JP4281880B2 - High corona resistant sandwich insulation - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an insulating material having an insulating material layer having a sandwich structure. The insulating layer is preferably a film of polymeric material, and the film preferably contains a corona resistant material such as alumina particles of submicron particle size in an amount sufficient to increase the corona resistance of the polymeric material and the mica layer. To do. The polymer film (preferably a polyimide film) is bonded to the mica paper layer by a suitable resin, which resin can preferably be a polymer material, and the polymer material itself may contain a corona resistant material. It does not need to contain. The polymer resin material is at least partially impregnated in a mica paper film and has the property of providing the necessary tack to bond the mica paper and polymer film into a single laminated sheet or tape. I have it.
[0002]
[Prior art]
With regard to the insulation of conductors in electrical machines, significant improvements have been made since the early machine development in the 19th century. Due to the demand for larger and more efficient machine supplies in industrial and commercial applications, the insulation systems used by designers have progressed to provide greater withstand voltages and in the machine. The space occupied by became smaller. It should be remembered that most electrical machines consist of conductive materials and insulation systems. Basically, the magnetic material and the conductive material are two materials that are effective in determining the mechanical performance and the output capacity, and the insulating material exists only to ensure that the current flows only in a predetermined path. Is. Therefore, the required insulation must occupy a minimum amount of space and provide the necessary insulation between adjacent conductors as well as between conductors and adjacent materials at ground potential.
[0003]
As voltage ratings go higher, designers have to find ways to increase the potential gradient so that the insulation does not occupy excessive space. The resistance to heat conduction through the insulating material varies linearly with the length of the path. That is, there are two prominent reasons for keeping the insulation thickness to a minimum. That is, as the thickness of the insulating material obtained decreases, the thermal performance of the insulating material improves.
[0004]
In the past, electrical machines have traditionally covered individual conductors with varnishes, enamel compounds or glass coatings to provide “turn to turn” insulation for the desired primary strands or individual conductors. Was offered. In particular, in a rotating machine, such a conductor is wound to form a coil, and a secondary insulating medium is applied to each coil, and the secondary insulating material is individually molded into a predetermined shape for forming the coil. It takes the form of insulating tape or wrapping material wrapped around a group of conductors. In early low-voltage machines, the varnish had a satisfactory function, but it was replaced by enamel, and more recently by polymer materials such as polyester, polyesteramide, polyesteramideimide and polyimide, It is only used for a few commercial conductor coatings.
[0005]
Coil insulation has progressed from cotton tape, layered in the form of lapping to provide the necessary insulation, to asphalt insulation. The asphaltic insulation consists of a wrapping coil with a tape coated with a petroleum-based compound which is then coated with a mica flake layer. The mica flakes provided insulation resistance to a phenomenon commonly known as “corona”, which tends to become a greater problem as the operating voltage level of the rotating machine increases.
[0006]
It is also effective to prevent the corona degradation of the individual conductor insulation in the individual conductors forming the coil, so now corona resistant materials are added to the polymer conductor insulation. Has become a common law. Canadian Patents 1,168,857 and 1,208,325 add various compounds, such as submicron sized particles of alumina or silica, to polymer compositions used to coat individual conductors. The example which shows that it is effective in improving the corona tolerance of a conductor is given. By adding alumina particles or silica particles, it is possible to improve the heat conduction characteristics of the conductor insulating material.
[0007]
Tape-type insulation applied to coils has also changed progressively. Glass fiber tape has been increasingly used as a carrier for mica flakes, and a number of polymeric materials have been used to provide the necessary adhesion to keep the flakes in place on the tape. . The coil is wound by a conventional wrapping method, then placed in a coil former and subjected to a vacuum impregnation (VPI) process to impregnate the tape coil with an appropriate insulating material such as an uncured polymer material and wrapping. The insulating material was filled with voids or crevices, the coil was heated, and the composite of the coil and the insulating material was cured by a polymerization process.
[0008]
Another method for insulating a coil of an electric machine is to apply the desired number of turns to the coil or strand and apply heat and pressure to the coil or strand to gel the polymeric material. A coil or stranded wire is wound with a layered tape that is gently covered with a "B" stage polymer resin by standard lapping.
[0009]
During the heating and pressurization process, it is observed that the viscosity of the “B” stage polymer material first decreases, and the applied pressure squeezes out excess resin and assumes the coil to its final shape.
[0010]
The above resin-rich tape apparently has some form of mica flakes as one of its components to provide the required insulation capacity.
[0011]
The functions of the mica flakes are to improve the corona resistance of the secondary insulator and to maintain good heat conduction characteristics of the secondary insulator.
[0012]
Over time, glass fibers, polymer films, mica flakes or mica paper (films made of mica flakes produced in the same process as paper production) are used for insulating tape, The coil having the tape applied thereto was cured through a VPI process or a pressure curing process to form a coil.
[0013]
[Problems to be solved by the invention]
However, polymer films tend to interfere with complete impregnation in the insulating tape layer during the VPI process, which causes problems when using certain tapes. Thereby, when a space | gap arises in an insulating material layer and a voltage is loaded, each space | gap plays the role of the main site | part of corona generation | occurrence | production.
[0014]
In nature, sandwich-type insulating tape has been shown to be an insulating material that is particularly adaptable and sensitive to changes. Some form of mica is usually seen as one of the components of the sandwich.
[0015]
Of the thermally conductive insulating materials available, it is well known that aluminum oxide has excellent insulating properties and excellent thermal conductivity. Depending on the particle size of the aluminum oxide, both the thermal conductivity and the corona resistance of the tape are improved when it is included in the tape, but the degree of improvement is largely due to the specific particles of the alumina particles selected. It depends on the diameter. Regarding its application field, since the most interesting is to improve the corona resistance of the insulating tape, the preferable particle diameter of alumina particles is on the order of 0.5 micron or less.
[0016]
As described above, it has been clarified that the sandwich type insulating tape is effective in providing excellent insulating properties when applied to a rotating electric machine. To date, the voltage load applied per unit layer thickness has increased significantly. That is, the voltage rating of a particular machine can be increased with the same thickness of insulation. By using thermally conductive materials such as finely pulverized alumina, silica, and beryllia, the thermal conductivity of the insulating material has been increased. Therefore, heat can easily flow through the relatively low temperature machine part, and as a result, the current rating of the coil can be increased.
[0017]
As the withstand voltage increased, the resistance of the insulating material to corona breakdown gradually improved. As a result, designers have been able to reduce the thickness of the insulating layer over the years to the current thickness.
[0018]
Due to the stability of the polymer material in a high temperature environment, the thermal breakdown temperature of the insulating tape steadily increased and the performance and capacity of the machine improved.
[0019]
Finally, it is important to investigate the physical properties of the insulating tape used in electric machines.
[0020]
Since most coils are insulated by winding the coil with a roll of insulating tape, the tape has a tensile strength and a winding strength so that the coil does not break under normal tension conditions. Obviously, it must be wound around the conductor. The tape must be flat and will not cause swelling or the like in the resulting insulator layer.
[0021]
The roll of insulation must be stored for a period of time, and any layer of insulation tape should never delayer or delaminate. Therefore, it is essential that the insulating tape has such a property that it can be easily unwound without damaging the tape even when it has been stored for a long time. It is very important that the coil has no voids after curing.
[0022]
[Means for Solving the Problems]
The present invention has been made in view of the above object. That is, the present invention
(1) An insulating material having a polymer film in which a corona resistant material is incorporated,
The film has a mica paper layer laminated to it to form a composite insulating layer;
The corona resistant polymer material is selected from the group consisting of polyester, polyesteramide, polyesteramideimide, polyimide, polyamide, polyamideimide, polyetherimide, polycarbonate, polysulfone and polyether;
The corona resistant material is in the range of 10 to 40% based on the weight of the polymer film, and consists of boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, beryllium oxide, silicon oxide, zirconium oxide and titanium oxide. Containing at least one compound selected from
An insulating material wherein the particle size of the compound is less than 0.1 microns;
(2) A mica paper layer having a corona-resistant polyimide material layer having a layer thickness of about 24 μm, and having a mica paper having a layer thickness of about 100 μm, which is impregnated with a suitable polymer resin at least partially. A composite insulating material having a withstand voltage of about 13.8 volts / μm for at least 250 hours;
(3) A corona resistant polymer material layer having a layer thickness of about 25.4 μm selected from the group consisting of polyester, polyesteramide, polyesteramideimide, polyimide, polyamide, polyamideimide, polyetherimide, polycarbonate, polysulfone and polyether. Have
The layer is laminated with a mica paper layer having a layer thickness of about 100 μm impregnated with a polymer resin selected from the group consisting of epoxy, polyester, silicone, bismaleimide and cyanate ester at least partially;
The corona resistant material is at least selected from the group consisting of boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, beryllium oxide, silicon oxide, zirconium oxide and titanium oxide in a range of 10 to 40% by weight. Containing one compound,
The selected compound is present as particles having a particle size of less than 0.1 microns and the resulting laminated insulator has a dielectric strength of about 13.8 volts / μm for at least 250 hours;
(4) An insulating tape or wrapper for insulating electric coils of rotating electrical machines,
A corona resistant polymer material film having a layer thickness of about 24 μm selected from the group consisting of polyester, polyesteramide, polyesteramideimide, polyimide, polyamide, polyamideimide, polyetherimide, polycarbonate, polysulfone and polyether;
A mica paper layer having a layer thickness of about 100 μm laminated to the corona resistant polymer material film with a polymer resin selected from the group consisting of epoxy, polyester, silicone, bismaleimide and cyanate ester;
The corona-resistant polymer material is in the range of 10-40% by weight based on boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, beryllium oxide, silicon oxide, zirconium oxide and particles having a particle size of less than 0.1 microns. Containing at least one compound selected from the group consisting of titanium oxide,
The polymer resin in the mica paper layer is 10-40% by weight based on boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, beryllium oxide, silicon oxide, oxidized with a particle size of less than 0.1 microns. Containing a corona resistant material selected from the group consisting of zirconium and titanium oxide;
An insulating tape or wrapper having a withstand voltage of about 13.8 volts / μm for at least 250 hours; and (5) a method for insulating a coil of an electric machine by wrapping a wire bundle around a laminate tape to form a coil.
A corona-resistant polyimide film having a layer thickness of about 25 μm containing aluminum oxide particles having a particle size of less than 0.1 μm at 10 to 40% by weight, and a layer thickness of about 25 μm laminated on the polyimide material with an epoxy resin The present invention relates to an insulating method for forming a laminated tape having a withstand voltage of about 13.8 kV / mm formed with a 100 μm mica paper layer.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Basically, the present invention preferably comprises a filled film material such as a polymer material such as polyester, polyesteramide, polyesteramideimide, polyamide, polyimide, polyamideimide, polyetherimide, polycarbonate, polysulfone or polyether. Is. These polymer materials are preferably boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, beryllium oxide, silicon oxide, zirconium oxide, titanium oxide, etc. to extend the life of the film in voltage load environment A finely pulverized material having a corona resistance of 5 is filled. As can be seen from this description, it can be seen that these compounds are preferred corona resistant materials. The aforementioned commercially available mica paper is laminated on the polymer.
[0024]
The mica paper is effectively laminated to the polymer film by a polymer resin that may itself have a corona resistant material. The obtained tape is easy to unwind from its roll state, and can be easily stored for a reasonable period without difficult storage conditions. The withstand voltage and service life are significantly improved over the conventionally used glass fiber cloth tape-mica paper-polymer film laminate.
[0025]
【Example】
FIG. 1 is a perspective view showing a laminated tape of the present invention.
[0026]
FIG. 2 is a schematic diagram of an apparatus used to implement the present invention.
[0027]
In these figures, 10 indicates the tape of the present invention (which is considerably enlarged). The tape is made of a polymer material film 12 (in this case, "CR KAPTON" (registered trademark, DuPont polyimide, CR is used for corona resistance)). Paper film 14 is bonded, the two films being bonded together by a polymer resin suitable for that purpose.
[0028]
The polymer material film 12 can be in any of the groups described above, but in the description herein, CR Kapton is the preferred film from the standpoint of physical and electrical insulation. The thermal conductivity and corona resistance of the polymer film can be improved by adding fine powdered alumina to the film. When the particle size is smaller than 0.5 microns, the corona resistance is greatly improved, and those having a particle size larger than 0.5 microns to 15 microns can increase the thermal conductivity of the polymer film. Usually, it is considered preferable to contain fumed alumina, silica, beryllia and the like at a concentration of 10 to 40% based on the weight of the polymer film.
[0029]
Mica papers are commercially available in various thicknesses and are known in the art and are manufactured by a process very similar to that used in paper manufacture. The properties of mica paper are such that another material, such as glass fiber, tape or "Daclon" (trade name) or other material having the desired tensile strength and withstand voltage, is conventionally bonded to the mica paper film. It is recognized that In the present invention, the mica film is preferably bonded to the polymer film by an epoxy resin to form the required bond. Preferably, the polymer resin can be any selected from the group consisting of epoxy, polyester, silicone, bismaleimide or cyanate ester, but for the purposes of the present invention, the applicant may use epoxy. I think it is preferable. Whatever polymer resin is selected, its corona resistance can be improved by adding a very small particle size of any of the compounds selected from alumina, silica, beryllia, etc. . Corona resistance is improved by adding 10-40% fumed alumina with a particle size of less than 0.5 microns (see Canadian Patent Nos. 1,168,857 and 1,208,325). If it is desired to improve the thermal conductivity of the resin, a corona resistant material having a larger particle size than that described above can be used (see Canadian Patent 1,289,610).
[0030]
The product of FIG. 1 can be manufactured by many methods, but the laminated tape can be produced using the apparatus of FIG.
[0031]
A mica paper roll 20 of a predetermined width and thickness is fed at the beginning of the process. The mica paper layer is fed onto the guide roll 22 and then onto the coating device 24 where it is “kissed” with resin liquid 26 underneath the layer. The coated mica paper then passes through an oven 28 where the solvent is removed and the resin is impregnated into the mica paper.
[0032]
The mica paper 30 impregnated with the resin is overlapped with the CR Kapton film sent from the roll 32 to the pressure device 34. The CR kapton and impregnated mica paper are combined in apparatus 34 to form an integral laminated sandwich that is subsequently wound on roll 36. As a result, a spiral roll of laminated sandwich insulation is obtained.
[0033]
The resulting laminated tape is excellent in strength, and electrical properties are improved when filled polyamide is selected as the polymer film 32. Since the laminated film is at least partially cured, the laminated tape roll can be easily stored in a dry and cold environment and can be unwound at a later date without causing damage due to adhesion or delamination between layers. .
[0034]
The resulting laminate is excellent in electrical properties and physical properties. Since the mica paper is impregnated at least partially with a corona resistant material during the manufacturing process, the coil produced using the laminated tape already has the corona resistant material incorporated in the insulating tape layer, There are no significant problems caused by voids in the VPI process.
[0035]
The results of a laboratory test on a laminated tape made of CR kapton and mica paper manufactured by the above process are shown in FIG. It can be seen that in the case of CR Kapton-mica paper laminated insulation, the “withstand voltage period” is significantly longer.
[0036]
【The invention's effect】
Therefore, since the properties of the laminate are excellent, the efficiency of the electric machine can be improved by the physical properties and electrical properties of the tape obtained. This allows electrical machine designers to increase the rating of existing machines that are being remanufactured, with the ratings that would inevitably have to make the machine larger when using conventional insulation systems. Can be achieved by manufacturing smaller machines.
[0037]
Since the laminated tape has excellent corona resistance, a machine having a coil manufactured using the wrapping tape of the present invention has a long usable life.
[Brief description of the drawings]
FIG. 1 is a perspective view of a tape laminate of the present invention.
FIG. 2 shows a basic apparatus for realizing the present invention.
FIG. 3 is a graph showing that the performance of the insulating material of the present invention is higher than that of the prior art insulating material.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Laminated tape 12 Polymer material film 14 Mica paper film 20 Mica paper roll 22 Guide roll 24 Coating device 26 Resin liquid 28 Oven 30 Mica paper impregnated with resin liquid 32 Roll 34 Pressure device 36 Roll

Claims (8)

An insulating material comprising a polymer film incorporating a corona resistant material,
The film has a mica paper layer laminated to it to form a composite insulating layer;
The corona resistant polymer material is selected from the group consisting of polyester, polyesteramide, polyesteramideimide, polyimide, polyamide, polyamideimide, polyetherimide, polycarbonate, polysulfone and polyether;
The corona resistant material is in the range of 10 to 40% based on the weight of the polymer film, and consists of boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, beryllium oxide, silicon oxide, zirconium oxide and titanium oxide. Containing at least one compound selected from
An insulating material having a particle size of the compound of less than 0.1 microns. The insulating material of claim 1, wherein the composite layer insulating medium has a thickness of approximately 240 µm and a withstand voltage of 13.6 volts / µm for at least 250 hours. A mica paper layer comprising a mica paper having a layer thickness of about 100 μm, comprising a corona-resistant polyimide material layer having a layer thickness of about 24 μm and at least partially impregnated with a suitable polymer resin, is laminated, and at least 250 A composite layer type insulating material having a withstand voltage of about 13.8 volts / μm over time. From boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, beryllium oxide, silicon oxide, zirconium oxide and titanium oxide having a polymer resin content of 10 to 40% by weight and a particle size of less than 0.1 microns 4. The composite layer type insulating material according to claim 3, comprising at least one compound selected from the group consisting of: Having a corona resistant polymer material layer having a layer thickness of about 25.4 μm selected from the group consisting of polyester, polyesteramide, polyesteramideimide, polyimide, polyamide, polyamideimide, polyetherimide, polycarbonate, polysulfone and polyether. Become
The layer is laminated with a mica paper layer having a layer thickness of about 100 μm impregnated with a polymer resin selected from the group consisting of epoxy, polyester, silicone, bismaleimide and cyanate ester at least partially;
The corona resistant material is at least selected from the group consisting of boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, beryllium oxide, silicon oxide, zirconium oxide and titanium oxide in a range of 10 to 40% by weight. Containing one compound,
A laminated insulating material wherein the selected compound is present as particles having a particle size of less than 0.1 microns and the resulting laminated insulator has a withstand voltage of about 13.8 volts / μm for at least 250 hours. An insulating tape or wrapper for insulating electrical coils of rotating electrical machines,
A corona resistant polymer material film having a layer thickness of about 24 μm selected from the group consisting of polyester, polyesteramide, polyesteramideimide, polyimide, polyamide, polyamideimide, polyetherimide, polycarbonate, polysulfone and polyether;
A mica paper layer having a layer thickness of about 100 μm laminated to the corona resistant polymer material film with a polymer resin selected from the group consisting of epoxy, polyester, silicone, bismaleimide and cyanate ester;
The corona-resistant polymer material is in the range of 10-40% by weight based on boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, beryllium oxide, silicon oxide, zirconium oxide and particles having a particle size of less than 0.1 microns. Containing at least one compound selected from the group consisting of titanium oxide,
The polymer resin in the mica paper layer is 10-40% by weight based on boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, beryllium oxide, silicon oxide, oxidized with a particle size of less than 0.1 microns. Containing a corona resistant material selected from the group consisting of zirconium and titanium oxide;
An insulating tape or wrapper having a withstand voltage of about 13.8 volts / μm for at least 250 hours. The tape or wrapper according to claim 6, wherein at least a part of the mica paper layer is impregnated with the polymer resin. In a method for insulating a coil of an electric machine in which a coil is formed by wrapping a wire bundle around a bundle of conductive wires,
A corona-resistant polyimide film having a layer thickness of about 25 μm containing aluminum oxide particles having a particle size of less than 0.1 μm at 10 to 40% by weight, and a layer thickness of about 25 μm laminated on the polyimide material with an epoxy resin An insulating method for forming a laminated tape having a withstand voltage of about 13.8 kV / mm, formed with a 100 μm mica paper layer.

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