Abstract: This method employs a rotatable mandrel having a circular outer peripheral portion comprising a section that is removably held in place within the peripheral portion and has an arcuate outer surface forming a part of said circular outer peripheral portion. As the mandrel is rotated, there is formed about the circular outer peripheral portion a toroidal core form that comprises laminations of amorphous steel strip having ends that meet in a joint region that extends angularly about a restricted zone of the toroidal core form. This forming step is so controlled that said restricted zone angularly aligns with the removable section of the mandrel. After the core-forming step, the removable section is removed from the mandrel thereby exposing an inner peripheral portion of the toroidal core form that angularly aligns with said restricted zone.

Abstract: This method of making packets of amorphous metal strip adapted to be wrapped about the arbor of a transformer-core-making machine comprises providing first and second composite strips, each comprising many thin layers of amorphous metal strip stacked in superposed relationship. The composite strips have leading ends that are located in initial positions (i) axially spaced from each other at the start of a packet-making operation and (ii) at opposite ends of a stacking zone where the packets are built up during a packet-making operation. The composite strips are cut to detach first sections of strip from the first composite strip and to detach second sections of strip from the second composite strip; and the detached sections are axially advanced forwardly of the respective composite strips from which they are detached into said stacking zone. The second sections are stacked in alternating relationship upon the first sections in the stacking zone.

Abstract: This method of making packets of amorphous metal strip adapted to be wrapped about the arbor of a transformer-core-making machine comprises providing first and second composite strips, each comprising many thin layers of amorphous metal strip stacked in superposed relationship. The composite strips have leading ends that are located in initial positions (i) axially spaced from each other at the start of a packet-making operation and (ii) at opposite ends of a stacking zone where the packets are built up during a packet-making operation. The composite strips are cut to detach first sections of strip from the first composite strip and to detach second sections of strip from the second composite strip; and the detached sections are axially advanced forwardly of the respective composite strips from which they are detached into said stacking zone. The second sections are stacked in alternating relationship upon the first sections in the stacking zone.

Abstract: This wrapping apparatus comprises a belt nester for wrapping stacks of thin amorphous steel strips about an arbor. The belt nester includes (a) a belt wrapped about the arbor and movable along its length to impart rotary motion to the arbor and (b) means for successively feeding individual ones of the stacks into the space between the belt and the arbor. The wrapping apparatus further comprises means defining a first substantially-flat surface upon which the stacks are supported as they are fed into the space between the belt and the arbor and additional means defining a second substantially-flat surface extending parallel to the first flat surface. Control means operates when a stack that is being wrapped on the arbor passes between said flat surfaces to bias one of the flat surfaces toward the other and to compress the stack between the two flat surfaces as the stack is wrapped.

Abstract: Groups of amorphous steel strips, cut to appropriate length from a composite strip, are stacked in longitudinally-staggered relationship to form packets. The groups are made up by a process that comprises a pre-spooling operation that results in the strips and groups in each packet adhering together, even though dry. The individual packets are fed successively into a belt nester that includes a rotatable arbor and wrapping means that wraps the packets in superposed relationship about the arbor as the arbor rotates, thereby building up a hollow core form. The above-described adhesive effect precludes the strips and groups from shifting longitudinally while the packets are being wrapped about the arbor.

Abstract: This method of making a transformer core from strips of amorphous metal utilizes an arbor that has a longitudinal axis and an external surface surrounding the axis that includes a portion of concave configuration forming a depression in the external surface. A plurality of packets are assembled, each packet comprising a plurality of groups of amorphous metal strips, the groups in each packet (i) comprising many aligned amorphous metal strips and (ii) having transversely-extending edges that are staggered with respect to each other longitudinally of the packet. The packets are sequentially wrapped about the arbor in superposed relationship while the arbor is held against rotation, thereby building up a core form about the arbor. Each packet prior to its being wrapped about the arbor is located so that when wrapped, opposite ends of each group meet in overlapping relationship in a location angularly aligned with said surface portion of concave configuration.

Abstract: This method is practiced by first providing a plurality of spools of amorphous steel strip in each of which the strip is wound in single-layer thickness. Then, in a pre-spooling machine, the single-layer thickness strips are unwound from said plurality of spools and combined to form strip of multiple-layer thickness which is wound onto a plurality of master reels, on each of which the strip is wound in multiple-layer thickness. These master reels are then placed on a plurality of payoffs, and the multiple-layer thickness strip is unwound from these payoffs and combined into a composite strip that has a thickness in strip layers equal to the sum of the strip layers in the combined multiple-layer thickness strips. Then the composite strip is cut into a plurality of sections, or lengths, of composite strip, and with these sections a hollow core form is constructed, which form has a window about which the sections are wrapped.

Abstract: Groups of amorphous steel strips, cut to appropriate length from a composite strip, are stacked in longitudinally-staggered relationship to form packets. The groups are made up by apparatus preforming a process that comprises a pre-spooling operation that results in the strips and groups in each packet adhering together, even though dry. The individual packets are fed successively into a belt nester that includes a rotatable arbor and wrapping means that wraps the packets in superposed relationship about the arbor as the arbor rotates, thereby building up a hollow core form. The above-described adhesive effect precludes the strips and groups from shifting longitudinally while the packets are being wrapped about the arbor.

Abstract: Certain transformer cores are manufactured by wrapping about an arbor packets of amorphous metal strip, each packet comprising a plurality of groups of strip, and each group comprising many thin layers of strip.

Abstract: This method of making a transformer core from strips of amorphous metal utilizes an arbor that has a longitudinal axis and an external surface surrounding the axis that includes a portion of concave configuration forming a depression in the external surface. A plurality of packets are assembled, each packet comprising a plurality of groups of amorphous metal strips, the groups in each packet (i) comprising many aligned amorphous metal strips and (ii) having transversely-extending edges that are staggered with respect to each other longitudinally of the packet. The packets are sequentially wrapped about the arbor in superposed relationship while the arbor is held against rotation, thereby building up a core form about the arbor. Each packet prior to its being wrapped about the arbor is located so that when wrapped, opposite ends of each group meet in overlapping relationship in a location angularly aligned with said surface portion of concave configuration.

Abstract: This method of making packets for transformer-core manufacture comprises: (i) providing a composite strip comprising many thin layers of amorphous steel strip, (ii) advancing the leading end of the composite strip forward, (iii) cutting the composite strip at a location spaced rearwardly of the leading edge of the strip, thereby detaching a first section of multi-layer strip and creating a new leading end just behind the cutting location, and (iv) then clamping the detached section to a supporting surface. Then the following steps (a) and (b) are carried out. (a) The new leading end of the composite strip is advanced forward, and the strip is cut at a location spaced rearwardly of the new leading edge, thus detaching an additional section of multi-layer strip and creating another new leading end just behind the latter cutting location.

Abstract: This method is practiced by first providing a plurality of spools of amorphous steel strip in each of which the strip is wound in single-layer thickness. Then, in a pre-spooling machine, the single-layer thickness strips are unwound from said plurality of spools and combined to form strip of multiple-layer thickness which is wound to form strip of multiple-layer thickness which is wound onto a plurality of master reels, on each of which the strip is wound in multiple-layer thickness. These master reels are then placed on a plurality of payoffs, and the multiple-layer thickness strip is unwound from these payoffs and combined into a composite strip that has a thickness in strip layers equal to the sum of the strip layers in the combined multiple-layer thickness strips. Then the composite strip is cut into a plurality of sections, or lengths, of composite strip, and with these sections a hollow core form is constructed, which form has a window about which the sections are wrapped.

Abstract: A laminated amorphous-metal transformer core having four sides joined by corner regions includes (a) joints located in a joint region in one of its sides and (b) side portions between the joint region and two corner regions. After annealing the core and while restraining the core laminations in a core region remote from the joint region, the joints are separated by displacing each of the side portions into a position of approximate alignment with the side of the core interconnected therewith at a corner region. Then a splint is applied to each of the side portions and the aligned interconnected side, thus holding these two parts in approximately aligned relation. The splint is relied upon to facilitate insertion of the aligned parts into the window of a coil, following which the splint is slid off the aligned parts, and core-lacing is completed.

Abstract: This transformer comprises preformed coil structure and a wound core of closed-loop configuration extending about a window and having joints in a localized region thereof that allow the core to be opened at the joints to permit insertion into the window of the preformed coil structure. The core comprises superposed laminations of thin amorphous ferromagnetic strip material which extend around the core from the localized joint region. The laminations include predetermined portions adjacent the joints that are displaced to provide a wide opening into the core window for insertion of the coil structure. A coating of adhesive bonding agent applied before said displacement is present on the lateral edges of the laminations in regions of the core not including said predetermined portions, thereby holding the laminations in correct assembled relationship when the core is opened, yet without interfering with displacement of said predetermined portions.

Abstract: A first annular form used for making a transformer core is wound from a strip of amorphous ferromagnetic material and is thereafter cut. The resulting laminations are then arranged in a second annular form with distributed gap joints, each joint involving a plurality of superposed laminations. The second annular form is then formed into a rectangular shape core and is then annealed. Then a bonding agent is applied to the transverse edges of the laminations over a region of the core removed from the joints. The joints are then separated to open the core, allowing displacement of unbonded regions of the core. Thereafter, preformed coil structure is inserted into the window of said opened core to surround a portion of the core. Then the unbonded regions of the core are returned to their original positions to remake the joints.

Abstract: To reduce the material in a transformer core and winding assembly, the edges of the core winding legs are relieved so as to achieve improved conformity with the inside corners of the coils disposed thereabout. More intimate spacing of the coils relative to the legs is therefore accommodated with consequent material savings in both the core and the winding coils. Methods for relieving the leg edges by bevelling and notching are disclosed.

Abstract: To reduce the material in a transformer core and winding assembly, the edges of the core winding legs are relieved so as to achieve improved conformity with the inside corners of the coils disposed thereabout. More intimate spacing of the coils relative to the legs is therefore accommodated with consequent material savings in both the core and the winding coils. Methods for relieving the leg edges by bevelling and notching are disclosed.

Abstract: An annular form of magnetic steel comprises a plurality of elongated sheets wound in superposed relationship about a reference axis. The sheets respectively define reference annuli, which are of progressively greater diameter as the annular form is wound about said reference axis. At least one of said reference annuli has a substantially greater diameter at one edge of the annular form than at the opposite edge of the form. At least some of the sheets that are located radially outward of said one reference annulus are provided with thickening means giving these sheets an effective thickness at one side greater than at their other side. Said one side is located on the opposite side of the longitudinal center line of the sheet from said one edge of the annular form.

Abstract: In this method, a plurality of elongated sheets of magentic steel are provided, and these sheets are wound in superposed relationship about an arbor, thereby forming an annulus of gradually increasing diameter about the arbor. As the sheets are so wound, any telescoping action by the sheets and the direction thereof are sensed. Following the occurrence of a predetermined amount of said telescoping in a sheet, I provide sheets that subsequently enter the annulus with thickening means effectively thickening said subsequent sheets at one side relative to their other side, said one side being located at a side of the thickened sheet's longitudinal center-line opposite to the direction in which said telescoping occurs.The article made by this method is also disclosed and claimed.

Abstract: A precut nested magnetic core having a locking outer turn. The locking turn is formed of magnetic core steel and has a pair of locking slots in one end and a single locking tab in the opposite end. The precut annular core is locked by using the second or inner slot with the locking tab while the formed annealed core is locked by using the first or outer slot with the locking tab.