Line element with insulation, and production method therefor
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-02-03
- Publication Date
- 2026-08-13
Smart Images
Figure EP2026052758_13082026_PF_FP_ABST
Abstract
Description
[0001] 202500487
[0002] 1
[0003] Description
[0004] Conductor element with insulation and manufacturing process thereof
[0005] The invention relates to an electric rotating machine, such as an electric traction motor and / or an electric industrial motor with an improved insulation system for the conductor elements, and to a method for producing insulation for a conductor element. In particular, the invention relates to the insulation of a laminated core of an electric rotating machine, as well as the insulation of all electrically conductive elements, sub-elements and / or connecting pieces, for example also at the end face of the laminated core.
[0006] Technical field
[0007] Electric rotating machines in the medium and high voltage range, such as electric motors and / or electric generators, are well-known. These machines are characterized by a wide variety of designs and applications. They are used in all areas of technology, industry, everyday life, transportation, medicine, and other fields. The power range of electric machines extends from orders of magnitude below one microwatt, for example in microsystems technology, to well over one gigawatt, i.e., one thousand times one million watts, as in the power plant sector. Between these two extremes lies the medium-voltage application with traction and drive motors in the automotive and rail vehicle sectors, etc., starting at a rated voltage of approximately 700 V, which is the focus of this discussion.
[0008] Increasingly powerful electric rotating machines are being developed, as advancing technology demands ever higher power densities. A high-performance motor and / or generator, in particular, has a stator with a stator lamination stack and a number of slots in which the conductor, usually in the form of a winding, and thus also the insulation or insulation system, are located.
[0009] All electrically rotating machines have in common conductive elements such as the winding head, circuitry (e.g., in the form of a switching ring), flat copper wire for the winding (e.g., also in hairpin technology), and / or wire coils through which electric current flows. For electrical insulation of the current-carrying components...202500487
[0010] 2
[0011] Electrical machines have at least simple insulation or complete insulation systems between conductor elements and between them and the external environment.
[0012] Technical background
[0013] Rotating electric machines, such as electric motors and generators with a rated voltage of 700 V or higher, comprise a rotor surrounded by a stator. The stator has a laminated core with slots into which the electrical conductors, in the form of coils or individual bars welded or soldered together, are inserted. Two corresponding individual bars can be soldered together to form a coil. The electrical conductors within the coil are insulated from each other. The coil is additionally insulated with a main layer of mica-containing insulating tape and, optionally depending on the voltage level, with a conductive glow plug, in particular an external and / or end glow plug, so that the surface of the coil is at the same potential as the laminated core.This construction is also called an "ordered" winding, in contrast to electrical rotating machines with wires in a "wild" winding, which generally refers to electrical rotating machines with a rated voltage of less than 700 volts.
[0014] In electric rotating machines operating in the high and / or medium voltage range, coils are made up of conductor sections insulated from each other, for example, by winding and / or enamel coating. These coils are formed from blanks, such as a coil core, by drawing and twisting so that they can be inserted into the slots of a stator body, i.e., into the laminated core of the electric motor. The coils are connected to each other via so-called winding heads and contacted by appropriate terminals.
[0015] The current-carrying coils are insulated from each other, from the laminated core, and finally from the environment by an insulation system. This insulation system typically includes the main insulation, which is a pure insulator, and the glow-protection system, which comprises external glow protection and / or end-glow protection components. Glow protection is generally made of the same material as the main insulation but also exhibits low electrical conductivity for improved partial discharge resistance. 202500487
[0016] 3
[0017] The live coil is largely insulated from the grounded laminated core by the main insulation made of polymer-based materials. To extract maximum power from the machine, it is operated at the highest possible current densities, which, however, also results in significant heat losses.
[0018] For large electric motors, the maximum typical operating temperature is approximately 155°C. For these operating temperatures, it is common practice to use an insulation system made of mica tape and epoxy-based plastics. The motor is designed so that the maximum temperature rise – including that of the insulation – does not exceed 155°C, or only does so negligibly.
[0019] To increase the power density of such a machine, either the voltage or the current is increased. If the voltage were increased, a higher electric field strength would have to be continuously dissipated via the insulation system. Conventional epoxy-based insulation systems are not designed for this.
[0020] If the current is increased, the insulation system is subjected to greater thermal stress, at least briefly even exceeding 200°C. For this purpose, insulation systems made from materials based on mAramid and / or polyesterimide are used.
[0021] Currently, in rotating electrical machines, such as traction motors and industrial motors, the winding head is insulated with the same insulating tape used in the slot of the active part. In the conventional impregnation process, the winding head is therefore impregnated with the same winding tape and impregnating resin and then cured as the active part.
[0022] Winding the winding head is time-consuming and therefore also expensive. The impregnation process with resin, which has been required until now, is also time-consuming and expensive. For example, insulating the winding head of a traction motor requires up to 20 minutes of pure working time for processing.
[0023] The field strengths present in the winding head during operation are many times lower than in the active part and are less than 500 V / mm in the wound insulation itself. Partial discharges cannot occur there during operation. Nevertheless, according to the state of the art, the winding head is insulated like the active part because separating the insulation production between the active part and the winding head would be much more complex. 202500487
[0024] 4
[0025] Winding head insulation primarily ensures a dielectric barrier and prevents phase flashovers and / or ground faults in the event of contamination. Since the winding head design is generally partial discharge-free, the winding head insulation does not require increased resistance to partial discharges, but it must possess a certain minimum dielectric strength. This is particularly important for traction motors with an insulation temperature resistance exceeding 200°C, corresponding to thermal class 200. Examples of such "traction motors" include traction motors used in railway applications with a rated power output of 40 to 2000 kW.
[0026] During the operation of an electric rotating machine, high voltages are generated. These voltages are dissipated through the insulation system in the insulating volume between the high-voltage conductor element and the laminated core at ground potential. This process creates, for example, field peaks at the edges of the laminations within the core, which in turn cause partial discharges. When these partial discharges encounter the insulation system, they cause localized, intense heating and damage the surface through chemical reduction reactions. The organic components of the insulation system are regularly damaged in this process, decomposing into increasingly smaller molecular units until volatile products, such as CO2, are formed and the insulation ultimately fails.
[0027] To extract maximum performance from a machine, it is operated at the highest possible current densities, which, however, also results in significant losses in the form of heat. Traction motors, for example, are operated at high temperatures. The typical organic components of polymers used in insulation systems are generally high-performance polymers, which are elaborately applied in the form of films and / or tapes wrapped around the conductors. These are limited to a few polymer types, each with its own advantages and disadvantages.
[0028] Traditionally, mAramid and / or polyimide in the form of, for example, Kapton, a poly(4,4'-oxydiphenylene-promellitimide), are mostly used here because they combine high thermal stability with good electrical insulation properties, thus increasing the service life and reliability of the motors.
[0029] The main insulation of the winding, based on epoxy resin-impregnated winding tape, especially mica tape, provides shielding of the live conductor, up to the high-voltage conductor element, usually copper conductors, against the 202500487
[0030] 5
[0031] grounded stator. The main insulation has a high partial discharge inception voltage, so that it can, for example, permanently dissipate up to 3.5 kV per millimeter.
[0032] The essential elements of a fully insulated winding, viewed from the inside out, are first the conductors, especially copper conductors, i.e. the electrical coil, which are pressed together to form rods, if necessary an internal potential control applied to the rods, IPS, the main insulation and on top of that the external glow protection AGS and, if necessary, depending on the rated voltage, an end glow protection EGS.
[0033] To increase the power density of motors, the voltage and / or current is increased. However, neither of these would be possible with currently available organic components of insulation systems. An increase in current tends to lead to higher thermal stress, whereas an increase in voltage leads to higher field strengths that must be dissipated between the coil and the laminated core by the insulation system. Both types of increased stress resulting from higher power density would lead to a shorter service life and reduced reliability with currently common organic components of the insulation system.
[0034] Components of the insulation system, such as IPS, main insulation, AGS, and EGS, are currently typically wound onto the spool as tapes, with some parts, like the EGS, being applied manually. The other components cannot be applied automatically because either the quantity makes automation uneconomical and / or the risk of air entrapment in the folds prevents the required winding quality. Tapes used for the main insulation are generally laminates of mica paper and carrier substrates. However, the state of the art generally consists exclusively of winding tapes made of bonded mica paper, which serve to lengthen the erosion path within the insulation system—that is, the direct path from the high-voltage side, i.e., the conductor elements, to the grounded laminated core—resulting in a significantly longer service life for the insulation system.
[0035] 6
[0036] Summary of the invention
[0037] The object of the present invention is to provide an insulation material that meets the thermal requirements of an insulation system of thermal class 200 or even 220 °C, whereby it would be particularly advantageous if the insulation material could also be applied automatically to the conductor element, such as the winding head.
[0038] Accordingly, the invention relates to a conductor element such as a winding head, a circuit and / or a wire of an electrical rotating machine with a rated voltage greater than 700 V, which has insulation that can be applied as a powder coating, wherein the powder coating formulation used comprises a polyimide and a filler in the form of an oxide and / or nitride.
[0039] Furthermore, the invention relates to a method for producing insulation for a conductor element of an electrical rotating machine by powder coating with a powder coating formulation as described above, wherein a corona and / or fluidized bed process is used, in which the powder coating formulation is first fluidized in an upward flowing gas stream, thereby forming a fluidized bed and subsequently the conductor element is immersed in the fluidized bed.
[0040] Embodiments of the invention
[0041] Powder coating formulations or powder coating recipes generally consist of binders, processing aids, fillers, and additives. Synthetic resins, which act as binders, form the main component. For example, these synthetic resins are polyimides, particularly bismaleimide, such as derivatives of biscitraconimide, whose structural formula is shown in Figure 1.
[0042] Other possible polyimide-containing binders include, for example, bisallyl nadicimide, 1,4-phenylene bismaleimide, 4,4'-diphenylmethane bismaleimide, polyphenylmethane bismaleimide, and / or 2,4-(bismaleimido)-toluene, which are used, for example, also with biscitraconimide, individually or as any mixtures, copolymers, and / or blends in powder coating formulations.
[0043] 7
[0044] The polyimide used as a binder in the powder coating formulation is also present, for example, in a mixture with a siloxane. Likewise, the polyimide in the binder can also be present as a copolymer with another carbon-based or silicon-based polymer.
[0045] According to another exemplary embodiment, the polyimide in the powder coating formulation is present in 50 to 100 parts by mass, i.e. as the main component and up to 100%, of the binder.
[0046] These powder coating formulations, with polyimide as the main component, offer high insulation properties, high temperature resistance, and are solvent-free and free of heavy metals, making them environmentally friendly and sustainable. Due to the high material efficiency achieved through material recovery during the processing of a powder coating formulation, resources are conserved in the powder coating process. Technical processing is carried out either by powder coating at thicknesses of 5 µm to 500 µm, preferably at thicknesses of 150 µm to 400 µm, and / or by corona and / or tribo coating systems at suitable curing temperatures.
[0047] According to another exemplary embodiment of the invention, the binder comprises a polyimide with a fully conjugated backbone.
[0048] The term "through-conjugable" refers to the electronic structure and bonding in a polymer. Through-conjugable polymers have a continuous chain of conjugated double bonds and / or heteroatoms with a lone pair of electrons in the polymer backbone. This allows the so-called "TT" electrons to move delocally throughout the entire polymer chain. This influences the polymer's properties and its suitability for various technical applications.
[0049] According to a further exemplary embodiment of the invention, the binder comprises a polyimide with a backbone that is at least partially non-conjugated.
[0050] However, a high proportion of delocalized TT electrons is generally desired because this is good for the temperature resistance of the insulation system.
[0051] In addition to the classic copper conductor elements, such as those found in the winding in the slots of the laminated core, the term "conducting element" also includes contact and connection-202500487
[0052] 8
[0053] Conducting elements, such as winding head, motor winding circuit and / or for all types of connection points of the winding wires, such as flat wires, for example copper and / or aluminum flat wires, these also understood as part of a hairpin construction, an electrical rotating machine.
[0054] According to another exemplary embodiment, thermally conductive oxides and nitrides, for example metal oxides such as titanium oxide, aluminum oxide, manganese oxide, chromium oxide and / or nitrides, such as boron nitride, are used as fillers.
[0055] Fillers can be used monomodally or multimodally, i.e., in different fractions. For example, the filler fractions differ in particle size, particle shape, material, structure – e.g., core-shell particles – and / or in surface properties, such as coating and / or surface treatment by polarization.
[0056] The proposed powder coating eliminates the need for the complex winding process with mica-containing tapes when insulating the conductor elements. Furthermore, the costly and time-consuming impregnation process with impregnating resin and epoxy resin can be avoided. For example, an insulation system as claimed here requires no epoxy resin at all if the powder coating formulation, as provided in an exemplary embodiment of the invention, contains 100 parts by mass of polyimide as a binder.
[0057] Exemplary embodiments of the drawing
[0058] Fig. 1 shows the structural formula of an exemplary polyimide, biscitraconimide.
[0059] Fig. 2 shows the thermogravimetric analysis (TGA) for evaluating the temperature stability of biscitraconimide compared to commercially available epoxy-based powder coating formulations.
[0060] Fig. 3 shows in tabular form the composition of advantageous formulations for the powder coating formulation based on biscitraconimide.
[0061] Fig. 4 shows a further thermogravimetric analysis of the examples 1 to 3 listed in Figure 5 and reference 4.
[0062] Figure 5 shows in tabular form the composition of examples 1 to 3, which were evaluated in Figure 4.
[0063] Fig. 6 shows a test setup for evaluating partial discharge resistance and 202500487
[0064] 9
[0065] Figure 7 shows the test results from the evaluation of the tests. Figure 6 shows examples 1 to 3.
[0066] Detailed description of the exemplary implementations
[0067] Explanation of the figures
[0068] Figure 1 shows a structural formula from a section of a polymeric compound of the class of bismaleimides, biscitraconimide.
[0069] The structural formula of the basic framework of the compound can be seen, as it is used, for example, as a binder in a powder coating formulation according to an exemplary embodiment of the invention.
[0070] As shown in Figure 1
[0071] R here for
[0072] R = H, alkyl, aryl, phenyl, benzyl, toluoyl, with any heteroatom substitution and / or
[0073] R = stands for -CH2-R1, where R1 = H or an alkyl group with 1 to 18 carbon atoms. The subscript "n" after the square bracket indicates that the structural unit shown is repeated n times in the polymer.
[0074] Figure 2 shows a thermogravimetric analysis in which the mass change of a sample is measured as a function of temperature and time. This allows the temperature stability of the compound to be assessed by measuring the mass change of a solid sample, such as a powder coating formulation, during the heating process. The mass is plotted on the ordinate shown in Figure 2, starting at room temperature at 100% and decreasing with increasing temperature. Figure 2 shows a graph of various polyimides, with biscitraconimide, used in Examples 1 to 3 (see Table 5), showing the best measurement results.
[0075] The wide melting range of 70°C to 120°C provides a good starting point for the development of a powder coating formulation. After complete thermal curing, the binder achieves a glass transition temperature of up to 310°C. Temperature stability can be assessed using thermogravimetric analysis (TGA) as shown in Figure 2. The TGA performed shows that the binder biscitraconimide has a temperature index (TI) of approximately 210°C according to DiCerbo – see “DiCerbo: “Thermogravimetric202500487”.
[0076] 10
[0077] The analysis demonstrates the need for standard procedures and is therefore suitable for use in a high-temperature insulation system. Comparative measurements of commercially available epoxy-based powder coating formulations only achieve a TI of approximately...
[0078] 180°C (see also Figure 5).
[0079] Regarding fillers, different particle size fractions are used, for example, due to improved processability. Microfillers and / or nanofillers can be used, for instance.
[0080] All commercially available particle size distributions can be used for microfillers.
[0081] The amount of filler depends on the processability as a powder coating and comprises amounts of 1 to 90 parts by mass, based on the total powder coating formulation, in particular 1 to 70 parts by mass, preferably 15 to 50 parts by mass.
[0082] In particular, two or three filler fractions are used. These include a nitride, especially boron nitride "BN", and aluminum oxide "AL". The fillers can be used individually or together in various particle size distributions ("PFDs").
[0083] Examples of possible particle size distributions for 3 filler fractions:
[0084] Fraction I: d10 = 5 to 10 m
[0085] Fraction II: d10 = 20 to 50 pm
[0086] Fraction III: d10 = 60 to 80 pm
[0087] Fraction I: d10 = 10 to 20 pm
[0088] Fraction II: d10 = 30 to 70 pm
[0089] Fraction III: d10 = 100 to 150 pm
[0090] Fraction I: d10 = 0.5 to 5 pm
[0091] Fraction II: d10 = 3 to 7pm
[0092] Fraction III: d10 = 10 to 30 pm
[0093] Fraction I: d10 = 1.5 to 3 pm
[0094] Fraction II: d50 = 4.5 to 8 pm
[0095] Fraction III: d90 = 10 to 20 pm202500487
[0096] 11
[0097] For example, the filler is made of pure boron nitride in several particle sizes and different particle size distributions – fractions. Another example involves the use of metal oxides, such as aluminum oxide, and / or polymeric fillers, such as PEEK. See the compilation of powder coating formulations in Figure 3.
[0098] For example, a nitride, specifically a boron nitride with a small fraction density (SFD) of three size fractions, is used as a filler. A quantity of approximately 20 parts by mass of this filler was tested. Alternatively, a filler containing at least one aluminum oxide filler fraction was used in the powder coating formulation.
[0099] Figure 3 shows a table that displays the filler content of the individual formulations.
[0100] The recipes B1, B2 and B3 are listed in the left column.
[0101] The formulations, which are embodiments of the invention, B1, B2 and B3, have 100% biscitraconimide as a binder.
[0102] Examples B1 and B2 contain aluminum oxide as a filler at 35% by mass. B2 also contains polyetheretherketone (PEEK) as a filler at 11% by mass.
[0103] For example, B3 has boron nitride as a filler with only 20% mass fraction.
[0104] All examples contain propellant agents such as castor oil and other additives, all additives in a total quantity of less than 2% by mass.
[0105] Various additives are used. For example, rheology additives can be used to improve the film-forming properties of the powder coating formulation.
[0106] For example, a castor oil derivative was successfully tested as a process additive in amounts of 0.5 to 2 parts by mass, particularly preferably in amounts of 0.7 to 1.5 parts by mass.
[0107] Three example formulations were tested, and their temperature stability was again evaluated against a reference epoxy-based powder coating formulation, as shown in Figure 4. The results clearly show that neither filler nor additive has a noticeable influence on the temperature index. The polyimide-based biscitraconimide-containing formulations (202500487)
[0108] 12
[0109] Powder coating formulations show a significantly higher temperature index of between 208 and 211°C compared to the epoxy-containing variant, whereas the reference is only 185°C.
[0110] Figure 4 shows a thermogravimetric analysis (TGA) of exemplary embodiments of the invention B1, B2 and B3 in comparison to an epoxy-based powder coating as reference R.
[0111] It is clearly evident that the reference sample, the epoxy-based powder coating, represented in the graph by a dash-dot-dash line, has the lowest temperature stability, as the graph shows the most rapid decline. The graph also clearly shows that the non-combustible residual masses roughly correspond to the filler levels. The evaluation of the thermal stability of examples B1 to B3 shows that none of the individual components has a strong influence on the thermal instability (TI) of the powder coating formulation – see Figure 5 – as long as it is biscitraconimide-based and not epoxy-based.
[0112] Figure 5 shows again in tabular form the composition of the examples and the temperature indices TI resulting from Figure 4.
[0113] Figure 6 shows a test setup for evaluating the partial discharge resistance of specimens. Planar glass substrates were electrostatically coated with the three powder coating formulations B1, B2, and B3 to a thickness of approximately 2 mm to produce the specimens. These specimens were then subjected to controlled aging in accordance with IEC 60343. Figure 6 shows the test setup.
[0114] Figure 6 shows a Toepler test setup in detail 6 (a) and as a complete test setup 6 (b). A Toepler test setup is generally used for quality control and testing the insulation strength of high-voltage components.
[0115] The test setup for the Toepler test comprises a high-voltage electrode 1 with a cover 2, which has ventilation slots 4 and rests on a support 3. The support 3 is arranged on a test specimen 5, which is grounded, i.e., connected to a ground electrode 6.
[0116] A number of high-voltage electrode(s) 1 and test specimens 5 are mounted in an encapsulated test arrangement – see Figure 1b – as a Toepler test arrangement on a grounded grid 11. In Figure 1, four such Toepler test arrangements are grouped together. (See Figure 202500487)
[0117] 13
[0118] To perform the test, the assembly is placed in a test box 13 containing dry air or another insulating gas. The test box 13 has a gas inlet 15 and one or more gas outlets 14. An aging voltage of 10 kV was applied to the test specimens 5, which are approximately 1 to 5 mm thick (in this case, approximately 2.3 mm). The test box 13 was purged with air (50% relative humidity) for the entire aging period of 100 hours.
[0119] To assess the partial discharge resistance of the test specimens 5, an optical examination of the resulting erosion is performed using a surface profilometer, as shown in Figure 7.
[0120] Figure 7 shows the results of the Toepler test for the three examples in the order B2, B1, and B3 from left to right. Partial discharge resistance is assessed by optically observing the resulting erosion using a surface profilometer – see Figure 7.
[0121] It is clearly evident that in example B2, a certain degree of superficial damage, with a shallow depth of approximately 20 to 30 pm, has occurred. The ring-shaped damage, recognizable by the centrally located circle 6, represents the outline of the cylindrical cover of the high-voltage electrode, which rests directly on the specimen during the test setup. However, this ring-shaped damage is only visible in example B2 with the formulation biscitraconimide, containing 11% PEEK, 35% filler Al₂O₃, and 1% flow agent castor oil derivative.
[0122] The other two formulations, B1 and B3, show no damage, see Figure 7. In particular, the powder coating formulation B3 with only 20% boron nitride filler shows little damage after 100h of electrical aging in the Toepler test.
[0123] Figure 7B shows B1 still vaguely the circular outline of the earth electrode 6, however, the undamaged areas, which are shown in grey, predominate everywhere.
[0124] Completely black spots are visible that do not show damage from corrosion (i.e., decomposition of the organic components), but rather, on the contrary, a thickening of the undamaged powder coating. This thickening can be caused, for example, by surface roughness of the powder coating, agglomeration of the fillers, and / or particularly large particles in the powder coating, which are always possible in the particle size distribution. Furthermore, thickening can occur due to uneven application of the coating. (202500487)
[0125] 14
[0126] The phenomenon of "raised" powder coating is also visible in Figure 7c – Example 7C. Again, the black spots indicate areas where thickening is observed. The observable thickenings are approximately 20 µm in diameter.
[0127] To achieve uniform heat distribution and dissipation, fillers with high intrinsic thermal conductivity were used. In a powder coating formulation containing boron nitride, a thermal conductivity of up to 0.586 W / mK was measured. Aluminum-containing fillers deviate from this even at higher filler concentrations and yield poorer values, for example, 0.286 W / mK.
[0128] The proposed method of insulating electrical rotating machines with a rated voltage greater than 700V using a powder coating, either through a powder coating process or fluidized bed sintering, eliminates the need for the expensive winding tape impregnation process. This makes it possible to forgo mica tapes and, if necessary, replace all or at least some parts of the insulation system with mica-free insulation. This also allows for a shift from manual to automated coating, significantly increasing productivity.
Claims
202500487 15 Patent claims 1. Conductor element of an electrical rotating machine with a rated voltage greater than 700V, which has insulation that can be applied as a powder coating, wherein the powder coating formulation used has a polyimide as a binder and a filler in the form of an oxide and / or nitride.
2. Conductor element according to claim 1, which is a winding wire.
3. Conductor element according to claim 1, which is a winding head.
4. Conductor element according to claim 1, which is a circuit of a motor winding.
5. Conducting element according to one of claims 1 to 4, wherein the binder in the powder coating formulation is a mixture of different polyimides.
6. Conducting element according to one of the preceding claims, wherein the binder in the powder coating formulation comprises a copolymer with a bismaleimide.
7. Conducting element according to one of the preceding claims, wherein the binder in the powder coating formulation comprises biscitraconimide.
8. Conducting element according to one of the preceding claims, wherein the binder in the powder coating formulation comprises a derivative of a biscitraconimide.
9. Conducting element according to one of the preceding claims, wherein the filler in the powder coating formulation comprises several fractions.
10. Conducting element according to one of the preceding claims, wherein the filler in the powder coating formulation comprises several fractions with different particle sizes.
11. Conducting element according to one of the preceding claims, wherein the filler in the powder coating formulation is a microfiller and comprises several fractions with different particle sizes up to d90 = 10 pm to 20 p. 202500487 16 12. Conducting element according to one of the preceding claims, wherein an additive is included in the powder coating formulation.
13. Conducting element according to one of the preceding claims in which a rheology additive is included in the powder coating formulation.
14. Method for producing insulation for a conductor element with a powder coating formulation according to any one of claims 1 to 13 by a powder coating process.
15. Method for producing insulation for a conductor element with a powder coating formulation according to any one of claims 1 to 13 by fluidized bed sintering.