WO2014009199A2 - Method for producing a main insulation around an electrical conductor of a coil or bar winding for an electric motor or generator - Google Patents

Description

description

Method for generating a main insulation around an electrical conductor of a coil or rod winding for an electric motor or generator

The invention relates to a method for producing a

Main insulation around an electrical conductor of a coil or rod winding for an electric motor or generator by means of a heat shrink tubing or a heat shrink tubing combination. The invention also relates to an electric motor or electric generator which has a heat-shrinkable tube as a main insulation around at least a portion of an electrical conductor or conductor bundle of the reel spool.

Electrical machines such as electric motors or

 (Electric) generators usually have a stator and a rotor, with the aid of which - in the case of an electric motor - electrical energy into mechanical energy or - in the case of a generator - mechanical energy can be converted into electrical energy.

On the conductors of the stator windings lie in the operation of these machines electrical voltages. Therefore, the conductors of the stator windings must be electrically isolated to avoid a short circuit.

Stator windings in electrical machines can be designed differently. A frequently used construction provides that a plurality of insulated against each other individual conductors are bundled and to provide the resulting conductor bundle, which is often referred to as a conductor bar, with a so-called main insulation. The conductor bars can be either roughened (so-called Röbel bars), ie with twisted individual conductors, or not rusted, ie with untwisted single conductors running parallel to one another. "

As a material for the main insulation of the conductor of stator windings fine fine is used as a semi-discharge resistant barrier material in the form of fine lint paper according to the prior art. The insulation materials consist of laminates of fine lint paper with various substrates such as glass fabrics, films (polyethylene terephthalate (PET), polyimide (PI)), or nonwovens (polyethylene terephthalate (PET)) with a low content of binder resins for the vacuum pressure impregnation (VPI) or with a high proportion of binder resin for the coil pressing process (Resin Rieh = RR)).

The application of these insulation materials can be done in band or wide stock, manually or mechanically.

The thickness of the main insulation and thus the number of layers of the mica tapes depend on the rated voltage and the permissible electric field strength of the machine. The winding of prefabricated coils is complex and complicated, since depending on the geometry and bending radii usually not the entire coil can be wound mechanically and manual reworking is required. This is accompanied by a proven higher error rate in the hand-wound areas compared to the machine-wound sections. A winding of straight Röbelstäben is easier, but is still relatively expensive.

Furthermore, the heat class / insulating class is of particular importance. For machines, and thus also for the insulating materials, for a thermal class C (200 ° C) or

R (220 ° C) are designed, only very few polymeric carrier materials for the mica tapes are suitable.

Against this background, it is an object of the present invention to provide an improved method for insulating coils and / or bars in electric motors and generators as well as an improved electric motor and generator. These objects are achieved by the method according to claim 1 and the electric motor and the electric generator according to claim 9. Advantageous developments of the invention are the subject of the dependent claims.

According to the invention, a method is proposed for generating a main insulation around an electrical conductor of a coil or rod winding for an electric motor or generator, which is characterized in that at least one heat-shrinkable tube to at least one pre-insulated, electrical conductor or a pre-insulated, electrical conductor bundle is applied, and is subjected to at least one heat shrink tubing heat treatment, such that the

Shrink tubing shrinks on pre-insulated electrical conductor or conductor bundle.

The inventive method is characterized by simple applicability and excellent automation. In addition, it provides a large variability with respect to the insulating layer thickness and the cross section of the electrical conductors to be insulated or the coil to be insulated. According to a first advantageous development of the invention, it is further provided in the method according to the invention that the electrical conductor or the conductor bundle after the heat treatment is formed into a winding coil or a part of a winding coil.

According to a second advantageous development of the invention, it is provided in the method according to the invention that the heat treatment takes place by means of hot air, infrared light or laser light.

According to a third advantageous development of the invention, it is provided in the method according to the invention that the heat-shrinkable tube is applied to only one or more sections. sections of the electrical conductor or conductor bundle is raised.

According to a further advantageous development of the invention, it is provided in the method according to the invention that the section (s) is / are selected such that it corresponds to / correspond to a later parallel coil leg (s) of the reel spool. According to yet another advantageous embodiment of the invention, it is provided that the shrink tube used in the method according to the invention contains or consists of a polyaryletherketone, a fluoropolymer, a polyamide or polyethylene terephthalate. It is also advantageous if, according to a further advantageous development, the heat-shrinkable tube has an adhesive on the inside facing the electrical conductor or conductor bundle. If the shrink tube contains a fluoropolymer, then this shrink tube can advantageously be a dual shrink tube.

The present invention also includes an electric motor or generator which is characterized by comprising a shrink tube as a main insulation around at least a portion of an electrical conductor or bundle of wires of the reel spool. Further, it is advantageous if the electric motor or electric generator has a winding coil, which is produced by the method according to the invention or one of its advantageous developments and thereby has at least one new and inventive feature.

The present invention will be explained in more detail with reference to the accompanying drawings.

Showing: 1 shows a schematic cross-sectional view of an electrical conductor with a shrink tube in the not yet shrunk state;

2 shows a schematic cross-sectional view of a

 electrical conductor with a shrink tube in the shrunk-on state;

3 shows a schematic, perspective view of a

 Conductor bundle with shrunk-on shrink tubing.

The illustrations in the figures are purely schematic and not to scale. Within the figures, the same or similar elements are provided with the same reference numerals.

The embodiments explained below represent preferred embodiments of the present invention. Of course, the present invention is not limited to these embodiments.

1 shows a schematic plan view of a cross section of an electrical conductor 1 with a surrounding this electrical conductor shrink tubing 2 in non-shrunk state. 3 shows a conductor bundle 3 with a plurality of substantially rectangular partial conductors 4 and a shrunk on the conductor bundle shrink tube 2. In the figures, for the sake of simplicity of a representation of / of pre-insulation / conductor insulation / internal corona protection.

The electrical conductor 1 or partial conductor 4 can consist of any material which is suitable as an electrical conductor or partial conductor for a coil of an electric motor or electric generator. Usually, this is a metal or a metal alloy. Due to the good electrical conductivity are often used for electrical conductors copper or a copper alloy.

The cross-sectional shape of the conductor 1, partial conductor 4 or conductor bundle 3 can be arbitrary. In the example illustrated in FIGS. 1 and 2, the cross-sectional shape of the conductor 1 is essentially a circular shape. However, the present invention is not limited thereto. In order to achieve the highest possible space filling of the installation space available for the electrical conductors, electrical sub-conductors 4 having a substantially rectangular cross-sectional shape are often used, as illustrated in FIG. 3 using the conductor bundle 3 shown there. If the sub-conductors 4 shown in FIG. 3 are arranged correspondingly, a substantially rectangular cross-sectional shape of the conductor bundle 3 also results. Such electrical conductors and conductor bundles can, of course, likewise be electrically insulated by means of the method according to the invention. In the case of conductor bundles, the individual conductors are usually themselves surrounded by a partial conductor insulation. In addition, an internal corona shield may be provided between the conductors and / or around the conductors. For the present invention it is irrelevant in which way (for example type, material) a pre-insulation of the electrical individual conductors or sub-conductors and / or an internal corona protection is formed.

Shrinking hoses 2 are usually prefabricated hoses with a generally round cross-section. The shrink tubing 2 are stretched after production in the heated state and cooled. After cooling, the material of the shrink tubing 2 maintains its stretched shape. Upon renewed heating beyond the melting point of the crystalline centers, which fix the macromolecules in the cooled state in a stretched state, the crystalline centers dissolve, the macromolecules le again assume their unstretched state and thus the insulation is shrunk.

According to the invention, the heat treatment of the at least one heat-shrinkable tube 2 preferably takes place by means of hot air, infrared light or laser light. For this purpose, the electrical conductor 1, 3, 4 enveloped with a heat-shrinkable tube 2 can be introduced or passed, for example, into a heating oven, an infrared chamber, or a laser chamber. With regard to the effect of heat, care must be taken only that this on the one hand is sufficient to cause a sufficient shrinkage of the shrink tube 2, but on the other hand is not so strong that the material of the shrink tube 2 is adversely affected. Of course, with regard to the heat treatment, any suitable heat treatment process can be used for the process according to the invention.

After shrinking the shrink tube 2, the electrical conductor 1, 4 or the conductor bundle 3 is advantageously formed into a winding bobbin or a part of a winding bobbin for an electric motor or an electric generator. For the formation of the conductor 1, 4 or conductor bundle

3, there are no particular limitations and all suitable methods and devices can be used for this purpose.

In the method according to the invention, the insulation can be carried out with the shrink tube 2 over the entire length of the subsequent coil winding. However, it is also possible in an advantageous manner for the heat-shrinkable tube 2 to be formed only on one or more sections of the electrical conductor 1,

4 or conductor bundle 3 is wound. For example, the section (s) may be selected such that they correspond to one or more later parallel coil legs (n) of the reel spool. As a result, the amount of shrinking tube 2 required can advantageously be limited to the absolutely necessary level. Of course, the material of the heat-shrinkable tube 2 must meet the requirements with respect to the electrical insulation capability against the electrical voltages that occur in electric motors and generators. In addition, it must be ensured for which thermal class the machine is designed in which the electrical conductors 1, 4 or conductor bundles 3 insulated by means of a heat-shrinkable tube 2 are used.

For machines of thermal classes C (up to 200 ° C) and R (up to

220 ° C) are in particular shrink tubing 2 from the family of polyaryletherketones, e.g. Polyetheretherketone (PEEK), and fluoropolymers, e.g. Polytetrafluoroethylene (PTFE), perfluoroalkoxyalkalane (perfluoroalkoxy polymer, PFA), tetrafluoroethylene / hexafluoropropylene (FEP), fluoroelastomers etc. These insulating materials can be exposed to temperatures> 250 ° C for a short time. It is also advantageous with these insulating materials that they are resistant to the impregnating resins used for later impregnation, in particular to UP resins (unsaturated polyester resins).

For lower heat / insulation classes, it is possible according to the invention to use, for example, shrink tubing 2 from the family of polyamides (PA) or polyethylene terephthalate (PET).

By "from the family of" is meant in the present case that the shrink tubing 2 consist of at least one compound of said classes of compounds, or at least one

Compound from the respective class of compounds as a main component.

Furthermore, it may be advantageous if the heat-shrinkable tube 2 has an adhesive on the inside facing the electrical conductor 1, 4 or conductor bundle 3. This adhesive can, for example, provide a good connection to the pre-insulation of the metallic conductors 1, 3, 4. When Adhesive may be any suitable adhesive, for example silicone adhesive or epoxy adhesive. Which adhesives are suitable is known to the person skilled in the art or can be found out by a few experiments.

If heat-shrinkable tubes 2 from the family of fluoropolymers are used, heat-shrinkable tubes can advantageously be used in the form of a so-called dual-tube. Dual hoses are usually coated with a thermoplastic inner adhesive. In a heat treatment, this inner adhesive is flowable.

By means of an adhesive on the inside of the heat-shrinkable tube 2 not only a good connection to the pre-insulation of the metallic conductors 1, 3, 4 is achieved, but also gussets and cavities can be filled and an excellent seal against moisture can be achieved.

For the thickness of the material of the heat-shrinkable tube 2, any suitable dimension can be selected. The appropriate measure (thickness) results in particular with regard to the required electrical insulation properties (partial discharge resistance, dielectric strength, etc.). Also, more than one shrink tube can be shrunk as insulation according to the invention. For example, with the aid of a first heat-shrinkable tube 2, an inner insulation layer of / with a first material and with the aid of a second heat-shrinkable tube 2 an outer insulation layer of / with a second material can be applied. In this way, further layers can be generated around a conductor 1, 4 or a conductor bundle 3. As a result, for example, special requirements for the insulation of the conductor can be met (for example, with respect to bending strength, abrasion resistance, dielectric strength).

It can all or at least several layers

Shrink tubing 2 on the conductor 1,4 or the conductor bundle 3 and shrunk by a common heat treatment step. Or it can, for example, the different shrink tubing 2 individually wound one after the other and shrunk in a separate heat treatment step.

Also, according to the invention, various sections of the electrical conductor 1, 4 or conductor bundle 3 with different types (in terms of material, thickness, etc.) of

Shrink tubing can be coated and insulated.

In the production of coil and bar windings of electric motors and generators, in particular when bending the conductors and when installed in the stator, the insulation must have a sufficiently high mechanical strength. During operation of the machines, the voltage present in the conductor or sub-conductors and the stator create an electric field, by which the insulation is subjected to dielectric stress. The insulation is also thermally stressed by the heat generated during operation of the machines in the conductor or in the sub-conductors.

The present invention proposes an easy-to-use method for producing a main insulation of electrical conductors 1, 3, 4 in winding coils, which not only enables a high degree of automation, but also very variable with respect to the material of the shrink tubing used, the insulating layer thickness and the cross section of the coil to be insulated. The thus applied to a conductor 1, 4 and a conductor bundle 3 main insulation meets all the requirements specified above.

The inventive application of a shrink tubing 2 on an electrical conductor 1, 3, 4 requires no complex facilities (machines) and can be automated throughout. As already mentioned above, shrink tubes 2 are available in various materials, diameter gradations, wall thicknesses and shrinkage ratios. Thus, the wall The insulation can be easily adjusted via the corresponding shrinkage ratio and the corresponding diameter takes into account the coil cross section. The thus insulated coil windings can then be impregnated, for example, by means of a vacuum pressure impregnation method (VPI) or further modified for groove installation with subsequent full encapsulation.

The present invention also relates to an electric motor and electric generator, each of which is characterized in that around at least a portion of an electrical conductor 1, 4 or conductor bundle 3 of its winding spool a shrink tube 2 as a main insulation is present. Furthermore, the present invention also encompasses an electric motor or electric generator, which is characterized in that its winding coil is produced by one of the methods described above.

The inventive method and its advantageous developments, a reliable and durable electric motor and electric generator can be provided. In addition, by the inventive method previously available sources of error in the production of

The main insulation in coil and bar windings of electric motors and generators can be eliminated and at the same time the production costs for the production of coil and bar windings and thus also the total costs for the production of electric motors and electric generators can be reduced.

Claims

claims A method of producing a main insulation around an electrical conductor (1, 3, 4) of a coil or bar winding for an electric motor or generator, characterized in that at least one heat-shrinkable tube (2) is applied to at least one pre-insulated electrical conductor (1, 4) or a pre-insulated electrical conductor bundle (3), and the at least one heat-shrinkable tube (2) is subjected to a heat treatment such that the heat-shrinkable tube (2 ) on the pre-insulated conductor (1, 4) or conductor bundle (3) shrinks. 2. The method according to claim 1, characterized in that the electrical conductor (1, 4) or the conductor bundle (3) is formed after the heat treatment to a reel spool or a part of a reel spool. 3. The method according to claim 1 or 2, characterized in that the heat treatment is effected by means of hot air, infrared light or laser light. 4. The method according to any one of the preceding claims, characterized in that the shrink tube (2) on a portion or a plurality of subsections of the electrical conductor (1, 4) or conductor bundle (3) is mounted. 5. The method according to claim 4, characterized in that the / the section (s) is / are selected such that he / she corresponds to one / the later parallel coil leg (s) of the reel spool / correspond. 6. The method according to any one of the preceding claims, characterized in that the shrink tube (2) contains a polyaryletherketone, a fluoropolymer, a polyamide or polyethylene terephthalate or consists of this. 7. The method according to any one of the preceding claims, characterized in that the shrink tube (2) on the said electrical conductor (1, 4) or conductor bundle (3) facing the inside has an adhesive. 8. The method according to claim 6 or 7, characterized in that a dual shrink tube as the fluoropolymer-containing shrink tube (2) is used. 9. electric motor or electric generator, characterized in that it has around at least a portion of an electrical conductor (1, 4) or conductor bundle (3) of the reel spool a shrink tube (2) as a main insulation. 10. Electric motor or electric generator according to claim 9, characterized in that its winding coil is produced by a method according to one of claims 1 to 8.