DE102009039457A1 - Conductor mechanism for use in e.g. electrical machine, has set of rectangular conductors braced by impregnating resin that comprises nano-particles, where impregnating resin is cyclo-aliphatic epoxy resin or silicone resin - Google Patents

Abstract

The mechanism (16) has a set of rectangular conductors (24) braced by impregnating resin that comprises nano-particles, where the impregnating resin is cyclo-aliphatic epoxy resin or silicone resin. Outer and end corona shielding devices (30, 32) are provided at a top side of the mechanism and comprised of lacquer or resin. The shielding devices are designed as bands, where the nano-particles comprise silicon dioxide, alumina, titanium oxide, sulfate, lithopone, aluminum nitride, silicon carbide or soot. The conductors are surrounded by an insulating tape (26) and formed by mica tapes (28).

Description

The invention relates to a conductor device according to the preamble of claim 1. It also relates to an electric machine and a traction machine with such a conductor device.

The invention is particularly intended for an electrical machine which is operated at high voltages. In such an electric machine measures are taken, prevented by the partial discharges or at least reduced. In particular, a complex insulation is provided, which is designed so that as few defects are given that may be the starting point of partial discharges.

For example, in electrical machines, conductors are individually surrounded with an insulating winding. Several conductors are then combined into a bundle.

The conductor bundle is z. B. wrapped with a mica tape. Such a mica tape is conventionally made by applying mica paper to a substrate by suitable means for attachment, typically adhered to the substrate.

The mica tape is then soaked by a so-called impregnating resin and coated. The impregnating resin is usually made of bisphenol-A or bisphenol-F. The impregnating resin penetrates into all intermediate spaces between the mica tape and the individual conductors and creates a firm bond after it has hardened. The impregnating resin also has an insulating effect. The present invention is based on the use of an impregnating resin, in conjunction with a mica tape or not.

In electrical machines there are sometimes very different potentials at different points. In order to prevent certain electrical phenomena, a so-called corona protection, termed "corona protection", ensures a smooth course of the potentials both in the conductor devices (in the so-called internal corona protection) and on the surface of the conductor devices. In the area of a laminated core of an electric machine, the so-called external corona protection is provided, which is to be conductive. The potentials should then drop gently in the transition from the laminated core to a free area (to air), and for this purpose a so-called end corona protection is provided, which is typically semiconducting.

In electrical machines, partial discharges may occur despite all measures to prevent defects in the insulation. This is true even if mica tapes are provided which are more resistant to such partial discharges. Partial discharges cause all components of a conductor device, as described above, to wear out and age. The entire conductor device no longer remains sufficiently mechanically stable or loses its electrical function.

Nanoparticles are particles having a length of at most 100 nm in one direction, e.g. B. spheres with a diameter of less than 100 nm.

Nanoparticles have recently found diverse applications. The technology for their production is sufficiently well developed. It is known to mix materials with nanoparticles, so embed nanoparticles in a base material. Techniques for such embedding have been developed in recent years. There are products available on the market in which nanoparticles are embedded. Such products are also referred to as "nanomodified". For example, there are nanomodified epoxy resins. In the context of nanomodification, the chemically reactive surfaces of nanoparticles are brought into contact with mediating substances, which in turn are also compatible with the base material. This makes it possible to embed the nanoparticles individually well in such a base material.

It is an object of the invention to further develop a conductor device according to the preamble of claim 1 that their insulation has as few defects as possible, so that it is permanently resistant and less rapidly by partial discharges aging than previous conductor devices of this type.

The object is achieved by a conductor device having the features according to patent claim 1. Within the scope of the invention, an electric machine and a traction machine with at least one such conductor device are also provided.

The conductor device according to the invention is thus characterized in that the impregnating resin contains nanoparticles.

It is a finding of the present inventors that nanoparticles can increase the resistance of the conductor device with the mica tape. In particular, the nanoparticles in the impregnating resin can ensure that weak spots in the mica tape do not become the starting point for damage in the mica tape. Such weaknesses exist for example at the joints of individual mica particles or due to porosity within the mica paper itself. They are in areas with reduced mica density, ie wrinkles, cracks in the mica paper, gaps due to the fabric structure of the support carrying the mica paper, etc. The nanoparticles of the impregnating resin fill in particular small gaps perfectly and increase there both the mechanical stability, and in particular the electrical Strength. As a result, the operational field strength in the production of the insulation can be increased. There is also an increased process reliability in the production of insulation.

In the manufacture of a nanomodified impregnating resin, it has been found that certain impregnating resins other than bisphenol epoxy resins are more suitable, for example a silicone resin and / or a cycloaliphatic epoxy resin.

Depending on the desired properties, which may be due to the field of application of the conductor device, a suitable impregnating resin can be selected. For example, because of their good resistance to high voltages, cycloaliphatic epoxy resins are advantageous for electrical machines, whereas silicone rubbers are used in traction machines because of their temperature resistance.

An aspect of the invention is the production of such nanomodified impregnating resins: Nanoparticles, for example of silicon dioxide or of aluminum oxide, are brought into contact with substances which contain epoxy-silane groups. These attach themselves to the chemically highly reactive surfaces of the nanoparticles. The resulting mixture of substances can then be added to a cycloaliphatic epoxy resin. Because of the Epoxisilangruppen clumping of the nanoparticles is prevented. For the preparation of a nanomodified silicone resin, the procedure is analogous, working only with vinyl silanes instead of epoxy silane groups.

Alternatively or additionally, the glow protection device of the conductor device may contain nanoparticles. If the smoldering device is made of lacquer, this can be mixed with nanoparticles. If the smoldering device is provided in the form of a band, nanoparticles may be contained in the band. A tape is typically produced by slurrying particles with the corona protection graphite particles, the end corona protection silicon carbide particles, with a resin, and applying this filled resin to a fabric or non-woven backing.

If one wants to provide the bands with nanoparticles, it is particularly appropriate to also slurry nanoparticles with the resin simultaneously with the graphite or silicon carbide particles or to add such nanoparticles before or after the resin. Likewise, however, the nanoparticles may also be provided on or in the fabric or nonwoven backing. The tape may also be a pure film material or a fabric with nanoparticles.

Oxides, for example silicon dioxide, aluminum oxide and / or titanium oxide, are particularly suitable as material for the nanoparticles; silicates, sulfates, lithopones, aluminum nitride, silicon carbide or carbon black are also suitable. The latter two components are particularly suitable for the nanoparticles in the anti-corrosive devices, all other nanoparticles especially for the impregnating resin.

Hereinafter, a preferred embodiment of the invention will be described with reference to the drawing, in which

1 shows a detail of an electrical machine with conductor devices according to the invention in a perspective view in an illustration illustrating the structure of the conductor devices.

One in total with 10 designated electrical machine has a laminated core 12 in, in the grooves 14 are formed. In the grooves 14 are in whole with 16 designated conductor devices arranged, two such conductor devices 16 per groove 14 , wherein the conductor devices 16 by supporting elements 18 are supported in the groove or on each other or such elements 18 provide a cover to which a separate degree 20 can be added. The conductor devices 16 should form coils and therefore also come out of the grooves 14 out, in one area 22 these are curved.

Each ladder device 16 consists of a plurality (shown here: 14 ) of substantially rectangular conductors 24 , This ladder 24 are from an electrical tape 26 wrapped. There are two such leaders 24 with the insulating tape 26 arranged side by side and a plurality, in the present case seven, such conductors 24 stacked. This plurality of ladders 24 with electrical tape 26 is in its entirety of mica tapes 28 wrapped. Mica tapes consist of a carrier, namely a glass fabric, a film, or a nonwoven, glued to the mica paper. To stabilize the arrangement is the mica paper 28 with the ladders wrapped in it 24 impregnated and permeated with an impregnating resin, and this impregnating resin was allowed to harden. The impregnating resin is in the 1 not recognizable as such.

Over the mica ribbons 28 with the impregnating resin is located in the region of the grooves 14 a so-called external corona protection 30 , This outer corona 30 is electrically conductive, so that is on the laminated core 12 trainee potential over the length of the ladder 24 balance out. In the area 22 the curvature goes the outer corona protection 30 in an end corona protection 32 over, which is less conductive than the external corona protection 30 , By the end corona protection 32 becomes a transition from the potential on the laminated core 12 prevails, created for airborne potential. The external corona protection 30 can consist of paint with integrated soot particles, so a conductive paint, the end corona 32 from a semiconductive paint. So can the outside corona protection 30 and the end corona protection 32 also be provided in the form of conductive or semiconductive tapes. Such bands are produced by slurrying particles with the external corona shielding graphite particles, with end corona protection silicon carbide particles, with a resin. The resin is then applied to a fabric or nonwoven backing and the material is processed as a ribbon.

The in 1 The structure shown corresponds to a conventional construction of an electric machine 10 or of ladder devices 16 in such a. The invention is realized in the embodiment that individual components of the conductor devices 16 and thus the electric machine 10 Nanoparticles are added. Macroscopically then sees the conductor device according to the invention 16 still as in 1 , the electric machine 10 as well as in 1 shown in detail.

If in any component of the ladder device 16 , except at most the ladder 24 , Nanoparticles are included, becomes the conductor device 16 age resistant: In electrical machines 10 occur regularly at the ladder facilities 16 Partial discharges on. The nanoparticles prevent or reduce such partial discharges and their effect on the mechanical and electrical resistance of the conductor devices 16 or their individual components.

The mica tapes 28 include nanoparticles. The mica paper contained in the mica tape is formed by adding nanoparticles to a pulp of mica particles, for example, silica, alumina, titania, silicates, sulfates, lithopones or aluminum nitride. When the pulp is then applied to a screen to dry and be formed into paper, the finished mica paper finely distributes the nanoparticles in such a manner as to increase the resistance of the mica paper to partial discharges. Also in or on the support, on which the mica paper is attached, nanoparticles are included. In the case of a carrier made of glass fabric, prior to weaving, the individual glass fibers may be coated with synthetic resin which is nanomodified, ie contains nanoparticles. This is called "plain". When using a film or a nonwoven as a carrier, the nanoparticles can be incorporated into a polymer matrix which forms the film or the nonwoven. Likewise, they may also be contained in a surface coating of the film or the nonwoven, be it formed from paints or provided by plasma coating.

Nanoparticles are also included in the adhesive, with which the mica paper to form the mica tapes 28 is attached to the carrier. If an adhesive resin is used, it can be nanomodified, meaning that nanoparticles can be added to it. When using a powder bed of a solid resin which becomes an adhesive by adding a sealing resin, both the powder and the sealing resin may contain the nanoparticles.

In the present case is also the impregnating resin, which stabilize and attach the mica tapes 28 serves, on the one hand to be more resistant to partial discharges and on the other hand to increase the resistance of the entire system against partial discharges, because the impregnating resin penetrates the mica tapes with the nanoparticles and so be compensated by the nanoparticles in the impregnating resin weak points in the mica tapes.

In the present case, bisphenol-A or F is not used as the impregnating resin, because the addition of nanoparticles to these impregnating resins does not leave the system stable and causes the nanoparticles to agglomerate. A cycloaliphatic epoxy resin or a silicone resin is used.

In the case of using a cycloaliphatic epoxy resin, the nanoparticles, for example silica or alumina particles, are first contacted with materials containing epoxy silane groups. As a result, the reactivity of the surface of the nanoparticles is reduced, and at the same time allow the Epoxisilangruppen a good integration into the cycloaliphatic epoxy resin such that it does not lead to clumping of a plurality of nanoparticles. Rather, the nanoparticles remain finely distributed. In the case of a silicone resin, the nanoparticles are first brought into contact with vinyl silanes. As a result, the vinylsilanes deposit on the surface, which is thus no longer highly reactive. At the same time, the vinyl silanes make it possible to embed the nanoparticles in the silicone resin well.

In the case of the electric machine 10 Preferred impregnating resin is a cycloaliphatic epoxy resin. This is particularly resistant to partial discharge due to the nanomodification at higher voltages and etc. In other environments, for example traction means such as locomotives, etc., a ladder device is in the manner of the ladder device 16 better impregnated with a silicone resin, because this is better designed for the temperatures prevailing in such traction agents.

Also the Glimmschutzeinrichtungen, namely the outer corona 30 and the end corona protection 32 contain nanoparticles in the present case. Used for the anti-corrosive equipment 30 and 32 used a paint or a resin may be added to these nanoparticles. If wound tapes are used, as with the mica tapes 28 the carrier (glass fiber material, nonwovens) be provided with nanoparticles in the manner described above. Since on such a carrier, a resin is applied, the outer corona 30 Graphite particles and the end corona protection 32 Containing silicon carbide particles, in the manufacture of the bands for the anti-corrosive device 30 and 32 In addition, nanoparticles are added.

For the anti-corrosive devices, the materials mentioned above for the mica pulp are suitable for nanoparticles, but in particular also silicon carbide and carbon black as the starting material for the nanoparticles.

By providing nanoparticles in a plurality of components of a conductor device 16 , namely in the mica ribbons 28 , an impregnating resin for fixing or stabilizing these mica tapes, and in an outer corona protection 30 and in an end corona protection 32 , prevents or reduces the entire conductor device 16 Partial discharges and also has a particularly high resistance to the occurrence of partial discharges. This will increase the life of the conductor device 16 and thus also the electric machine 10 elevated.

Claims (9)

Ladder device ( 16 ) with a ladder ( 24 ) or a plurality of ladders ( 24 ), with the conductor ( 24 ) or the totality of ladders ( 24 ) is formed by means of a impregnating resin, a dressing, characterized in that the impregnating resin contains nanoparticles. Ladder device ( 16 ) according to claim 1, characterized in that the impregnating resin comprises a cycloaliphatic epoxy resin. Ladder device ( 16 ) according to claim 1, characterized in that the impregnating resin comprises a silicone resin. Ladder device ( 16 ) according to one of the preceding claims, in which on the upper side at least one Glimmschutzeinrichtung ( 30 . 32 ), characterized in that the at least one anti-corrosive device ( 30 . 32 ) Contains nanoparticles. Ladder device ( 16 ) according to claim 4, wherein the anti-corrosive device ( 30 . 32 ) has nanoparticle-added lacquer or resin mixed with nanoparticles. Ladder device ( 16 ) according to claim 4, wherein the anti-corrosive device ( 30 . 32 ) is provided in the form of at least one band in which nanoparticles are contained. Ladder device ( 16 ) according to one of the preceding claims, in which nanoparticles a) comprise at least one oxide, in particular silicon dioxide, aluminum oxide and / or titanium oxide, b) at least one silicate, c) at least one sulfate, d) at least one lithopone, e) Aluminum nitride f) of silicon carbide and / or g) are formed from carbon black. Electric machine ( 10 ) with at least one conductor device ( 16 ) according to one of claims 1 to 7. Traction machine with at least one ladder device ( 16 ) of any one of claims 1 to 7.

Images