US3544936A - Symmetrical shaded pole electromagnet - Google Patents

Symmetrical shaded pole electromagnet Download PDF

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Publication number
US3544936A
US3544936A US749863A US3544936DA US3544936A US 3544936 A US3544936 A US 3544936A US 749863 A US749863 A US 749863A US 3544936D A US3544936D A US 3544936DA US 3544936 A US3544936 A US 3544936A
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United States
Prior art keywords
armature
pole
core
poles
electromagnet
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Expired - Lifetime
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US749863A
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English (en)
Inventor
Wesley V De Forest
Marvin M Graham
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Robertshaw Controls Co
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Robertshaw Controls Co
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Publication date
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Publication of US3544936A publication Critical patent/US3544936A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
    • H01F7/10—Electromagnets; Actuators including electromagnets with armatures specially adapted for alternating current
    • H01F7/12—Electromagnets; Actuators including electromagnets with armatures specially adapted for alternating current having anti-chattering arrangements
    • H01F7/1205—Electromagnets; Actuators including electromagnets with armatures specially adapted for alternating current having anti-chattering arrangements having short-circuited conductors

Definitions

  • An electromagnet having a U-shaped core comprising a first portion defining a first pole and a second portion defining second and third poles symmetrically disposed around a fourth shaded pole, and an electromagnetic operator comprising the electromagnet, an electrical winding on the first portion of the core and a keeper armature disposed on the first pole for fulcrum action and having a contact end extending over the second portion of the core to contact the fourth pole when the winding is energized.
  • the present invention pertains to an electromagnet and particularly to an electromagnet utilizing a symmetrical arrangement of shaded and unshaded poles.
  • Another object of the present invention is to eliminate vibrations in an electromagnetic operator by symmetrically disposing a plurality of unshaded poles around a shaded pole.
  • a further object of the present invention is to prevent armature bounce and vibration in an electromagnetic operator by constructing the electromagnet as a four-pole piece with one pole acting as a fulcrum for the armature.
  • the present invention has another object in that armature vibrations in an electromagnetic operator are eliminated by disposing a plurality of unshaded poles sym- "Ice metrically with respect to a shaded pole and the armature.
  • the present invention is advantageous over conventional electromagnetic operators in that armature bounce and vibration is substantially eliminated to to thereby provide accurate operation of the devices to be operated upon.
  • the present invention is generally characterized in that an electromagnet comprises a first leg defining a first pole, a plurality of second legs symmetrically disposed around the first leg to define a plurality of second poles, and shading means disposed around the first leg and an electromagnetic operator comprises the electromagnet described above in combination with an armature disposed so as to contact another pole of the electromagnet as a fulcrum and extending over the first and second poles.
  • FIG. 1 is a view in perspective of an electromagnetic core of the present invention.
  • FIG. 2 is a front elevational view, partially in section, of an electromagnetic operator of the present invention.
  • FIG. 3 is a side elevational view in section of the electromagnetic operator of FIG. 2 in a closed position.
  • FIG. 1 is a perspective view of a core 10 of an electromagnet constructed in accordance with the present invention.
  • Core 10 is substantially U-shaped and comprises two upstanding portions, indicated generally as 12 and 14, connected together by a fiat bottom portion 16.
  • Portion 12 defines a pole face 18 that extends the entire width of core 10, and portion 14 is separated into three legs 20, 22, and 24 each defining a pole face 26, 28, and 30, respectively, with the areas of pole faces 26 and 30 being equal.
  • Core 10 may be made of any conventional soft magnetic material suitable for use in electromagnets, and the specific shape of core 10 shown in FIG. 1 is not meant to be limiting in that the important criterion is that the outside legs of portion 14 be symmetrically spaced from the center leg as will be explained hereinafter.
  • FIG. 2 An electromagnetic operator utilizing core 10 is shown in FIG. 2 and is supported by a right angled frame 32, preferably constructed of material not susceptible to being magnetized in order to prevent the establishment of diversionary magnetic fields.
  • Core 10 has a circular recess 34 adapted to accommodate the flattened head of a protrusion 36 which extends from frame 32 through a bore 38 aligned with recess 34 in core 10 in order to secure core 10 to frame 32.
  • Portion 12 of core 10 has an electrical winding 40 wound therearound, which winding is adapted to be connected to any conventional source of varying electrical energy such as an AC. voltage source.
  • Pole 18 associated with portion 12 of core 10 acts as a fulcrum for a keeper armature 42 which is biased at one end by a spring 44 that may be connected with any stationary structure such as frame 32.
  • Armature 42 may be constructed of any conventional easily magnetizable material and is elongated in order to permit contact with pole 28. While armature 42 is shown as being planar, it should be noted that armature 42 may have any shape convenient to the operation of the electromagnetic operator.
  • Armature 42 may also be shaped to accommodate the device operated to provide snap action.
  • armature 42 The width of armature 42 is approximately equal to the width of core 10, as can be seen from FIG. 3, and a semispherical bulge or nipple 46 is pressed out at the contact end of armature 42 to provide equalized air gaps between poles 26 and 30 and armature 42 and firm contact with pole 28.
  • a leaf spring 48 having an offset end 50 is secured to frame 32 by a screw 52 such that offset end 50 is in contact with armature 42 directly above pole 18 to aid in the fulcrum action thereat.
  • a shading ring 54 is disposed around leg 22 and may be made of any conventional shading material such as copper.
  • FIG. 3 is an elevational sectional view of portion 14 of core and armature 42 in a closed poisiton, it is seen that poles 26 and are symmetrically spaced from shaded pole 28, and due to this symmetry and the configuration of armature 42 the horizontal components of the magnetic fiux at poles 26 and 30 are equal and opposite in their effect on armature 42.
  • armature 42 When the electromagnetic operator is in an unenergized state, armature 42 is forced away from portion 14 of core 10 by bias spring 44 which may be disposed in tension between a stationary portion of the valve and the operating end of armature 42.
  • the distance between armature 42 and portion 14 of core 10 may be controlled by providing an independent stop for armature 42, by designing leaf spring 48 to act as a stop due to abutment with armature 42 or by balancing the weight of armature 42 with the force of bias spring 44.
  • bias spring 44 forces the operating end of armature 42 down to, for instance, close the valve.
  • the current through coil 40 cause magnetic fiux to be established in core 10.
  • This magnetic flux which is concentrated at poles 18, 26, 28, and 30 magnetizes armature 42 and pulls the contact end down so that nipple 46 contacts shaded pole 28.
  • the initial downward force on armature 42 is provided by unshaded poles 26 and 30 because shading ring 54 delays the magnetic flux concentrated at pole 28. Due to their symmetry with respect to shaded pole 28 and armature 42 and their equal area pole faces, unshaded poles 26 and 30 prevent lateral movement of armature 42 and reduce the normal tendency of the armature to bounce or slide on the electromagnet.
  • the delay or phase displacement of magnetic flux at shaded pole 28 caused by shading ring 54 permits armature 42 to be in firm contact with core 10 throughout each entire cycle of alternating current energizing coil 40. That is, the phase displacement of magnetic fiux permits flux to be concentrated at pole 28 when the alternating current is at a Zero level.
  • the operating end of armature 42 moves up upon energization of the electromagnetic operator to force nipple 46 to contact pole 28, and the operating end may be connected directly or through mechanical linkage to a valve member to open the valve.
  • the shape of the armature to be used with an electromagnetic operator constructed in accordance with the present invention should be considered in designing the leg position of the core; however, when the armature has a longitudinal axis in parallel with the spacing between the two portions of the core and passing through the shaded pole, it is suflicient to dispose the unshaded poles symmetrically with respect to this axis.
  • the most important criterion in constructing an electromagnetic operator in accordance with the present invention is that the shaded and unshaded poles be disposed symmetrically with respect to each other and to the longitudinal axis of the armature.
  • the present invention thus, provides an electromagnetic operator that may be used with sensitive devices such as switches and valves and substantially eliminates the normal armature vibrations associated with conventional electromagnetic operators.
  • An electromagnetic operator comprising a core having a first portion defining a first pole and a second portion including first, second and third legs defining second, third and fourth poles, respectively;
  • shading means disposed around said first leg of said second portion of said core
  • armature means disposed to contact said first pole as a fulcrum and extending over said second portion of said core
  • said third and fourth poles being disposed symmetrically about said second pole whereby said armature means may be pulled in without vibration when said electrical winding is energized.
  • An electromagnetic operator comprising:
  • a unitary core having a first portion defining a first pole and a second portion having a plurality of legs defining a plurality of second poles and a third pole;
  • shading means disposed around one of said plurality of legs
  • armature means disposed so as to be in contact with said first pole and having a contact end extending over said second portion of said core and an operating end, said first pole acting as a fulcrum for said armature means;
  • said second poles being symmetrically disposed around said third pole whereby said armature means may be pulled in without vibration.
  • bias means is connected with the operating end of said armature means.
  • a unitary core for an electromagnet comprising: pole. a first upstanding portion defining a first pole; and o 10.
  • An electromagnet comprising: 2,282,065 5/1942 Krautwig 335-244 a generally unitary U-shaped core having a first up- 2,370,752 3/1945 Ray 335245 standing portion spaced from a second upstanding 15 2,591,773 4/1952 'Blanchet 335-276 portion by a bottom portion, said first upstanding 2,736,343 2/1956 Douglas et 335245X portion defining a first pole and said second upstanding portion having first, second and third legs defining second, third and fourth poles, respectively; 20 said third and fourth poles being disposed symmetri- 335-281 GEORGE HARRIS, Primary Examiner US. Cl. X.R.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electromagnets (AREA)
  • Manufacture Of Motors, Generators (AREA)
US749863A 1968-08-02 1968-08-02 Symmetrical shaded pole electromagnet Expired - Lifetime US3544936A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US74986368A 1968-08-02 1968-08-02

Publications (1)

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US3544936A true US3544936A (en) 1970-12-01

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Application Number Title Priority Date Filing Date
US749863A Expired - Lifetime US3544936A (en) 1968-08-02 1968-08-02 Symmetrical shaded pole electromagnet

Country Status (7)

Country Link
US (1) US3544936A (enrdf_load_stackoverflow)
BE (1) BE736951A (enrdf_load_stackoverflow)
DE (1) DE1938897A1 (enrdf_load_stackoverflow)
ES (1) ES370128A1 (enrdf_load_stackoverflow)
FR (1) FR2014987A1 (enrdf_load_stackoverflow)
GB (1) GB1276899A (enrdf_load_stackoverflow)
NL (1) NL6911745A (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3723925A (en) * 1972-05-30 1973-03-27 Essex International Inc Electromagnetic relay
FR2175028A1 (enrdf_load_stackoverflow) * 1972-03-06 1973-10-19 Trw Inc
DE3634582A1 (de) * 1985-10-15 1987-04-16 Elettrocondutture Polarisierte elektromagnetische betaetigungsvorrichtung
US4749977A (en) * 1984-11-26 1988-06-07 United Technologies Corporation Coil mounting arrangement and its method of manufacture
DE3834445A1 (de) * 1988-10-10 1990-04-12 Mesenich Gerhard Elektromagnetisches einspritzventil mit kippanker
CN1047254C (zh) * 1992-12-24 1999-12-08 库恩克有限公司 电磁装置
EP1154452A4 (en) * 1999-09-28 2002-11-20 Idec Izumi Corp RELAY AND METHOD FOR THE PRODUCTION THEREOF
US20060250202A1 (en) * 2005-05-06 2006-11-09 Song Chuan Precision Co., Ltd. Relay structure improvement
CN104051123A (zh) * 2014-06-09 2014-09-17 常熟开关制造有限公司(原常熟开关厂） 电磁铁结构

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1286306B (de) * 1966-06-25 1969-01-02 Philips Patentverwaltung Tonbandkassette
DE2406429C3 (de) * 1974-02-11 1982-07-08 M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8000 München Elektromagnet, mit mehreren ihn speisenden Quellen und relativ dazu beweglichem Anker

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2162465A (en) * 1936-09-05 1939-06-13 G M Lab Inc Electric magnet
US2282065A (en) * 1938-06-03 1942-05-05 Gen Electric Electromagnetic device
US2370752A (en) * 1942-02-23 1945-03-06 William A Ray Electromagnetically operated valve
US2591773A (en) * 1948-04-22 1952-04-08 Telemecanique Electr Soc Electromagnetic actuator for contactors and circuit breakers
US2736843A (en) * 1952-07-25 1956-02-28 Cutler Hammer Inc Alternating current electromagnets

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2162465A (en) * 1936-09-05 1939-06-13 G M Lab Inc Electric magnet
US2282065A (en) * 1938-06-03 1942-05-05 Gen Electric Electromagnetic device
US2370752A (en) * 1942-02-23 1945-03-06 William A Ray Electromagnetically operated valve
US2591773A (en) * 1948-04-22 1952-04-08 Telemecanique Electr Soc Electromagnetic actuator for contactors and circuit breakers
US2736843A (en) * 1952-07-25 1956-02-28 Cutler Hammer Inc Alternating current electromagnets

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2175028A1 (enrdf_load_stackoverflow) * 1972-03-06 1973-10-19 Trw Inc
US3723925A (en) * 1972-05-30 1973-03-27 Essex International Inc Electromagnetic relay
US4749977A (en) * 1984-11-26 1988-06-07 United Technologies Corporation Coil mounting arrangement and its method of manufacture
DE3634582A1 (de) * 1985-10-15 1987-04-16 Elettrocondutture Polarisierte elektromagnetische betaetigungsvorrichtung
DE3834445A1 (de) * 1988-10-10 1990-04-12 Mesenich Gerhard Elektromagnetisches einspritzventil mit kippanker
US5115982A (en) * 1988-10-10 1992-05-26 Siemens Automotive L.P. Electromagnetic fuel injector with tilt armature
CN1047254C (zh) * 1992-12-24 1999-12-08 库恩克有限公司 电磁装置
US6545575B1 (en) 1998-09-28 2003-04-08 Idec Izumi Corporation Relay and method of manufacture thereof
EP1154452A4 (en) * 1999-09-28 2002-11-20 Idec Izumi Corp RELAY AND METHOD FOR THE PRODUCTION THEREOF
US20060250202A1 (en) * 2005-05-06 2006-11-09 Song Chuan Precision Co., Ltd. Relay structure improvement
CN104051123A (zh) * 2014-06-09 2014-09-17 常熟开关制造有限公司(原常熟开关厂） 电磁铁结构

Also Published As

Publication number Publication date
ES370128A1 (es) 1971-04-01
DE1938897A1 (de) 1970-02-05
FR2014987A1 (enrdf_load_stackoverflow) 1970-04-24
NL6911745A (enrdf_load_stackoverflow) 1970-02-04
GB1276899A (en) 1972-06-07
BE736951A (enrdf_load_stackoverflow) 1970-01-16

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