Coil manufacturing process using UV transparent mica tape for main insulation

Abstract

The invention relates to a coil manufacturing process using a UV transparent mica tape for main insulation. A method for electrically insulating a metallic conductor is provided wherein the electrically insulating material represents a UV curable insulating tape comprising a resin formulation comprising at least a thermosetting resin and a dielectric insulator (both UV transparent), and a photoinitiator. In the method, the UV curable insulating tape is in a prepreg state prior to being applied to the metal conductor. Upon application of the prepreg UV curable insulating tape to a metal conductor, it can be fully cured by the use of UV radiation. Due to the characteristics of the resin formulation, the provided method not only allows for insulating metal conductors or providing major insulation, but also allows for the repair of pre-existing but damaged insulation materials.

Description

Technical Field

[0001] The present disclosure relates to a method of insulating, particularly metallic conductors, using UV curable insulating tape. Background Art

[0002] Proper insulation, especially primary insulation, is one of the key features required to ensure the functionality of an electric machine and avoid hazards by preventing short circuits. However, providing functional insulation can be a challenging task if the electric machine includes more than one conductive element and / or these conductive elements have a complex structure (such as, for example, coil wires or stator windings). In these cases, the conductors and / or their elements need to be insulated not only from each other but also from other components at ground potential, making primary insulation necessary.

[0003] To provide insulation for metallic conductors, especially primary insulation, there are established methods such as resin-rich (RR) or vacuum pressure impregnation (VPI). However, these methods can be very time-consuming and require high temperatures and pressures. Therefore, there is an unmet need for an insulation method that works under milder conditions and requires less time.

[0004] Once insulated, a common problem, particularly for coils, can be winding failure, which often requires rewinding the rotor or stator. However, this becomes a problem for industry because of potential downtime and associated costs associated with the associated motor. Therefore, there is another unmet need for an insulation method that can be used to quickly replace and repair damaged insulation in winding coils. Summary of the Invention

[0005] In view of the above, a method for electrically insulating a metal conductor according to claim 1 , a use according to claim 14 , and a tape according to claim 15 are provided.

[0006] The method includes providing a prepreg tape comprising a UV curable dielectric resin formulation in a semi-cured B-stage, applying the prepreg tape to a metal conductor as an electrical insulator, and fully curing the prepreg tape to a C-stage by applying UV radiation to the prepreg tape.

[0007] Further advantages, features, aspects and details which can be combined with the embodiments described herein are apparent from the dependent claims, the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The following is a detailed description with reference to the accompanying drawings, in which:

[0009] Figure 1 is a flow chart of a method for electrically insulating a metal conductor according to an embodiment of the present disclosure.

[0010] Figures 2a to 2c Possible embodiments for an insulating tape in the sense of the present disclosure are shown.

[0011] Figures 3a to 3c Possible embodiments for providing insulation for metallic conductors in the sense of the present disclosure are shown.

[0012] Figures 4a to 4b A possible embodiment in the sense of the present disclosure for removing air and / or excess resin from an insulating tape applied to a metal conductor is shown. DETAILED DESCRIPTION

[0013] Reference will now be made in detail to various embodiments, one or more examples of which are shown in each of the figures. Each example is provided by way of explanation and is not intended to be limiting. For example, features shown or described as part of one embodiment or aspect may be used in or combined with any other embodiment or aspect to produce yet another embodiment or aspect. This disclosure is intended to encompass such modifications and variations.

[0014] In one embodiment, Figure 1 As shown in the flowchart in , the method for electrically insulating a metal conductor includes providing a prepreg tape including a UV-curable dielectric resin formulation in a semi-cured B-stage (S02), applying the prepreg tape as electrical insulation to the metal conductor (S04), and fully curing the prepreg tape by applying UV radiation to the prepreg tape (S06).

[0015] In another embodiment, a method of electrically insulating a metal conductor includes providing a prepreg tape including a UV-curable dielectric resin formulation in a semi-cured B-stage (S02), applying the prepreg tape to the metal conductor as electrical insulation to ground (S04), and fully curing the prepreg tape by applying UV radiation to the prepreg tape (S06).

[0016] Without departing from the scope of the present disclosure, the method may include further steps (S02A, S04A):

[0017] In one embodiment, the method includes, for example, step S02A, at least partially removing pre-existing damaged insulation of the metal conductor at and / or around locations where the pre-existing damaged insulation of the metal conductor has been at least partially removed (S04) before applying insulation to the metal conductor.

[0018] In another embodiment, the method further includes, for example, step S04A, a customized time span between applying the prepreg tape to the metal conductor ( S04 ) and fully curing the prepreg tape ( S06 ).

[0019] Additionally and / or alternatively, one of the additional steps (S04A) may involve removing air that is sealed during and / or for a custom time span after the prepreg tape is applied as electrical insulation to the metal conductor. Additionally and / or alternatively, one of the steps (S04A) may involve removing excess resin that may be required prior to fully curing the prepreg tape by applying UV radiation to the prepreg tape (S06).

[0020] To this end, another embodiment of the method according to the present disclosure involves applying high-frequency vibration to the metal conductor to which the prepreg tape has been applied. The frequency can be selected from a high-frequency range. Preferably, the frequency can be at least 15 kHz and at most 60 kHz, more preferably at least 20 kHz, and even more preferably 25 kHz and / or at most 45 kHz.

[0021] In another embodiment, the method further comprises applying pressure to the metal conductor to which the prepreg tape has been applied. The pressure may be selected to be greater than or equal to 1 atmosphere (atm). The pressure may be selected to be less than 1 atmosphere (atm). If high frequency vibration is not applied to the metal conductor, the pressure may be as low as 100 to 500 millibars (mbar).

[0022] High frequency vibrations and / or pressure may be applied via, for example, a (compressible) UV transparent mould or a shrink tape.

[0023] While the foregoing is directed to embodiments, other and further embodiments may be devised without departing from the basic scope as defined by the claims.

[0024] Next, general aspects of the present invention are described. Unless otherwise stated, each aspect can be combined with any other aspect or embodiment:

[0025] According to a first aspect, a UV curable dielectric resin formulation includes a thermosetting resin and a dielectric insulator, both of which are UV transparent, and a photoinitiator.

[0026] According to a second aspect, the method according to the present disclosure may be used to provide primary insulation for a metallic conductor.

[0027] An advantage of an embodiment is that the curing process for obtaining a B-stage insulation tape and / or for obtaining a C-stage insulation tape can be performed under milder conditions and in a shorter time than required by other insulation methods (eg, the RR process).

[0028] According to a third aspect, a customizable time span can occur after the prepreg tape is applied to the metal conductor. The metal conductor can be wrapped with the prepreg tape, but full curing of the tape is not necessary immediately prior to applying the prepreg tape to the metal conductor. Thus, another advantage of the method according to the present disclosure may be that damage to the metal conductor's insulation, which could occur, for example, during transportation of the metal conductor to its destination, can be avoided.

[0029] Embodiments are also directed to properties of the UV curable insulation tape, such as, for example, its composition, instant cure properties, or the structural organization of the insulation tape. The instant cure properties may be advantageous for repairing existing insulation, such as for winding coils.

[0030]

Coil

[0031] One aspect of the present invention is a metal conductor to be insulated. As the metal conductor, a single or multiple conductors can be used. The metal conductor can be arranged, for example, in a layered, bundled, coiled or wired structure. According to one aspect, the metal conductor is a coil. The coil can be preformed. If the coil is to be insulated using any method according to the present disclosure, the rated voltage of the coil can be at least 200 volts (V) and at most 15 kilovolts (kV). The insulation according to one aspect of the present invention can be the main insulation of the metal conductor (such as, for example, a coil). To this end, the metal conductor can already be provided with inter-winding insulation, and the insulation of the metal conductor can be the application of the main insulation to an insulator that has already been provided with inter-winding insulation. More generally, the metal conductor can already be provided with an insulating layer. In an alternative embodiment, the metal conductor can be provided as a bare conductor without any insulating layer thereon.

[0032]

Resin formula

[0033] According to one aspect of the present disclosure, a UV-curable dielectric resin formulation includes a UV-transparent resin, such as a polyester, vinyl ester, or epoxy resin. Furthermore, the UV-curable dielectric resin formulation includes a photoinitiator, such as, for example, Irgacure 819, in an amount up to 10 wt.%, preferably between 5 wt.% and 10 wt.%. The UV-curable dielectric resin formulation also includes a UV-transparent dielectric insulator, such as fluorophlogopite, in an amount up to 20 wt.%.

[0034]

Insulating tape

[0035] Figures 2a to 2c Possible embodiments for an insulation tape in the sense of the present disclosure are depicted. According to one embodiment, the insulation tape comprises a matrix of an insulation material (200), such as, for example, fiberglass, carrying a UV curable dielectric resin formulation (202; Figure 2aThe UV-curable dielectric resin formulation (202) may include at least a UV-transparent thermosetting resin (204), a UV-transparent dielectric insulator (206), and a photoinitiator (208). The matrix material may be woven or layered regularly or irregularly to incorporate spaces for carrying the UV-curable dielectric resin formulation. If glass fiber is selected as the matrix material, the type of glass fiber fabric may be, for example, a warp-knitted stitched mat, a lattice-stitched mat, or a lattice-stitched mat.

[0036] In another embodiment, the UV curable dielectric resin formulation (202) is applied to a film-like material (210; Figure 2b In another embodiment, the UV curable dielectric resin formulation may be sandwiched between two film-like materials (210, 212; Figure 2c )between.

[0037] By combining a UV-curable dielectric resin formulation with a fiber or film-like material in specific ratios, the final thickness of the insulating tape can be tailored to the intended application. Preferably, the ratio of resin to fiber or film-like material can be selected from 25% / 75% to 50% / 50%. In addition to the final thickness, the ratio of resin to fiber or film-like material can also affect the instant cure characteristics of the resulting insulating tape. In one embodiment, the UV-curable insulating tape exhibits instant cure characteristics. The tape's ability to instantly cure can be beneficial for insulating, for example, coil winding as described in accordance with any of the methods of the present disclosure.

[0038] As far as the properties of the insulating tape are concerned, three stages can be distinguished. The uncured stage can refer to all conditions of the insulating tape once it is obtained and before further processing (e.g. exposure to UV radiation). The prepreg stage or B-stage can be achieved by applying UV radiation to the insulating tape in the uncured stage. The B-stage insulating tape can be described as having a degree of cure completion of between 30% and 70%, preferably 50%. This can be achieved by applying UV radiation with a power of 250 to 400 watts (W) to the uncured insulating tape. Depending on the inherent properties of the insulating tape (such as, for example, its thickness) and the power of the UV radiation, achieving the B-stage insulating tape by exposing the uncured insulating tape to UV radiation may take less than 100 seconds (s), preferably less than 50 seconds (s), more preferably less than 25 seconds (s), but at least 10 seconds (s).

[0039] Once the tape reaches the B-stage, it may still be tacky. This tackiness of the prepreg tape is important for its ability to be applied intact to the metal conductor. To maintain its properties, the prepreg tape may need to be covered with a passivating and / or inert foil-like material, such as, for example, a synthetic polymer or aluminum. In particular, the use of a covering material may be necessary if the prepreg tape is to be transported, stored, or used in any other manner prior to being applied to the metal conductor and / or reaching a fully cured stage.

[0040] It will be appreciated that the covering material is impermeable to any UV radiation, which could unexpectedly harden or otherwise alter the prepreg tape. In addition to protecting against UV radiation, the covering material is selected to prevent any damage caused by dust or other influences that may be encountered during transport, storage, use, or handling of the prepreg tape. Preferably, the covering material is also selected to possess a degree of flexibility that allows the covered prepreg tape to be rolled out and / or applied intact to the metal conductor to be insulated.

[0041] Finally, in accordance with the present disclosure, a C-stage or fully cured stage is achieved by applying UV radiation having a power of 250 to 400 watts (W) to the prepreg tape until at least 80% cure completion is achieved. Depending on the inherent characteristics of the prepreg tape (such as, for example, its thickness) and the power of the UV radiation, achieving a C-staged tape by exposing the B-staged tape to UV radiation may require less than 50 minutes, preferably less than 30 minutes, more preferably less than 10 minutes, but at least 5 minutes.

[0042] In one embodiment, B-staging is performed under standard conditions starting with an uncured tape by applying UV radiation to the uncured tape as described above. In another embodiment, C-staging is performed under standard conditions starting with an uncured tape by applying UV radiation to the B-stage tape as described above. In another embodiment, B-staging is performed under standard conditions starting with an uncured tape by applying UV radiation to the uncured tape as described above, and C-staging is performed under standard conditions starting with an uncured tape by applying UV radiation to the B-stage tape as described above. Note that "standard conditions" herein refer to normal temperature (293.5 Kelvin) and normal pressure (1 atmosphere).

[0043] [Time span]

[0044] According to one aspect, there may be a customizable time span between applying the prepreg UV curable dielectric insulation tape to the metal conductor and fully curing the prepreg tape by applying UV radiation to the prepreg tape.

[0045] This custom time span can be selected based on the specific circumstances. For example, the custom time span can be the time it takes to prepare the prepreg tape for full curing (e.g., to provide the necessary tools). Such a time span may occur, for example, if the method for electrically insulating a metal conductor according to the present disclosure is performed on-site. In this context, "on-site" means that the prepreg tape (UV-curable dielectric insulation tape) can be applied to the metal conductor and then fully cured directly (e.g., immediately).

[0046] Alternatively, the custom time span may also be an interruption that may be caused by the fact that the application of the prepreg tape to the metal conductor is not performed at the same location as the complete curing of the prepreg tape. For example, if the prepreg tape is applied to the metal conductor in, for example, a centralized workshop, while the complete curing can be performed elsewhere, the custom time span may include the time to transport the metal conductor to which the prepreg tape is applied.

[0047]

Completion of curing of prepreg tape

[0048] According to one aspect, the insulating tape can be described by the degree of completion of curing. Within the scope of the present disclosure, the curing progress should be understood as the degree to which the curing of the material is complete. The degree of curing completion can be obtained by comparing the insulating material at different stages.

[0049] The degree of curing completion can be described by the integral of the UV radiation power absorbed by the tape during the time the tape is exposed to UV radiation. The degree of curing completion can be expressed as the current integrated power as a percentage of the total integrated power at the end of the process. Thus, the degree of curing completion can be determined by comparing a partially cured tape (such as, for example, a B-stage tape) with a fully cured tape, with the value for the fully cured tape being considered the maximum.

[0050] Additionally and / or alternatively, the degree of completeness of the cure may be described by the degree of cure.

[0051] In one embodiment, the degree of cure is determined by differential scanning calorimetry (DSC). For example, a DSC scan of a partially cured tape (such as, for example, a B-stage tape) can be compared to a DSC scan of a freshly mixed, uncured tape material. The ratio of the heat flows generated can then provide an indication of the degree of cure completion.

[0052] In another embodiment, the degree of cure is determined by measuring the glass transition temperature (Tg), for example, via DSC. The Tg of a partially cured tape (e.g., a B-stage tape) can then be compared to the Tg of a fully cured tape. The Tg of the fully cured tape is considered a maximum, and the Tg of the partially cured tape compared to the maximum can provide an indication of the degree of cure completion.

[0053] Additionally and / or alternatively, the degree of completeness of curing may be described by the degree of cross-linking or cross-link density.

[0054] In one embodiment, the degree of crosslinking or crosslink density is determined by an expansion test. For the purposes of this disclosure, a crosslinked sample can be embedded in a suitable solvent at a specific temperature, and the change in mass and / or volume can then be measured. Within the scope of this disclosure, standards ASTM D2765 and ASTM F2214 are considered suitable for determining the degree of crosslinking or crosslink density. For example, expansion tests can be performed on partially cured tape (e.g., B-stage tape) and fully cured tape. The corresponding crosslink density or degree of crosslinking can then be calculated from these expansion tests, and this comparison can provide an indication of the degree of cure completion. Alternatively, since an increase in the degree of crosslinking or crosslink density in a sample results in less expansion, the degree of cure completion can be approximated by directly comparing the expansion of partially and fully cured tapes. Expansion can be linearly related to the degree of cure completion, such that if an expansion test shows that the B-stage tape expands by x% compared to the C-stage tape, the B-stage tape may be x% cure complete (expansion is the additional expansion relative to the uncured tape and can be positive or negative). For example, if the expansion test shows that the B-stage tape expands 50% as much as the C-stage tape, the B-stage tape may be 50% cured.

[0055] In another embodiment, the crosslink density or degree of crosslinking is determined by dynamic mechanical analysis (DMA) or by using a rheometer. For example, a dynamic temperature ramp test can be run on a partially cured insulation tape (e.g., a B-stage insulation tape) and a fully cured insulation tape to determine the storage modulus. From the rubbery plateau, the crosslink density can be calculated separately. The degree of curing completion can then be determined by comparing the crosslink density or degree of crosslinking of the partially cured and fully cured insulation tapes.

[0056] It may be desirable to use additional and / or alternative methods to those described above, for example, during a service operation (such as, for example, in a centralized shop or repair shop), or if the UV curable dielectric tape is applied "on-site." In the context of the present disclosure, these methods may be those of the following methods.

[0057] In one embodiment, the degree of cure completion can be determined by dielectric measurements. For example, the frequency response of the losses in the real and imaginary parts of the dielectric constant can be plotted versus frequency. Comparing the results for a partially cured tape (such as a B-stage tape) with a fully cured tape can then provide an indication of the degree of cure completion.

[0058] In another embodiment, the degree of cure completion can be determined by ultrasonic measurement. For example, ultrasonic waves can be applied to a partially cured tape (e.g., Class B tape) and a fully cured tape, and the velocity and attenuation of the ultrasonic waves can be measured. The degree of cure completion can then be determined by comparing the values ​​for the fully cured and partially cured tapes.

[0059] In another embodiment, the degree of completion of the cure can be determined by spectroscopic measurements such as, for example, FTIR or Raman spectroscopy. These spectroscopic measurements can be performed by handheld devices known to those skilled in the art that can be connected to a device such as, for example, a mobile phone. The degree of cure can be determined by comparing the results of a partially cured tape (e.g., a B-stage tape) with the results of a fully cured tape.

[0060]

Application of prepreg tape: UV transparent mold, winding structure

[0061] According to one aspect of the present invention, the prepreg UV curable insulation tape may be wrapped around the metal conductor one or more times. Figures 3a to 3c A possible embodiment of a UV curable insulating tape (302) or UV curable insulating foil (304) wrapped around a metal conductor (300) is shown. The metal conductor may have pre-existing insulation (306), which can be supplemented by, for example, applying the UV curable insulating tape (302) after removing the damaged portion (such as, for example, in step S02A).

[0062] Once the insulating tape applied to the metal conductor is fully cured, the slot corona protection can be applied. The slot corona protection can also be a UV curable material. In one embodiment, the slot corona protection is applied after the insulating tape applied to the metal conductor is fully cured (e.g., in situ). In another embodiment, the slot corona protection is applied after the insulating tape applied to the metal conductor is fully cured, but before the now insulated metal conductor is inserted into its desired location for use.

[0063] According to another aspect, the metal conductor (onto which the prepreg tape may be applied) can be placed in a UV-transparent mold. The UV-transparent mold can help shape the metal conductor into its final geometry. Its material does not have to withstand the high pressures typically used in conventional RR processes. Preferably, the UV-transparent mold is made of PMMA.

[0064]

Remove excess resin and / or trapped air

[0065] According to another aspect, excess resin and / or air encapsulated in the insulation provided by the prepreg tapes in the sense of the present disclosure can be removed by applying pressure. The applied pressure can be selected to be greater than or equal to 1 atmosphere (atm), or less than 1 atmosphere (atm). Additionally and / or alternatively, excess resin and / or air encapsulated in the insulation provided by the prepreg tapes in the sense of the present disclosure can be removed by applying vibration. The applied vibration can be selected to have a high frequency, preferably 15 to 60 kilohertz (kHz), more preferably 20 to 45 kilohertz (kHz).

[0066] Figure 4a Shown is the use of a UV transparent mold (400A) having an upper half (402A) and a lower half (404A) to cure a B-stage insulating tape (406) on a metal conductor (408) with UV irradiation by means of a radiation source (410), and applying high frequency vibrations by means of a vibration generator (412) and / or pressure by means of a pressure pump (414).

[0067] In such embodiments, excess resin and air trapped in the insulation provided by the prepreg tapes in the sense of the present disclosure may be removed by applying high frequency vibrations between 20 kHz and 45 kHz and pressures between 100 and 500 mbar.

[0068] Figure 4b Shown is the use of a compressible UV transparent mold (400B) having an upper half (402B) and a lower half (404B) to cure a B-stage insulating tape (406) on a metal conductor (408) with UV irradiation by means of a radiation source (410), and applying high frequency vibrations by means of a vibration generator (412) and / or applying pressure by means of a hydraulic press (416) with a clamp (418).

[0069] In such an embodiment, excess resin and air trapped in the insulation provided by the prepreg tapes of the present disclosure may be removed by applying high frequency vibrations between 20 kHz and 45 kHz and pressures above 1 atm.

[0070] UV radiation

[0071] According to the present invention, UV radiation can be used to cure a UV-curable dielectric resin formulation. For example, to achieve the C-stage of a UV-curable dielectric tape, the UV radiation can be selected such that the intensity of the UV light wavelength allows for the complete curing process. The present disclosure contemplates that the UV radiation interacts with the photoinitiator in the UV-curable resin formulation in the dielectric tape, activating the chemical cross-reactions necessary for curing.

[0072] In one embodiment, the UV radiation is emitted by a portable UV lamp. The use of a portable UV lamp can facilitate the curing process and adapt it to the requirements imposed by the metal conductor being insulated by any of the methods claimed herein. In this context, "integrated" should be understood as referring to the structural and / or spatial conditions defined by the location of use of the metal conductor. The location of use can be, for example, a motor to which the metal conductor belongs or into which it can be inserted.

[0073] In the context of UV radiation, it should also be mentioned that the UV transparency of the prepreg insulating tape, which can be applied to the metal conductor as described in any of the methods of the present disclosure, is at least 75% and / or at most 90%. The UV transparency is preferably defined with respect to UV radiation in the wavelength range between 300 nm and 420 nm and / or with a power between 250 Watts (W) and 400 W.

[0074] List of reference numerals

[0075] 200 Matrix material

[0076] 202 UV curable dielectric resin formula

[0077] 204 UV transparent thermosetting resin

[0078] 206 UV Transparent Dielectric Insulator

[0079] 208 photoinitiator

[0080] 210, 212 film-like materials

[0081] 302 UV curable insulation tape

[0082] 304 UV curable insulation foil

[0083] 300, 408 metal conductors

[0084] 306 Pre-existing insulation of metal conductors

[0085] 400A, B (compressible) UV transparent mold

[0086] 402A, B (compressible) UV transparent mold upper part

[0087] 404A, B (compressible) UV transparent mold lower half

[0088] 406 B-stage, UV curable insulation tape

[0089] 410 UV radiation source

[0090] 412 Vibration Generator

[0091] 414 Pressure Pump

[0092] 416 hydraulic press

[0093] 418 clamp.

Claims

1. A method for electrically insulating a metal conductor, the method comprising: providing a prepreg tape comprising a UV curable dielectric resin formulation in a semi-cured B-stage, applying the prepreg tape as electrical insulation to the metal conductor, and Fully curing the prepreg tape to a C-stage by applying UV radiation to the prepreg tape; The step of providing a prepreg tape comprises partially curing the prepreg tape from an uncured stage to the B-stage by applying UV radiation having a power of 250W to 400W and achieving a cure completion of less than 70% but at least 30%.

2. The method according to claim 1, wherein The UV curable dielectric resin formulation includes: UV transparent thermosetting resin, Photoinitiators, and UV transparent dielectric insulator.

3. The method according to claim 1 or 2, wherein The step of providing a prepreg tape comprises partially curing the tape from an uncured stage to said B-stage by applying UV radiation having a power of 250W to 400W and achieving a cure completion of less than 70% but at least 30%.

4. The method according to claim 1 or 2, wherein The step of fully curing the prepreg tape includes applying UV radiation at a power of 250W to 400W to the prepreg tape until the curing completion reaches at least 80%.

5. The method according to claim 1 or 2, wherein The step of fully curing the prepreg tape is performed at room temperature and / or 1 atmosphere.

6. The method according to claim 1 or 2, comprising: Pressure is applied to the metal conductor to which the prepreg tape has been applied.

7. The method according to claim 1 or 2, wherein The UV transparency of the prepreg tape in the wavelength range between 300 nm and 420 nm is at least 75% and / or at most 90%.

8. The method according to claim 1 or 2, wherein The metallic conductor is a coil having a rated voltage of at least 200 V and at most 15 kV.

9. The method of claim 8, comprising applying the prepreg tape as primary insulation to the coil.

10. The method according to claim 1 or 2, wherein Before applying the prepreg tape, the metal conductors are placed in a UV transparent mold.

11. The method according to claim 1 or 2, further comprising extracting air trapped in the prepreg tape applied to the metal conductor via the UV transparent mold by applying a pressure below 1 atmosphere and by applying frequency vibrations of at least 20 kHz and / or at most 45 kHz to the prepreg tape before the final curing step.

12. A method of producing an electrically insulated metallic conductor, the method comprising providing a metallic conductor, and electrically insulating the metallic conductor by a method according to any one of claims 1 to 11, wherein the prepreg tape is provided as primary insulation.

13. A method of repairing pre-existing insulation of a metallic conductor, said pre-existing insulation having a damaged insulation segment, said method comprising: at least partially removing the damaged insulation segment; as well as The metallic conductor is electrically insulated by a method according to any one of claims 1 to 11, the method comprising applying the prepreg tape to the region of the damaged insulation section.

14. Use of an electrically insulating prepreg tape comprising a UV curable dielectric resin formulation in a semi-cured B-stage for a method according to any one of claims 1 to 13.

15. An electrically insulating prepreg tape comprising a UV curable dielectric resin formulation in a semi-cured B-stage and configured for electrically insulating a metal conductor according to the method of any one of claims 1 to 11.

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