EP3769403A1

EP3769403A1 - Electric insulation system of an electric motor, and associated manufacturing process

Info

Publication number: EP3769403A1
Application number: EP19723735.7A
Authority: EP
Inventors: Tobias Katzenberger; Bastian PLOCHMANN
Original assignee: Siemens AG
Current assignee: Innomotics GmbH
Priority date: 2018-05-04
Filing date: 2019-05-03
Publication date: 2021-01-27
Also published as: WO2019211461A1; CN112219341B; EP3565090A1; CN112219341A; US20210242760A1

Abstract

The invention relates to an improved electric insulation system of an electric motor, in particular an electric insulation system (EIS) that better insulates the wire windings in the slots of the laminated core from the laminated core. The invention further relates to a cost-effective manufacturing process for making such an improved electric insulation system of an electric motor. To this end, the impregnating resin for forming the potting compound of the conductor in the slot is introduced into the conductor by a carrier medium such as a fiber.

Description

description

Electrical insulation system of an electric motor and

Manufacturing process thereto

The invention relates to an improved electrical insulation system of an electric motor, in particular with respect to the insulation of the wire windings in the grooves of

Sheet metal packs against the laminated core improved electrical insulation system EIS. In addition, the invention relates to a manufacturing method for producing such an improved th electrical insulation system of an electric motor.

Are known laminated cores of electric motors, the grooves with a wire winding, usually a copper wire winding, wherein the wire is electrically insulated by a wire enamel include. Depending on the size and performance classes, there are different options for manufacturing electric motors.

In the order of magnitude of shaft height 63mm to 450 mm and accordingly the power of 150W to 1.6 MW is typically the so-called stator, so the laminated core equipped with pre-wound wire windings. These windings are mechanically introduced into the stator and then connected ßend. The electrical insulation of the individual wires with each other and with respect to lying on ground core package is ge by surface insulation materials, such as Pa, and the wire enamel of the individual winding wires gege ben. Due to the geometric requirements of the grooves such as the Nutzahn, which serves to form closed as possible Mag netfeldlinien, a maximum groove filling of 85 vol% with copper wire including wire enamel is possible because otherwise the Einziehkräfte would be too large and thus the surface insulation and / or the wire enamel could be damaged, for example by scratches, cracks and / or by stretching. As a result, at least 15% by volume free volume remains in the grooves of the laminated core. Part of it is free because the winding does not exactly fill the corners of the groove, but within the winding existing voids in the impregnation process as completely as possible filled with impregnating resin.

Unfortunately, it has been shown that there are significant gaps here, because the impregnating resin when removing the stator from the immersion bath is often still so fluid that there is no sufficient filling of the cavities also inside the conductor, ie the wire winding.

For this purpose, one or more stators are immersed in a liquid immersion resin tank usually in a dipping process, so that the liquid impregnating resin in the cavities between the individual wires, the wire winding and the sheet metal flow package and can fill these cavities. Finally, the so impregnated stators are tempered by exposure to temperature and / or UV irradiation over a period of time. As a result, the finished casting, for example in the form of a fully cured from the liquid and / or alloyed impregnating resin which fills the cavities of the winding as far as possible in the dipping

Duromers as potting compound.

The quality of the impregnation is ultimately defined by the highest possible degree of filling of the cavities and the lowest possible residual enthalpy of the impregnating resin. Optimal are firstly completely filled with impregnating resin cavities of the stator and secondly a complete cross-linking of the impregnating resin.

A disadvantage of impregnation processes in general and the dip impregnation in particular is that for the impregnation tion of various types of stator, the rheology, as well as the che mix reactivity of the impregnating resin in the bath to the jewei time stator type is set, thus a completeness ended filling the cavities is guaranteed. Different types of stator differ in their impregnation behavior - not only in immersion baths - especially due to different temperature profiles, heat capacities and different flow paths.

Depending on the type of stator, a higher or lower viscosity is required so that the impregnating resin ensures complete filling of the cavities and at the same time rapid gelation. However, this makes it difficult subsequent to the drainage of the impregnating resin in the removal of the

Stators from the impregnation, such as the dip.

Thus different stator types in a common

Impregnating station can be economically impregnated, the rheology, viscosity and / or the chemical composition of the composition is set to a mean value oh ne optimization with respect to a stator type. A suitable impregnating resin is technically highly developed in terms of rheology, thixotropy, and chemical reactivity with regard to gelling time and / or residual enthalpy and is therefore correspondingly expensive. Although due to their mechanical, electrical and chemical properties and cheaper impregnating resins for use in the stator suffi accordingly, but are not suitable for a dip in the various types of stator are impregnated.

A disadvantage of the usual immersion baths is in particular also that the thermal pre-crosslinking, also called gelation, must succeed in the winding, so that the liquid impregnating resin in the winding when removing the stator from the

Immersion remains, this requirement is in contrast to the requirement that excess impregnation resin on the outer wall of the stator when removing from the

Dive should drain as completely as possible again. However, the liquid impregnating resin, which has been in contact with a hot stator and drips back into the dipping bath, contaminates the dipping bath and deteriorates the impregnating resin quality of the bath for subsequent impregnation. Object of the present invention is therefore to create a possi probability, which allows a targeted filling of the wire windings of a conductor with impregnating resin. The aim is in particular also within the Flächenisolati on, so for example, the paper winding, which encloses the conductor, so the wire winding, the homogeneity of the

Impregnating resin filling of the cavities to increase.

This object is achieved by the subject of the present invention, as disclosed in the description, the figures and the entitlements.

The subject of the present invention is therefore an electrical insulation system EIS of an electric motor, comprising at least one conductor with wire winding in a groove of a laminated core of a stator, characterized in that a casting around the wires in the conductor by impregnating on and in at least one Carrier, which is loaded with impregnating resin and disposed between the winding wires in the conductor, he is holding, such that the cavities of the conductor are impregnated with the impregnating resin of the carrier, wherein the content of impregnating resin in the carrier for potting the wires in the head of Blechpakets sufficient.

In addition, the subject of the present invention is an electrical insulation system EIS of an electric motor with wire winding as a conductor in the grooves of a laminated core in which the wire winding and at least one carrier in the conductor are embedded in a potting, wherein the potting in the conductor to the Wires and the at least one support around evenly distributed, because the impregnating resin is not carried out from the outside Shen in the head, but by the carrier, which are loaded with impregnating resin in the B state and remain with the winding wires in the winding ,

The "evenly distributed" stands here in contrast to

Impregnating resin distribution in the conductor, for example a Tauchbadimprägnierung results in which the resin is still liquid at least partially leaked from the conductor again. The points in the ladder, which leave the dipping bath according to the state of the art first, usually have even more unfilled cavities than the points in the ladder, which linger even longer in the dipping bath when taking out. In any case, it is assumed that in the Tauchbadimprägnierung no uniform distribution of the potting around the wires ei ner winding around exist.

In addition, the subject of the present invention is a method for producing an electrical insulation system EIS of an electric motor, comprising the following method steps:

- winding a conductor of winding wire and

Impregnating carrier

- Pulling the conductor thus formed in the grooves of a laminated core of a stator of the electric motor

and

- Hardening of the impregnated winding wire carrier insulation.

General knowledge of the invention is that the time-consuming and unsatisfactory impregnation dipping process in the manufacture position of an electric winding wire insulation system EIS of an electric motor by introducing a sufficient amount of resin as a prepreg and / or in a carrier, such as a fiber , can be saved.

As "carrier" or "impregnating resin carrier" are presently preferably used prepreg fibers, alone or in combination with wei direct carriers. Further carriers in this sense Kings nen, for example, sponges and / or foams.

In the present case, a "conductor" is a winding of wires which are wound together in surface insulation material, such as paper, for example, and form a bundle of wedge-shaped wires which are inserted into a groove of a laminated core. is withdrawn. For example, up to 200 wires may be present per conductor within the wire winding wrapped by surface isolation material.

If a conductor according to the present invention is cut in cross-section, the circles showing the diameters of the wires, which in the best case are arranged according to the pattern of a "densest" spherical packing in the crystal, are discernible For example, the individual wires that make up the large circles, for example, single points that point to a carrier, such as a fiber.This is true in the case that the cross section of the

Prepreg fiber is small compared to the cross section of the wire.

In most cases, however, the wire winding will not be filled with wires arranged completely in parallel, so that as a rule a so-called "wild winding" will be present, as shown in Figure 1. Analogous to the space filling of the ball packing you test, which is 74% is, it is therefore assumed that the remaining at least 26 vol% of cavity in the conductor with carrier, such as fibers, braids and / or fiber bundles are filled.

It is desirable according to the invention to fill as much of this cavity, which anyway can not be used by the wires for dimensional reasons, with carrier. Based on the fact that in the head ideally in the ideal case 26 vol%, so estimated in real cases up to 35Vol% or more, depending on the quality of the winding, are not occupied by wire, ver remain for the filling with impregnating 35 vol% in the head.

By the carrier is a sufficient amount of

Impregnating resin introduced into the winding, which ideally fills up to 100%, preferably up to 80% and more preferably between 30 and 80% of said above at least free 35 vol% in the conductor by impregnating resin respectively encapsulation and carrier. In this case, it is particularly advantageous if the carrier, for example, the prepreg fibers, simultaneously with the winding of the wires, in particular the copper wires are wound up and so between the winding wires in the conductor with these in the winding and finished Electric motor vorlie conditions.

Basically, the number of prepreg fiber turns, if their diameter is comparable to the diameter of the wire, is chosen to be as small as necessary relative to the winding wire turns so as not to waste space in the groove that would be fillable with winding wire ,

The number of prepreg fiber turns and the size of the

Prepreg fiber volume is accordingly in the voltage field between high enough that as complete as possible Verguss the conductor after curing is present and as low as possible, so that the Volumenfüllgrad in the groove with Leitungsmate rial, preferably with copper wire, does not suffer from selected , By introducing the impregnating resin on a support in the head while the amount and type of

Depending on the type of motor, impregnating resin can be easily varied during winding by adding / reducing the wound prepreg fibers in a wide range.

This shows the enormous flexibility of the production of the electrical insulation system EIS of an electric motor according to the present invention.

For example, are long and / or continuous fibers in the conductor with approximately the same diameter with winding wire in the ratio of 1 fiber to 7 wires, in particular 1 fiber to 5 wires th and most preferably 1 fiber to 3 wires in the winding before.

The ratio of prepreg fiber to winding wire can also be in favor of the fiber, for example in the range of 5 fibers. per wire to one fiber per wire, ie 1: 1. Ratio in the winding. The respective proportions depend, for example, on the absorbency of the fiber, ie the resin content per volume fraction of fiber, the diameter of the fiber, etc.

According to an advantageous embodiment of the invention ver increases the volume of the fiber in the impregnation with resin through the resin receptacle and decreases accordingly in the formation of the potting again.

According to a further embodiment of the invention, the fibers are laid, drawn and / or spun in addition to the bundling or alternatively to the winding wires.

As suitable fibers, for example, thin yarns are used, in particular "atomized" fibers, such as dental flosses, and / or linear fibers in which the fibrils are present in untwisted form.

Polyethylene fiber, PET fiber, polyethylene imide fiber,

Polyamide-imide fiber and / or cotton fiber, as well as beliebi ges mixture of the above fiber in fiber bundles, fiber pigtails or the like. It is also possible to use short fibers or fabrics in a sensible way, so that there are no limits to the selection of the carrier.

The fiber and / or the material of the carrier is chosen so that the tensile strength is sufficient for the winding process. Before geous enough, the fiber material, the structure and / or the surface finish is selected so that a high wettability and / or impregnability with the jewei time impregnating resin is given sufficient tensile strength and, of course, electrical insulation at the carrier.

To prepare the prepreg prepreg fibers, they are impregnated with a resin that is B-staged. The term "B-state of a resin" in the present case is a resin, for example a thermoset, which-especially at room temperature-is gelled, optionally slightly tacky, but not yet cured, this state being also referred to as prepolymer of the thermoset as prepolymer.

This condition of the prepolymer is given when the

Impregnating resin is crosslinked only to a small extent, but it receives superficial stability, so that it is not solid and crosslinked but also no longer liquid. In the B state, a thermoset can be remelted and liquefied without decomposing.

The impregnating resin of the prepreg fiber is in the B state, that is, it may be superficially slightly tacky rig. Following this, in the curing process, which generally occurs with temperature elevation and / or irradiation, this impregnating resin melts in the B state of the prepreg fibers, travels around the conductor wires and within the groove around the winding wires, and chemically cures until a Casting is formed. A casting is made of synthetic resin and called the finished by hardened duromer, which is no longer malleable, but only machinable.

In the present case, the conductor comprising winding wire and fibers, in the finished electric motor in such a

Casting before.

The carriers used according to the invention in the production of the conductor, ie the winding of the conductive and wire enamel insulated Wi ckel wires are prepreg carrier, so for example prepreg fibers. The preimpregnation of the fiber for producing the prepreg fiber can be carried out, for example, by a dip impregnation of the fibers. In this case, fibers are immersed in a dipping bath which dilutes the impregnating resin, for example with a solvent. The fiber is passed through the dip at a predetermined rate pulled through, the fiber only once superficially and depending on the absorbency of the fiber within the fiber, for example, in open pores and / or braiding or Verfil tion cavities, impregnating resin absorbs. After completion of the immersion bath, the preimpregnated fiber is dried and freed from solvent. In this case, the B state of the impregnating resin is produced in and on the fiber. It is possible that the fiber wetted with impregnating resin in the B state is superficially slightly tacky.

The so-impregnated and dried fiber is then called "prepreg fiber." The carrier filled with impregnating resin, as well as the prepreg fiber, also fall under the term "semi-finished product". In contrast, the carrier and / or fiber, which has little or no residual content of impregnating resin, is simply called "fiber".

It has been found that atomized fibers in which the fibrils are present in a non-linear, vortexed and / or felt-like manner, in some cases also adhesively bonded, exhibit a higher impregnation resin absorption than fibers of linear, parallel or quasi linear, parallel attached fibers.

In the present case, a "small fibril" is defined as a small thin fiber which under certain circumstances may not be recognizable to the naked eye.) Several fibrils, for example hundreds of them, form a fiber, such as an endless fiber or a long fiber, as described in US Pat present inven tion for producing a prepreg fiber is used.

The carrier, for example, at least partially comprising prepreg fibers are introduced into the winding in the winding process and can thus be placed in the geometrical interstices of the wire enamel-insulated winding wires, preferably copper wires. The product of the winding is the conductor which is inserted into the groove and is a winding of conductive hend, insulated winding wires with intermediate prepreg fibers.

Since the prepreg impregnation resin is soft and can be plastically deformed, it preferably lies in the intermediate spaces of the wires and / or is displaced by the harder wires of the winding there, so that in general no losses with respect to the Volumenfüllgrads the groove with winding Wire are to be feared.

It can be essentially "same" or different

Prepreg fibers form a conductor with the winding wires. Naturally, the "same" refers to a realistically possible equality, for example a cotton fiber, regardless of the impregnation resin filling, will always be considered "equal" to a comparable cotton fiber.

The prepreg fibers may be the same or different in length, material, diameter, cross-sectional shape and / or arrangement of the fibrils. The prepreg fibers may be the same or different in terms of their content of impregnating resin per unit volume of fiber.

The impregnating resin of the prepreg fibers of a conductor may also be the same, that is, made of uniform reaction resin or different, each of prepreg fiber to prepreg fiber un ferent reaction resin.

In particular, a mixture of fibers can be used in combination with a mixture of impregnating resin. It is also possible to use mixtures of different prepreg fibers, braided and / or bundled prepreg fibers, fiber composites as required and engine type.

Figure 1 shows the prior art with EIS, which can be produced by a dive of conductors in impregnating baths. In Figure 1, left to overview a housing 1 of a

Stators with a laminated core 2 and grooves 3, and the jewei time winding head 4 shown.

The detail A of the groove winding is shown enlarged on the right in Figure 1 ver.

Evident are the individual winding wires that form the same directional, but not necessarily parallel bright stripes 5. According to the example shown here, there is no optimum packing of the winding wires in the slot 3 in the groove 3, so there are the larger cavities, such as the cavity at the bottom left 7. In addition to the light stripes representing the winding wires 5 and the dark stripes showing the voids between the wires filled with impregnating resin 7, in this detail view of FIG These are interstices 6 which are unfilled cavities between the winding wires 5. These cavities 6 show how

Prior art dip impregnation only partially filled a wild coil with impregnating resin.

In contrast, Figure 2 shows a conductor according to a Ausfüh tion of the present invention in cross section. FIG. 2 shows FIG. 2a on the left and FIG. 2b on the right, which follow one another in terms of time in the setting process. Figure 2 b does not yet show the finished insulation system, but only an intermediate stage in which it can be seen how formed the prepreg fiber 9 in the winding during curing ver.

The conductor was cut, in FIG. 2 a the hel len circles are the cross sections of the winding wires 5, which are coated with wire enamel 8, as interpreted by the dark edge 8 at. The prepreg fibers 9 provided between the winding wires 5 are laid during the winding plastically deformable in the spaces formed by the winding wires 5.

Figure 2b shows the beginning of the curing of the Isolationsssys system according to an embodiment of the present inven tion, wherein it can be seen that the impregnating resin portions of the prepreg fibers 9 melt during curing and liquefy by. The liquid impregnating resin spreads and fills the existing cavities 6 in particular also by acting in the head Ka pillarkräfte. During curing, the impregnating resin cross-links and becomes a permanent encapsulation of wire and carrier. In the finished insulation system up to 35% by volume, in particular up to 26% by volume, before given to up to 20% by volume of impregnating resin and carrier can then be present in the conductor.

By the present invention can be dispensed with in the production ei Nes electrical insulation system EIS of an electric motor on the time-consuming and costly Tauchimprägnierprozess without significantly alter the previous Wickelpro zessschritt. Thus, a much larger manufacturing variance is given, the production time for production is reduced and thereby also the pro duction costs.

A particular advantage is that the impregnating resin is introduced by a carrier medium, such as a carrier fiber during the winding process in the stator. This eliminates the procedural step of dip impregnation. This is possible by means of the prepreg fiber, which introduces sufficient impregnating resin into the conductor.

The invention relates to an improved electrical insulation system of an electric motor, in particular with respect to the insulation of the wire winding in the grooves of the

Sheet metal packs against the laminated core improved electrical insulation system EIS. Moreover, the invention relates to a cost-effective manufacturing method for producing such an improved electrical insulation system of a The electric motor. This is achieved by introducing the impregnating resin into the conductor to form the potting of the conductor in the groove by a carrier medium such as a fiber.

Claims

claims

1. Electrical insulation system EIS of an electric motor, comprising at least one conductor with wire winding in a groove of a laminated core of a stator, characterized in that a potting around the wires in the conductor by impregnating resin on and in at least one carrier loaded with impregnating be and disposed between the winding wires in the conductor, is available, such that the cavities of the conductor are filled with the impregnating resin from the carrier, wherein the content of impregnating resin, which comes by introducing the carrier in the conductor, for the potting of the cavities in the head of the laminated core is sufficient.

2. Isolation system according to claim 1, wherein the carrier

Includes prepreg fibers.

The insulation system according to any one of claims 1 or 2, wherein the prepreg fibers comprise turbulent fibrils.

4. Insulation system according to one of the preceding claims, wherein the prepreg fibers comprise plastic fibers.

The insulation system of any one of the preceding claims, wherein the prepreg fibers comprise glass fibers.

The insulation system of any one of the preceding claims, wherein the prepreg fibers comprise felts.

7. Insulation system according to one of the preceding claims, wherein the prepreg fibers are substantially equal.

An insulation system according to any one of the preceding claims, wherein the prepreg fibers comprise fiber blends of fibers of various lengths.

An insulation system according to any one of the preceding claims, wherein the prepreg fibers comprise fiber blends of fibers of various materials.

10. Insulation system according to one of the preceding claims, wherein in the conductor up to 35% by volume, in particular up to 26% by volume of impregnating resin and carrier is present.

11. Insulation system according to one of the preceding claims, wherein in the conductor in volume proportions prepreg carrier to winding wire is at most 5% by volume of prepreg fiber to 1% by volume winding wire before.

12. Electrical insulation system EIS of an electric motor with wire winding as a conductor in the grooves of the laminated core, in which the wire winding and at least one carrier in the conductor are embedded in a potting, wherein the potting in the conductor around the wires and the at least one carrier is uniformly distributed around lar, because the impregnating resin is not performed from the outside Shen in the head, but by the carrier, which are loaded with impregnating resin in the B state and remain with the winding wires in the winding.

13. A method for producing an electrical insulation system EIS of an electric motor, comprising the following method steps:

- winding a conductor of winding wire and

Impregnating carrier

and

- Hardening of the impregnated winding wire carrier insulation.

14. The method of claim 13, wherein hen between the Einzie hen of the conductor and curing an intermediate step to

Heating the stator in a hot-air oven and / or by current heating to a temperature at which the prepreg Impregnating resin melts in and on the impregnating resin carrier and evenly distributed in the adjacent spaces between the individual winding wires in the groove.

15. The method according to any one of claims 13 or 14, wherein the uniform distribution of the impregnating resin between the winding wires of the conductor and within the groove is at least partially via capillary forces.