Abstract:
Disclosed are methods, apparatuses, and systems with regard to laminations. In an embodiment, an apparatus includes a lamination having a variable thickness and a spacer connected with the lamination at a location, wherein the location of the spacer is based on a determined thickness of the lamination.

Description:
TECHNICAL FIELD 
     The technical field generally relates to stator cores of power generator and more specifically laminations for stator cores of power generator. 
     BACKGROUND OF THE INVENTION 
     In all types of stator construction, the central iron core is constructed from thin coated steel laminations stacked together. By making the coated laminations very thin the resistivity of the steel sheet itself is high and surface insulation of laminations is complete, reducing the eddy current losses through the core. These steel laminations vary in thicknesses from between 0.2 mm to 0.5 mm. The laminations are electrically insulated from each other by a very thin coating of insulating varnish or the like. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Disclosed herein are systems and apparatus with regard to laminations. In an embodiment, an apparatus comprises a lamination having a variable thickness and a spacer connected with the lamination at a location, wherein the location of the spacer is based on a determined thickness of the lamination. 
     In an embodiment, a stator core comprises a plurality of laminations, the plurality of laminations are substantially all of the laminations found in the stator core, wherein each lamination of the plurality of laminations has an integral spacer. 
     In an embodiment, a system may include a processor and a memory coupled to the processor, the memory having stored thereon executable instructions that when executed by the processor cause the processor to effectuate operations. The operations may include providing instructions to determine a thickness at a location on a lamination, the lamination having a variable thickness and providing instructions to add a spacer of a first thickness at the location on the lamination based on the determined thickness of the lamination at the location. 
     This Brief Description of the Invention is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Brief Description of the Invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to limitations that solve any or all disadvantages noted in any part of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings wherein: 
         FIG. 1  displays a front view of a lamination; 
         FIG. 2  displays a stack of laminations with exaggerated thickness imperfections; 
         FIG. 3  displays a front view of a lamination with continuous integral spacers; 
         FIG. 4  displays a close up side view of a portion of two laminations with exaggerated integral spacers; 
         FIG. 5  displays close-up side views of portions of laminations and coating configuration. 
         FIG. 6  displays an exemplary stack of laminations with integral spacers on each lamination; 
         FIG. 7  displays close up view of laminations with integral spacers displayed in  FIG. 6 ; 
         FIG. 8  is a block diagram of a side view of a system that attaches integral spacers; 
         FIG. 9  is a block diagram of a top view of an exemplary system that attaches integral spacers; 
         FIG. 10  is a block diagram of a side view of a system that attaches integral spacers; 
         FIG. 11  is a block diagram of a top view of a system that attaches integral spacers; 
         FIG. 12  displays an embodiment of lamination with an integral spacer comprising individual insulation pads; 
         FIG. 13  displays a cross section of a system that attaches integral spacers when a tap is not punched; 
         FIG. 14  displays a cross section of a system that attaches integral spacers when a tape is punched; 
         FIG. 15  displays a side view of an exemplary process for powder deposition and curing to create a lamination with integral spacers; 
         FIG. 16  displays a front view of a lamination with separated integral spacers; 
         FIG. 17  displays a front view of a lamination with individual step stripe integral spacers; 
         FIG. 18  illustrates a non-limiting exemplary method of creating an integral spacer; and 
         FIG. 19  is an exemplary block diagram representing a general purpose computer system in which aspects of the methods and systems disclosed herein or portions thereof may be incorporated. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  displays a front view of a thin lamination  100  that may be used in generator core construction. A lamination often has thickness imperfections that make it thicker in the middle, for example near line  102 , than on both ends. The thickness imperfections may be the result of materials not adequately flowing out to sides and edges of the original steel sheet, even under high roller pressure. Steel billets are rolled into thin steel sheet and then coiled in the mill plant. When many layers are stacked, the thickness imperfection may cause the stacked core being formed from successive layers of the laminations to incur a parallelism error (i.e., “crowning”), as shown in  FIG. 2 . This parallelism error occurs because in stacking the laminations, the relatively thicker portions of the laminations directly overlay one another, and the relatively thinner portions of the laminations directly overlay one another. For example, in  FIG. 2 , after the stacking of the individual laminations, the middle portion  202  of stack  200  becomes higher than the edges at  201  and  203 , which in turn results in a crowning of stack  200 . Currently, in order to correct the parallelism error, a manual process of shimming a spacer is done after stacking several laminations, which may be in the tens or hundreds of laminations. 
       FIG. 3  shows continuous integral end spacer  306  and integral end spacer  308  attached to dovetail end  302  and tooth end  304  of a lamination  300  to offset the parallelism error. The inclusion of integral spacers with each lamination that creates a generator core allows for a stable stack or core under flange compression.  FIG. 4  displays close-up side views of portions of laminations. Lamination  402  and lamination  404  have an attached integral end spacer. The integral spacer may include a substance that comprises one of a thick film coating, partial varnish coating, an attached direct sheet, or adhesive tapes. The spacer substance may be applied to the spacer areas of a steel sheet and then punched into laminations with spacers on a single side (e.g., lamination  402 ) or both sides (e.g., lamination  404 ). 
     The lamination may be coated with insulation varnish or the like. A flange may be used to compress the laminations with the integral spacers in stacking. In an embodiment, integral spacers, as discussed herein, may be designed to be slightly thicker than what would make a single lamination look level in thickness, for example, to account for shrinking under different compression to level the crown. The higher spacers shrink more under more pressure, while the crown shrinks much less even under the highest pressure. 
     In an embodiment, the crown height may vary around an average value, e.g. 0.5 mil. For an individual lamination, the crown height can be slightly different from the spacer height. In some areas a spacer of a lamination may be higher than the crown, while in other areas the spacer height may be lower than the crown. On average, the spacer height may be equal to the crown height. When many laminations are stacked, the entire stack does not display a crown. The spacer material may be softer than the mill coating and precoating. The softer spacer shrinks under compression to level with the middle crown. The middle crown made of stiffer mill coating, precoating, and steel barely shrinks. If the spacer is slightly higher, e.g. 0.55 mil on average, than the crown, e.g., 0.5 mil on average, each individual layer may level better under compression. The above techniques may allow canceling the variable crown without tracking the random crown variations. In another embodiment, the crown height variation can be tracked (per lamination or the entire stack) and spacer thickness/height may be adjusted accordingly. In another embodiment, the spacer may have the same thickness or height, e.g. 0.5 mil, which would match an expected average height for a crown of each lamination, e.g., 0.5 mil. 
     Laminations may be punched along a steel coil. The steel coil may be coated with insulation such as precoat and mill coat. Spacers in both sides may be coated or taped before punching. After punching, the lamination can be recoated. Spacers can also be applied before recoat or after recoat.  FIG. 5  displays different coating and spacer configurations. Lamination  501  has steel  502 , top precoat  504 , bottom precoat  506  and an integral spacer  508 . Lamination  510  has steel  512 , top precoat  514 , recoat  515 , bottom precoat  516 , bottom recoat  517 , and integral spacer  518 . Lamination  520  has steel  522 , top precoat  524 , bottom precoat  526 , integral spacer  528 , and top recoat  529 , and bottom recoat  527 . The aforementioned coating and spacer configurations are contemplated for laminations with integral spacers on both sides. The precoats may consist of single or multiple layers including mill coatings. The recoat may consist of single or multiple layers. 
       FIG. 6  displays an exemplary stack of laminations  600  with integral end spacers on each lamination. The spacers, which are usually much thinner than the steel layer, is exaggerated in  FIG. 6  and  FIG. 7 .  FIG. 7  displays close up view of laminations  600  with integral end spacers displayed in  FIG. 6 . A close up view  610  of  600  shows end spacer  612  and a cooling gap  614 . As shown in  FIG. 7 , cooling gaps exist between the middle crown and end spacers. A gap of about 5-25 micrometers allows natural convection between two adjacent layers especially when the teeth are hot in generator operation. The end spacers may increase insulation to critical areas, such as tooth edges, where interlaminar voltage is the highest. Insulation thickness may be increased by three to six times at tooth edges. The added spacers may also increase the tolerance to dings of the tooth edges. In addition, a layer of insulating magnetic particles as part of the end spacer, may increase the core permeability at the tooth ends, where magnetic flux is usually the strongest. 
       FIG. 8  is a block diagram of a side view of an exemplary system  800  that may attach adhesive tape used as an integral spacer.  FIG. 9  is a block diagram of a top view of exemplary system  800  that attaches adhesive tape.  FIG. 8  displays a steel roll  802  (e.g., grain oriented or non-grain oriented steel) and an adhesive tape roll  804 . System  800  may also comprise a punching machine  808  that punches a thin sheet of steel into a lamination  810 , which is shown in  FIG. 9 . The devices (e.g., punching machine, etc.) in system  800  may be communicatively connected to a server  809  or other computing device that provides instructions to devices in system  800  to perform operations consistent with creating laminations and/or integral spacers. The tapes from roll  804  may be made with high temperature (e.g., withstand at least 100 degrees Celsius) polyester, or other high temperature polymers, with a silicone adhesive back. Tapes without adhesive back may be attached by applying inline adhesive and heating via a heater  806 , as shown in system  800 . After tape is attached to both coil ends, the composite sheet may enter punching machine  808  to output lamination  810  with attached adhesive tape (integral spacer). The adhesive tape integral spacers found on lamination  810  are continuous and cover the critical end edges, the dovetail  812  and teeth  814  (also called fingers) of lamination  810 . In an embodiment, the adhesive tape spacers may be attached after the steel thin sheet is punched (i.e., after the lamination is created). The taping and punching process may be separated rather than continuous as shown. First the material is uncoiled, taped, and recoiled. The taped coil is then uncoiled and punched to create laminations to be collected. 
       FIG. 10  is a block diagram of a side view of an exemplary system  1000  that may attach enamel resin as an integral spacer.  FIG. 11  is a block diagram of a top view of exemplary system  1000  that attaches enamel resin. As shown  FIG. 10 , system  1000 , may apply enamel resin to sheets from metal coil  1002  by using a group of rollers that include roller  1004  and roller  1005 . The enamel resin may be applied to the metal sheet before being punched by punching machine  1006 . The enamel resin may be of C-3 organic type or C-6 organic enamel with solid filler. Other lamination coatings may also be used. Thin coatings may be applied on both top and bottom sides to give adequate thickness to offset the parallelism error. After resin is applied to both coil sides, the coil ends may be heated via a group of heaters  1012  to cure the enamel resin. The enamel resin integral spacers found on lamination  1024  cover the critical end edges of the dovetail  1020  and teeth  1022  of lamination  1024 . In an embodiment, the enamel resin integral spacers may be attached after the thin metal sheet is punched (i.e., after a lamination is created). The coating can be applied on one side of the sheet if the crown size is small. The coating and punching process may be separated rather than continuous as shown. First the material may be uncoiled, coated, and recoiled. The partially coated coil is then uncoiled and punched to create laminations to be collected. 
       FIG. 12  displays an embodiment of lamination  1200  with an integral spacer that has individual insulation pads (e.g., pad  1206 ) that may be applied to the dovetail  1202  and teeth end  1204  of lamination  1200 . After the application of enamel resin for the recoat, but before high temperature curing, individual pads may be applied to the still wet surface of the lamination  1200 . Polymer tapes from rolls may supply the material continuously to a designated pad location.  FIG. 13  and  FIG. 14  display a cross section of an exemplary system  1300  to stamp and attach the aforementioned pads. In an embodiment, there may be a punch  1302  and a die plate  1306 . A polymer tape  1304  may be placed over the die plate  1306  and under the punch  1302 , as shown in  FIG. 13 . A lamination  1308  may be located in a manner to receive polymer tape  1304  when punched.  FIG. 14  displays tape  1304  punched into pad  1312 . Pad  1312  may be placed on a wet surface of lamination  1308 . After pad  1312  sticks to the enamel surface of lamination  1308 , heating power from an oven or infrared irradiation may be applied to cure the enamel with pad  1312 . Tape with an adhesive back may be similarly applied on a dry lamination surface after the enamel is cured, for example. 
       FIG. 15  displays a side view of an exemplary process for powder deposition and curing to form end spacers  1508  and  1509  for lamination  1501 . Enamel resin is applied to the surface of lamination  1501  first at  1502 ; the enamel doesn&#39;t get heated right away. At  1504 , polymer and/or ceramic powders may be applied to the wet surface of the lamination  1501  by electrostatic spraying or other spraying methods. The amount of deposited material depends on spraying time and flow density. At  1506 , infrared, ultraviolet, or oven heating may be applied to cure the integral spacers  1508  and  1509  as well as the wet enamel surface of lamination  1501 . 
     Besides continuous integral end spacers as shown in  FIG. 3 , individual pads may also be placed on a lamination surface. After the application of enamel recoat over the mill coat or precoat, ceramic and/or polymer powders may be sprayed or printed to end locations within a limited scope, such as  1602  and  1604 , as shown in  FIG. 16 . Wet enamel may not be cured when the powder is applied. Powder that falls off the edge of the lamination may be collected for later application. The scope of the powder application, as shown in  FIG. 16  may cover the lamination end edges.  FIG. 17  displays an embodiment of integral spacers which comprises individual step stripes that may have different heights to address the parallelism error step wise. There may be many different structural patterns of integral spacers. Generally integral spacers for each lamination, as discussed herein, offset the parallelism error on one or more lamination ends. Individual integral end spacers, such as  FIG. 12  or  FIG. 16 , may also offset the parallelism error, but give more cooling gaps for convection flow. 
     Applicable polymeric materials for integral spacers as disclosed herein include high temperature polyester, polyurethane, phenolics (PF) or enamel, and polyimide. Applicable ceramic powder materials include alumina, zirconia, silicate, and the like. Applicable insulating magnetic materials for the powders include ferrites and the like. 
       FIG. 18  illustrates a non-limiting exemplary method of creating an integral spacer to correct or minimize the parallelism error. Method  1800  may be performed, at least in part, by computing equipment including servers, mobile devices, or another other device that can execute computing functions. In an embodiment at step  1805 , thickness across a thin sheet of metal is determined. The thickness may be determined by measuring the thin sheet once or periodically (e.g., a periodic time period or roll length). The measurement may then be extrapolated throughout the application of the integral spacer to the thin sheet of a roll of metal. In an alternative embodiment, the thickness may be measured continuously. 
     At step  1810 , after the thickness of the thin sheet is measured, the appropriate thickness and position of the integral spacer to correct the parallelism error is determined. The integral spacers may be made of material that is plastic or flexible and able to adjust to address the parallelism error while under pressure, so an acceptable tolerance range of thickness for the integral spacer may also be determined. At step  1815 , the integral spacer of predetermined thickness and position is attached to the thin sheet. In other embodiments, the measurements and/or subsequent attachment of the spacer may be done before or after the lamination is created from a thin sheet of the steel roll. Afterwards the lamination with an integral spacer is stacked on top of another lamination with an integral spacer to eventually create a generator core. 
     In an embodiment, an integral spacer may be made of a constant thickness and placed on each lamination. Afterwards a measurement may be taken to determine how to adjust (e.g., file down) the integral spacer to the appropriate thickness for a consistent thickness across the length of the lamination. 
     Without in any way limiting the scope, interpretation, or application of the claims appearing herein, a technical effect of one or more of the example embodiments disclosed herein is to provide methods to correct the parallelism error that may occur when stacking several laminations (e.g., tens or hundreds of laminations). The prior art process interrupts stacking of laminations to shim or align every 2 to 3 inches, for example. The process disclosed herein may address the parallelism error as the laminations are being created. The disclosed process also provides additional insulation, cooling, permeability, plus the non-grain oriented (NGO) mechanical rigidity for higher power output. The disclosed methods also provide for strengthened core insulations at bar slots and tooth edges as well as offsets issues with edge dings that may happen during handling and punching. The laminations with integral spacers may be stacked consecutively and may be a substantial amount (e.g., fifty to one-hundred percent) of laminations in the stator core. 
       FIG. 19  and the following discussion are intended to provide a brief general description of a suitable computing environment in which the methods and systems disclosed herein and/or portions thereof may be implemented. Although not required, the methods and systems disclosed may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer, such as a client workstation, server or personal computer. Generally, program modules include routines, programs, objects, components, data structures and the like that perform particular tasks or implement particular abstract data types. Moreover, it should be appreciated the methods and systems disclosed herein and/or portions thereof may be practiced with other computer system configurations, including hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers and the like. A processor may be implemented on a single-chip, multiple chips or multiple electrical components with different architectures. The methods and systems disclosed herein may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices. 
       FIG. 19  is a block diagram representing a general purpose computer system in which aspects of the methods and systems disclosed herein and/or portions thereof may be incorporated. As shown, the exemplary general purpose computing system includes a computer  1920  or the like, including a processing unit  1921 , a system memory  1922 , and a system bus  1923  that couples various system components including the system memory to the processing unit  1921 . The system bus  1923  may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. The system memory includes read-only memory (ROM)  1924  and random access memory (RAM)  1925 . A basic input/output system  1926  (BIOS), containing the basic routines that help to transfer information between elements within the computer  1920 , such as during start-up, is stored in ROM  1924 . 
     The computer  1920  may further include a hard disk drive  1927  for reading from and writing to a hard disk (not shown), a magnetic disk drive  1928  for reading from or writing to a removable magnetic disk  1929 , and an optical disk drive  1930  for reading from or writing to a removable optical disk  1931  such as a CD-ROM or other optical media. The hard disk drive  1927 , magnetic disk drive  1928 , and optical disk drive  1930  are connected to the system bus  1923  by a hard disk drive interface  1932 , a magnetic disk drive interface  1933 , and an optical drive interface  1934 , respectively. The drives and their associated computer-readable media provide non-volatile storage of computer readable instructions, data structures, program modules and other data for the computer  1920 . As described herein, computer-readable media is a tangible, physical, and concrete article of manufacture and thus not a signal per se. 
     Although the exemplary environment described herein employs a hard disk, a removable magnetic disk  1929 , and a removable optical disk  1931 , it should be appreciated that other types of computer readable media which can store data that is accessible by a computer may also be used in the exemplary operating environment. Such other types of media include, but are not limited to, a magnetic cassette, a flash memory card, a digital video or versatile disk, a Bernoulli cartridge, a random access memory (RAM), a read-only memory (ROM), and the like. 
     A number of program modules may be stored on the hard disk, magnetic disk  1929 , optical disk  1931 , ROM  1924  or RAM  1925 , including an operating system  1935 , one or more application programs  1936 , other program modules  1937  and program data  1938 . A user may enter commands and information into the computer  1920  through input devices such as a keyboard  1940  and pointing device  1942 . Other input devices (not shown) may include a microphone, joystick, game pad, satellite disk, scanner, or the like. These and other input devices are often connected to the processing unit  1921  through a serial port interface  1946  that is coupled to the system bus, but may be connected by other interfaces, such as a parallel port, game port, or universal serial bus (USB). A monitor  1947  or other type of display device is also connected to the system bus  1923  via an interface, such as a video adapter  1948 . In addition to the monitor  1947 , a computer may include other peripheral output devices (not shown), such as speakers and printers. The exemplary system of  FIG. 19  also includes a host adapter  1955 , a Small Computer System Interface (SCSI) bus  1956 , and an external storage device  1962  connected to the SCSI bus  1956 . 
     The computer  1920  may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer  1949 . The remote computer  1949  may be a personal computer, a server, a router, a network PC, a peer device or other common network node, and may include many or all of the elements described above relative to the computer  1920 , although only a memory storage device  1950  has been illustrated in  FIG. 19 . The logical connections depicted in  FIG. 19  include a local area network (LAN)  1951  and a wide area network (WAN)  1952 . Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets, and the Internet. 
     When used in a LAN networking environment, the computer  1920  is connected to the LAN  1951  through a network interface or adapter  1953 . When used in a WAN networking environment, the computer  1920  may include a modem  1954  or other means for establishing communications over the wide area network  1952 , such as the Internet. The modem  1954 , which may be internal or external, is connected to the system bus  1923  via the serial port interface  1946 . In a networked environment, program modules depicted relative to the computer  1920 , or portions thereof, may be stored in the remote memory storage device. It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used. 
     Computer  1920  may include a variety of computer readable storage media. Computer readable storage media can be any available media that can be accessed by computer  1920  and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media include both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computer  1920 . Combinations of any of the above should also be included within the scope of computer readable media that may be used to store source code for implementing the methods and systems described herein. Any combination of the features or elements disclosed herein may be used in one or more embodiments. 
     In describing preferred embodiments of the subject matter of the present disclosure, as illustrated in the Figures, specific terminology is employed for the sake of clarity. The claimed subject matter, however, is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. Although integral spacers are discussed to be attached at the end of the lamination, the integral spacer may be placed in any area of the lamination that will eventually cause stacking issues related to a parallelism error without the spacers. Mill coating may be considered the coating applied when the steel mill plant rolls the sheet. Precoating may be considered the coat applied on the coil before punching, while recoating may be considered the coat applied on the lamination after punching. Polymer or organic coating may be applied in different processes. For example, wet (e.g., liquid) resin application or powder application. Both get cured and leveled under high temperature. The resin of these insulation coatings may be filled with inorganic particles. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.