US3355689A - Ferromagnetic core with an adjustable air gap - Google Patents

Ferromagnetic core with an adjustable air gap Download PDF

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Publication number
US3355689A
US3355689A US467263A US46726365A US3355689A US 3355689 A US3355689 A US 3355689A US 467263 A US467263 A US 467263A US 46726365 A US46726365 A US 46726365A US 3355689 A US3355689 A US 3355689A
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United States
Prior art keywords
laminations
core
apertures
tool
holes
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Expired - Lifetime
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US467263A
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English (en)
Inventor
Paddison Eric
Lally Gordon John
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English Electric Co Ltd
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English Electric Co Ltd
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Publication date
Application filed by English Electric Co Ltd filed Critical English Electric Co Ltd
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Publication of US3355689A publication Critical patent/US3355689A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0206—Manufacturing of magnetic cores by mechanical means
    • H01F41/0233—Manufacturing of magnetic circuits made from sheets

Definitions

  • such a core comprises a plurality of first laminations provided with first-shaped through-holes in alignment and normal thereto and a plurality of second laminations provided with second-shaped through-holes in alignment and normal thereto are arranged alternately one with another, or in alternate groups, the said first-shaped through-holes and the said second-shaped through-holes overlapping one another and arranged so that an adjusting-tool may be inserted through these holes for engagement with either or both of the said first and second laminations whereby to effect on rotation, about an axis fixed in space and normal to the laminations, relative movement of the said first and second laminations in a predetermined direction.
  • first-shaped and the second-shaped holes are similar triangularly shaped holes, these holes being arranged in a complementary and overlapping manner so that an adjusting-tool may be inserted to engage each hole at the apex whereby rotation of the adjusting-tool induces relative motion of the first and the second laminations by engagement with both first and second laminations.
  • the first-shaped holes are clearance holes and the secondshaped holes are slots, the adjusting-tool being inserted through the first-shaped holes to engage only the secondshaped holes;
  • the core has first and second outer frame members disposed at either side of the core each provided with a bearing hole for supporting the adjusting-tool and defining its axis of rotation.
  • the core has an air-gap disposed so that rotation of the adjusting-tool efiects a change in the air-gap reluctance.
  • the air-gap is displaced symmetrically in the core and the laminations are arranged to each have a first-shaped hole and a second-shaped hole for enabling the laminations to be readily used as either a said first or a said second lamination.
  • first and second laminations may be generally F- shaped.
  • the adjusting-tool has an outer collar arranged to engage the bearing hole in one of the outer frame members, the collar acting as a bearing for an inner shaft, lateral movement of the inner shaft with respect to the collar permitting the adjusting-tool to be used for various laminated core thicknesses.
  • FIG. 1 shows a pictorial view-of a laminated core
  • FIG. 2 shows a pictorial view of an adjusting-tool
  • FIG. 3 and FIG. 4 shows F-shaped laminations for use in the core
  • FIG. 5 shows an E-shaped lamination together with a T-shaped lamination for use as an alternative in the core.
  • a laminated core 11 (FIG. 1) comprises sets of F-shaped laminations (FIG. 3) clamped between outer frame members 12 and 13 by four clamping bolts 14 passing through the laminations.
  • the outer frame member 12 has clearance holes 15 and 16 and the outer frame member 13 has guideholes (not shown) on the same axes as the clearance holes 15 and 16; each outer frame member has lower circular holes 17 and upper slotted holes 13 for the clamping bolts 14.
  • the core has an air-gap 19.
  • the sets of laminations are an upper left, a lower left, an upper right and a lower right set of laminations and are interleaved with one another. Slots 20 of the upper left set of laminations are overlapped by clearance holes 21 of the lower left set of laminations and the clearance hole 16. Similarly, slots 20 of the upper right set of laminations are overlapped by clearance holes 21 of the lower right set of laminations and the clearance hole 15. Clamping bolts 14 pass through holes 22 in each lamination and holes 17 in the frame members thereby aligning each lamination to form sets of laminations. The air-gap 19 is formed between a surface 23 of each of the laminations.
  • Movement of the slots 20 of the upper sets of laminations with respect to the clearance holes 21 of the lower sets of laminations effects air-gap adjustment, varying the length of the air-gap 19.
  • An adjusting-tool (FIG. 2) machined at one end to form a clearance hole hearing has a collar which slides on a shaft 24. At a remote end of the adjusting-tool there is a guide-hole bearing disposed on the same axis as the shaft. A surface 25 between the remote end of the adjusting-tool and the shaft is shaped eccentrically with respect to the axis of the shaft.
  • the adjusting-tool may be inserted into the clearance holes 15 and 16 with the remote end bearing in the said guide-holes and the collar bearing on the hole 15 or 16, and is thus supported for rotation by the outer frame members 13 and 16.
  • the surface 25 engages in the slots 21) to effect adjustment of the'air-gap 19 on rotation of the adjusting-tool.
  • the slotted-holes 18 allow the upper sets of laminations to move only in a vertical direction as seen in the drawing.
  • the laminated core is built-up round an electric coil (not shown) to form an electromagnet.
  • Calibration of the electromagnet is effected by applying and measuring a voltage and a current to the coil and simultaneously adjusting the air-gap as desired using adjustingtools as described. The clamping bolts are then tightened to maintain a desired calibration of the electromagnet.
  • the F-shaped laminations of FIG. 4 may be arranged in sets of laminations in a manner as described above to form the core but have triangular holes for effecting adjustment of the air-gap.
  • An adjusting-tool suitably and symmetrically shaped is used for air-gap adjustment, both upper and lower sets of laminations moving simultaneously with respect to the axis of rotation of the adjusting-tool. If the lower set of laminations are restrained by outer frame members as in the core described the axis of the adjusting-tool will move With respect to the outer frame members and requires no support.
  • E-shaped and T-shaped laminations may be arranged alternately and complementarily to form the core. Rotation of an adjusting tool eifects adjustment of the air-gap by direct interaction with the E-shaped laminations only; the T-shaped laminations are constrained or moved, according to theirposition in the core, by the clamping bolts in conjunction with the E-shaped laminations.
  • the E-shaped laminations may have triangular-holes instead of clearance holes and slots shown and provide adjustment of the air-gap in the same manner as the F-shaped laminations in FIG. 4.
  • Adjustment of the air-gap may be effected by a single adjusting-tool or two adjusting-tools acting together. Further, with modified outer frame members a single adjusting-tool may enter the core either through clearance hole 16 for example, or from the opposite direction; that is, from the opposite direction the tool will pass through clearance holes 21 in the upper right set of laminations to engage slots 20 in the lower right set of laminations, appropriate clearance and guide-holes being provided in the modified outer frame members.
  • the invention is in no way limited to symmetrical cores. It will be appreciated that in the core 11 the upper sets of laminations must have slotted holes 20 but need not have clearance holes 21. Similarly, the lower sets of laminations require only clearance holes 21. The shapes of upper and lower sets need not be the same but slotted holes of one set of laminations must be overlapped by clearance holes of another set of laminations throughout desired adjustment of a variable reluctance portion of the core by relative movement of the one set of laminations with the other set of laminations.
  • the holes in the laminations preferably do not exceed half the width of the limbs otherwise undesired saturation may occur in the region of such holes.
  • a ferro-magnetic core of stacked laminations in combination with an elongated tool said stacked laminations being movable relatively to one another by said elongated tool which is rotatable about its longitudinal axis and has an offset portion for effecting relative movement between the laminations, said core com-prising first laminations each defining an aperture and all being identical in shape and size, and
  • first laminations cooperating with the second laminations to define an air gap for the core
  • the locating means for disposing the first laminations such that all oi its apertures are in alignment and for disposing the second laminations such that all of its apertures are in alignment, the apertures of the first laminations partially overlapping the apertures of the second laminations to define a through hole in the stack for receiving said tool to enable the first laminations to be moved relative to the second laminations to adjust the width of said air gap.
  • a core according to claim 1 in which the apertures of said first laminations are slots extending transversely of the direction of relative movement of said first laminations and said second laminations, and in which the apertures of said second laminations are circular and have a diameter which is greater than the width of said slots, said offset portion being engaged with the edges of said slots to effect said relative movement.
  • a core according to claim 5 in which the base of each triangular aperture is disposed parallel to an edge of its respective lamination, the'triangular apertures in said first laminations having their bases disposed adjacent an outer edge of their respective laminations and the triangular apertures in said second laminations having their bases disposed adjacent an inner edge of their respective laminations.
  • a means for varying the reluctance in the circuit including a ferro-magnetic core of stacked laminations movable relatively to one another, and
  • said core comprising,
  • first laminations each defining a first aperture and a second aperture
  • first laminations interleaved with said first laminations and each defining a third aperture and a fourth aperture
  • the first laminations co-operating with the second laminations to define an air gap for the core
  • the first and third apertures being of identical shape and size
  • the second and fourth apertures being of identical shape and size
  • first laminations and the second laminations for disposing the first laminations and the second laminations such that the first apertures and the third apertures are in alignment with the first apertures partially overlapping the thirdapertures to define a first through hole, and such that the second apertures and the fourth apertures are in alignment with the second apertures partially overlapping the fourth apertures to define a second through hole of identical shape to-said first through hole, said first through hole and said second through hole being engageable by the offset portion of said tool to enable said first laminations to be moved relative to said second laminations.
  • a means for varying the reluctance in the circuit including a ferromagnetic core of stacked laminations movable relative to one another, and
  • said core comprising,
  • first laminations each defining a series of apertures-of an identical shape and size
  • said locating means for aligning said apertures to define a through hole in said stack for receiving said tool to enable said first laminations to be moved relative to said second laminations to determine the width of said air gap, said locating means having a first wall on one side of said stack defining an aperture, and having a second wall on the opposite side of said stack defining an aperture, the apertures on said first and second Walls being aligned with said through hole and being engageable by said bearing means.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)
  • Linear Motors (AREA)
  • Electromagnets (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)
US467263A 1964-07-03 1965-06-28 Ferromagnetic core with an adjustable air gap Expired - Lifetime US3355689A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB27512/64A GB1088411A (en) 1964-07-03 1964-07-03 Ferro-magnetic cores

Publications (1)

Publication Number Publication Date
US3355689A true US3355689A (en) 1967-11-28

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Application Number Title Priority Date Filing Date
US467263A Expired - Lifetime US3355689A (en) 1964-07-03 1965-06-28 Ferromagnetic core with an adjustable air gap

Country Status (5)

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US (1) US3355689A (enrdf_load_stackoverflow)
CH (1) CH437512A (enrdf_load_stackoverflow)
DE (1) DE1489840B2 (enrdf_load_stackoverflow)
GB (1) GB1088411A (enrdf_load_stackoverflow)
SE (1) SE326763B (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USD290456S (en) 1984-10-02 1987-06-23 Marelco Power Systems, Inc. Transformer
US20060244562A1 (en) * 2005-04-28 2006-11-02 Tyco Electronics Corporation Electrical Transformers and assemblies
US9980396B1 (en) 2011-01-18 2018-05-22 Universal Lighting Technologies, Inc. Low profile magnetic component apparatus and methods

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2261323A (en) * 1940-07-26 1941-11-04 Union Switch & Signal Co Means for adjusting the impedance of electromagnetic devices
US2930998A (en) * 1956-02-09 1960-03-29 Ward Leonard Electric Co Fluorescent lamp dimming ballast

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2261323A (en) * 1940-07-26 1941-11-04 Union Switch & Signal Co Means for adjusting the impedance of electromagnetic devices
US2930998A (en) * 1956-02-09 1960-03-29 Ward Leonard Electric Co Fluorescent lamp dimming ballast

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USD290456S (en) 1984-10-02 1987-06-23 Marelco Power Systems, Inc. Transformer
US20060244562A1 (en) * 2005-04-28 2006-11-02 Tyco Electronics Corporation Electrical Transformers and assemblies
US7656267B2 (en) * 2005-04-28 2010-02-02 Tyco Electronics Corporation Electrical transformers and assemblies
US9980396B1 (en) 2011-01-18 2018-05-22 Universal Lighting Technologies, Inc. Low profile magnetic component apparatus and methods

Also Published As

Publication number Publication date
GB1088411A (en) 1967-10-25
CH437512A (fr) 1967-06-15
DE1489840B2 (de) 1970-09-10
SE326763B (enrdf_load_stackoverflow) 1970-08-03
DE1489840A1 (de) 1969-04-03

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