Patent Application
20240425420
The present invention generally relates to electromechanical devices, and more particularly relates to an electromechanical device having components with electrically insulative coating layers thereon that are capable of surviving in environmental conditions with temperatures exceeding 180° C. over a long term.
Electric motors can generate relatively large amounts of heat during powered operation. More specifically, during motor operation, current flow through electromagnetic coils causes heat to be generated due, in part, to the resistance of the coils (e.g., copper loss). This heat causes the coil and device temperatures to rise. As the coil temperature increases, the generated heat is typically transferred from the coils toward area(s) with lower temperatures. The temperature that the coil and motor assembly can handle depends mainly on the temperature limits of the electrical insulation used. The higher the temperature the coils and motor assembly can handle, the higher the power density of the motor.
Typically, electromagnetic coils are coated with an organic-based (e.g., polyamide) wire electrical insulation, and other components of the motor assembly are insulated from the electromagnetic coils with various insulators such as slot liners, insulating paper materials, potting materials, adhesive insulating (e.g., fiberglass, polyimide, etc.) tapes, ceramic inserts, and the like. Due to the material properties of these insulators, the operational temperature of the electromagnetic coils of motor assemblies such as these may be limited to less than 240° C. over a short term (e.g., less than 10 hours), and less than 150° C. over a long term. This consequently imposes limits on the applied current and/or electrical potential to the electromagnetic coils, as well as the ambient conditions surrounding the motor. This, in turn, limits the achievable power density, cooling system requirements, and potential operating environments, of the motor (or other electromagnetic devices). Additionally, the heat that is generated in, and transferred away from, the electromagnetic coils, can increase the temperatures of various other components to undesirable levels.
Improving the thermal and environmental capability of electromagnetic devices, such as electric motors, has the potential to dramatically reduce overall size/weight and improve overall efficiency while further improving the power density. The efficiency improvements can be realized by reducing the additional power draw and/or system complexity and/or weight typically required for cooling system components to keep an organically insulated electromagnetic coil/device cool. The ability to operate the electromagnetic device with increased power input and/or at higher temperature would also increase power density.
Hence, there is a need for a method of improving the thermal and environmental capabilities of electromagnetic devices. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.
This summary is provided to describe select concepts in a simplified form that are further described in the Detailed Description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
In various embodiments, a method is provided that includes forming an intermediate coating product from a ceramic powder for application of the coating powder, applying the intermediate product to a surface of a component of an electromechanical device, and thermally processing the intermediate product at a temperature of 800° C. or less to melt the intermediate product and thereby form an electrically insulative coating layer on the surface of the component that is configured to survive in operating environments having temperatures in excess of 180° C. for a long term.
In various embodiments, an electromechanical device is provided that includes components each having one or more surfaces formed of one or more metallic materials and susceptible to operating environments having temperatures in excess of 150° C. for a long term, and electrically insulative coating layers formed on the one or more surfaces of the components. The coating layer is configured to survive in operating environments having temperatures in excess of 180° C. for a long term.
Furthermore, other desirable features and characteristics of the electromechanical device and method will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the preceding background.
The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” Thus, any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described herein are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary, or the following detailed description.
Components of electromechanical devices having at least one electrically insulative layer or coating layer on surfaces of the components and methods for forming the electrically insulative coating layer on the surfaces of the components are disclosed herein. The components may be parts of various systems and configured for use in various environments. In some embodiments, the components are parts of electromechanical devices such as, but not limited to, linear variable differential transformers (LVDTs), electric motors, generators, transformers, inductors, relays, solenoids, actuators, and sensors. As nonlimiting examples, the components may be portions of a stator (e.g., stator interfaces, stator teeth, stator back-iron, etc.), portions of a rotor, stator and rotor stack inter-laminate insulation, cores, frames, motor end bells, magnetic return walls, various surfaces of enclosures or housings, feedthroughs, and conductor joints. In some embodiments, the components may be parts of electromechanical devices configured for use in automotive, aerospace, medical, industrial, oil and/or gas down-hole drilling, fuel cell, and/or household applications. In various embodiments, the components may be parts of systems that are typically electrically insulated with a separate insulator such as, but not limited to, slot liners, insulating paper materials, adhesive insulating (e.g., fiberglass, polyimide, polyester, etc.) tapes, ceramic inserts, fiber mats (e.g., Nomex® by DuPont de Nemours, Inc.), etc.
The components of the electromechanical devices and the coated surfaces thereof may be formed of or include various materials, including certain metallic, ceramic, and composite materials. In various embodiments, the coated surfaces of the component are formed of or include a conductive material, such as a metallic material. In various embodiments, the coated surfaces of the component may be formed of or include a magnetic material, such as but not limited to iron or ferrite. In various embodiments, the coated surfaces of the component may be formed of or include ASTM A801 Alloy Type 1 (e.g., Hiperco® 50 and Vacudur® 49), electrical steel, samarium cobalt, neodymium, or Mu-metal. In various embodiments, the coated surfaces of the components may be formed of or include a non-magnetic material, such as stainless steel, copper, aluminum, or alloys thereof. In various embodiments, the coated surfaces of the components may be formed of or include Inconel® alloys.
The coating layer may include various electrically insulative materials. In various embodiments, the coating layer may be formed of insulative materials that are capable of surviving in operating environments having temperatures in excess of 180° C. over a long term. As used herein, the phrase “long term” may refer to a minimum operating life, a desired operating life, or an extended operating life of the component and/or a system in which the component is installed. For example, in some embodiments, the phrase long term refers to a period of time in excess of about 40,000 hours, such as about 70,000 hours, such as about 100,000 hours or more. As used herein, the phrase “short term” refers to about 10 hours or less. In various embodiments, the coating layer may provide various properties to the underlying surface of the component in addition to electrical insulation.
In various embodiments, the coating layer may be formed of one or more inorganic materials. In various embodiments, the coating layer includes a mixture of ceramic materials. In various embodiments, the coating layer includes a mixture of B2O3, Al2O3, BaO, SiO2, ZnO, Bi2O3, MgO, ZrO2, and TiO2. In various embodiments, the coating layer includes a mixture of B2O3, Al2O3, SiO2, and BaO. In various embodiments, the coating layer includes a mixture of B2O3, SiO2, ZnO, BaO, and Bi2O3. In various embodiments, the coating layer includes a mixture of B2O3, Al2O3, BaO, SiO2, MgO, ZrO2, and TiO2. The coating layer may have various microstructures and textures. In various embodiments, the coating layer may be amorphous. In various embodiments, the coating layer may be crystalline or semi-crystalline.
In various embodiments, the coating layer includes between 40 and 54 weight percent B2O3, between 3 and 5 weight percent Al2O3, between 12 and 17 weight percent SiO2, and between 28 and 38 weight percent BaO. In various embodiments, the coating layer includes between 40 and 54 weight percent B2O3, between 3 and 5 weight percent Al2O3, between 12 and 17 weight percent SiO2, between 28 and 38 weight percent BaO, greater than 5 weight percent Li2O, and a remainder including one or more additional constituents or components each having a weight percent of less than one. In various embodiments, the coating layer includes a mixture consisting essentially of B2O3, Al2O3, SiO2, and BaO, wherein any other constituents or components thereof are incidental impurities each having a weight percent of less than one, such as less than 0.5 weight percent.
In various embodiments, the coating layer includes between 47 and 64 weight percent B2O3, between 5 and 7 weight percent SiO2, between 9 and 14 weight percent ZnO, between 6 and 9 weight percent BaO, and between 16 and 22 weight percent Bi2O3. In various embodiments, the coating layer includes between 47 and 64 weight percent B2O3, between 5 and 7 weight percent SiO2, between 9 and 14 weight percent ZnO, between 6 and 9 weight percent BaO, between 16 and 22 weight percent Bi2O3, and a remainder including one or more additional constituents or components each having a weight percent of less than one. In various embodiments, the coating layer includes a mixture consisting essentially of B2O3, SiO2, ZnO, BaO, and Bi2O3, wherein any other constituents or components are incidental impurities each having a weight percent of less than one, such as less than 0.5 weight percent.
In various embodiments, the coating layer includes between 27 and 33 weight percent B2O3, between 24 and 30 weight percent BaO, between 12 and 16 weight percent MgO, between 11 and 13 weight percent SiO2, between 5 and 7 weight percent Al2O3, between 3 and 4 weight percent ZrO2, and between 2.5 to 3.5 weight percent TiO2. In various embodiments, the coating layer includes between 27 and 33 weight percent B2O3, between 24 and 30 weight percent BaO, between 12 and 16 weight percent MgO, between 11 and 13 weight percent SiO2, between 5 and 7 weight percent Al2O3, between 3 and 4 weight percent ZrO2, and between 2.5 to 3.5 weight percent TiO2, and a remainder including one or more additional constituents or components each having a weight percent of less than one. In various embodiments, the coating layer includes a mixture consisting essentially of B2O3, BaO, MgO, SiO2, Al2O3, ZrO2, and TiO2, wherein any other constituents or components are incidental impurities each having a weight percent of less than one, such as less than 0.5 weight percent.
In various embodiments, the coating layer includes a eutectic system formed from the mixture.
Referring to
At 514, the method 500 may include processing the ceramic powder to form an intermediate coating product for application of the coating powder, and at 516, the method 500 may include applying the intermediate product to a surface of a component of an electromechanical device. The method 500 is not limited to any particular type of intermediate coating product or any particular application process. In various embodiments, the coating layer may be formed by applying the intermediate product to the surface of the component by various processes including, but not limited to, certain dipping, spraying, taping, brushing, and painting processes.
In various embodiments, the intermediate coating product may include a slurry. In some embodiments, the slurry may include the ceramic powder, a carrier fluid (e.g., water and/or an organic solvent), and, optionally, one or more additional components such as, but not limited to, certain surfactants, chelators, stabilizers, and pH adjusters. In various embodiments, the carrier fluid may include a polymer with solvents, surfactants, and one or more suitable chemicals. Some nonlimiting examples of a suitable carrier fluid include 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, poly(iso-butyl methacrylate), ethyl cellulose, dimethyl silicone oil, dibutyl phthalate, or polyethylene glycol. In various embodiments, the slurry may have a solids loading of about 30 to 40 wt. %. In various embodiments, the slurry may be applied to the surface of the component via a spraying process, and have a solids loading of less than 30 wt. %. In some embodiments, the slurry may be thinned or diluted prior to application thereof on the surface of the component.
In various embodiments, the intermediate coating product may include a paste. In some embodiments, the paste may include the ceramic powder, a carrier fluid (e.g., water and/or an organic solvent), and, optionally, one or more additional components such as, but not limited to, certain thickeners, dispersants, or thinning agents (e.g., ester alcohol (Texanol™) or alpha-terpineol). In various embodiments, the paste may have a solids loading of about 65 to 85 wt. %. In various embodiments, the paste may be applied to the surface of the component via a spraying process or a painting process (e.g., brushing, troweling, etc.). In some embodiments, the paste may be thinned or diluted prior to application thereof on the surface of the component.
In various embodiments, the intermediate coating product may include a non-adhesive precursor tape. In some embodiments, the precursor tape may include a precursor layer and, optionally, a substrate layer. The precursor layer may include the ceramic powder, a matrix material, and, optionally, one or more additional components. The substrate layer may provide flexible support structure configured to temporarily support the precursor layer. In various embodiments, the tape may have a solids loading of about 30 to 60 wt. %. In various embodiments, the precursor tape may be cut to shape and applied to the surface of the component manually or by an automated process. In various embodiments, the tape may have a composition similar to the slurry described above.
In some embodiments, the applied intermediate coating product may undergo a drying process in, for example, an oven, box furnace, vacuum furnace, belt furnace, and any of numerous suitable heating techniques. The drying process, when implemented, may occur at a first predetermined temperature for a first predetermined time period, to remove solvents and produce a dried green coating (i.e., green state) on the surface of the component.
It will be appreciated that the first predetermined temperature and the first predetermined time may vary depending, for example, on the composition and type of the intermediate coating product. In some embodiments, the intermediate coating product may include an alcohol solvent, the first predetermined temperature may be a temperature that is 150° C. or less, and the first predetermined time period may be between 5 and 30 minutes. In some embodiments, the intermediate coating product may include water soluble solvents, the first predetermined temperature may be a temperature that is 100° C. or less, and the first predetermined time period may be between 10 and 60 minutes.
In some embodiments, the dried green coating may then undergo a binder burnout process (if necessary) in, for example, an oven, box furnace, vacuum furnace, belt furnace, or any of numerous suitable heating techniques. The binder burnout process, when implemented, may occur at a second predetermined temperature for a second predetermined time period to remove organics to produce a burned out, or brown coating on the surface of the component. In some embodiments, the drying process may be omitted and the binder burnout process may be performed on the applied intermediate coating product.
It will be appreciated that the second predetermined temperature and the second predetermined time may vary. In various embodiments, the second predetermined temperature may be a temperature of about 300° C. or less and the second predetermined time period may be between 5 and 30 minutes.
At 518, the method 500 may include performing a heat treatment in, for example, an oven, box furnace, vacuum furnace, belt furnace, and any of numerous suitable heating techniques, at a third predetermined temperature for a third predetermined time period to thermally process and melt the intermediate coating product, the brown coating, or the green coating, whichever is present. In various embodiments, the intermediate coating product, the brown coating, or the green coating, whichever is present, is entirely melted (inorganics) and/or burned out (organics) during the heat treatment. As such, in some embodiments, the drying process forms the green coating from the intermediate coating product, the binder burnout process forms the brown coating from the green coating, and the heat treatment is performed to melt the brown coating. In some embodiments, the drying process is omitted, the binder burnout process forms the brown coating from the intermediate coating product, and the heat treatment is performed to melt the brown coating. In some embodiments, the drying process and the binder burnout process are omitted, and the heat treatment is performed to melt and burnout the intermediate coating product.
The third predetermined temperature and third predetermined time period that are used to produce the intermediately processed coil may also vary depending, for example, on the composition of the ceramic powder and/or the intermediate coating product. In various embodiments, the third predetermined temperature may be based on the properties of the underlying surface of the component. In various embodiments, the underlying surface of the component includes non-magnetic or soft magnetic materials. In various embodiments, the third predetermined temperature may be a temperature sufficiently low such that magnetic properties of the component are not negatively affected.
In various embodiments, the surface of the component includes permanent magnetic properties, and the third predetermined temperature may be a temperature below a Curie temperature of the surface of the component. In various embodiments, the third predetermined temperature may be a temperature of 800° C. or less, such as 400 to 800° C., such as 750° C. or less, such as 700° C. or less, such as 650° C. or less, such as 600° C. or less, such as 550° C. or less, such as 500° C. or less, or such as 450° C. or less. In various embodiments, the third predetermined time may be between 10 and 30 minutes, such as between 15 and 30 minutes.
The resulting melt may then be cooled and solidified to form the coating layer on the surface of the component. In various embodiments, the coating layer is capable of surviving for a long term use in operating environments having temperatures in excess of 150° C., such as 180° C. or more, such as 200° C. or more, such as 220° C. or more, such as 240° C. or more, such as 260° C. or more, such as 280° C. or more, such as 300° C. or more, such as 320° C. or more, and/or such as 350° C. or more. The method 500 may end at 520.
In various embodiments, the method 500 may include applying the intermediate coating product, prior to thermally processing thereof, to all surfaces of all components of the electromechanical device that are likely to experience or are susceptible to operating environments having temperatures in excess of 150° C. for a long term during operation of the electromechanical device.
The electromechanical devices, components thereof, and methods of coating the components thereof disclosed herein provide various benefits over certain existing devices, components, and methods. For example, electromechanical devices typically include insulators that includes organic materials (e.g., polyamides) which are limited to long term operating temperatures of 150° C. or less. Operating at higher temperatures may result in the electrical insulation properties of the organic insulators decreasing significantly and thereby increasing a likelihood of arc-flashing, poor breakdown voltage, reduced lifetime, etc. Electromechanical devices having components with the coating layers described herein are capable of operating at elevated temperatures, such as above 180° C. over a long term. As such, the electromechanical devices are capable of improved voltage breakdown and thermal conductivity. In addition, the coating layers described herein may provide additional benefits such as, but not limited to, oxidation protection, chemical/environmental protection, and improved aesthetics.
In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Numerical ordinals such as “first,” “second,” “third,” etc. simply denote different singles of a plurality and do not imply any order or sequence unless specifically defined by the claim language. The sequence of the text in any of the claims does not imply that process steps must be performed in a temporal or logical order according to such sequence unless it is specifically defined by the language of the claim. The process steps may be interchanged in any order without departing from the scope of the invention as long as such an interchange does not contradict the claim language and is not logically nonsensical.
As used herein, the term “substantially” denotes within 5% to account for manufacturing tolerances. Also, as used herein, the term “about” denotes within 5% to account for manufacturing tolerances.
While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.
