JPH0468510A - Manufacture of heat resistant insulated coil - Google Patents

Abstract

PURPOSE:To enable stable use for a long time at a high temperature of 300 deg.C or higher and also to enable use at a high voltage without lowering of insulation performance by heat cycle by winding a mica type without applying adhesive, which is formed by laminating an inorganic reinforcement material on a conductor with inorganic adhesive. CONSTITUTION:A conductor 1 is formed by winding a mica tape 3 which is formed by laminating an unbaked soft composite mica sheet on a straight angle line which consists of alumina dispersion reinforced copper 2 which is plated with nickel with adhesive of a little amount of silicon. It is formed by using inorganic adhesive 4, etc. The unbaked composite mica is further lined for reinforcement and a mica tape 5 is wound 6 times in half-lap winding without applying adhesive at all. An insulating tape 6 which consists of alumina fiber cloth is further wound once in half-lap winding as an inorganic insulating tape without adhesive. Then, thread which consists of alumina fiber is wound from above an end of the winding of the insulating tape 6 to form an insulating layer.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention is intended for use in electrical equipment used at high temperatures of 300°C or higher, such as electromagnetic pumps for circulating liquid sodium in fast breeder reactors. The present invention relates to a method for manufacturing a heat-resistant insulated coil.

(Prior Art) Heat-resistant insulated wire wheels that can be used at high temperatures of 300° C. or higher are hardly known. Heat-resistant insulated wires such as the MI cable (a product of Furukawa Electric Co., Ltd.) that are filled with magnesium oxide powder between the conductor and the metal sheath are known, but because they have a metal sheath, they have no eddy current countermeasures. Moreover, since the conductor space factor becomes low, it is not suitable for wires of large-capacity electrical equipment.

In addition, Special Publication No. 62-1241 and Special Publication No. 62-12
No. 42 discloses that silicone resin or
Filled with silicone resin and high melting point inorganic powder and/or
Alternatively, a heat-resistant insulated coil characterized in that an inorganic layer is formed by coating and firing is described.

In addition, Japanese Patent Publication No. 62-57086 and Special Publication No.
Publication No. 57087 describes a method for manufacturing a heat-resistant insulated coil device, in which a heat-resistant insulated wire is wrapped around a conductor to form an inorganic insulating layer or a processed coil is fixed at high temperatures such as during an abnormality during use. ing.

(Problem to be solved by the invention) However, these heat-resistant insulated wires cannot be used in high-voltage equipment because they cannot form a very thick inorganic layer and the insulation layer itself is rough, resulting in a low dielectric breakdown voltage. There were drawbacks. Therefore, in the case of high-voltage equipment, glass mica tape using an adhesive made of inorganic polymer (a polymer that can become mineralized at high temperatures) is wound as the main insulation, and this is heated and pressurized to form and then baked, making it completely inorganic. A possible method is to form an insulating film with a thin film.

However, with insulation that is entirely glued together, thermal stress occurs due to the difference in thermal expansion coefficient between the conductor and the insulation layer when a device starts up or stops, and when this heat cycle is repeated, the insulation deteriorates due to fatigue. Cracks occur in the insulation, and the insulation performance deteriorates. This phenomenon is particularly likely to occur in large windings for large-capacity machines and in equipment operated at higher temperatures.

Therefore, insulated coils used at high temperatures of 300° C. or higher, such as liquid sodium submerged uncooled electromagnetic pumps used in fast breeder reactors, must have high heat resistance so that they can be stably used at high temperatures for long periods of time. Large-capacity machines require high-voltage insulated wire rings that do not deteriorate due to heat cycles.

The present invention was made in response to these demands, and can be used stably for a long period of time at high temperatures of 300°C or higher.
It is an object of the present invention to provide a method for manufacturing a heat-resistant insulated coil that can be used even at high voltages without deteriorating its insulation performance due to heat cycling.

[Structure of the invention]

(Means for Solving the Problems) According to the present invention, a mica tape formed by bonding an inorganic reinforcing material onto a conductor using an inorganic adhesive is wound without applying an adhesive. Furthermore, a heat-resistant inorganic insulating tape that does not have adhesive is wrapped over this, and the ends are treated to prevent the insulating tape from coming loose, and then baked at a high temperature of 300°C or higher. .

Here, examples of the inorganic adhesive include inorganic silicone and inorganic paint that become inorganic by baking at high temperatures.

Examples of inorganic silicones include alkyl silicate silicone AY 49-208 (trade name of Toshi Silicone Co., Ltd.), inorganic filled borosiloxane paint SM
These include R-109 (trade name of Showa Electric Wire and Cable Pillars), pressure sensitive adhesive YR3286 (trade name of Toshiba Silicone Co., Ltd.) made of methylpolysiloxane, and the like.

Furthermore, inorganic paints include phosphates such as aluminum monophosphate and silicon phosphate, colloidal silica, and colloidal alumina.

If inorganic silicone is blended with an inorganic filler, it will generally become thermally stable and will be cheaper.

Here, as the inorganic filler, alumina (Aff2
0. ), magnesia (MgO), :/Rika (Sin
2), Zirconia (ZrO□)-Steatite (MgO
-5in2), fluoride, kaolin, mica powder, high melting point glass frit, etc.

In addition, heat-resistant materials such as alumina, alumina-boria-silica (for example, 3M's product name Nextel), and silica are used as reinforcing materials for mica tape and heat-resistant inorganic insulating tapes that do not have adhesives. Use woven or non-woven fabric made from fibers with high mechanical strength.

Here, when bonding the mica and the reinforcing material, the amount of adhesive is adjusted so that the adhesive does not penetrate too much into the fibers of the reinforcing material. This is because when the entire fiber is hardened with adhesive, it becomes brittle.
This is to prevent easy breakage due to heat cycles during use. The method for bonding mica tape is to impregnate or apply an adhesive to mica in advance, and then bond the reinforcing material to this. In this case as well, point adhesion is desirable. If the amount of adhesive exceeds 35% by weight, the amount of penetration into the fibers increases and the adhesive becomes brittle after firing. Note that by forming an insulating layer by alternately winding a mica tape and an insulating tape without adhesive, a high voltage insulation with a thick insulating layer and excellent heat cycle properties can be formed.

To prevent the ends of the insulating tape from loosening, either wrap them with a thread made of inorganic fibers such as alumina, alumina, boria, or silica, or apply the above-mentioned inorganic silicone or inorganic paint to the ends of the insulating tape, and then perform high-temperature baking. Glue it with

(Function) Mica tape is used here because mica has high heat resistance and excellent dielectric breakdown voltage and withstand voltage characteristics. In addition, since the reinforcing material of the mica tape is a bonded inorganic tape that has strong mechanical strength at high temperatures, it is possible to prevent the mica tape from falling apart even if thermal stress is applied. Moreover, since the amount of bonding adhesive is small, it does not penetrate into all the fibers of the reinforcing material and does not make it brittle.

When wrapping the mica tape, no adhesive is applied, so there is no adhesive between the mica tapes. Therefore, the thermal stress caused by the heat cycle that occurs when the equipment starts and stops is absorbed by the misalignment between the mica tapes.

The inorganic insulating tape wrapped on the mica tape layer is
Since no adhesive is applied, it absorbs thermal stress caused by heat cycles by deforming itself. In addition, since there is no adhesive, the inherent cushioning properties of insulating tape can be utilized, and the insulating coil incorporated in the iron core can be protected from electromagnetic vibration. If the stress is carried by the insulating tape, the reinforcing material for the mica tape does not require much mechanical strength and has the advantage of being inexpensive.

Mica tape's reinforcing material and insulating tape are porous, which improves air circulation, which is essential when inorganic silicone turns into an inorganic substance at high temperatures.

High voltage insulation allows for easy firing even if the insulation layer is thick.

If an insulating tape without an adhesive is wrapped around the surface, the insulating tape will loosen, so a loosening prevention measure as described above is required.

(Example) Example 1 In Fig. 1, the conductor 1 is made of nickel-plated alumina dispersion-strengthened copper 2 (trade name G12id, manufactured by Glidden Metal Co., Ltd.).
CopaQ-15) with a thickness of 50 um.
A mica tape 3 made by bonding a silica cloth of After winding this conductor 1 into a pancake shape with an inner diameter of 500 m, an outer diameter of 900 m, and a thickness of 40 m, the conductor 1 was rolled into a pancake-like shape with an inner diameter of 500 m, an outer diameter of 900 m, and a thickness of 40 m. -208) or an inorganic adhesive 4 such as alumina. Furthermore, from this top, the thickness is 50
μs alumina cloth is lined and reinforced with 100-thick unfired laminated mica, and inorganized silicone containing the above-mentioned inorganic filler (trade name of Toshi Silicone Co., Ltd. A Y 49) is used.
-208) and a silicone pressure-sensitive adhesive (trade name YR3286, manufactured by Toshiba Silicone Co., Ltd.) coated at 20% by weight, the mica tape 5 was wound 6 times in 1/2 overlap without applying any adhesive. I turned it. Further, as an inorganic insulating tape without adhesive, an insulating tape 6 made of alumina fiber cloth having a thickness of 300 mm was wound once on top of the insulating tape with a 1/2 overlap. Subsequently, a thread made of alumina fibers was wound while being pressed from above the winding end of the insulating tape 6 to prevent the end of the insulating tape from loosening, thereby forming an insulating layer.

On the other hand, for comparison, instead of mica tape 5 with an adhesive amount of 20% by weight, a mica tape with an increased adhesive amount of 50% by weight was wound 6 times with 1/2 overlap. moreover.

Instead of the insulating tape 6 made of alumina fiber cloth without adhesive, an inorganic silicone (trade name AY 49-208 manufactured by Toshi Silicone Co., Ltd., manufactured by Toshi Silicone Co., Ltd.) containing the inorganic filler in alumina fiber cloth and an inorganic filler were used. Borosiloxane resin paint (trade name SMR~109 of Showa Denshin Co., Ltd.)
) and insulating tape.

While applying inorganic silicone containing an inorganic filler (product name AY 49-2011 of Toray Silicone Co., Ltd.), the above-mentioned mica tape was wound once with 1/2 overlap to form an insulating layer. .

A polytetrafluoroethylene tape (not shown) for mold release is wrapped around the outside of the insulating layer thus formed.
After applying the iron plate, wrap a heat-shrinkable polyester tape (it may be in the form of a film, tube, or woven fabric) and heat it for 1 hour at 80°C and 2 hours at 130°C for 150°C.
It was cured by heating at 180°C for 2 hours and then at 180°C for 15 hours. After that, the heat-shrinkable polyester tape, the iron plate, and the polytetrafluoroethylene tape for mold release were removed, and the wire was fired in air at 300°C for 8 hours and at 600°C for 8 hours, and the heat-resistant insulated wire I got a ring.

In the above manufacturing process, the pressure applied during heat curing is performed by heat shrinking the heat shrinkable polyester tape, and the organic components contained in the insulating layer are scattered and burned away by heating and baking at high temperatures, becoming inorganic ( (ceramic), and a completely inorganic insulating layer was formed.

Example 2 As shown in Figure 2, on the conductor of Example 1, glass cloth with a thickness of 50 mm was reinforced by backing it with unfired laminated mica with a thickness of 100 mm, and this was inorganized with an inorganic filler. silicone(
Toshiba Silicone Co., Ltd. (trade name: AY49-208) and silicone pressure-sensitive adhesive (Toshiba Silicone Co., Ltd. (trade name: YR32)
Mica tape 5 made by applying 20% by weight of 1.86) and 1. without any adhesive. It was wound once with /2 overlap winding.

Furthermore, an insulating tape 6 made of alumina fiber cloth having a thickness of 100 μs and having no adhesive was wound once on top of the tape by butt winding. In this way, the mica tape and the insulating tape were alternately wrapped six times each to form an insulating layer. The winding ends of the insulating tape on the surface of the coil were coated with the above-mentioned inorganic silicone (trade name AY 49-208, manufactured by Toshi Silicone Co., Ltd.).

Thereafter, a heat-resistant insulated coil was manufactured in the same manner as in Example 1.

The heat-resistant insulated wire wheels obtained in Examples 1 and 2 were placed in a tank and nitrogen gas was filled in the tank. 5 between room temperature and 600℃
When the heat cycle was performed 00 times, in the case of the comparative example, the inner insulation layer and the alumina cloth layer on the surface were cranked or broken at various places.

The dielectric breakdown voltage was also reduced to 65% of the initial value, whereas in the samples obtained in Examples 1 and 2, there was no such rupture of the alumina cloth, and the dielectric breakdown voltage was 95% of the initial value. was maintained, and there was almost no insulation deterioration.

Further, after the heat cycle test was completed, the insulating layer was decomposed, and as a result, in the insulated coil of the comparative example, a part of the adhesive in the innermost layer remained unmineralized. This is because air was not sufficiently supplied during the firing process because the insulating layer was adhered with adhesive. In the heat-resistant insulated coils of Examples 1 and 2 of the present invention, every corner of the insulating layer was mineralized.

〔Effect of the invention〕

As explained above, according to the present invention, the electrical characteristics.

Mica tape, which has excellent heat resistance, is wound without applying adhesive, and an inorganic insulating tape, which has high mechanical strength and excellent heat resistance, and does not contain adhesive, is wound on top of it, so electrical and A mechanically superior heat-resistant insulated coil can be obtained.

In addition, this heat-resistant insulated 1# wire ring can withstand repeated heat cycles caused by the start and stop of 9 devices.

There is no cranking into the insulation layer, and there is almost no deterioration in insulation performance. Therefore, it is possible to provide a method for manufacturing an insulated coil used at high temperatures of 300° C. or higher, such as an electromagnetic pump for circulating liquid sodium in a fast breeder reactor.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a heat-resistant insulated wire according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of a heat-resistant insulated wire according to a second embodiment of the present invention. 1... Conductor 2... Nickel plated alumina dispersion strengthened copper 3.5.
・Mica tape 4...Inorganic silicone or inorganic adhesive 6...Inorganic insulation tape without adhesive Agent Patent attorney
Kensuke Noriyuki

Claims (2)

[Claims] (1) Mica tape, which is made by bonding an inorganic reinforcing material with an inorganic adhesive containing an inorganic filler, is wound around the conductor without applying an adhesive, and then wrapped around the conductor, which has high mechanical strength and excellent heat resistance. A method for producing a heat-resistant insulated coil, which comprises winding an inorganic insulating tape without adhesive and then firing the tape at a temperature of 300° C. or higher. (2) Mica tape, which is made by bonding an inorganic reinforcing material with an inorganic adhesive containing an inorganic filler, is wound around the conductor without applying an adhesive, and is then wrapped around the conductor to provide high mechanical strength and excellent heat resistance. Then, after winding an inorganic insulating tape without an adhesive and then alternately wrapping the mica tape and an inorganic insulating tape without an adhesive in the same manner as above, A method for manufacturing a heat-resistant insulated wire ring characterized by firing at a certain temperature.