EP4183028A1 - Formulation de revêtement en poudre pour un système d'isolation d'une machine électrique, machine électrique présentant un système d'isolation de ce type et procédé de production d'un système d'isolation de ce type - Google Patents

Formulation de revêtement en poudre pour un système d'isolation d'une machine électrique, machine électrique présentant un système d'isolation de ce type et procédé de production d'un système d'isolation de ce type

Info

Publication number
EP4183028A1
EP4183028A1 EP21769404.1A EP21769404A EP4183028A1 EP 4183028 A1 EP4183028 A1 EP 4183028A1 EP 21769404 A EP21769404 A EP 21769404A EP 4183028 A1 EP4183028 A1 EP 4183028A1
Authority
EP
European Patent Office
Prior art keywords
powder coating
coating formulation
insulation system
insulation
filler particles
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP21769404.1A
Other languages
German (de)
English (en)
Inventor
Jürgen Huber
Steffen Lang
Marek Maleika
Lisa Sponsel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP4183028A1 publication Critical patent/EP4183028A1/fr
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/30—Windings characterised by the insulating material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/002—Inhomogeneous material in general
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/002—Inhomogeneous material in general
    • H01B3/006—Other inhomogeneous material
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/10—Applying solid insulation to windings, stators or rotors
    • H02K15/105—Applying solid insulation to windings, stators or rotors to the windings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K15/00—Methods or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
    • H02K15/12—Impregnating, heating or drying of windings, stators, rotors or machines
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/32—Windings characterised by the shape, form or construction of the insulation
    • H02K3/40—Windings characterised by the shape, form or construction of the insulation for high voltage, e.g. affording protection against corona discharges

Definitions

  • Powder coating formulation for an insulation system of an electric machine electric machine with such an insulation system and method for producing such an insulation system
  • the invention relates to a powder coating formulation for an insulation system of an electrical machine, in particular a rotating electrical machine with a rated voltage of at least 500V to 700V.
  • the invention also relates to an electrical machine with such an insulation system and a method for producing an insulation system of an electrical machine.
  • a powerful generator such as a turbo generator
  • the insulation system usually in the form of windings.
  • a wound insulation is used from a rated voltage of 1000V, with electrical machines below 1000V, for example in traction motors, slot insert insulation is used.
  • the insulation system is of decisive importance for the reliability, safety and efficiency of an electrical machine, for example a generator for the rated voltage range of at least 500V, in particular at least 700V, up into the high-voltage range. This affects the low-voltage range as well as the high-voltage range of more than 52kV.
  • the insulation system of generators based for example on mica tapes impregnated with epoxy resin, ensures the insulation of the high-voltage conductor(s) against the grounded stator. It has a high partial discharge inception voltage, which makes it possible to permanently dissipate up to 3.5 kV per millimeter or more.
  • Formulations based on resin that are currently known for the production of insulation systems often include fillers with a high specific surface area in addition to a curable resin formulation, for example based on epoxide.
  • further additives can be added, e.g. initiators or accelerator substances, which have an initiating effect on the hardening of an applied impregnation and/or powder coating formulation to form a solid insulation system.
  • a waterproofing formulation is essentially liquid, whereas a powder coating formulation is a powdery mixture and is a mixture of solids.
  • mica is used as a filler, for example, because as a particulate, in particular as a platelet-shaped, inorganic barrier material, it effectively and durably prevents electrical erosion under electrical partial discharges, preferably over the entire service life of the machine or the generator, is able to retard and has good chemical and thermal resistance.
  • the object of the present invention is to create a formulation, in particular a powder coating formulation, which makes it possible to produce an insulation system with improved insulation properties. Further objects of the invention are to create an electric machine with a correspondingly improved insulation system and a method for producing a correspondingly improved insulation system of an electric machine.
  • a powder coating formulation as can be used here preferably comprises the following components: a) resin mixture, b) hardener, c) accelerator d) filler, e) additives: in particular comprising at least one degassing additive and/or at least one leveling additive.
  • a first aspect of the invention relates to a powder coating formulation for an insulation system of an electrical machine, in particular a rotating electrical machine the high-voltage or low-voltage range, comprising at least one curable resin mixture, it being provided according to the invention that the powder coating formulation additionally comprises spherical filler particles made of silicon dioxide --SiO 2 --.
  • the powder coating formulation additionally comprises spherical filler particles made of silicon dioxide --SiO 2 --.
  • round particles are provided as filler in the powder coating formulation. This allows the production of an insulation system with improved insulation properties, since round particles have a significantly smaller specific surface compared to platelet-shaped fillers such as mica. This makes it possible to introduce more filler into the powder coating formulation with the same viscosity or, conversely, to achieve a lower viscosity with the same filler content.
  • the powder coating formulation is therefore preferably free of mica flakes. More filler in the powder coating formulation and/or a lower viscosity of the powder coating formulation leads to improved application and degassing properties of the powder coating formulation and thus to better insulation properties, better and/or higher surface quality of the resulting insulation system. In this way, an insulation system that is as free of air inclusions and/or pores as possible and with the highest possible filler concentration, which also has an advantageous effect on the matching of the respective thermal expansion coefficients, can be produced.
  • the epoxy resin which is conventionally in liquid form, is replaced by a solid and not by crystallites. Crystallinity of the resin would drive up the cost of the formulation with no improvement because the purity that crystallites need is destroyed by the addition of filler anyway.
  • the powder coating formulation additionally contains non-spherical filler particles, in particular irregularly shaped filler particles and/or platelet-shaped filler particles, in particular with a shape factor of between 1 and 3. but possibly also greater than 10.
  • some of the filler particles of the powder coating formulation do not have a spherical or primarily round shape, but are irregular and/or platelet-shaped.
  • the "shape factor" as used herein is a measure of the ratio of particle diameter to particle thickness for a population of particles of different size and shape and can be determined, for example, using the methods, apparatus and equations described in US Patent 5,576,617.
  • the form factor can be 60, 90, 120 or more.
  • the rheological properties of the powder coating formulation and the electrical insulation properties of the insulation system produced from it can be optimally adapted to the respective application.
  • the filler particles are dielectric and/or crystalline and/or amorphous. Since the filler particles are electrically non-conductive, a correspondingly good insulating property is ensured.
  • the rheological properties of the powder coating formulation and its degassing properties can be adjusted by using crystalline and/or amorphous filler particles.
  • SiO 2 filler particles to comprise quartz powder, quartz material and/or quartz glass.
  • Fused quartz and/or quartz glass is produced synthetically as an amorphous modification of quartz. It has a number of advantageous properties, in particular a very low coefficient of thermal linear expansion (0.5*10 -6 *K- 1 ) and excellent elasticity and resistance to temperature changes. It also has a high transformation and softening temperature and low thermal conductivity.
  • Spherical fused silica is more expensive than non- spherical fused silica, but as already mentioned has a significantly lower specific surface area and thus allows the above-mentioned advantages to be realised.
  • a commercially available filler that has these properties is the product BRUCAFIL® 1431 Quartz material from HPF Quartz Works GmbH, Frechen. Quartz glass also has high chemical resistance, a high softening point and temperature resistance, and low thermal expansion with high resistance to temperature changes. Silicon dioxide is generally very resistant to electrical discharges and can even soften under very strong discharges and form a kind of protective layer against electrical discharges.
  • the spherical or approximately spherical filler particles with a mass fraction between 5% by weight and 70% by weight, in particular between 30% by weight and 65% by weight, in particular between 40 % by weight and 60% by weight, based on the total mass of the powder coating formulation.
  • This also allows the rheological properties of the powder coating formulation and its degassing properties to be optimally adjusted to the respective application.
  • At least 30% of all filler particles are preferably spherical, in particular at least 50%, preferably at least 75% and in particular at least 80%.
  • the filler particles have a grain size distribution D 50 between 1 ⁇ m and 50 ⁇ m, in particular between 3 ⁇ m and 7 ⁇ m, and/or a maximum grain diameter of 100 ⁇ m, in particular 50 ⁇ m, and/or a coefficient of linear expansion of at most 20 * 10-
  • the D 50 value of the filler particles is preferably between approximately 30% and approximately 100% of the thickness of the subsequent insulation system.
  • the filler particles are preferably so small that they can be applied through a spray nozzle with or without compressed air.
  • the filler particles are at least partially surface-modified, in particular silanized.
  • a surface modification can be realized, for example, with silanes, whereby the filler surface can be epoxy-functionalized, amine-functionalized, vinyl-functionalized, etc., whereby the filler particles can be bonded covalently to the resin matrix.
  • the resin mixture of the sprayable, ie still uncured, powder coating formulation generally comprises at least one monomeric and/or oligomeric, possibly chain-extended, duromer resin component, in particular an epoxy resin component. After curing, the resin mixture forms the resin base of the filled insulation system.
  • novolaks, bisphenol-A and/or bisphenol-F diglycidyl ethers are suitable for this purpose, which can also be chain-extended, for example.
  • a resin mixture is advantageous which is solid at room temperature and comprises a monomeric and/or oligomeric, in particular epoxidized novolak mixture with bisphenol A and/or bisphenol F diglycidyl ether, in particular with chain-extended bisphenol A and/or bisphenol F , a di- or higher- epoxy carbon-based resin component and/or a monomeric and/or oligomeric resin mixture based on alkyl and/or aryl polysiloxane with at least one further resin component, all epoxy resin components preferably two or more glycidyl ester and/or glycidyl ether and/or comprising hydroxyl functionalities and/or that the resin mixture comprises at least one compound acting as a hardener and based on dicyandiamide and/or (poly)amine and/or amino and/or alkoxy functional alkyl/aryl polysiloxane.
  • compounds based on dicyandiamide and/or (poly)amine and/or amino- and/or alkoxy-functional alkyl/aryl polysiloxane are suitable as "hardeners”.
  • additives compounds that are used for degassing, for improving leveling and/or for preventing cratering in powder coatings are used as "additives”.
  • These can be, for example, those based on benzoin, polyester, acrylate and/or modified wax.
  • these compounds can also be adsorbed on silicon dioxide in the additive.
  • urons such as fenuron and/or monuron
  • fenuron and/or monuron are used as the “accelerator” or “catalyst”. These accelerators dissociate into isocyanate and dimethylamine when the temperature is increased.
  • Chain-lengthened is used here to refer to monomers or oligomers, for example of bisphenol A diglycidyl ether or BADGE or DGEBA.
  • BADGE diglycidyl ether
  • DGEBA diglycidyl ether
  • n is then greater Zero.
  • Compounds and mixtures which are solid at room temperature and under standard conditions, ie atmospheric pressure, etc., are only suitable for a powder coating formulation. In principle, liquids are not used for the production of powder coatings in a way that makes economic sense.
  • the uncured but solid and sprayable mixture is referred to here as “powder coating formulation”, while the mixture applied to the substrate is referred to as “powder coating”.
  • the chain extension of the resin base that can be used here which is solid at room temperature, i.e. "solid", in particular epoxy resins based on DGEBA, is not to be equated with the curing and/or crosslinking of the resin to form the duromer.
  • solid in particular epoxy resins based on DGEBA
  • the already chain-extended epoxy resins are used as a solid incorporated into the powder coating formulation.
  • the chain-extended solid epoxy resins are characterized, for example, by recurring groups “repeat units” with secondary hydroxyl groups.
  • the resin mixture contains a further monomeric and/or oligomeric, in particular di- or higher-epoxidized carbon and/or siloxane-based resin component includes.
  • a resin base in which the backbone of the polymer-crosslinked compound also has --[SiR 2 --O] n --units in addition to hydrocarbons.
  • the resin mixture comprises a monomeric and/or oligomeric resin component based on alkyl and/or aryl polysiloxane in a mixture with at least one, preferably two or more glycidyl ester and/or glycidyl ether functionalities and/or that the Resin mixture comprises at least one compound acting as a curing agent based on anhydride and/or (poly)amine and/or amino- and/or alkoxy-functional alkyl/aryl polysiloxane.
  • a resin and/or a resin mixture is provided as the resin mixture and/or resin-hardener mixture for the insulation material, in which at least part of the resin mixture and/or resin-hardener mixture that hardens to form a duromer the insulation system is a siloxane-containing compound that forms a [SiR 2 -O] n backbone in the fully cured duromer.
  • R stands for all types of organic residues that are suitable for curing and/or crosslinking to form an insulating material that can be used for an insulating system.
  • R stands in particular for -aryl, -alkyl, -heterocycles, nitrogen, oxygen and/or sulfur substituted aryls and/or alkyls.
  • R can be the same or different and can represent the following groups:
  • - Alkyl for example -methyl, -propyl, -isopropyl, -butyl, -isobutyl, -tertbutyl, -pentyl, -isopentyl, -cyclopentyl and all other analogs up to dodecyl, ie the homologue with 12 carbon atoms;
  • Aryl for example: benzyl, benzoyl, biphenyl, toluyl, xylenes and comparable aromatics, especially for example all aryl radicals, with one or more Rings whose structure corresponds to Hückel's definition of aromaticity,
  • Heterocycles in particular sulfur-containing heterocycles such as thiophene, tetrahydrothiophene, 1,4-thioxane and homologues and/or derivatives thereof,
  • Oxygen-containing heterocycles such as dioxanes, nitrogen-containing heterocycles such as those with -CN, -CNO, -CNS, -N3 (azide) substituents on the ring or rings and
  • Sulfur-substituted aryls and/or alkyls e.g. thiophene, but also thiols.
  • the Hückel rule for aromatic compounds refers to the fact that planar, cyclically conjugated molecules that contain a number of ⁇ electrons, which can be represented in the form of 4n + 2, have a special stability that also called aromaticity.
  • the resin mixture and/or resin-hardener mixture comprises not only the monomeric and/or oligomeric component which is functionalized for the polymerization and has a —[ SiR 2 —O] n — backbone, and at least one for the polymerization functionalized monomeric or oligomeric resin component with a carbon ie - [-CR i R 2 -] n _ units comprising backbone.
  • R is -hydrogen, -aryl, -alkyl, -heterocycles, nitrogen, oxygen and/or sulfur-substituted aryls and/or alkyls.
  • epoxy-functionalized components such as bisphenol F diglycidyl ether (BFDGE) or bisphenol A diglycidyl ether (BADGE), polyurethane and mixtures thereof are particularly suitable.
  • Epoxy resins based on bisphenol F diglycidyl ether (BFDGE), bisphenol A diglycidyl ether (BADGE) or mixtures thereof are preferred.
  • the monomeric or oligomeric component functionalized for polymerization which has a [SiR 2 -O] n - backbone with one or more -[-CR 1 R 2 -] n - backbone-containing components, is selected from the group consisting of the following Compounds to the resin mixture and/or resin-hardener mixture combined: undistilled and/or distilled, optionally reactively diluted bisphenol A diglycidyl ether, undistilled and/or distilled, optionally reactively diluted bisphenol F
  • Glycidyl-based and/or epoxy-terminated aryl and/or alkyl siloxanes are suitable as monomeric or oligomeric components functionalized for the polymerization and having a —[SiR 2 —O] n backbone , especially glycidoxy-terminated siloxanes.
  • a siloxane such as 1,3-bis(3-glycidyloxypropyl)tetramethyldisiloxane, DGTMS, and/or glycidoxy-terminated phenyldimethylsiloxane and/or phenylmethylsiloxane in monomeric and/or oligomeric form is suitable Form, as well as in any mixtures and / or in the form of derivatives.
  • any different, identical or different alkyl and/or aryl substituents can be present.
  • One of these already tested components is commercially available as “Silres® HP® 1250®. It has been shown that at least doubly functional lized siloxanes that can be used for the production of thermosets are suitable here.
  • the following compound suitable as a siloxane-based component is commercially available from Wacker AG:
  • Suitable curing agents for the homopolymerization are cationic and anionic curing catalysts, such as organic salts, such as organic ammonium, sulfonium, iodonium, phosphonium and/or imidazolium salts and amines, such as tertiary amines, pyrazoles and/or or imidazole compounds. Examples which may be mentioned here are 4,5-dihydroxymethyl-2-phenylimidazole and/or 2-phenyl-4-methyl-5-hydroxymethylimidazole.
  • compounds containing oxirane groups such as, for example, glycidyl ether, can also be used as hardeners.
  • the hardener can alternatively or additionally be replaced partially or completely by a compound with a [-SiR 2 -O-] n backbone, also referred to here as a siloxane-based compound.
  • high polymers, di- or trianhydride (derivatives) that are solid at room temperature can be useful as hardeners, such as 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA, CAS No. 2421 -28-5) are used.
  • hardeners such as 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA, CAS No. 2421 -28-5) are used.
  • BTDA 3,3',4,4'-benzophenonetetracarboxylic dianhydride
  • BTDA 3,3',4,4'-benzophenonetetracarboxylic dianhydride
  • Wacker AG the alkyl and/or aryl and/or alkoxy substituted Wacker HP 2000 or HP 2020.
  • Acid anhydrides are also commonly used successfully as hardeners in the insulation materials. However, their toxicology is no longer undisputed. For this reason, other hardeners, in particular those based on imidazole and/or pyrazole, are increasingly being used.
  • the carbon-based hardener be replaced entirely or partially by siloxane-based hardeners with the same functionalities.
  • the siloxane-containing component is therefore present in an amount of 10 to 50 mol% in the resin base, ie in the resin mixture and/or resin-hardener mixture of the powder coating formulation. It is particularly preferred if the amount of siloxane-containing component in the base resin is not more than 20 mol %, in particular not more than 18 mol % and particularly preferably not more than 15 mol %.
  • a reduced erosion volume could be seen with a substitution of the conventional resin component of 20-30%.
  • the partial discharge resistance of the insulating material is increased by the presence of a certain amount of [S1R 2 -O-] n - forming
  • a powder coating according to the invention can be applied both to a heated—hot—and to a cold substrate.
  • the powder coating can also be applied using an electrostatic process, in which the substrate can be hot or cold.
  • the powder coating can be applied by dipping the substrate into a fluidized bed filled with powder coating formulation.
  • the choice of the respective application process and the layer thickness of the applied powder coating layer vary from application to application. In general, the thinnest layers can be applied with electrostatic spraying on a cold substrate.
  • the substrates in question here are, above all, partial conductors that are already insulated from one another.
  • partial conductors are insulated from one another, for example by glass fabric, winding tape insulation, mica insulation, a PET polyethylene terephthalate film, PI polyimide film and/or other partial conductor insulation variants.
  • the respective partial conductor insulation is preferably pre-consolidated in the form of a prepreg.
  • two, a few or more or many partial conductors isolated from one another are baked together—for example in a hot press.
  • a package is, for example, a substrate for applying the powder coating formulation according to the invention.
  • the powder coating “formulation” refers to the form of the powder coating that has not yet been applied to the substrate and is not crosslinked.
  • the substrate has a rectangular cross-section rather than a rounded, oval, or round shape.
  • the powder coating formulation is applied to the substrate, e.g. through
  • Spraying with or without compressed air and/or applied by immersion in a fluidized bed with powder coating formulation for example, a cross section, preferably rectangular, in which the partial conductors are present in the substrate in the form of flat wires. These sub-conductors are "baked" via their sub-conductor insulation.
  • this is preheated to 130°C, 150°C or 200°C, for example, depending on the application and also depending on the heat class resistance of the substrate surface, the powder coating mululation, the partial conductor insulation and last but not least the prepreg made from a bonded bundle of mutually insulated partial conductors.
  • the cold or heated and/or electrically contacted substrate When the cold or heated and/or electrically contacted substrate is immersed in a fluidized bed, Weil has a layer of powder coating formulation on the surface of the substrate. This is melted and/or gelled either electrically or by temperature or by both. The melted and/or gelled powder coating then sticks to the substrate.
  • the immersion can be automated or at least partially automated.
  • the powder coating formulation is prepared as a preferably sprayable powder coating formulation.
  • a layer of the finished insulation system produced by spraying preferably has a thickness in the range from 50 ⁇ m to 150 ⁇ m, preferably 50 ⁇ m to 130 ⁇ m and particularly preferably from 70 ⁇ m to 120 ⁇ m.
  • insulation thicknesses in the range from 700 ⁇ m up to about 6 mm, in particular from 1.5 mm to 2.5 mm insulation thicknesses are often required, so that the sprayed insulation systems have several layers, for example up to 30 layers , in particular up to 20 layers, are applied. For example, 1 to 3 layers are applied on small machines and up to 20 layers on large electrical machines.
  • the first layer of powder coating serves as a substrate, it being preferred that the lower layer of powder coating is at least already degassed and/or gelled, so that a homogeneous surface can be used as a substrate for the upper layers is available.
  • the winding of electrical machines is usually made of copper.
  • the resin binder of the insulation system tems generally has at least four times greater thermal expansion than copper. By adding a filler with low thermal expansion, the thermal expansion of the insulation can be significantly reduced and shifted in the direction of the copper. Similar thermal expansion coefficients of the winding and insulation ensure a stable connection of the insulation system to the copper winding under thermal load changes by reducing thermally induced voltages. The same applies to other metals and metal alloys.
  • a further aspect of the invention relates to an electrical machine, in particular a rotating electrical machine, comprising at least one bundle of conductors and an insulation system which comprises insulation components for insulation, the insulation system being at least partially formed by applying a powder coating formulation once or several times - tion according to the first aspect of the invention and subsequent curing available and / or obtained.
  • the electrical machine which can be a generator, for example, has a correspondingly compared to the prior art with platelet-shaped - mica fillers - improved insulation system, since round and / or approximately round filler particles compared to platelet-shaped fillers such Mica have a significantly lower specific surface.
  • This makes it possible to add more filler to the powder coating formulation with the same viscosity or, conversely, to achieve a lower viscosity with the same filler content.
  • More filler in the powder coating formulation or the insulation system produced from it, and/or a lower viscosity of the powder coating formulation leads to improved application and degassing properties during application, adhesion to the substrate and curing of the powder coating formulation and This leads to better insulation properties and a higher surface quality of the resulting insulation system. This allows an almost non-porous insulation system be made with as high a filler concentration as possible. Additional features and their advantages can be found in the descriptions of the first aspect of the invention.
  • a third aspect of the invention relates to a method for producing an insulation system of an electrical machine, in particular a rotating electrical machine.
  • An improved insulation system for an electrical machine is produced, since round filler particles have a significantly smaller specific surface area than platelet-shaped fillers such as mica. This makes it possible to add more filler to the powder coating formulation with the same viscosity or, conversely, to achieve a lower viscosity with the same filler content. More filler in the powder coating formulation and/or a lower viscosity of the powder coating formulation leads to improved application and degassing properties of the powder coating formulation and thus to better insulation properties and a higher surface quality of the resulting insulation system. In this way, a pore-free insulation system with the highest possible concentration of fillers can be produced. Additional features and their advantages can be found in the description of the first aspect of the invention.
  • the method comprises at least the steps of a) producing a powder coating formulation according to the first aspect of the invention, b) preparing a substrate by heating and/or electrically contacting it, c) applying the powder coating formulation to the prepared substrate, in particular spraying and /or immersing the substrate in a fluidized bed of the powder coating formulation, d) melting, drying and/or gelling of the powder coating on the substrate, and e) curing of the powder coating to form the insulation system.
  • one of the polymerizable resin components of the resin mixture is selected from thermosets.
  • the powder coating formulation is sprayed onto a conductor, for example using a nozzle, in order to obtain the insulation system.
  • the spherical fillers have the advantage of low abrasiveness.
  • a sprayed powder coating formulation in particular for the production of a main insulation, enables a partially or fully automated production of insulation systems that are individually adapted to the respective machine.
  • the powder coating formulation and spray or fluidized bed technology enable an increase in the power density of electrically rotating machines, assuming that the insulation system produced using powder coating has the same electrical service life as a conventional insulation system.
  • the latter comprises quite a lot of components and requires many work steps with wrapping tape made of corona protection tape, tape adhesive, tape accelerator, possibly manually applied wrapping, then resin impregnation, if necessary at elevated temperature with overpressure or in a vacuum and finally resin -through curing.
  • FIG. 1 shows a schematic sectional view of a generator in the exit area of a winding from a laminated core according to an exemplary embodiment of the invention
  • FIG. 2 shows a DSC measurement of the resin mixture which is solid at room temperature.
  • FIG. 1 shows a schematic sectional view of an electrically rotating machine 10 embodied as a generator in the exit region of a conductor or a winding of mutually insulated partial conductors 8 from a laminated core 9 .
  • Electrically rotating machines have a very high efficiency of up to 99.5%.
  • the generator 10 has a main insulation 1, which can be produced by curing by applying a powder coating formulation, and a partial conductor insulation 2, which can be produced by winding. While the partial conductor insulation 2 is in the form of winding tape insulation, the main insulation 1 here is a pure coating that can be produced by applying and curing the powder coating formulation once or several times in accordance with a preferred exemplary embodiment of the present invention.
  • external corona protection 4 can also be seen.
  • the generator 10 comprises a fixing strip 5, a fixing strip 7, the winding of the partial conductors 8, which are insulated from one another, and the laminated core 9.
  • the main insulation 1 of the generator is based, for example, on powder coating made from a resin mixture containing chain-extended bisphenol-A, which is filled with spherical and fused silica-based filler in an amount of 55% by weight, based on the total mass of the powder coating formulation, and ensures the insulation of the conductors in the form of copper conductors 8 against the grounded stator, the laminated core
  • the main insulation has a high partial discharge inception voltage, which enables it to permanently dissipate 3.5 kV per millimeter.
  • Air has a relatively low dielectric strength, which means that partial discharges can occur even at relatively low field strengths. For this reason, the method for applying the powder coating formulation disclosed here for the first time avoids air inclusions as well as possible, particularly in the main insulation 1 .
  • the components of the present insulation system 12 include, viewed from the inside out, the copper (partial) conductors 8, i.e. the electrical coil, which are pressed together to form so-called twisted bars—at the prepreg stage, optionally one on the Internal potential control (IPS, not shown) applied to rods, the main insulation 1 and then the external corona protection 4 (AGS).
  • the generator or motor winding leaves the generator slots 14 at the end faces of the laminated core 9.
  • all of these components of the insulation system 12 (IPS, main insulation 1, AGS 4 and EGS) are predominantly wound onto the partial conductors 8 in the form of strips, with application being manual or at most semi-automatic, for example.
  • a bundle 8 of insulated sub-conductors is baked into a prepreg, for example by means of a hot press.
  • the bundle 8 is, for example, a "substrate" within the meaning of the invention, on which the powder coating formulation is applied, i.e. the powder coating formulation is coated with powder coating formulation either by dipping into a powder coating fluidized bed and/or spraying, "bepowdering". is covered. Because the substrate is either hot and/or electrostatically charged, the powder coating formulation sticks to it in at least one layer, either by melting because the substrate is 150° C. or 200° C. and/or by electrostatic adhesion.
  • This first layer is then gelled and hardened to such an extent that it can serve as a substrate for the second layer, again made of powder coating formulation sprayed on, for example.
  • FIG. 2 shows a DSC measurement, i.e. a “differential scanning calorimetry” measurement, in which the sample is heated at a specific measuring rate and it is measured how the heating of the sample actually leads to an increase in temperature or whether, for example the heating in the sample is used up by the melting energy of the solid and therefore the temperature of the sample does not rise despite continued heating.
  • a DSC measurement i.e. a “differential scanning calorimetry” measurement, in which the sample is heated at a specific measuring rate and it is measured how the heating of the sample actually leads to an increase in temperature or whether, for example the heating in the sample is used up by the melting energy of the solid and therefore the temperature of the sample does not rise despite continued heating.
  • the measurement was carried out using a perforated 0 mg aluminum crucible as a reference; the sample of powder coating formulation itself weighed 6.98 mg.
  • the measurement was carried out from 0 to 250°C_10K_min_twice/30-11-2020 15:21 segments :3/6;
  • Crucible Pan AL, pierced lid;
  • Atmosphere N2, 20.0ml/min ./. N2, 70mL/min; correction measurement Voltage/Range: 020/5000 ⁇ V.
  • the diagram, or FIG. 2 was generated with NETZSCH Proteus software.
  • FIG. 2 shows a DSC measurement of an exemplary resin mixture which is solid at room temperature and can be used in the present powder coating formulation.
  • a powder coating preferably comprises a resin mixture, hardener, accelerator, additive and/or fillers.
  • Finished powder coating comprising: f) resin mixture: here: epoxidized novolak, chain-extended DGEBA and polysiloxane, g) hardener: dicyandiamide h) accelerator: uron i) filler: spherical fused silica j) additives: degassing additive: benzoin leveling additive: acrylate
  • such a powder coating that is solid at room temperature comprises a resin mixture with a monomeric and/or oligomeric, in particular epoxidized, novolak Mixture with bisphenol A and/or bisphenol F diglycidyl ether, in particular with chain-lengthened bisphenol A and/or bisphenol F, a di- or higher epoxide carbon-based resin component and/or a monomeric and/or oligomer Resin blend based on alkyl and/or aryl polysiloxane, for example again with at least one further resin component, preferably comprising two or more glycidyl ester and/or glycidyl ether and/or hydroxyl functionalities.
  • the measurement was carried out on the unfilled powder coating. It was carried out using a standardized device from Netzsch, the Netzsch DSC 204F1 Phoenix 240-12-0411-L, the parameters are, as already described, heating rate 10 K/min in the range from 0°C to 250°C. A softening point at 49.4°C can be clearly seen; the epoxy resin is solid at lower temperatures.
  • the powder coating formulation according to the invention represents a possibility to supplement the conventional winding tape insulation and/or the VPI vacuum pressure impregnation process or even to dispense with it completely.
  • the insulating powder coating filled with spherical quartz is applied to the substrate in a layer structure in several layers, for example in 2 to 20 layers, and cured.
  • the individual layers of the powder coating formulation can, for example, be applied additively and thus (partially) automatically. Accordingly, a siloxane-modified epoxide filled with spherical particles is applied in powder form to the partial conductor winding 8 in an optionally multi-layer coating with a powdery powder coating formulation.
  • the siloxane ensures a significant extension of the electrical service life of the sprayed insulation system 12. Due to the filling with predominantly spherical particles, degassing of the applied and possibly already gelled powder coating is easily achieved.
  • a spherical compound such as spherical quartz material and/or spherical quartz glass (“fused silica") is therefore used as a filler in the powder coating formulation for electrical insulation systems 12.
  • Spherical quartz material consists of round, amorphous SiO 2 beads.
  • the amorphous silicon dioxide has a thermal expansion of
  • spherical quartz material has almost the same permittivity as conventional epoxy resins (approx. 3.5) and therefore ensures virtually no field increase in the insulation system 12. Silicon dioxide is resistant to electrical discharges and can be very strong discharges and form a kind of protective Form a layer against electrical discharges (if the filler particles are small enough).
  • spherical and/or almost spherical quartz material is more expensive than non-spherical quartz material, it has a significantly smaller specific surface area. This makes it possible to add more filler to the powder coating formulation (powder coating) with the same viscosity. More filler in the powder coating means more positive effects of the filler on the powder coating.
  • a surface modification or coating of the spherical quartz material can improve the binding of the filler to the resin formulation and at the same time optimize its processing properties.
  • Such a surface coating of the filler particles can usually be realized with silanes, as a result of which the filler surface can be epoxide-functionalized, amine-functionalized, vinyl-functionalized, and so on, if required. The surface can thus be bonded particularly well covalently to the respective resin matrix.
  • Typical filler concentrations are between about 5% by weight and 65% by weight, with 40-55% by weight being preferred.
  • Advantageous particle sizes D 50 are between 1 ⁇ m and 30 ⁇ m, preferably 3 ⁇ m and 7 ⁇ m.
  • a commercially available filler that has these properties is BRUCAFIL® 1431 from HPF. The filler may be present as one fraction or in multiple fractions.
  • the filler used is preferably electrically non-conductive, ie insulating.
  • filler particles of fundamentally different shape can be provided, in particular also irregularly shaped particles.
  • the filler particles can be crystalline and/or amorphous.
  • the curable resin base of the powder coating formulation may be a copolymer of a siloxane with a chain extended Bisphenol-A can be realized. In this way, with the aid of the powder coating formulation according to the invention, a pore-free insulation system 12 with the highest possible filler concentration can be implemented.

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Abstract

L'invention concerne une formulation de revêtement en poudre pour un système d'isolation (12) d'une machine électrique (10), en particulier une machine électrique tournante (10) présentant une tension nominale d'au moins 700 V, comprenant au moins un mélange de résine durcissable, la formulation de revêtement en poudre comprenant en outre des particules de charge de silice fondue sphériques. L'invention concerne en outre une machine électrique (10) comprenant au moins un conducteur (8) et un système d'isolation (12) de ce type, ainsi qu'un procédé de production d'un système d'isolation (12) de ce type pour une machine électrique (10).
EP21769404.1A 2020-09-03 2021-08-26 Formulation de revêtement en poudre pour un système d'isolation d'une machine électrique, machine électrique présentant un système d'isolation de ce type et procédé de production d'un système d'isolation de ce type Pending EP4183028A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102020211111.1A DE102020211111A1 (de) 2020-09-03 2020-09-03 Pulverlack-Formulierung für ein Isolationssystem einer elektrischen Maschine, elektrische Maschine mit einem solchen Isolationssystem und Verfahren zum Herstellen eines solchen Isolationssystems
PCT/EP2021/073655 WO2022048992A1 (fr) 2020-09-03 2021-08-26 Formulation de revêtement en poudre pour un système d'isolation d'une machine électrique, machine électrique présentant un système d'isolation de ce type et procédé de production d'un système d'isolation de ce type

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EP4183028A1 true EP4183028A1 (fr) 2023-05-24

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US (1) US20230318384A1 (fr)
EP (1) EP4183028A1 (fr)
CN (1) CN116057814A (fr)
DE (1) DE102020211111A1 (fr)
WO (1) WO2022048992A1 (fr)

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Publication number Priority date Publication date Assignee Title
DE102022202880A1 (de) * 2022-03-24 2023-09-28 Siemens Aktiengesellschaft Pulverlackformulierung zur Isolation des Wickelkopfes einer elektrischen rotierenden Maschine
CN115960514A (zh) * 2022-12-22 2023-04-14 老虎表面技术新材料（苏州）有限公司 一种绝缘粉末涂料组合物及其涂层

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CA1014645A (en) * 1973-12-10 1977-07-26 Whitney H. Mears Method and apparatus for cooling and insulating electrical equipment
GB2274337B (en) 1993-01-18 1996-08-07 Ecc Int Ltd Aspect ratio measurement
US6359232B1 (en) * 1996-12-19 2002-03-19 General Electric Company Electrical insulating material and stator bar formed therewith
CN1215490C (zh) * 1999-08-27 2005-08-17 株式会社日立制作所 绝缘材料和电机绕组及其制造方法
JP3712610B2 (ja) 2000-12-28 2005-11-02 ジャパンエポキシレジン株式会社 エポキシ樹脂結晶化物、硬化性組成物及び硬化物
DE102009039457A1 (de) * 2009-08-31 2011-03-03 Siemens Aktiengesellschaft Leitereinrichtung, elektrische Maschine sowie Traktionsmaschine

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US20230318384A1 (en) 2023-10-05
CN116057814A (zh) 2023-05-02
WO2022048992A1 (fr) 2022-03-10
DE102020211111A1 (de) 2022-03-03

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