JPS5937660B2 - Winding insulators for electrical machine coil windings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention describes a method for manufacturing insulated windings for electrical machines by using a strip-shaped insulator consisting of at least one layer of mica film coated on both sides with a synthetic resin and bonded with an adhesive. Regarding.

For reasons of manufacturing technology and construction, high-power motors as well as medium-power synchronous generators are constructed exclusively with so-called fully formed coils.

In these coils, a large number of windings are connected in series, and in this case it is necessary to insulate the windings from each other (winding insulation) and from the magnetic core (main insulation).

Therefore, the following method is actually used.

■1. A strip-like intermediate layer is placed between ordinary bare wires, 2. The fully formed coil is made from varnished solid wire, 3. The varnished solid wire is provided with an additional coating (mainly glass fiber, etc.), 4. Bare After forming the wire into a coil by hand, attach appropriate insulating tape.

A single coil has a main insulator.

This can be seen, for example, in the publication 3889D of Braun Bovary GmbH, Baden (Switzerland) ``Micadur Compact synthetic resin insulation for medium-volume high-voltage electrical machines: MicadurC
impact Kuns tharz -I so l
ierung Fur mi tt 1ere Hoc
This is done in one way as described in hspannungsmaschinenj.

Due to the excellent electrical, thermal, and mechanical properties of insulators manufactured by the complete impregnation method, medium-power output machines are now as reliable as large-scale high-voltage motors and synchronous generators. It can be manufactured.

In this way, it is now possible to connect such machines to medium-voltage power lines without the need for intermediately connecting transformers, which are expensive today.

However, this requires higher insulation costs and, especially at high nominal voltages (up to 20 kV), these machines are likely to be difficult to use due to voltage fluctuations and overvoltages that can occur on medium voltage power lines.

In this case, as the main insulator is strengthened, it is also necessary to increase the winding insulation.

According to currently known insulating materials, this can be achieved in practice simply by wrapping a mica-containing insulating tape around a single wire.

However, this insulating tape does not have strong mechanical stress when formed into a coil.

For this reason, it is possible to first form the bare wire into a fully formed coil and then apply the winding insulation, but this operation is very time consuming and difficult.

This is because insulating tape must be passed between the individual windings.

Therefore, mechanization is also impossible.

The same problem arises when forming the winding insulation of conductor stubs (Lebel stubs) of large high-voltage machines with a number of partial conductors twisted together. Even higher dielectric strength is required instead of the varnish insulation of conductor strands that has been used up until now.

The object of the invention is to provide a method for producing insulated windings for electrical machines, which does not have the disadvantages of the known ones, exhibits high mechanical, electrical and thermal strength and at the same time is easy to produce. It is something.

This problem is solved according to the invention in winding insulation of the type mentioned at the outset by:

That is, the insulating material is in the form of a tape, has at least one mica film, a plastic film is attached to both sides of the tape, and this is fixed with an adhesive that does not require a solvent.

In this method, the tape can first be wound around the (bare, unformed) wire as winding insulation in a continuous manner, first to form a fully formed coil or other shape, such as the partial conductor of a label stub.

The insulating tape according to the invention protects the sensitive insulating material in this case, in particular the very sensitive fine mica membrane, and thus covers both sides with a smooth membrane when bending the conductor, so that adjacent insulating tape layers overlap. It is possible for the scales to slide against each other.

From an operational standpoint, this material was previously considered disadvantageous because plastic membranes are generally not smooth.

However, if a thin film with a thickness of 5 to 15 μm is used with an adhesive or an impregnated material, especially one that can be dissolved by a synthetic resin,
These do not have any adverse effect on the discharge strength of the overall winding insulation.

Polymer films that are clearly not processed by mechanical or chemical methods are available, for example, from Leberkusen and Bayer under the name Macrofol-1, and these films with a thickness of 8 to 10 μm should be used. proved to be particularly advantageous.

The mica-containing insulating material consists, for example, of polyester breath or glass fibers and one or more high-quality mica films.

50 to 150 μm for nominal voltages up to 20 kV
A high quality mica film and 20 to 40 μm thick polyester breath or glass fiber were required.

As further detailed below, the plastic film is secured to an insulating material, such as a B-stage or semi-cured epoxy resin, by a solventless adhesive.

This adhesive at the same time serves against impregnation, especially in holding the entire insulating tape together.

In this case, the resin content is between 25 and 3 of the total tape weight.
It is necessary that it be between 5%.

According to the invention, the insulated winding is made in the following way.

Starting from a suitable bare wire, an at least partially overlapping mica-containing impregnable insulating material is wrapped around this wire.

This material has a plastic membrane on both sides that is bonded with a solvent-free adhesive.

In this connection, the insulated conductor is formed in a form suitable for the assembly present in the electrical machine and is further bonded by pressure and heat in the region where it enters the core part.

This method allows fully formed coils or label stubs to be produced economically and without problems, since further mechanization is now possible from hand-wound insulation.

With the aforementioned resin content of 25 to 35% of the total weight, reliable impregnation and adhesion of the components of the insulating tape are achieved.

Melting of the film also ensures that it is retained by the underlying film.

The overflowing resin can fill in the overlaps during the heat and pressure process, and it then serves to bond individual conductors that overlap or are adjacent to each other.

It has been found to be particularly suitable to choose a conductor-insulator overlap of between 40 and 60%, in particular about 50%.

This superposition ensures sufficient insulation in narrow curved areas, for example at the winding head.

It is self-evident that multilayer insulating tapes can also continue to be formed as long as this is required.

Also, in that case, the amount of overlapping described above will be limited.

In FIG. 1, an insulating tape 2 is wrapped around a copper wire 1.

The overlapping portion is about 50%. This insulating tape consists of a polyester film or glass fiber 3 and a high-quality mica layer 4, to which a plastic film 5 or 6 is adhered from the inside or outside, respectively.

The intermediate space 7 formed by the overlap is filled with synthetic resin, and this resin is removed from the inside of the insulating tape during the manufacturing process of the winding insulator.

In the figures, the single layer of insulating tape is exaggerated to emphasize its structure and is therefore not shown dimensionally accurate.

Actually, the following film thicknesses or materials are used.

Plastic film: 8.7 μm thick polycarbonate film (e.g. Macrophor) Glass fiber: Type 103 Glasstex with a thickness of about 25 μm and a weight per square meter of about 25 g/rri” (manufacturer: Kegi Co., Ltd.)
Fa, Kagi) High quality mica: approximately 100 μm thick Samica (manufacturer: Isola, Breitenbach, Switzerland: ISOL A-Wer)
k e ”: Artificial resin: BF3 type catalytic curing system Araldai t-F (manufacturer: Basel, Ciba: CIBA) In addition to the insulated single wire shown in Figure 1, similar insulation was applied according to the machine model. A single wire is connected (not shown).

This is advantageous because the plastic films 5 and 6 are bonded to each other via the synthetic resin formed in the overlapping areas during the pressurization and heat treatment, and the plastic films 5 and 6 are particularly susceptible to melting during this process. .

The method of manufacturing an insulated winding according to the invention includes the following implementation steps.

1. Manufacture of insulating tape 2 2. Wrapping insulating tape around the conductor 3. Forming of insulated conductor 4.Heating and pressure treatment The implementation of this method is shown schematically in FIG.

High-quality mica 4 or glass fiber 3 from two supply reels 8 and 9 enters an impregnating tank 11 via a feed reel 10, where it becomes an A-stage synthetic resin, that is, a liquid synthetic resin.

Two further supply reels 12,1 behind the impregnation tank 11
3 has a plastic film attached.

Films 5, 6 running on both sides of the tape made of fine mica strips and glass fibers and also impregnated with synthetic resin.
is pressed onto the tape by a pressure roll 14.

The ratio of resin can be adjusted by pressing the roll 14.

The insulating tape is then pre-dried in a connected resin device 15, where the synthetic resin is brought to the B stage and stored in a suitable manner.

The winding of the bare wire 1 in the second implementation stage is carried out by a winding machine 16 which is known per se.

Since such a machine can be easily conceived depending on the level of technology, it is not illustrated again.

A cutting machine 17 is connected to this winding machine 16, which sometimes serves only as a functional block.

Then, cut the insulated conductor to the desired length.

In the next step, the insulated conductor is cut in an electrical machine into a shape suitable for subsequent installation, for example into a fully formed coil or into a partial conductor of a label stub.

This operation is performed in the molding device 18. The heating and pressing of the fully formed coils or label stubs takes place in a pressing and hardening device 19 adapted to one of the respective conductor geometries, for the subsequent working process in the winding head.
Then only the regions of the conductor belonging to the core part are processed.

During this heating and pressure treatment, synthetic resin overflows into the overlapping area, but this is due to the adhesion of the overlapping single wires,
Helps fill in the gaps and spaces that occur when windings overlap.

After curing, the synthetic resin reaches the C stage and has sufficient mechanical and electrical properties to suit its final purpose;
), and in accordance with its intended use, is introduced into an electromechanical assembly, which is indicated by the functional block 21.

The primary insulator can be manufactured by hand or by machine, but
This is because relatively simplified conductor shapes (such as fully formed coils) should be processed in the future.

The operations corresponding to the implementation stage of "compression and heating" are no longer the subject of the above-mentioned invention, and are usually described in detail, for example, in the publication "Mikadoul Compact..." mentioned at the beginning.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a coil wire with winding insulation according to the present invention, and FIG. 2 is a partial block diagram of an embodiment of an insulated winding manufacturing apparatus according to the present invention. The relationship between the main components and reference numbers in the figure is as follows. 1: Conductor, 2: Insulating tape, 4: Mica film, 5,
6: Plastic membrane.

Claims (1)

[Claims] 1. An insulated winding for electric machines is produced by using a strip-shaped insulator consisting of at least one layer of mica film, both sides of which are covered with synthetic resin films and these synthetic resin films are bonded with an adhesive. In this method, the strip-shaped insulator 2 is wound around the surface of the bare conductor strand 1 while at least partially overlapping the surface, and then the conductor strand 1 subjected to the insulation treatment is shaped into a shape that conforms to the structure of the electric machine. After forming, the individual conductor strands of the part that goes into the core groove are bonded together by pressure and heating, the main insulation between the core and the core is applied to the bonded part, and finally it is assembled into an electrical machine. 1. A method for producing an insulated winding for electrical machines, characterized by carrying out post-impregnation and final curing. 2. In the method of manufacturing an insulated winding for an electric machine as set forth in claim 1, a material combination of an adhesive and a synthetic resin film is selected in advance, and then the synthetic resin film is heated and pressurized as required. A method in which the membrane is at least partially welded.