US3426305A - Choke having a winding of foil - Google Patents

Choke having a winding of foil Download PDF

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Publication number
US3426305A
US3426305A US643878A US3426305DA US3426305A US 3426305 A US3426305 A US 3426305A US 643878 A US643878 A US 643878A US 3426305D A US3426305D A US 3426305DA US 3426305 A US3426305 A US 3426305A
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foil
choke
winding
core
leg
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US643878A
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John M Keble
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British Lighting Industries Ltd
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British Lighting Industries Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/346—Preventing or reducing leakage fields
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F37/00—Fixed inductances not covered by group H01F17/00

Definitions

  • a choke having a laminated core comprising at least one leg with a plurality of evenly disposed air gaps in said leg and having a winding on said core consisting of a strip of metallic foil.
  • the invention relates to a choke having a Winding in the form of a strip of foil.
  • Chokes as used, for instance, for electric discharge lamp circuits, normally have a wire winding on a core leg which has an air gap at one end. It has been found that if the wire winding is replaced by a spiral winding of a strip of foil, the air gap causes an uneven ux linkage across the foil resulting in a marked eddy current loss. The loss arises because the foil extends parallel to the core leg.
  • a choke having a winding consisting of a strip of foil and a core in which there is a plurality of evenly disposed gaps in a leg of the core.
  • the gaps may be slots in some or all of the laminations and may be in one or more of the legs.
  • the invention can be used with cores of the core-type or shell-type construction.
  • FIG. 1 is a diagrammatic cross section of a conven tional choke core with a foil winding
  • FIGS. 2 to 4 are cross sections of choke cores constructed according to the invention.
  • FIG. l shows a conventional choke core 1 with an air gap 2 at one end of the centre leg of the core.
  • the choke is shown with a foil winding 3.
  • a current is passed through the coil a stray magnetic flux is generated as indicated the loops of llux 4 with the asymmetrical air gap causing a greater ux linkage on one side B of the ICC foil than on the other A.
  • this difference in ux linkage will result in a voltage being generated between the edges of each turn of foil causing an eddy current.
  • the wire of the windings is relatively narrow this eddy current only arisesin the case of a foil winding.
  • the embodiment of the invention which is shown in FIG. 2 is a choke in which the eddy current loss is substantially avoided.
  • the centre leg 5 f the core 1 has three symmetrically arranged air gaps ,6.
  • the stray magnetic ux produced by a current will 'ow link the foil in loops 4 delining three distinct regions 7, 8 and 9.
  • the eddy currents are confined to each region and are much smaller. The effect bears some resemblance to that obtained by splitting the foil lengthwise into three parts.
  • the air gaps may be slots 10 occurring in some or all of the core laminations, as shown in FIG. 3, in which they recur in any or each of the legs.
  • the invention may be applied to two-legged. cores, as in ⁇ FIG. 4, having a winding on each core, when either or both cores may have evenly disposed air gaps. Similarair gaps can also be used with shell-type cores and in any type of gapped core in which it may be desired to use foil winding.
  • a choke having a laminated core comprising at least one leg with a plurality of ⁇ evenly disposed air gaps in said leg and having a winding on said core consisting of a strip of metallic foil.
  • a choke as claimed in claim 1 having two legs each provided with evenly disposed air gaps.
  • a choke as claimed in clain'tl in which some of the core laminations have slots forming the said air gaps.

Description

f Feb- 4, 1969 J. M. KEBLE 3,426,305
CHOKE HAVING A WINDING OF' FOIL Filed June 6, 1967 vJOHN MERVYN KEBLE INVENTOR ATTORNEY United States Patent O 26,199/ 66 U.S. Cl. 336-178 Int. Cl. H01f 17/06, 27/28 Claims ABSTRACT 0F THE DISCLOSURE A choke having a laminated core comprising at least one leg with a plurality of evenly disposed air gaps in said leg and having a winding on said core consisting of a strip of metallic foil.
The invention relates to a choke having a Winding in the form of a strip of foil.
Chokes, as used, for instance, for electric discharge lamp circuits, normally have a wire winding on a core leg which has an air gap at one end. It has been found that if the wire winding is replaced by a spiral winding of a strip of foil, the air gap causes an uneven ux linkage across the foil resulting in a marked eddy current loss. The loss arises because the foil extends parallel to the core leg.
According to the present invention there is provided a choke having a winding consisting of a strip of foil and a core in which there is a plurality of evenly disposed gaps in a leg of the core.
We have found the replacement of the conventional single air gap by distributed gaps reduces the eddy. current loss.
The gaps may be slots in some or all of the laminations and may be in one or more of the legs. The invention can be used with cores of the core-type or shell-type construction.
Embodiments of the present invention will be described with reference to the accompanying drawings in which:
FIG. 1 is a diagrammatic cross section of a conven tional choke core with a foil winding, and
FIGS. 2 to 4 are cross sections of choke cores constructed according to the invention.
FIG. l shows a conventional choke core 1 with an air gap 2 at one end of the centre leg of the core. The choke is shown with a foil winding 3. When a current is passed through the coil a stray magnetic flux is generated as indicated the loops of llux 4 with the asymmetrical air gap causing a greater ux linkage on one side B of the ICC foil than on the other A. With an alternating current this difference in ux linkage will result in a voltage being generated between the edges of each turn of foil causing an eddy current. Because the wire of the windings is relatively narrow this eddy current only arisesin the case of a foil winding.
The embodiment of the invention which is shown in FIG. 2 is a choke in which the eddy current loss is substantially avoided. The centre leg 5 f the core 1 has three symmetrically arranged air gaps ,6. The stray magnetic ux produced by a current will 'ow link the foil in loops 4 delining three distinct regions 7, 8 and 9. In this embodiment the eddy currents are confined to each region and are much smaller. The effect bears some resemblance to that obtained by splitting the foil lengthwise into three parts.
The air gaps may be slots 10 occurring in some or all of the core laminations, as shown in FIG. 3, in which they recur in any or each of the legs. The invention may be applied to two-legged. cores, as in` FIG. 4, having a winding on each core, when either or both cores may have evenly disposed air gaps. Similarair gaps can also be used with shell-type cores and in any type of gapped core in which it may be desired to use foil winding.
I claim:
1. A choke having a laminated core comprising at least one leg with a plurality of` evenly disposed air gaps in said leg and having a winding on said core consisting of a strip of metallic foil.
2. A choke as claimed-in lclaim 1 in which the core has three legs and the said leg is the centre leg.
3. A choke as claimed in claim 2 in which the other legs also have evenly disposed air gaps.
4. A choke as claimed in claim 1 having two legs each provided with evenly disposed air gaps.
5. A choke as claimed in clain'tl in which some of the core laminations have slots forming the said air gaps.
References Cited UNITED STATES PATENTS 2,175,927 10/1939 Steinert 336-165 XR 2,521,513 9/1950 Gray 336-165 XR 2,998,583 8/1961 Worcester 336-232 XR LEwIs H. MYERS, Primary Examiner.
THOMAS J. KOZMA, Assistant Examiner.
U.S. Cl. X.R. 336-232
US643878A 1966-06-13 1967-06-06 Choke having a winding of foil Expired - Lifetime US3426305A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB26199/66A GB1080475A (en) 1966-06-13 1966-06-13 A choke having a winding of foil

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3828985C1 (en) * 1988-08-26 1989-09-14 Grundig E.M.V. Elektro-Mechanische Versuchsanstalt Max Grundig Hollaend. Stiftung & Co Kg, 8510 Fuerth, De
US5128646A (en) * 1989-10-20 1992-07-07 Aisan Kogyo Kabushiki Kaisha Ignition coil for an internal combustion engine
US5146198A (en) * 1991-06-28 1992-09-08 Westinghouse Electric Corp. Segmented core inductor
US5376912A (en) * 1992-03-12 1994-12-27 Casagrande; Serge Combined transformer and inductor
US5789907A (en) * 1991-03-29 1998-08-04 Top Gulf Coast Corporation Variable impedence transformer
US6211765B1 (en) * 1990-02-27 2001-04-03 Tdk Corporation Coil device
US7830236B2 (en) 2008-09-09 2010-11-09 Gm Global Technology Operations, Inc. DC-DC converter for fuel cell application using hybrid inductor core material
US20110169598A1 (en) * 2006-02-09 2011-07-14 Tamura Corporation Reactor part
US10128764B1 (en) 2015-08-10 2018-11-13 Vlt, Inc. Method and apparatus for delivering power to semiconductors
US10468181B1 (en) 2015-08-10 2019-11-05 Vlt, Inc. Self-aligned planar magnetic structure and method
DE102020127173B3 (en) 2020-10-15 2022-05-05 Tdk Electronics Ag Compact coupled inductor

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2175927A (en) * 1936-03-12 1939-10-10 Westinghouse Electric & Mfg Co Welding transformer
US2521513A (en) * 1948-08-18 1950-09-05 Gen Electric Stationary induction apparatus
US2998583A (en) * 1956-02-13 1961-08-29 Willis G Worcester Electrical apparatus and electromagnetic coils and method of making the same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2175927A (en) * 1936-03-12 1939-10-10 Westinghouse Electric & Mfg Co Welding transformer
US2521513A (en) * 1948-08-18 1950-09-05 Gen Electric Stationary induction apparatus
US2998583A (en) * 1956-02-13 1961-08-29 Willis G Worcester Electrical apparatus and electromagnetic coils and method of making the same

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3828985C1 (en) * 1988-08-26 1989-09-14 Grundig E.M.V. Elektro-Mechanische Versuchsanstalt Max Grundig Hollaend. Stiftung & Co Kg, 8510 Fuerth, De
US5128646A (en) * 1989-10-20 1992-07-07 Aisan Kogyo Kabushiki Kaisha Ignition coil for an internal combustion engine
US6211765B1 (en) * 1990-02-27 2001-04-03 Tdk Corporation Coil device
US5789907A (en) * 1991-03-29 1998-08-04 Top Gulf Coast Corporation Variable impedence transformer
US5146198A (en) * 1991-06-28 1992-09-08 Westinghouse Electric Corp. Segmented core inductor
WO1993000692A1 (en) * 1991-06-28 1993-01-07 Sundstrand Corporation Segmented core inductor
US5376912A (en) * 1992-03-12 1994-12-27 Casagrande; Serge Combined transformer and inductor
US8427271B2 (en) * 2006-02-09 2013-04-23 Tamura Corporation Reactor part
US20110169598A1 (en) * 2006-02-09 2011-07-14 Tamura Corporation Reactor part
DE102009040157B4 (en) * 2008-09-09 2012-07-12 GM Global Technology Operations LLC (n. d. Ges. d. Staates Delaware) DC-DC converter for a fuel cell application using a hybrid inductor core material
US7830236B2 (en) 2008-09-09 2010-11-09 Gm Global Technology Operations, Inc. DC-DC converter for fuel cell application using hybrid inductor core material
US10128764B1 (en) 2015-08-10 2018-11-13 Vlt, Inc. Method and apparatus for delivering power to semiconductors
US10454380B1 (en) 2015-08-10 2019-10-22 Vlt, Inc. Method and apparatus for delivering power to semiconductors
US10468181B1 (en) 2015-08-10 2019-11-05 Vlt, Inc. Self-aligned planar magnetic structure and method
US10651744B1 (en) 2015-08-10 2020-05-12 Vlt, Inc. Method and apparatus for delivering power to semiconductors
US10938311B1 (en) 2015-08-10 2021-03-02 Vicor Corporation Method and apparatus for delivering power to semiconductors
US11264911B1 (en) 2015-08-10 2022-03-01 Vicor Corporation Method and apparatus for delivering power to semiconductors
US11640873B1 (en) 2015-08-10 2023-05-02 Vicor Corporation Method of manufacturing a self-aligned planar magnetic structure
US11764686B1 (en) 2015-08-10 2023-09-19 Vicor Corporation Method and apparatus for delivering power to semiconductors
DE102020127173B3 (en) 2020-10-15 2022-05-05 Tdk Electronics Ag Compact coupled inductor

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