344A US2414583A US 2414583 A US2414583 A US 2414583A US 542203 A US542203 A US 542203A US 54220344 A US54220344 A US 54220344A US 2414583 A US2414583 A US 2414583A
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US
United States
Prior art keywords
relay
armature
core
permanent magnets
energization
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US542203A
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English (en)
Inventor
Sr George E Duffy
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SPX Corp
Original Assignee
General Railway Signal Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to NL66281D priority Critical patent/NL66281C/xx
Priority to BE482649D priority patent/BE482649A/xx
Application filed by General Railway Signal Co filed Critical General Railway Signal Co
Priority to US542203A priority patent/US2414583A/en
Application granted granted Critical
Publication of US2414583A publication Critical patent/US2414583A/en
Priority to CH269930D priority patent/CH269930A/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H51/00—Electromagnetic relays
    • H01H51/22—Polarised relays
    • H01H51/2272—Polarised relays comprising rockable armature, rocking movement around central axis parallel to the main plane of the armature
    • H01H51/2281—Contacts rigidly combined with armature

Definitions

  • This invention relates in general to electromagnetic relays, and more particularly pertains to relays. of the two-position polarized type which have their armatures biased to on position and which are actuated to the other position only in response to the energization of their coils with current of a particular polarity.
  • the relay of the present invention is to be considered in the nature of an improvement over the relay disclosed in the application of O. S. Field, Ser. No. 588,748, filed April 17, 1945, which is a division of his prior application Ser. No. 361,060, filed October 14, 1940, now Patent No, 2,376,534, granted May 22, 1945; and no claim is made herein to any subject matter disclosed in said applications.
  • relays of this type it is desirable to employ polarizing permanent magnets which have a high coercive force, so that the energization of such relays with current of a polarity which produces a magnetomotive force in opposition to the residual induction of the permanent magnets will not have any material effect in reducing such residual induction of the permanent magnets.
  • Permanent magnets of this type generally do not have as high a residual induction per unit of cross-sectional area as those having a lesser coercive force, and for this reason it is necessary to organize the relay structure so as to provide permanent magnets with a relatively large crosssectional area, and yet adapt such relay organization to the structure required to give the desired operating characteristics. This purpose has been accomplished by the organization of the present invention.
  • the permanent magnets are provided with keepers which are effective to reduce the demagnetizing efiects during the time the relay is not in use.
  • a further object of the present invention is to provide structure so that the core member of the relay which is normally arranged to shunt the permanent magnets and act as a keeper, cannot be removed without the removal of the permanent magnets, and thus avoid the possibility of the false operation of the relay armature by the flux of the permanent magnets with the core member removed.
  • a further object of the present invention is to so organize the relay structure that to effectively actuate the armature by reverse energization of the relay requires such a high operating potential, that such operation due to reverse energization will never occur even upon accidental en- 5.5 ably supported by bearing 6.
  • the armature A is to so organize the relay structure that to effectively actuate the armature by reverse energization of the relay requires such a high operating potential, that such operation due to reverse energization will never occur even upon accidental en- 5.5 ably supported by bearing 6.
  • Fig. 1 represents a fragmentary perspective view of the essential elements of a relay constructed in accordance with the present invention.
  • Fig. 2 is a sectional view taken on line 2--'2 of Fig. 1 looking in the direction of the arrows to show the manner in which the core members are joined with the permanent magnet structure of the relay.
  • the drawing has been made more for the purpose of showing the necessary structural characteristics of a relay embodying the present invention rather than showing the details of design of a completerelay. For this reason the drawing has been made fragmentary in nature eliminating the housing portions, terminal blocks, and the like, and reducing the showing of detail contact structures, coils and'the like to a minimum, it being believed that a disclosure and explanation of the essential structural characteristics will be sufiicient for an understanding-of the principles of the invention so that they may be readily adapted to any particular relay designed for specific purposes, such as railway signalling relays, telephone type relays, or the like.
  • the relay comprises a U-shaped core member C having its opposite legs connected to elongated pole pieces PI and P2 respectively, which pole pieces have pole shoes or faces with which a pivoted armature A is associated.
  • the armature A is pivoted by suitable trunnions 5, or other type bearings, suitalso carries movable contact, arms I which cooperate with front and back contacts 8 and 9.
  • keepers KI and K2 which are attached to the core member C and the elongated pole pieces Pl and P2 respectively as indicated in Fig. 2. More specifically, the keeper K2 contacts against a flattened portion of the left-hand leg of the core member C and these two members have holes through which a bolt B2 freely passes so that it can enter the threaded portion of the pole P e P2.
  • the pole piece P2 also has a flattened portion which bears against the opposite side of the left-hand leg of core member C and these three members make close mechanical contact due to the pressure exerted by the tightening of the-stud bolt B2.
  • bracket members t2 and 13 are provided to support the leakagestrip L2 and permanent magnet PM2 in their proper positions. These bracket members '10, 1
  • the core member C with its windings WI and W2 and associated permanent magnets are of course in the open, while the armature and its associated contacts, bearings, and the like, are suitably enclosed in a housing constructed of suitable insulating material, which has been merely indicated at M. course unessential to an understanding of the present invention, although quite necessary in the actual construction of a relay for practical fuses.
  • the armature A is ordinarily provided with a released air gap of the required dimensions to i give the desired pick up value with regard to the drop away value of the relay, and the armature A is prevented from making contact with the pole ,faces, when picked up, by suitable residual pins of non-magnetic material.
  • the core member C, the pole pieces PI and P2, armature A, and the keepers KI and K2 are formed of some suitable magnet material of relatively low reluctance, such ,for example, as the commonly used silicon steel.
  • the leakage strips LI and L2 are also formed of a suitable .ferrous material of relatively low reluctance, although it is not .essential that the reluctance of these leakage strips be as low as the reluctance of the core structure.
  • PMZ may be of any suitable permanent magnet steel having the desired characteristics, and as one example it may be mentioned that the material known under the trade-name of Black Streak Alnico has been found to be very Such details are of suitable, although it should be understood that any suitable material may be employed.
  • the permanent magnets PM] and PMZ are poled in the same direction such as with the north poles N to the left against the keeper 2.
  • the lines of induction produced by the residual magnetism in the permanent magnets passes through three paths in multiple.
  • the first and best magnetic path is from the permanent magnets through keepers KI and K2 and core member C.
  • the leakage strips LI and L2 are also direct multiple with this path, and in fact are in contact with the permanent magnets 7 along the side as well as in contact with the keepers Kl and K2. Thus, the leakage strips will be considered as providing the second path.
  • keeper has been applied to the members Ki and K2 for convenience in applying the nomenclature, but these members are not keepers in the true sense of each individually providing a complete path for the lines .of induction from its permanent magnet, but act as connecting links with the core member C so that they are a part of an actual closed path through the core member for the lines of induction from both the permanent magnets.
  • the third path for the lines of induction from the permanent magnets is through the pole pieces and the armature, but ince this path includes a substantial air gap, the lines of induction which pass'through it, and which comprise lines of force, are relatively small in number compared to the lines of induction passing through the first path including the core member C, or passing through the second path including the core members LI and L2.
  • the amount of remenance, or residual induction of the magnet in accordance with the present invention should be suiiicient to produce lines of induction in the core member C to a density relatively near to the knee of the magnetization curve of the core member C. In order to do this,
  • the biasing force on the armature A should be sufliciently great to overcomegany lines of force passing through the air gap with the coils or windings of the relay deenergized.
  • the biasing force is gravity, which of course depends upon the weight of the armature A, but it is to be understood that mechanical means, such as springs or the like, may be provided to give .the proper bias if desired.
  • the leakage strips LI and L2 are preferably arranged on the inside of the permanent magnets towards the core member C.
  • these leakage strips form a closed magnetic circuit with respect to the core member C with the permanent magnets on the outer side of such closed magnetic circuit.
  • the leakage strips give the greatest protection, against the operation of the relay when it is energized in the reverse direction.
  • the permanent magnets were arranged to be between the legs of the core, as is possible with some designs of relay, then the leakage strips should preferably be placed above the permanent magnets, that is, between the permanent magnets and the coils on the U-shaped core member 0.
  • the leakage strips are preferably formed to have a combined cross-sectional area within reasonable variations on either side of the cross-sectional area of the core member.
  • substantially the same normal operation of the relay occurs if the leakage strips have a crosssectional area slightly above the cross-sectional area of the core, but the combined cross-sectional area of the core and leakage strips should be but a fractional portion of the combined cross-sectional area of the permanent magnets. way, it is possible to maintain the desired degree of saturation in the core structure from the lines of induction produced by the residual magnetism in the permanent magnets.
  • the relay would then act substantially as a neu tral relay and the reverse working current values would be substantially the same as the normal working current values.
  • the provision of the leakage strips to complete a leakage path for magnetic flux upon reverse energization of the relay and upon energization of the relay in either direction when the permanent magnets are demagnetized provides protective features which are obviously new and useful. It might be noted here that the reluctance of the permanent magnets is so high that even when such magnets are completely demagnetized, practically none of the lines of induction produced by the energization of the windings is shunted by these permanent magnet pieces.
  • leakage strips provided in accordance with the present invention in connection with permanent magnets as disclosed in total effect appear to provide shunt paths for magnetic lines of induction under conditions where it is desirable to prevent operation of the relay, while on the other hand such leakage strips appear to have no substantial undesirable effects upon the normal operation of the relay.
  • the energization of the windings with the switch SW in the lower position for normal energization produces a flux in the core member in opposition to the flux produced therein by the permanent magnets. This opposition causes additional flux to pass through the air gap and armature so that the lines of force are suificient to pick the armature up.
  • the additional lines of induction in the leakage strips although increased to some extent, are not increased to any great extent due to the fact that the lines of induction already there by reason of the permanent magnets are at a density already at the knee of the magnetization curve, so that the lines of induction produced by the energization of the coils is very effective to cause lines of force to pass through the air gap.
  • the switch SW in a lower position provides for the normal energization of the relay at a proper value to efiect the picking up of the armature; while the operation of the switch SW to an upper position provides that the relay is energized in the reverse direction but since it is at the same degree of energization as for normal operation, the armature does not respond.
  • the armature In order for the armature to be picked up in response to the energization of the relay windings in the reverse direction, it is necessary to produce lines of induction in the armature air gap which is suflicient to oppose those lines of induction normally present due to the permanent magnet plus a sufiicient number of lines of force to cause the armature to be attracted. Since the degree of reverse energization of the relay windings with switch SW in an upper position, is incapable of producing such a number of lines or induction in the armature air gap, the armature does not respond.
  • the leakage strips provide the desired effect on the operation of the relay, since they have substantially no effect under normal operation of the relay when the flux densities are below the knee of the magnetization curve of the core member, and since they become very effective upon the reverse energization of the relay when the flux densities are well above the knee of the magnetization curve of the core member.
  • the degree of energization in a reverse direction required to efiect the picking up of the armature is an abnormal condition which has been discussed to merely bring out the degree of protection provided by the present invention against the response of the relay armature upon accidental energization in such reverse direction.
  • a U-shaped electromagnetic core a pivoted armature associated with the ends of said core and normally biased away from said core to a retracted position, a leakage member connected across the legs of said core to make a closed magnetic circuit through said core, a permanent magnet connected across the legs of said core in multiple with said leakage member for normally causing a relatively high density of magnetic flux in said core and said leakage member, windings on said core effective when energized with a current of one polarity to cause the induction of magnetic flux to oppose the lines of induction from said per manent magnet for causing the attraction of said armature toward said core, but eiiective when energized with current of the opposite polarity to produce lines of induction adding to the lines of induction from said permanent magnet in such a way as to fail to actuate the armature from its retracted position, whereby said leakage member is relatively inefiective on the normal operation of said relay because of relatively low flux densities in said core but is highly
  • said armature being actuated to an operated position when said winding is energized with one polarity of energization but remaining in its retracted position when said winding is energized with the opposite polarity of energization even if such opposite polarity of energization is several times the current value of the normal energization.
  • an electromagnetic core member having a pivoted cooperating armature, a shunt member connected across the electromagnetic core member, means for normally producing magnetic lines of induction in said core and said shunt member relatively'near the saturation point of said members, and an energizing winding on said core member energizable with current in either direction to thereby induce a magnetic flux in said core opposing said normal magnetic flux in said core member to cause the actuation of said armature but acting when energized with the opposite polarity to produce a magnetic flux which is additive with said normal magnetic flux in said core member to oppose the normal magnetic iiux in said armature to thereby allow said armature to remain in its retracted position.
  • an electromagnetic core having extending pole pieces, a permanent magnet and a leakage strip all magnetically connected in multiple between said extending pole pieces, a pivoted armature associated with said pole pieces in a manner to assume attracted or unattracted positions and normally biased away from said pole pieces by a torque suflicient to overcome the leakage flux from said permanent magnet with the armature in either an attracted or unattracted position, and windings on said core for producing a magnetic flux in said core in either direction depending upon the polarity of energization of said windings to thereby cause the attraction of said armature under one condition of energization but to allow said armature to remain in its biased position under another condition of energization, said leakage strip being a more efiective shunt for the flux in said core under said another condition of energization than under said one condition of energization.
  • armature in a, relay structure, a pair of pole pieces and a cooperating pivoted armature normally biased away from said pole pieces, an electromagnetic core connected across said pole pieces, a leakage strip connected across said pole pieces, a permanent magnet connected across said pole pieces to complete a closed magnetic circuit for the flux of said permanent magnet to pass through said core and said leakage strip in multiple with said armature including an air gap, and a winding on said core efiective when energized with current of one polarity to produce flux opposing the flux of said permanent magnet but aiding the flux of said permanent magnet in said air'gap and armature to thereby cause the flow of flux to effect the actuation of said armature toward said pole pieces, but eiTective when energized with current of the opposite polarity to produce flux that is in the same direction as the flux of said permanent magnet but opposing the flux of said permanent magnet in said air gap and armature and thereby allows said armature to remain in its biased position, whereby said leakage strip acts as a
  • a U-shaped electromagnetic core a pivoted armature associated with the end of said core with an intervening air gap and movable to attracted and retracted positions but normally biased away from said core to said retracted position
  • a permanent magnet of relatively high reluctance connected across the legs of said core to make a closed magnetic circuit through said core for a portion of the flux of said permanent magnet and to make a magnetic circuit for another portion of the flux of said permanent magnet through said air gap aid said armature, such magnetic flux through said armature being insufiicient to overcome said normal bias
  • windings on said core effective when energized with a normal current of one polarity to increase the magnetic flux in said air gap for causing the attraction of said armature toward said core, but effective when energized with a normal current of the opposite polarity to produce a magnetic flux in said air gap opposing the magnetic flux emanating from said permanent magnet whereby said armature is actuated to an attracted position by a.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Electromagnets (AREA)
US542203A 1944-06-26 1944-06-26 Polarized electromagnet Expired - Lifetime US2414583A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
NL66281D NL66281C (xx) 1944-06-26
BE482649D BE482649A (xx) 1944-06-26
US542203A US2414583A (en) 1944-06-26 1944-06-26 Polarized electromagnet
CH269930D CH269930A (fr) 1944-06-26 1947-12-30 Relais polarisé.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US542203A US2414583A (en) 1944-06-26 1944-06-26 Polarized electromagnet

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US2414583A true US2414583A (en) 1947-01-21

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US542203A Expired - Lifetime US2414583A (en) 1944-06-26 1944-06-26 Polarized electromagnet

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US (1) US2414583A (xx)
BE (1) BE482649A (xx)
CH (1) CH269930A (xx)
NL (1) NL66281C (xx)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2486086A (en) * 1945-08-21 1949-10-25 Gen Railway Signal Co Relay
US2502811A (en) * 1946-09-27 1950-04-04 Gen Railway Signal Co Polarized relay
US2535977A (en) * 1949-09-27 1950-12-26 Gen Railway Signal Co Magnetic stick relay
US2536244A (en) * 1946-09-27 1951-01-02 Gen Railway Signal Co Spring holder for permanent magnets
US2928029A (en) * 1957-10-07 1960-03-08 Westinghouse Brake & Signal Tractive armature relays
US2930889A (en) * 1955-02-17 1960-03-29 Laisons Electr Soc Ind De Magnetic signalling system for railways

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2486086A (en) * 1945-08-21 1949-10-25 Gen Railway Signal Co Relay
US2502811A (en) * 1946-09-27 1950-04-04 Gen Railway Signal Co Polarized relay
US2536244A (en) * 1946-09-27 1951-01-02 Gen Railway Signal Co Spring holder for permanent magnets
US2535977A (en) * 1949-09-27 1950-12-26 Gen Railway Signal Co Magnetic stick relay
US2930889A (en) * 1955-02-17 1960-03-29 Laisons Electr Soc Ind De Magnetic signalling system for railways
US2928029A (en) * 1957-10-07 1960-03-08 Westinghouse Brake & Signal Tractive armature relays

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Publication number Publication date
BE482649A (xx)
NL66281C (xx)
CH269930A (fr) 1950-07-31

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