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EP-4736301-A1 - FILLING A GROOVE WITH DUROMER IN AN ELECTRIC MACHINE

EP4736301A1EP 4736301 A1EP4736301 A1EP 4736301A1EP-4736301-A1

Abstract

A groove closure of a winding groove of an electric machine is to be efficiently produced. For this purpose, a viscous duromer emulsion is provided, the duromer matrix of which is mixed with solid particles as a curing agent and magnetizable particles. The viscous duromer emulsion is introduced into the groove (1) of the electric machine in the form of a bead (10) for example. The viscous duromer emulsion is then heated so that the solid particles melt and react with the duromer matrix. Finally, the heated duromer emulsion is cured.

Inventors

  • Büttner, Klaus
  • KATZENBERGER, TOBIAS
  • KIRCHNER, FLORIAN
  • KIRCHNER, KLAUS
  • PLOCHMANN, Bastian
  • WARMUTH, MATTHIAS

Assignees

  • Innomotics GmbH

Dates

Publication Date
20260506
Application Date
20240610

Claims (14)

  1. 1. Method for filling a slot (1) of an electrical machine characterized by - Providing a viscous duromer emulsion in whose duromer matrix solid particles are mixed as hardeners and magnetizable particles, - introducing the viscous duromer emulsion into the groove (1) of the electrical machine, - Heating the viscous duromer emulsion so that the solid particles melt and react with the duromer matrix, and - Curing of the heated duromer emulsion.
  2. 2. The method of claim 1, wherein the thermoset emulsion comprises a natural resin, an epoxy resin or an adhesive as the thermoset matrix.
  3. 3. The method of claim 1 or 2, wherein the hardener comprises an amine.
  4. 4. Process according to one of the preceding claims, wherein 75 to 90 percent by weight of magnetizable particles, in particular iron powder, are mixed into the duromer emulsion.
  5. 5. Process according to one of the preceding claims, wherein the heating of the viscous duromer emulsion is carried out just to the extent that the melting of the solid particles and the reaction of the hardener with the duromer matrix is enabled.
  6. 6. Method according to one of the preceding claims, wherein the introduction of the viscous duromer emulsion into the groove (1) of the electrical machine is carried out with the aid of a paste dosing system.
  7. 7. A method according to any one of the preceding claims, wherein the curing of the duromer emulsion takes place largely at room temperature.
  8. 8. Process according to one of the preceding claims, wherein after curing a thermosetting molding material with a glass transition temperature of above 60°C and in particular below 100°C is formed.
  9. 9. Method according to one of the preceding claims, wherein the heating of the viscous duromer emulsion takes place immediately before and/or immediately after the introduction of the viscous duromer emulsion into the groove (1) of the electrical machine.
  10. 10. Method according to one of the preceding claims, wherein during the introduction of the viscous duromer emulsion into the groove (1) of the electrical machine, a viscous strand (10) of the duromer emulsion is applied to a wire bundle (6) in the groove (1).
  11. 11. The method according to claim 10, wherein the wire bundle (6) is pressed in the direction of the groove base (3) immediately before the application of the viscous strand (10).
  12. 12. The method according to claim 11, wherein after the application of the viscous strand (10), the wire bundle (6) in the groove (1) relaxes and a part of the strand is pressed behind a groove projection (5) to form a positive connection.
  13. 13. Method according to one of the preceding claims, wherein the viscous strand (10) is pulled off flush with the surface after being introduced into the groove (1).
  14. 14. Device for filling a groove (1) of an electrical machine characterized by - a dispenser for providing a viscous duromer emulsion, in whose duromer matrix solid particles as hardeners and magnetizable particles are mixed, - a nozzle (9, 9') on the dispenser for introducing the viscous duromer emulsion into the groove of the electric machine, - a heating device (14) for heating the viscous duromer emulsion so that the solid particles melt and react with the duromer matrix, whereby the duromer emulsion hardens.

Description

Description Groove filling using duromer in electric machine The present invention relates to a method for filling a groove of an electrical machine. Furthermore, the present invention relates to a corresponding device for filling such a groove. Low-voltage motors are typically manufactured with a round wire winding, which is wound into coils in advance using a flyer/template winder and then drawn into the laminated core with the respective slots in a fully automated process. The critical point here is always the slot gap, which is defined by the two adjacent slot teeth. This is significantly smaller than the slot itself, which ideally means that the magnetic circuits close more effectively, but the entire copper winding has to be drawn through this cross-sectional taper. In order to generate ideal magnetic field properties in the laminated core, the slot gap would have to be chosen to be so narrow that the slot gap width is smaller than the diameter of a single wire in the winding. However, this would lead to major problems in terms of manufacturing, as typical winding drawing-in processes can no longer be used. The current sheet metal geometries are a kind of compromise that takes both requirements into account. The slot gap is approx. the clear width of two to four individual wires ( diameter ) , whereby the copper bundle is partially compressed to this width by a suitable lamella guide during insertion and the disadvantage with regard to the magnetic circuit dimensioning remains acceptable . Particularly in larger machines (medium voltage or high voltage motors) with higher requirements, the existing slot gap is then closed using a magnetic slot closure. This involves magnetic iron particles of various designs, which usually in combination with a plastic as a "compound". This "compound" (filler particles = iron, matrix = plastic) is often prefabricated and used as slot wedges, which are mechanically inserted. This has the disadvantage that the slot lock can loosen and come off during operation of the machine due to vibrations and forces, thus blocking the rotor and thus causing the machine to fail. On the other hand, prefabricated slot gaps are not an economical solution for a product portfolio with a wide variety of variants, as is often the case in the area of low-voltage motors. Another application for medium and high voltage machines is the use of a still uncrosslinked, highly filled paste consisting of iron filler particles and chemical reactive resin (mixing ratio approx. 90 percent by weight iron filler, 10 percent by weight polymer matrix). The mass must be kneaded for several hours under active cooling to ensure homogenization of the particles in the matrix and then stored and transported in a cool place, as it is a one-component, reactive mass. The matrix component is, for example, an anhydrite-cured epoxy resin, which hardens when exposed to a higher temperature (150°C, several hours) to form a molding material that has sufficient mechanical strength and a glass transition temperature of over 140°C, thus meeting the requirements of medium voltage and high voltage machines for the insulation system and the peripherals. Due to the choice of matrix and iron filler composition as well as the high mechanical requirements for the final molding material and during application, additional additives such as talcum (as a lubricant) and polymer fibers (as reinforcement of the mass and thixotropy during processing) in the single-digit weight percentage range are necessary. The material is applied at room temperature either manually ("spackling") or by a (partially) automated bead application and closing pressing in using a special squeegee. Thermal hardening is then brought about by a hot air oven or by applying current to the windings. The object of the present invention is to propose an economical and low-energy possibility for slot filling, especially in low-voltage machines. According to the invention, this object is achieved by a method and a device according to the independent claims. Advantageous further developments of the invention emerge from the subclaims. The invention is based on the knowledge that low-voltage motors that have a high level of efficiency have only very low power losses, which manifest themselves in heating of the rotor and the stator, whereby a temperature of over 100 °C is almost impossible, particularly in the area of a possible slot closure. This allows a new perspective on the thermal stability of the insulation system and its periphery. In particular, the periphery (e.g. the cover slide) can be well below the thermal class F/H (155 °/180 °C, 20,000 h) otherwise required for the primary insulation system, without negatively affecting the service life or performance of the machine. Based on this development, the invention presents an alternative polymer solution for slot filling, which represents an economical and at the same time CCt-friendly solution (with regard to ap