US3456219A - Electromagnetic devices - Google Patents

Electromagnetic devices Download PDF

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Publication number
US3456219A
US3456219A US521261A US3456219DA US3456219A US 3456219 A US3456219 A US 3456219A US 521261 A US521261 A US 521261A US 3456219D A US3456219D A US 3456219DA US 3456219 A US3456219 A US 3456219A
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US
United States
Prior art keywords
pole pieces
core
magnetic
winding
air gap
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
US521261A
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English (en)
Inventor
Eric Paddison
Gordon John Lally
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.)
English Electric Co Ltd
Original Assignee
English Electric Co Ltd
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
Application filed by English Electric Co Ltd filed Critical English Electric Co Ltd
Application granted granted Critical
Publication of US3456219A publication Critical patent/US3456219A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F29/00—Variable transformers or inductances not covered by group H01F21/00
    • H01F29/08—Variable transformers or inductances not covered by group H01F21/00 with core, coil, winding, or shield movable to offset variation of voltage or phase shift, e.g. induction regulators
    • H01F29/12—Variable transformers or inductances not covered by group H01F21/00 with core, coil, winding, or shield movable to offset variation of voltage or phase shift, e.g. induction regulators having movable coil, winding, or part thereof; having movable shield
    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D25/00—Woven fabrics not otherwise provided for

Definitions

  • An electromagnetic device defining a closed magnetic circuit includes a shell-type laminated magnetic core having a centre limb carrying a winding and having a pair of pole pieces whose opposing surfaces are spaced apart from one another. The winding is energisable to cause the pole pieces to assume opposite polarities.
  • a tapered elongate magnetic member is disposed between the pole pieces with its major axis extending transversely of the center limb of the core to provide two air gaps one on each side of the major axis of the member.
  • the member is mounted on the core and movable along its major axis between stop positions to vary the reluctance of the magnetic circuit.
  • the opposing surfaces of the pole pieces and the member have the same shape and the same angle of taper so that, for any position to which the member is moved, each air gap is of constant length over the whole of the opposing surface of the respective pole pieces.
  • This invention relates to electromagnetic devices, and particularly relates to means for varying the reluctance of a magnetic circuit defined by such a device.
  • the present invention consists in an electromagnetic device comprising a magnetic core defining a closed magnetic circuit and having opposing poles spaced apart from one another with an air gap therebetween, and a magnetic member mounted in said gap and relatively movable between the poles, the surfaces of the poles and/or the member being so shaped that the mean spacing between opposing surfaces of the pole and member varies in response to said movement whereby to vary the reluctance of the magnetic circuit.
  • the magnetic reluctance of the device is varied without substantially altering the cross-sectional area of the flux path.
  • the invention is of particular utility in transactors employed in protective relays in which the ratio of the secondary voltageto primary current may be varied by the movement referred to above.
  • FIG. 1 shows a cross-sectional view of the device hav ing a movable member for adjusting the reluctance
  • FIG. 2 shows a circuit diagram of an adjustable transactor whose windings are wound on the laminated magnetic core in FIG. 1.
  • a winding 8 having input terminals 9, is mounted on a shell-type laminated core which has two magnetic pole pieces 11 and 12 defining between them a tapered air gap of rectangular cross section.
  • A- similarly tapered laminated member 13 is disposed transversely in the air gap, the member being internally threaded and mounted on' an adjusting screw 14 which is in turn supported by limbs 15 and 16 of the core.
  • the member 13 has two non-magnetic stops 17 and 18 arranged to prevent the member moving beyond desirable limits of movement; that is, beyond either side of 3,456,219 Patented July 15, 1969 the air gap between the poles 11 and 12.
  • a spring 19 between the limb 15 and the stop 17 is efifective to urge the member 13 in a direction away from the head of the screw 14-to prevent undesirable movement of this member, when magnetised for example, due to back-lash" in the adjusting screw threads.
  • a pointer 20 is arranged to be moved around a scale 21 in response to movement of the member 13 and is held against the stop 18 by a spring 22.
  • the scale 21 may conveniently be calibrated so that it can exhibit predetermined settings of inductance possessed by the device.
  • the air gap may be anywhere within the magnetic circuit of the core and that the air gaps between the poles and the member may be any shape in cross-section, e.g. rectangular or part-annular, provided that the effective length of the air gap may be adjusted by limited relative movement between the member and the pole pieces 11 and 12 without substantially altering the effective cross-sectional area of the flux path between these two poles.
  • the magnetic core itself may be in any form defining a continuous magnetic circuit having one or more air gaps, for example, the core may be shaped substantially as a ring or the letter C.
  • one application of the device of FIG- URE 1 is in the adjustable transactor of FIGURE 2 which includes a primary winding 23 energisable from a current source 24 and a secondary winding 25 connected to a load 26.
  • the windings would be wound on the centre limb of the magnetic core 10 in a similar manner to that shown by the winding 8 in FIGURE 1.
  • the secondary ampere-turns are arranged to be small compared with the magnetising (primary) ampere-turns so that when the primary winding 23- is energised a voltage output will be produced from the secondary winding 25 which is proportional to the current in the primary winding 23 but approximately out of phase therewith.
  • the ratio between the secondary volts and primary current may be varied.
  • the scale may then be calibrated in terms of this ratio or in terms of the primary current for a specific output voltage.
  • An electromagnetic device comprising a magnetic core defining a closed. magnetic circuit
  • said core having pole pieces with opposing surfaces spaced apart from one another
  • a tapered elongate magnetic member mounted between the pole pieces with part of the member'lying between the whole of said opposing surfaces of the pole pieces to define between said member and the pole piecestwo air gaps one on each side of the major axis of said member
  • each air gap is of constant length over the whole of the opposing surface of the respective said ment is dependent on the relative position of said pole piece. member and said pole pieces.
  • a current supply means for ener- 5 IT STATES PATENTS gizing the primary winding to induce a voltage into the 2 4 795 1/1954 it g 3364434 XR secondary winding, the secondary ampere-turns being 1076:2358 4/1937 I small compared with the primary ampere-turns sufiicient 32192 442, v 5/1965 warrington et a1: 317-36 to insure that said'voltage is proportional to said primary 3,193,729 7 1965 Paddison current at any width of said air gap, the said movement 10 3 207 9 1 9 9 5 m- 5 of the member being effective to vary'the ratio between 3,278,875 10/1966 McDonough 335 272 the secondary voltage and the primary current. 3,325,660 6/1967 Boyer.
  • a device including indicating means for indicating the position of said 15 BERNARD GILHEANY, Prlmal'y Examlner member relative to said pole pieces, said indicating 11 M, MORGAN, Assistant E i Q means having a pivotally mounted element operatively connected to U.S. Cl. X.R.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Textile Engineering (AREA)
  • Electromagnets (AREA)
US521261A 1965-02-01 1966-01-18 Electromagnetic devices Expired - Lifetime US3456219A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4287/65A GB1138604A (en) 1965-02-01 1965-02-01 Electromagnetic devices

Publications (1)

Publication Number Publication Date
US3456219A true US3456219A (en) 1969-07-15

Family

ID=9774301

Family Applications (1)

Application Number Title Priority Date Filing Date
US521261A Expired - Lifetime US3456219A (en) 1965-02-01 1966-01-18 Electromagnetic devices

Country Status (3)

Country Link
US (1) US3456219A (fr)
CH (1) CH442523A (fr)
GB (1) GB1138604A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5926664A (en) * 1996-03-15 1999-07-20 Eastman Kodak Company Core made of a soft magnetic material for use in an electromagnetic actuator

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2076858A (en) * 1935-02-23 1937-04-13 Teletype Corp Electromagnet
US2664795A (en) * 1950-04-29 1954-01-05 Graflex Inc Photographic flash lighting and synchronizing system
US3192442A (en) * 1961-03-03 1965-06-29 English Electric Co Ltd Electrical protective relay systems
US3193729A (en) * 1957-03-11 1965-07-06 English Electric Co Ltd Electrical relay systems having inverse time characteristics
US3207961A (en) * 1963-09-25 1965-09-21 Gen Motors Corp Linear relay actuator
US3278875A (en) * 1963-12-30 1966-10-11 United Carr Inc Rotary solenoid
US3325660A (en) * 1964-05-21 1967-06-13 Airfab Inc Reciprocating solenoid motor

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2076858A (en) * 1935-02-23 1937-04-13 Teletype Corp Electromagnet
US2664795A (en) * 1950-04-29 1954-01-05 Graflex Inc Photographic flash lighting and synchronizing system
US3193729A (en) * 1957-03-11 1965-07-06 English Electric Co Ltd Electrical relay systems having inverse time characteristics
US3192442A (en) * 1961-03-03 1965-06-29 English Electric Co Ltd Electrical protective relay systems
US3207961A (en) * 1963-09-25 1965-09-21 Gen Motors Corp Linear relay actuator
US3278875A (en) * 1963-12-30 1966-10-11 United Carr Inc Rotary solenoid
US3325660A (en) * 1964-05-21 1967-06-13 Airfab Inc Reciprocating solenoid motor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5926664A (en) * 1996-03-15 1999-07-20 Eastman Kodak Company Core made of a soft magnetic material for use in an electromagnetic actuator

Also Published As

Publication number Publication date
CH442523A (fr) 1967-08-31
GB1138604A (en) 1969-01-01

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