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Publication numberUS2446999 A
Publication typeGrant
Publication dateAug 17, 1948
Filing dateNov 7, 1945
Priority dateNov 7, 1945
Publication numberUS 2446999 A, US 2446999A, US-A-2446999, US2446999 A, US2446999A
InventorsCamilli Guglielmo
Original AssigneeGen Electric
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Magnetic core
US 2446999 A
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Description  (OCR text may contain errors)

Aug. 17, 1948. cAMlLLl 2,446,999

IAGNETIC CORE Filed NOV. 7, 1945 Inventor-z Guglielmo C'amilli,

His Attorney.

Patented Aug. 17, 1948 MAGNETIC CORE Guglielmo Camilli, Pittsfield, Mass., assignor to General Electric Company, a corporation of New York Application November 7, 1945, Serial No. 627,226

1 Claim.

This invention relates to magnetic cores for induction apparatus and more particularly to improvements in multi-section cores and to the method of making such cores.

Ring type magnetic cores having a plurality of sections between which there are air gaps are used. among other places, in bushing type current transformers in order to prevent core saturation and give linear current reproduction over a wide range of primarycurrents. This is especially important in bus differential protective systems in which the operation. depends upon the differential output current of two or more current transformers. For large diameter cores or cores having a small radial build the type of core shown in my Patent 2,382,857, which is assigned to the assignee of this application, has proved very satisfactory but because the air gaps between the sections or segments of the core are not exactly uniform this type of core construction is not well suited to small diameter cores or cores having a large radial build because in those cases the non-uniformity of the air gaps would become excessive. A well known way of making multi-segment ring type cores with uniform air gaps is to build the segments up out of core punchings which lie in radial planes. However, this necessitates the use of different shaped and size punchings for each different diameter core and each core having a different radial build and consequently a different die for making the core laminations is required in a l such cases.

In order to eliminate the above disadvantages of the prior art I cut the core laminae for magnetic strip on an automatic indexing machine which merely varies the length of the cut pieces. One such machine forms the subject matter of Somerville Patent 2,369,617 which is assigned to the present assignee. The laminae are then fiatwise bent to conform to the curvature of the ring shaped or toroidal core and are then strain relief annealed and set in this bent shape.

An object of the invention is to provide a new and improved magnetic core.

Another object of the invention is to provide a new and improved multi-segment toroidally shaped magnetic core.

The method of making this core forms the subject matter of my divisional application Serial No. 748,271, filed May 15, 1947, and assigned to the present assignee.

The invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claim.

In the drawing Fig. 1 shows an axial section through a transformer embodying my invention, Fig. 2 is a perspective view of a completed core made in accordance with the teachings of my invention, and Fig. 3 is a partially disassembled view illustrating one of the intermediate steps in the method of making my core.

Referring now to the drawing and more particularly to Fig. 1, there is shown therein a core I surrounded by a winding 2 which may be the secondary winding of a bushing type current transformer in which the primary winding is a conductor which passes through the center of the torodial assembly shown in section in Fig. 1.

In Fig. 2 the core is shown as including by way of example twelve similar segments 3, of laminations, which are substantially equally spaced apart around an insulating cylinder 4 which may be made of any suitable material, such as cloth which has been saturated with a hardened phenolic resin. The segments 3 are clamped to.

the cylinder 4 by means of bands 5 which are preferably made of non-magnetic material, such as brass or stainless steel. The laminations in each segment are held together by bolts 6. The uniform gaps between adjacent segments are filled with any suitable material, such as Portland cement or sand held together by a resin binder.

In making my improved core the various length pieces of magnetic strip which are required are cut in any suitable manner such as by means of an automatic index shearing machine, an example of which is described in the above-identified Sonierville patent. For example, in the case of the twelve segment core illustrated, twelve equal length pieces corresponding to, say, the outer lamination of each segment are cut and then the machine will cut twelve more pieces of slightly lesser length which correspond to the next innermost: lamination of each segment and so on until all of the laminations are cut. They are then stacked into groups of progressively different length and each group is bolted together by bolts passing through registering holes in the laminae, which holes are also made by the same machine which cuts the laminae. The assembled and bolted together groups of laminations which, of course, are still flat are then placed about a steel mandrel 7 and clamps similar to the bands 5 in Fig. 2 but preferably made of steel are passedaround the assembly and drawn up tight, thus curving all of the laminae and making the various bolted together stacks of laminae into the shape of toroidal segments 3. This assembly is then annealed at the proper temperature in a suitable 3 furnace so as to relieve all stress in the magnetic material, with the result that the segments 3 are set in their proper shape. The clamping bands are then removed and segments 3 lifted away from the mandrel I, as shown in Fig. 3, after which they are transferred to the cylinder 4 in Fig. 2 which is of the same size as the mandrel I. The non-magnetic clamping bands 5 are then placed around the core and drawn up tight and the ends welded together as indicated at 8, after which the gaps between the segments are filled with any suitable material, examples of which have previously been given. It is a simple matter to calculate the progressively different size of flat cut laminae so that when they are flatwise bent they will form true segments of a ring or toroid in which the sides of adjacent ones lie in radial planes and thus provide uniform air gaps.

While there has been shown and described a particular embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the invention and, therefore, it is aimed in the appended claim to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

A ring shaped magnetic core comprising, a hollow cylinder of insulating material having a plurality of holes through the wall thereof, a plurality of radially laminated fiatwise curved segmentally shaped members, clamping rods extending radially through each of said members and terminating in an enlarged raised head'on the inner and outer surfaces of each member, said members being located on the outer surface of said cylinder with the raised head on the inner surface of each member fitted into one of the holes in the wall of said cylinder, a pair of non-magnetic clamping bands surrounding said core on opposite sides of the raised heads on the outer surface of said segmentally shaped members, said members being separated by uniform gaps of substantial length, and solid non-magnetic inserts in said gaps.

' GUGLIELMO CAMILLI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,251,651 Espenschied Jan. 1, 1918 1,812,520 Ellwanger June 30, 1931 2,382,857 Camilli Aug. 14, 1945 2,391,229 DEntremont Dec. 18, 1945 FOREIGN PATENTS Number Country Date 424,765 Great Britain Feb. 25, 1935 527,874 Great Britain Oct. 17, 1940

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1251651 *Sep 17, 1917Jan 1, 1918American Telephone & TelegraphCore for magnetic coils.
US1812520 *Feb 23, 1928Jun 30, 1931Bosch RobertIgnition coil
US2382857 *Apr 15, 1943Aug 14, 1945Gen ElectricElectric induction apparatus
US2391229 *Nov 27, 1943Dec 18, 1945Gen ElectricElectric induction apparatus
GB424765A * Title not available
GB527874A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2488961 *Nov 7, 1945Nov 22, 1949General Electric CompanyMethod of making magnetic gores
US2557249 *Sep 7, 1946Jun 19, 1951Gen Mills IncStator for induction motors
US2567717 *Dec 11, 1947Sep 11, 1951Raytheon Mfg CoTransformer
US2648018 *Nov 28, 1950Aug 4, 1953Gen ElectricDynamoelectric machine member
US2695978 *Apr 27, 1951Nov 30, 1954Allis Chalmers Mfg CoClamping means for electromagnetic cores
US2963776 *Apr 18, 1956Dec 13, 1960Mc Graw Edison CoMethod of construction for magnetic core
US2965864 *Oct 26, 1956Dec 20, 1960Burroughs CorpMagnetic core assembly
US3043971 *Aug 1, 1956Jul 10, 1962Gen ElectricImproved laminated frame and method of making same
US3465273 *Dec 14, 1967Sep 2, 1969Hunterdon Transformer CoToroidal inductor
US3772625 *May 10, 1972Nov 13, 1973E RaupachTransformer for producing or measuring high and very high potentials or for measuring currents at high potentials in cascade connection
US4080724 *Jan 13, 1976Mar 28, 1978Zephyr Wind Dynamo CompanyMethod of forming electrical machine care from E-laminations
US4603314 *Oct 18, 1983Jul 29, 1986Tdk CorporationInductor
US5165162 *Sep 16, 1991Nov 24, 1992General Electric CompanyMethod for making a segmented toroidal inductor
US6064134 *Jul 24, 1998May 16, 2000General Motors CorporationRotor for a synchronous reluctance machine
US6261437Nov 4, 1997Jul 17, 2001Asea Brown Boveri AbDevice comprising holder configured to support and hold metallic conductor wire at contact points in predetermined position during anodizing, including cam guides each having guide slots, said wire being spirally wound in guide slots
US6279850Nov 4, 1997Aug 28, 2001Abb AbCable forerunner
US6357688Feb 2, 1998Mar 19, 2002Abb AbCoiling device
US6369470Nov 4, 1997Apr 9, 2002Abb AbAxial cooling of a rotor
US6376775May 27, 1997Apr 23, 2002Abb AbConductor for high-voltage windings and a rotating electric machine comprising a winding including the conductor
US6396187Nov 4, 1997May 28, 2002Asea Brown Boveri AbLaminated magnetic core for electric machines
US6417456May 27, 1997Jul 9, 2002Abb AbInsulated conductor for high-voltage windings and a method of manufacturing the same
US6429563Feb 2, 1998Aug 6, 2002Abb AbMounting device for rotating electric machines
US6439497Feb 2, 1998Aug 27, 2002Abb AbMethod and device for mounting a winding
US6465979Feb 2, 1998Oct 15, 2002Abb AbSeries compensation of electric alternating current machines
US6525265Nov 30, 1998Feb 25, 2003Asea Brown Boveri AbHigh voltage power cable termination
US6525504Feb 23, 2000Feb 25, 2003Abb AbMethod and device for controlling the magnetic flux in a rotating high voltage electric alternating current machine
US6577487May 27, 1997Jun 10, 2003Asea Brown Boveri AbReduction of harmonics in AC machines
US6646363Feb 2, 1998Nov 11, 2003Abb AbRotating electric machine with coil supports
US6801421Sep 29, 1998Oct 5, 2004Abb AbSwitchable flux control for high power static electromagnetic devices
US6822363May 27, 1997Nov 23, 2004Abb AbElectromagnetic device
US6825585Feb 2, 1998Nov 30, 2004Abb AbEnd plate
US6828701Feb 2, 1998Dec 7, 2004Asea Brown Boveri AbSynchronous machine with power and voltage control
US6831388May 27, 1997Dec 14, 2004Abb AbSynchronous compensator plant
US6867674Nov 30, 1998Mar 15, 2005Asea Brown Boveri AbTransformer
US6873080Sep 29, 1998Mar 29, 2005Abb AbSynchronous compensator plant
US6885273Feb 14, 2002Apr 26, 2005Abb AbInduction devices with distributed air gaps
US6891303May 27, 1997May 10, 2005Abb AbHigh voltage AC machine winding with grounded neutral circuit
US6894416May 27, 1997May 17, 2005Abb AbHydro-generator plant
US6906447May 27, 1997Jun 14, 2005Abb AbRotating asynchronous converter and a generator device
US6919664May 27, 1997Jul 19, 2005Abb AbHigh voltage plants with electric motors
US6936947May 27, 1997Aug 30, 2005Abb AbTurbo generator plant with a high voltage electric generator
US6940380May 27, 1997Sep 6, 2005Abb AbTransformer/reactor
US6970063Feb 2, 1998Nov 29, 2005Abb AbPower transformer/inductor
US6972505May 27, 1997Dec 6, 2005AbbRotating electrical machine having high-voltage stator winding and elongated support devices supporting the winding and method for manufacturing the same
US6995646Feb 2, 1998Feb 7, 2006Abb AbTransformer with voltage regulating means
US7019429Nov 27, 1998Mar 28, 2006Asea Brown Boveri AbMethod of applying a tube member in a stator slot in a rotating electrical machine
US7045704Apr 19, 2001May 16, 2006Abb AbStationary induction machine and a cable therefor
US7046492Dec 20, 2004May 16, 2006Abb AbPower transformer/inductor
US7061133Nov 30, 1998Jun 13, 2006Abb AbWind power plant
US7141908Mar 1, 2001Nov 28, 2006Abb AbRotating electrical machine
US8833112 *Jun 14, 2007Sep 16, 2014Lg Electronics Inc.Stator of motor and washing apparatus having the same
US20110016929 *Jun 14, 2007Jan 27, 2011Lg Electronics Inc.Stator of motor and washing apparatus having the same
WO1998034242A1 *Feb 2, 1998Aug 6, 1998Asea Brown BoveriA transformer/reactor and a method for manufacturing a transformer/reactor
Classifications
U.S. Classification336/178, 336/210, 336/174, 174/DIG.240, 310/271, 29/609, 336/212, 336/229
International ClassificationH01F41/02
Cooperative ClassificationH01F41/024, Y10S174/24
European ClassificationH01F41/02A3B